Electron beam welding of pure titanium and nickel

Electron beam welding of pure titanium and nickel | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Electron beam welding of pure titanium and nickel Egor V. Terentyev, Andrey P. Sliva, Aleksey L. Goncharov, Artem Y. Marchenkov, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7659950/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 31 Jan, 2026 Read the published version in The International Journal of Advanced Manufacturing Technology → Version 1 posted 5 You are reading this latest preprint version Abstract This study presents the results of investigating the influence of welding parameters — beam power, beam offset relative to the joint, welding speed, and scanning frequency — on the formation of welded joints between commercially pure titanium grade VT1-0 and nickel grade NP2. It is shown that the weld metal structure consists of various types of intermetallic compounds, eutectics, and solid solutions based on nickel and titanium, with their ratio determined by the degree of penetration of the welded materials. The features of weld formation caused by the differences in the physical properties of the materials are described. The welding parameter ranges enabling high-quality weld formation have been identified. It is demonstrated that the presence in the weld metal of low-melting intermetallic Ti 2 Ni and eutectic Ti 2 Ni–Tiβ increases the tendency to crack formation and leads to brittle fracture of the welded joint. Almost all specimens fractured during tensile testing in zones containing a high proportion of Ti 2 Ni and Ti 2 Ni–Tiβ eutectic — either near the fusion lines or within the weld metal. Welded joints whose weld metal predominantly consisted of Ti 2 Ni and Ti 2 Ni–Tiβ eutectic failed before testing or within the elastic region of the tensile curve. A high content of titanium nickelide (NiTi) in the weld metal contributes to improving the strength of the welded joint. The maximum ultimate tensile strength of the welded joint reached 384 MPa, corresponding to 95% of the ultimate tensile strength of commercially pure titanium VT1-0. Dissimilar joints Electron beam welding Titanium Nickel Titanium nickelide Microstructure Intermetallic compounds Brittle interlayers Mechanical properties Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 1. Introduction The integration of titanium and nickel alloys provides an optimal combination of titanium’s high strength-to-weight ratio and nickel’s heat resistance [1–3]. Eliminating mechanical fasteners not only reduces the weight and size of critical components but also enables novel design solutions and decreases moments of inertia, which is particularly relevant for rotor assemblies. However, producing permanent fusion welds between titanium and nickel alloys remains a significant challenge. Metallurgical incompatibility stems from the formation of brittle intermetallic phases such as Ti₂Ni and Ni₃Ti, as well as differences in thermophysical properties, atomic radius, and crystal structures. To date, solid-state welding methods including explosive welding [4–8], diffusion welding [9–12], friction stir welding [13, 14] and thermal explosion welding [15] have been applied. However, these techniques are typically limited by relatively simple joint geometries. Fusion welding of titanium with nickel and most other structural materials is hindered by the formation of brittle intermediate phases [16–18]. To prevent such phases, interlayers are often employed. Nickel [19–23], niobium [23–25], copper [21, 26] and other monometallic interlayers [18] are used in welding titanium nickelide (TiNi) to steels and steel–titanium alloy joints. At the same time, there is a tendency to abandon monometallic layers in recent researches. Instead, it is proposed to form complex-alloyed alloys or high-entropy alloys in the weld area by using appropriate filler materials or ensuring a given penetration [18, 27, 28]. However, neither the use of monometallic nor complex-alloyed layers always allow avoiding the formation of brittle interlayers and leads to the emergence of new technological difficulties [18, 25, 29]. Therefore, developing fusion welding processes without interlayers remains a pressing issue today. Early attempts to weld commercially pure titanium and nickel resulted in unsatisfactory outcomes, with widespread cracking and pronounced macrosegregation observed in the welds [30]. Despite this, it was hypothesized that welds primarily composed of the titanium nickelide phase (NiTi) might yield viable joints. The Ti–Ni phase diagram (Fig. 1 ) highlights the existence of TiNi, an intermetallic phase known for its combination of high strength and ductility [31]. Subsequent research demonstrated the formation of brittle interlayers near fusion lines on both titanium and nickel sides, containing Ti 2 Ni and Ni 3 Ti phases that reduce joint strength [32, 33]. Welding parameters, especially welding speed and beam offset relative to the joint, have a decisive influence on weld formation. Welding speed affects heating and cooling rates across the joint, weld geometry, and residual stresses and distortions [34]. It also controls molten metal flow and dwell time in the liquid state, thereby influencing chemical and structural heterogeneity and brittle interlayer thickness. Beam offset and material property differences affect edge penetration, which determines weld metal composition and microstructure. Consequently, welding speed and beam offset are key parameters controlling the microstructure of titanium–nickel welds. A detailed study of electron beam welded titanium–nickel joints revealed a weld microstructure dominated by a Ni 3 Ti + NiTi eutectic mixture, corresponding to approximately 60–65 atomic percent nickel penetration [35]. While crystallization sequences and growth directions of constituent phases were characterized, optimal welding regimes for defect-free joints with desirable mechanical properties were not established. Laser welding investigations showed that beam offsets up to 35 µm did not significantly affect pore and crack formation, whereas simultaneous increases in welding speed and beam power reduced their incidence [36]. Further work found that a 0.5 mm laser beam offset toward the nickel plate produced defect-free welds with a solid solution of titanium in nickel and a transition layer no wider than 200 µm at the titanium fusion boundary. In contrast, the same offset toward titanium caused crack formation [37]. These studies, however, insufficiently explored the correlation between weld microstructure and defect occurrence, leaving crack formation mechanisms unclear. Attempts to establish a correlation between EBW modes and the formed microstructure and mechanical properties were noted by the authors of the work [38]. The main variable parameters were heat input and beam offset relative to the joint. Like others, the authors note that cracks are initiated in the region of Ti 2 Ni formation [38]. Unfortunately, it was not possible to establish a correlation between the ultimate tensile strength and heat input, which may be due to an insufficient number of tests. Thus, the majority of studies on nickel-to-titanium welding do not provide the results of mechanical tests for the produced joints. Without this data, it is impossible to evaluate their performance capability. Furthermore, even the data that is presented is often insufficient. Crucially, even if a weld joint is produced without defects, its structural strength under operational load conditions may still be unsatisfactory The present work aims to elucidate the relationship between weld microstructure, welding parameters across a broad range, crack formation likelihood, and the mechanical properties of titanium–nickel welded joints. 2. Materials and Methods Electron beam welding (EBW) was employed to join nickel and titanium due to its wide process parameter control range, precise beam positioning relative to the joint, and the vacuum environment that ensures effective protection of the weld pool—particularly critical for titanium-based alloys [39]. Beam deflection was additionally utilized to modify the power density distribution within the penetration channel and control molten metal flow velocity in different weld pool regions [40], thereby influencing the chemical and structural heterogeneity of the joint. Welding was performed on an ELA-40I EBW unit operating at an accelerating voltage of 60 kV, with a vacuum chamber pressure of 10 − 3 mm Hg. Plates of commercially pure titanium (98.6–99.7% Ti) and nickel (> 99.5% Ni + Co), 2 mm in thickness and 50 × 100 mm in size, were used. The prepared samples are shown in Fig. 2 . The beam current I B and focusing current I F were adjusted to ensure complete penetration at the lowest possible beam power. Welding speed was varied between 100 and 6000 mm/min. The application of electron beam scanning accelerates molten metal flow in the weld pool, which is expected to enhance the chemical homogeneity of the weld metal. Furthermore, employing a “sawtooth” scanning pattern reduces weld width [40], thereby potentially lowering residual stresses and distortions in the joint. In the experiments, a sawtooth scan with a frequency of 15–200 Hz was used. The weld metal composition was adjusted by offsetting the electron beam relative to the joint. The maximum offset corresponded to the occurrence of incomplete penetration at the weld root, amounting to 0.6 mm for offsets toward titanium and 0.7 mm for offsets toward nickel. Metallographic examinations were performed on transverse sections of the welded joints. Microstructural etching was conducted using a reagent composed of 5 mL HNO 3 + 2.5 mL HF + 2.5 mL HCl + 90 mL H 2 O. For revealing the nickel-side structure, a reagent of 8 g FeCl 3 + 25 mL HCl + 100 mL H 2 O was employed. Etching time ranged from 20 to 40 s. Microstructural analysis was carried out using a Zeiss Observer Z1m optical microscope at magnifications from 50× to 2400×, and a Tescan MIRA 3 LMU scanning electron microscope equipped with an energy-dispersive spectrometer. Microhardness HV0.01 was measured by the Vickers method on an Instron Tukon 2500 hardness tester, with a 10 s dwell under load. Static tensile tests were conducted on transverse specimens cut from welded plates to determine the ultimate tensile strength of the weakest zone in the joint. For comparison, specimens of identical geometry were fabricated and tested from base nickel and titanium plates. Tensile tests were performed on an Instron 8801 universal testing machine at a deformation rate of 0.5 mm/min. Three specimens from nickel, three from titanium, and at least three from each EBW mode were tested. 3. Results A total of 51 welded joints were produced under the conditions listed in Table 1 . A comparison of transverse cross-sections of welds obtained at different welding speeds without beam offset reveals a reduction in weld width with increasing welding speed (Figs. 3 and 4 ). Figure 4 presents the relationships between welding speed and both the minimum weld width and the weld crown width. It is evident that the minimum weld width is significantly less sensitive to welding speed. Reducing the welding speed yields a more homogeneous weld structure throughout the joint volume, except for the transition zones (Fig. 3 a), whereas at higher welding speeds a pronounced structural heterogeneity is observed beyond these zones (Fig. 3 b). The welds exhibit noticeable asymmetry, manifested in the different degrees of edge melting and the varying geometry of crown and root widening. This asymmetry decreases with increasing welding speed (Fig. 3 ). The offset magnitude has a decisive influence on penetration depth, which in turn determines the chemical and structural composition of the weld metal. Figure 5 illustrates the microstructure of welds produced at different offsets. Offset affects not only weld structure and width but also weld shape. In all cases, widening at both crown and root is greater on the titanium side than on the nickel side. Attempts to produce weld–braze joints by offsetting toward nickel (the lower-melting metal) were unsuccessful due to significant titanium melting in the widened regions (Fig. 5 a). Increasing nickel penetration leads to lack of fusion before the widening becomes negligible. Conversely, offsetting toward titanium can minimize nickel melting and produce a weld predominantly consisting of α-titanium solid solution. However, this requires precise electron beam positioning: at 2000 mm/min, a 0.4 mm offset causes lack of root fusion, while a 0.3 mm offset results in the formation of undesirable brittle β-titanium (Fig. 5 c). Implementation of electron beam deflection scanning increases the velocity of molten metal flow in the weld pool, thereby enhancing melt mixing. Figure 6 compares the microstructures of weld joints produced without beam offset, both with and without scanning. Compared with the weld produced without scanning (Fig. 6 a), the joint obtained with scanning (Fig. 6 b) exhibits a more uniform distribution of local chemical heterogeneities across the weld. However, it should be noted that scanning did not significantly affect the width of the interlayer transition zones, which, due to their brittleness, have a decisive influence on the mechanical properties of the joints. It is evident that in the weld metal the concentrations of nickel and titanium vary from 0 to 100% across the fusion zone, from one fusion boundary to the other. However, except for the transition zones near the fusion boundaries, the weld metal microstructure in all specimens is relatively homogeneous, particularly in welds produced at low travel speeds. Overall, for all specimens, the weld metal microstructure at the given chemical composition corresponded to the Ti–Ni equilibrium phase diagram (Fig. 1 ). Since three types of intermetallic compounds and three eutectic mixtures can form under equilibrium conditions in the Ti–Ni system, local variations in chemical composition lead to significant structural changes, as confirmed by the observations. As an example, the microstructure of a weld produced at a travel speed of 1000 mm/min without beam offset and without scanning is considered. Figure 7 shows the weld structure near the titanium fusion boundary, where characteristic structural constituents can be clearly distinguished. Along the fusion boundary, a dark layer approximately 5 µm thick is observed, consisting of quenched titanium-based solid-solution structures. In fusion welding, dendritic growth from remelted grains of the base metal is typical; however, in the present case, dendrites of Ti-based solid solution are virtually absent at the fusion boundary, presumably due to suppression by a steep concentration gradient. Elongated white dendrites growing toward the fusion boundary are identified as Ti 2 Ni intermetallic crystals. The interdendritic liquid solidifies as a eutectic mechanical mixture (Ti 2 Ni + β-Ti). With increasing distance from the weld, the eutectic fraction decreases, giving way to a continuous layer composed solely of Ti 2 Ni. Further from the fusion line, Ti 2 Ni regions contain dendrites of TiNi mononickelide. Such a microstructure is characteristic of a substantial portion of the weld. Figure 8 presents the weld metal microstructure near the fusion boundary with nickel. Dendritic growth of nickel-based solid solution is likewise absent, inhibited by the high concentration gradient. Instead, a thin layer (1–5 µm) of solid solution is located directly at the fusion boundary, followed by a 1–15 µm layer of TiNi 3 intermetallic, which transitions into a eutectic mechanical mixture TiNi 3 + TiNi. At greater distances from the fusion boundary, the TiNi 3 + TiNi eutectic is embedded between TiNi dendrites growing toward the fusion line. From the TiNi-only layer, TiNi dendrites also grow toward the weld center, while Ti 2 Ni intermetallic crystallizes in the interdendritic spaces via a peritectic reaction, consistent with the decrease in nickel concentration away from the fusion boundary. The microstructure of the weld central zone in joints produced without offset is predominantly composed of freely grown TiNi dendrites surrounded by the intermetallic Ti 2 Ni. In regions with locally increased nickel concentration, rounded areas are observed from which TiNi dendrites emanate, with Ti 2 Ni crystallizing in the interdendritic space (Fig. 9 ). Given the relatively wide homogeneity range of titanium nickelide at elevated temperatures (Fig. 1 ), supersaturated solid solution formation is expected in nickel-enriched regions. Prolonged etching of the weld revealed contrast between TiNi dendrites of different chemical compositions, enabling differentiation between supersaturated and near-equilibrium titanium mononickelide. In Fig. 9 , nickel-supersaturated titanium nickelide is denoted as “TiNi′” and appears darker. In the lower right corner of Fig. 9 , dendrites of supersaturated TiNi are surrounded by a eutectic mixture of TiNi–TiNi 3 . The homogeneity range towards titanium is an order of magnitude narrower according to the Ti–Ni equilibrium diagram (Fig. 1 ); thus, TiNi dendrites growing towards regions of decreasing nickel concentration can be considered of near-equilibrium composition. These dendrites, denoted as “TiNi” in Fig. 9 , exhibit a lighter contrast. Microhardness measurements at a 10 g load for various structural constituents indirectly support the above assumptions. Absolute HV0.01 values often have large uncertainties due to proximity of other phase boundaries and indentation sizes exceeding the grain dimensions in some cases. Nevertheless, comparative evaluation provides insight into phase hardness levels. The hardness of equilibrium TiNi does not exceed 400 HV0.01, whereas Ni-supersaturated TiNi reaches ~ 710–730 HV0.01. The highest hardness is exhibited by a secondary Ni-rich phase within locally Ni-enriched regions (presumably nonequilibrium Ti 3 Ni 4 or Ti 2 Ni 3 ), attaining 891 HV0.01. Microhardness assessment of Ti 2 Ni is less reliable due to the narrowness of its interstitial veins between TiNi dendrites; its hardness is estimated to be not less than 560 HV0.01. Microstructural analysis of similar weld regions revealed that Ni-supersaturated TiNi may contain up to 55–57 at.% Ni (spectrum 2, 3, and 6 in Fig. 10 ). Within these grains, secondary-phase precipitates are observed, likely representing nonequilibrium Ti 3 Ni 4 or Ti 2 Ni 3 . The secondary Ni-rich phases in locally enriched regions (bright areas in the left part of Fig. 10 , spectrum 1) are identified, based on chemical composition, as nonequilibrium intermetallics, since their Ni content is significantly lower than that of equilibrium TiNi 3 . The beam offset towards titanium in the welding process initially results in an increase in the concentration of Ti 2 Ni and a decrease in the number of TiNi dendrites. Subsequently, there is an appearance and increase in the proportion of the eutectic (Ti 2 Ni + β-Ti). It is noteworthy that the microstructure comprising the eutectic (Ti 2 Ni + β-Ti) and Ti 2 Ni dendrites exhibits the presence of microcracks in any region of the weld (Fig. 11 ). A further increase in the beam offset towards titanium leads to the appearance of β-Ti dendrites and localization of Ti 2 Ni dendrites near the nickel fusion line. At the maximum beam offset, which ensures the formation of a welded joint devoid of non-welded regions, α'-Ti martensitic grains appear in the weld with a minimum amount of β-Ti. In such a scenario, the distribution of Ti 2 Ni and the eutectic is confined to a narrow band along the fusion line of nickel. In this case, Ti 2 Ni and eutectic (Ti 2 Ni + β-Ti) dendrites are located in a narrow band along the nickel fusion line. Beam deflection toward the Ni side increases the regions of Ni-supersaturated TiNi, the TiNi–TiNi 3 eutectic, and the formation of large TiNi 3 crystals. With further deflection toward Ni, the fraction of TiNi 3 intermetallic increases (Fig. 5 a). Continued deflection promotes a higher fraction of Ni-rich γ-phase. Tensile tests were conducted to determine the ultimate tensile strength (UTS) of the base metals and welds. The results for the welds are summarized in Table 1 . The average UTS of titanium was 407 MPa, and for nickel, 506 MPa. Notably, the first six specimens were used to study the weld-metal formation process and were entirely sectioned into transverse metallographic samples. As shown in Table 1 , some specimens fractured prior to testing, most frequently during specimen extraction for tensile testing due to variable bending stresses. The maximum UTS was recorded for a specimen extracted from weld No. 49, reaching 384 MPa, corresponding to 95% of the UTS of titanium. Figure 12 presents the ultimate tensile strength of the welds as a function of weld metal chemical composition at a welding speed of 2000 mm/min. The maximum tensile strength is achieved for Ni content of about 85–90%, when the weld structure is represented by a supersaturated solid solution of Ti in Ni and a secondary excess phase along the grain boundaries. The local maximum is observed at a Ni concentration of about 10%, when the weld is formed by solid solutions based on titanium. When the titanium concentration in the weld is about 25–30% and the structure is represented by Ti 2 Ni and eutectic dendrites (Ti 2 Ni + β-Ti), the welded joints are broken down before testing. The second local maximum is observed at a Ti concentration of 55%, when the weld metal structure consists mainly of a nickel-supersaturated solid solution of titanium nickelide. The decrease in strength at the extreme points is associated with the lack of fusion. Table 1 EBW parameters and tensile test results of the welded joints Sample № Welding speed, mm/min. Beam current, mА Beam oscillation amplitude, mm Beam oscillation frequency, Hz Beam offset toward titanium, mm Ultimate tensile strength MPa 1 1000 25…15 - - 0…1 were used only for metallographic studies 2 1000 16 - - 0,1…0,3 3 1000 16 - - 0,3…0,6 4 1000 16 - - 0,15 5 1000 22 - - 0 6 1000 24 1 100 0 7 1000 24 1 100 0,7 80 8 1000 16 1 50 0,7 broke down before testing 9 2000 28 1 50 0,7 10 1000 16 1 66 0,5 118 133 11 2000 28 1 66 0,3 84 113 137 12 2000 40 1 100 0 85 188 13 2000 40 1 100 -0,4 139 261 14 2000 32 1 100 0 78 122 15 2000 30 1 100 0,2 broke down before testing 16 2000 25 1 100 -0,2 123 227 17 2000 30 1 100 -0,5 145 156 18 1000 16 1 132 0,5 179 142 19 2000 24 1 132 0,3 227 210 20 500 11 1 33 0,5 179 142 21 500 11 1 33 0,8 170 168 22 2000 30 1 132 -0,6 200 215 23 500 15 1 66 0 198 189 24 3000 34 1 200 0 91 247 25 3000 29 1 200 0,3 62 46 26 100 10 - - 0 150 27 100 10 1 15 0 broke down before testing 28 100 8 1 30 0 147 29 100 8 1 45 0 broke down before testing 31 100 7..8 1 45 0 32 2000 30 1 133 -0,7 338 276 193 33 6000 60 - - 0 204 34 6000 80 - - 0 158 35 6000 90 - - 0 226 36 6000 90 - - 0 broke down before testing 37 2000 30 - - 0,4 50 138 154 38 2000 30 - - 0,2 102 111 111 39 2000 30 - - 0,6 125 143 40 6000 80 - - 0,2 57 58 114 41 6000 80 - - 0,4 88 68 155 42 6000 90 - - 0,6 127 94 115 43 2000 30 - - 0,2 155 208 127 44 2000 30 - - -0,4 208 193 213 45 2000 30 - - -0,6 173 194 125 46 6000 80 - - -0,2 155 198 141 47 6000 80 - - -0,4 186 170 55 48 6000 90 - - -0,6 281 188 188 49 2000 30 - - -0,6 384 235 323 50 6000 60 - - -0,4 199 212 142 51 6000 70 - - -0,4 139 230 93 4. Discussion The dependence of weld width on welding speed is well established and is consistent with the present observations. Increasing the welding speed reduces the volume of molten metal, thereby decreasing residual stresses and distortions in the welded structure. However, this simultaneously increases the thermal gradient around the weld pool and accelerates cooling, which promotes localized stress accumulation during electron-beam welding (EBW), formation of nonequilibrium phases, and enhanced structural and chemical heterogeneity across the weld cross-section. Weld widening at the crown and root can be attributed to Marangoni convection, which is characteristic of all welds due to the high temperature gradient at the liquid-metal surface. Welding of nickel to titanium exhibits pronounced asymmetry, likely due to differences in thermophysical properties and the strong influence of composition on the solidification temperature. For instance, the flow of superheated equiatomic liquid toward the titanium side promotes heating and melting of titanium, reducing the nickel concentration in the melt. This reduction lowers the solidification temperature, reaching a eutectic minimum at 24% Ni, and prolongs the residence time of the metal in the liquid state. Consequently, the temperature difference between the center and the titanium side of the weld pool is amplified, enhancing Marangoni convection. The relatively low thermal conductivity of titanium further slows cooling, creating conditions for elongated widening on the titanium side. Conversely, on the nickel side, higher thermal conductivity and the smaller effect of nickel enrichment on the solidification temperature result in less pronounced widening. Variations in surface tension of liquid metal with different composition may also affect Marangoni convection under high concentration gradients. Because convective transport is inertial, the extent of crown and root widening decreases with reduced liquid residence time, as observed at higher welding speeds. Beam deflection did not significantly reduce chemical heterogeneity or the width of the transition zones; therefore, achieving chemically and structurally homogeneous welds is more effective at lower welding speeds. However, low welding speeds negatively affect weld shape, making the selection of an optimal welding speed a compromise between chemical homogeneity and minimization of residual stress through shape optimization. Post-weld microstructural analysis indicated that failure consistently occurred along the eutectic (Ti 2 Ni + β-Ti) and Ti 2 Ni intermetallic phases, irrespective of beam displacement or welding speed. Ti 2 Ni and the eutectic (Ti 2 Ni + β-Ti) solidify at temperatures over 300°C lower than TiNi and over 600°C lower than titanium, resulting in high deformation rates during solidification and elevated stress in these phases. This promotes microcrack formation and the development of mechanically weak structures, as confirmed by microstructural examination of the welds. The problem of rapid deformation of low-melting phases is further aggravated by differential thermal contraction during cooling due to the mismatch in thermal expansion coefficients among phases. For example, Ti 2 Ni exhibits nearly twice the thermal expansion of titanium [30], generating tensile stress at Ti–Ti 2 Ni interfaces upon cooling. Additionally, the TiNi intermetallic exhibits a complex temperature-dependent thermal expansion due to phase transformations, and the discontinuous volume changes associated with phase transformations in TiNi may increase residual stress and promote microcracking [31]. Therefore, Ti 2 Ni and the eutectic (Ti 2 Ni + β-Ti) are the most susceptible to crack formation, being relatively low-melting phases with high thermal expansion coefficients. Consequently, when the titanium content in the weld is about 25–30%, the welded joints break down brittlely even at the stage of machining under low loads. From a weldability perspective, experimental conditions should limit the formation of these brittle phases. Functional welds formation can be achieved if the weld predominantly consists of TiNi intermetallic or nickel/titanium solid solutions, as can be seen in Fig. 12 . Producing a weld through nickel–titanium solid solutions requires significant beam displacement and a “weld–braze” approach. In such schemes, the lower-melting metal—nickel in this system—is melted first. Marangoni-driven transport of nickel toward titanium causes substantial melting of titanium at both root and crown, enriching the liquid in titanium and forming a solidified structure consisting mainly of grains of a supersaturated solid solution based on nickel, eutectic (TiNi + TiNi 3 ) and TiNi 3 grains. However, it is with this weld structure that the maximum strength of the welded joint is achieved. This can be explained by the minimal width of the interlayer containing Ti 2 Ni and the eutectic phase (Ti 2 Ni + β-Ti). Additionally, the linear expansion coefficients of TiNi 3 and nickel phase are closely matched, so there are no significant stresses at the interface during cooling in the contact zone. Beam displacement toward titanium allows formation of a titanium-rich solid solution weld but demands precise positioning to avoid lack of fusion. Simultaneously, a transition layer of Ti 2 Ni dendrites and eutectic (Ti 2 Ni + β-Ti) forms at the nickel interface, limiting weld strength. Formation of the weld metal mainly due to titanium nickelide provides a local maximum that is displaced towards nickel. This means that the maximum strength is not achieved with a chemical composition that corresponds to titanium nickelide, but rather with a nickel concentration of about 55%, when nickel-supersaturated TiNi is formed. This is due to the fact that elements distribution in the weld metal becomes uneven, as a result, with an equal content of nickel and titanium in the weld, areas with a reduced nickel content inevitably appear with an undesirable Ti 2 Ni phase. A certain excess of nickel can minimize the proportion of this phase, but it also leads to TiNi solid solution saturation and eutectic (TiNi + TiNi 3 ) formation, which do not have such a negative impact on the weld strength. 5. Conclusions From a weld-metal microstructural perspective, functional Ni–Ti joints can be achieved via two approaches: a “weld–braze” scheme or formation of titanium mononickelide (TiNi) within the weld. The preferred strategy is to produce nickel-supersaturated TiNi rather than titanium-rich TiNi, due to the narrow homogeneity range on the titanium side and the risk of forming the brittle, low-melting Ti 2 Ni intermetallic in the weld. All welds exhibit a low-melting, brittle layer composed of Ti 2 Ni and the eutectic (Ti 2 Ni + β-Ti). This layer frequently contains microcracks, attributable to the high deformation rates of these phases and their limited ductility, particularly at elevated temperatures. Microstructural analysis of the fracture region after tensile testing revealed that most specimens failed along the Ti 2 Ni + eutectic (Ti 2 Ni + β-Ti) layer. The reduced tensile strength of the welds is thus evidently associated with residual welding stresses and the presence of microcracks in these brittle layers. The ultimate tensile strength of Ni–Ti welds can reach at least 384 MPa, corresponding to approximately 95% of the base metal strength. Declarations Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgments The research was carried out with the financial support of the Ministry of Science and Highter Education of the Russian Federation (project No. FSWF-2023-0016). Data Availability Data will be made available on request. References Boyer RR (1996) An Overview on the Use of Titanium in the Aerospace Industry. 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Materials 13(15):3310. https://doi.org/10.3390/ma13153310 Sliva AP, Dragunov VK, Terentyev EV, Goncharov AL (2018) EBW of aluminium alloys with application of electron beam oscillation. J Phys Conf Ser 1089:012005. https://doi.org/10.1088/1742-6596/1089/1/012005 Cite Share Download PDF Status: Published Journal Publication published 31 Jan, 2026 Read the published version in The International Journal of Advanced Manufacturing Technology → Version 1 posted Editorial decision: Major Revisions Needed 23 Nov, 2025 Reviewers agreed at journal 07 Oct, 2025 Reviewers invited by journal 07 Oct, 2025 Editor assigned by journal 22 Sep, 2025 First submitted to journal 22 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7659950","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":525867446,"identity":"1bd628d9-acb5-41aa-a512-7b7062ec60c5","order_by":0,"name":"Egor V. 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1","display":"","copyAsset":false,"role":"figure","size":242465,"visible":true,"origin":"","legend":"\u003cp\u003eTi–Ni phase diagram\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/ae43fb0f897ca9f38533b8f3.jpeg"},{"id":93965795,"identity":"5b638ea1-b667-4a36-8959-4ea7ad6fbc1f","added_by":"auto","created_at":"2025-10-20 18:41:29","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":74942,"visible":true,"origin":"","legend":"\u003cp\u003ePlates prepared for welding in the fixture\u003c/p\u003e","description":"","filename":"groupimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/55929cc002edcf398e2e46f4.jpeg"},{"id":93965796,"identity":"08c2f15d-636d-4b4d-a578-5482883176f5","added_by":"auto","created_at":"2025-10-20 18:41:29","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":895329,"visible":true,"origin":"","legend":"\u003cp\u003eMicrostructure of welds produced at welding speeds of 500 mm/min (a) and 3000 mm/min (b)\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/94afcfeb4cad85054dd583bb.jpeg"},{"id":93965264,"identity":"9f2e9674-af5f-45c8-b9ee-1b13ded6d295","added_by":"auto","created_at":"2025-10-20 18:33:29","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":952614,"visible":true,"origin":"","legend":"\u003cp\u003eDependence of weld width on welding speed during electron beam welding without beam offset (in butt configuration)\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/a443c72a290ad0f854d3da52.jpeg"},{"id":93965799,"identity":"011dcf11-c77d-465c-99d1-d95710300971","added_by":"auto","created_at":"2025-10-20 18:41:29","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":160610,"visible":true,"origin":"","legend":"\u003cp\u003eWeld microstructures at an electron beam offset of 0.6 mm (a) and 0.2 mm (b) toward nickel, without offset (c), and 0.3 mm toward titanium (d).\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/ad60313a94c6c2d7ae28e2f6.jpg"},{"id":93965261,"identity":"353d1677-f95c-4140-8f62-9399689359be","added_by":"auto","created_at":"2025-10-20 18:33:29","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":749181,"visible":true,"origin":"","legend":"\u003cp\u003eWeld microstructures obtained at a welding speed of 1000 mm/min: without beam oscillation (a) and with saw-type oscillation at 100 Hz frequency and 1 mm amplitude (b)\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/b37ca6705095ad8835343326.jpeg"},{"id":93965266,"identity":"c21ff5cd-9056-4bd6-92f8-ac56306311dd","added_by":"auto","created_at":"2025-10-20 18:33:29","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":1157327,"visible":true,"origin":"","legend":"\u003cp\u003eMicrostructure near the Ti fusion line of the weld produced at a welding speed of 1000 mm/min without beam offset or oscillation, magnification 1000×\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/b02d8b43ac15608ab4ae5f8d.png"},{"id":93965800,"identity":"56ba1a03-d6d4-4a74-9f5a-b681e86d1baf","added_by":"auto","created_at":"2025-10-20 18:41:29","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":1317315,"visible":true,"origin":"","legend":"\u003cp\u003eMicrostructure near the Ni fusion line of the weld produced at a welding speed of 1000 mm/min without beam offset or oscillation, magnification 1000×\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/8d7a2697358e6a88b15e7340.png"},{"id":93965801,"identity":"6c5a99b8-5128-4753-a6d4-3c8d79e03c07","added_by":"auto","created_at":"2025-10-20 18:41:29","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":1542785,"visible":true,"origin":"","legend":"\u003cp\u003eMicrohardness measurements near the Ni fusion line of the weld produced at a welding speed of 1000 mm/min without beam offset or oscillation, magnification 2400×\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/7f9e08ae71b219ea418612c5.png"},{"id":93966586,"identity":"41455ae4-0110-48ff-b53b-09099c1d810a","added_by":"auto","created_at":"2025-10-20 19:05:29","extension":"jpeg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":964491,"visible":true,"origin":"","legend":"\u003cp\u003eStructural and chemical inhomogeneity of the weld produced at a welding speed of 1000 mm/min without beam offset or oscillation\u003c/p\u003e","description":"","filename":"floatimage8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/27630e8bd23c2b4efeb45f69.jpeg"},{"id":93965265,"identity":"6f945267-3860-4995-ad1b-0ad6ee47566a","added_by":"auto","created_at":"2025-10-20 18:33:29","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":1146237,"visible":true,"origin":"","legend":"\u003cp\u003eMicrostructure of the weld center produced at a welding speed of 1000 mm/min with a 0.2 mm beam offset toward titanium, magnification 1000×\u003c/p\u003e","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/a58c6dd029401d5761b069e3.png"},{"id":93966417,"identity":"ceefce3c-8254-499d-85b6-e9999465e7b7","added_by":"auto","created_at":"2025-10-20 18:57:29","extension":"jpeg","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":288009,"visible":true,"origin":"","legend":"\u003cp\u003eDependence of the tensile strength of welded joints on its chemical composition\u003c/p\u003e","description":"","filename":"floatimage10.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/8db8592ec3ce3d0a32535a28.jpeg"},{"id":101690566,"identity":"c23fb141-9b88-4985-a0af-2b3268739d21","added_by":"auto","created_at":"2026-02-02 16:05:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":12556715,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7659950/v1/c009dcb4-a6ac-4778-8edb-b45b96b00343.pdf"}],"financialInterests":"","formattedTitle":"Electron beam welding of pure titanium and nickel","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe integration of titanium and nickel alloys provides an optimal combination of titanium\u0026rsquo;s high strength-to-weight ratio and nickel\u0026rsquo;s heat resistance [1\u0026ndash;3]. Eliminating mechanical fasteners not only reduces the weight and size of critical components but also enables novel design solutions and decreases moments of inertia, which is particularly relevant for rotor assemblies.\u003c/p\u003e\u003cp\u003eHowever, producing permanent fusion welds between titanium and nickel alloys remains a significant challenge. Metallurgical incompatibility stems from the formation of brittle intermetallic phases such as Ti₂Ni and Ni₃Ti, as well as differences in thermophysical properties, atomic radius, and crystal structures. To date, solid-state welding methods including explosive welding [4\u0026ndash;8], diffusion welding [9\u0026ndash;12], friction stir welding [13, 14] and thermal explosion welding [15] have been applied. However, these techniques are typically limited by relatively simple joint geometries.\u003c/p\u003e\u003cp\u003eFusion welding of titanium with nickel and most other structural materials is hindered by the formation of brittle intermediate phases [16\u0026ndash;18]. To prevent such phases, interlayers are often employed. Nickel [19\u0026ndash;23], niobium [23\u0026ndash;25], copper [21, 26] and other monometallic interlayers [18] are used in welding titanium nickelide (TiNi) to steels and steel\u0026ndash;titanium alloy joints. At the same time, there is a tendency to abandon monometallic layers in recent researches. Instead, it is proposed to form complex-alloyed alloys or high-entropy alloys in the weld area by using appropriate filler materials or ensuring a given penetration [18, 27, 28]. However, neither the use of monometallic nor complex-alloyed layers always allow avoiding the formation of brittle interlayers and leads to the emergence of new technological difficulties [18, 25, 29]. Therefore, developing fusion welding processes without interlayers remains a pressing issue today.\u003c/p\u003e\u003cp\u003eEarly attempts to weld commercially pure titanium and nickel resulted in unsatisfactory outcomes, with widespread cracking and pronounced macrosegregation observed in the welds [30]. Despite this, it was hypothesized that welds primarily composed of the titanium nickelide phase (NiTi) might yield viable joints. The Ti\u0026ndash;Ni phase diagram (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) highlights the existence of TiNi, an intermetallic phase known for its combination of high strength and ductility [31].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eSubsequent research demonstrated the formation of brittle interlayers near fusion lines on both titanium and nickel sides, containing Ti\u003csub\u003e2\u003c/sub\u003eNi and Ni\u003csub\u003e3\u003c/sub\u003eTi phases that reduce joint strength [32, 33]. Welding parameters, especially welding speed and beam offset relative to the joint, have a decisive influence on weld formation. Welding speed affects heating and cooling rates across the joint, weld geometry, and residual stresses and distortions [34]. It also controls molten metal flow and dwell time in the liquid state, thereby influencing chemical and structural heterogeneity and brittle interlayer thickness. Beam offset and material property differences affect edge penetration, which determines weld metal composition and microstructure. Consequently, welding speed and beam offset are key parameters controlling the microstructure of titanium\u0026ndash;nickel welds.\u003c/p\u003e\u003cp\u003eA detailed study of electron beam welded titanium\u0026ndash;nickel joints revealed a weld microstructure dominated by a Ni\u003csub\u003e3\u003c/sub\u003eTi\u0026thinsp;+\u0026thinsp;NiTi eutectic mixture, corresponding to approximately 60\u0026ndash;65 atomic percent nickel penetration [35]. While crystallization sequences and growth directions of constituent phases were characterized, optimal welding regimes for defect-free joints with desirable mechanical properties were not established.\u003c/p\u003e\u003cp\u003eLaser welding investigations showed that beam offsets up to 35 \u0026micro;m did not significantly affect pore and crack formation, whereas simultaneous increases in welding speed and beam power reduced their incidence [36]. Further work found that a 0.5 mm laser beam offset toward the nickel plate produced defect-free welds with a solid solution of titanium in nickel and a transition layer no wider than 200 \u0026micro;m at the titanium fusion boundary. In contrast, the same offset toward titanium caused crack formation [37]. These studies, however, insufficiently explored the correlation between weld microstructure and defect occurrence, leaving crack formation mechanisms unclear.\u003c/p\u003e\u003cp\u003eAttempts to establish a correlation between EBW modes and the formed microstructure and mechanical properties were noted by the authors of the work [38]. The main variable parameters were heat input and beam offset relative to the joint. Like others, the authors note that cracks are initiated in the region of Ti\u003csub\u003e2\u003c/sub\u003eNi formation [38]. Unfortunately, it was not possible to establish a correlation between the ultimate tensile strength and heat input, which may be due to an insufficient number of tests.\u003c/p\u003e\u003cp\u003eThus, the majority of studies on nickel-to-titanium welding do not provide the results of mechanical tests for the produced joints. Without this data, it is impossible to evaluate their performance capability. Furthermore, even the data that is presented is often insufficient. Crucially, even if a weld joint is produced without defects, its structural strength under operational load conditions may still be unsatisfactory\u003c/p\u003e\u003cp\u003eThe present work aims to elucidate the relationship between weld microstructure, welding parameters across a broad range, crack formation likelihood, and the mechanical properties of titanium\u0026ndash;nickel welded joints.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cp\u003eElectron beam welding (EBW) was employed to join nickel and titanium due to its wide process parameter control range, precise beam positioning relative to the joint, and the vacuum environment that ensures effective protection of the weld pool\u0026mdash;particularly critical for titanium-based alloys [39]. Beam deflection was additionally utilized to modify the power density distribution within the penetration channel and control molten metal flow velocity in different weld pool regions [40], thereby influencing the chemical and structural heterogeneity of the joint.\u003c/p\u003e\u003cp\u003eWelding was performed on an ELA-40I EBW unit operating at an accelerating voltage of 60 kV, with a vacuum chamber pressure of 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e mm Hg. Plates of commercially pure titanium (98.6\u0026ndash;99.7% Ti) and nickel (\u0026gt;\u0026thinsp;99.5% Ni\u0026thinsp;+\u0026thinsp;Co), 2 mm in thickness and 50 \u0026times; 100 mm in size, were used. The prepared samples are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The beam current I\u003csub\u003eB\u003c/sub\u003e and focusing current I\u003csub\u003eF\u003c/sub\u003e were adjusted to ensure complete penetration at the lowest possible beam power. Welding speed was varied between 100 and 6000 mm/min.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe application of electron beam scanning accelerates molten metal flow in the weld pool, which is expected to enhance the chemical homogeneity of the weld metal. Furthermore, employing a \u0026ldquo;sawtooth\u0026rdquo; scanning pattern reduces weld width [40], thereby potentially lowering residual stresses and distortions in the joint. In the experiments, a sawtooth scan with a frequency of 15\u0026ndash;200 Hz was used.\u003c/p\u003e\u003cp\u003eThe weld metal composition was adjusted by offsetting the electron beam relative to the joint. The maximum offset corresponded to the occurrence of incomplete penetration at the weld root, amounting to 0.6 mm for offsets toward titanium and 0.7 mm for offsets toward nickel.\u003c/p\u003e\u003cp\u003eMetallographic examinations were performed on transverse sections of the welded joints. Microstructural etching was conducted using a reagent composed of 5 mL HNO\u003csub\u003e3\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;2.5 mL HF\u0026thinsp;+\u0026thinsp;2.5 mL HCl\u0026thinsp;+\u0026thinsp;90 mL H\u003csub\u003e2\u003c/sub\u003eO. For revealing the nickel-side structure, a reagent of 8 g FeCl\u003csub\u003e3\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;25 mL HCl\u0026thinsp;+\u0026thinsp;100 mL H\u003csub\u003e2\u003c/sub\u003eO was employed. Etching time ranged from 20 to 40 s.\u003c/p\u003e\u003cp\u003eMicrostructural analysis was carried out using a Zeiss Observer Z1m optical microscope at magnifications from 50\u0026times; to 2400\u0026times;, and a Tescan MIRA 3 LMU scanning electron microscope equipped with an energy-dispersive spectrometer. Microhardness HV0.01 was measured by the Vickers method on an Instron Tukon 2500 hardness tester, with a 10 s dwell under load.\u003c/p\u003e\u003cp\u003eStatic tensile tests were conducted on transverse specimens cut from welded plates to determine the ultimate tensile strength of the weakest zone in the joint. For comparison, specimens of identical geometry were fabricated and tested from base nickel and titanium plates. Tensile tests were performed on an Instron 8801 universal testing machine at a deformation rate of 0.5 mm/min. Three specimens from nickel, three from titanium, and at least three from each EBW mode were tested.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003eA total of 51 welded joints were produced under the conditions listed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eA comparison of transverse cross-sections of welds obtained at different welding speeds without beam offset reveals a reduction in weld width with increasing welding speed (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e presents the relationships between welding speed and both the minimum weld width and the weld crown width. It is evident that the minimum weld width is significantly less sensitive to welding speed.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eReducing the welding speed yields a more homogeneous weld structure throughout the joint volume, except for the transition zones (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea), whereas at higher welding speeds a pronounced structural heterogeneity is observed beyond these zones (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb).\u003c/p\u003e\u003cp\u003eThe welds exhibit noticeable asymmetry, manifested in the different degrees of edge melting and the varying geometry of crown and root widening. This asymmetry decreases with increasing welding speed (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe offset magnitude has a decisive influence on penetration depth, which in turn determines the chemical and structural composition of the weld metal. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e illustrates the microstructure of welds produced at different offsets. Offset affects not only weld structure and width but also weld shape. In all cases, widening at both crown and root is greater on the titanium side than on the nickel side.\u003c/p\u003e\u003cp\u003eAttempts to produce weld\u0026ndash;braze joints by offsetting toward nickel (the lower-melting metal) were unsuccessful due to significant titanium melting in the widened regions (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea). Increasing nickel penetration leads to lack of fusion before the widening becomes negligible. Conversely, offsetting toward titanium can minimize nickel melting and produce a weld predominantly consisting of α-titanium solid solution. However, this requires precise electron beam positioning: at 2000 mm/min, a 0.4 mm offset causes lack of root fusion, while a 0.3 mm offset results in the formation of undesirable brittle β-titanium (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eImplementation of electron beam deflection scanning increases the velocity of molten metal flow in the weld pool, thereby enhancing melt mixing. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e compares the microstructures of weld joints produced without beam offset, both with and without scanning. Compared with the weld produced without scanning (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea), the joint obtained with scanning (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb) exhibits a more uniform distribution of local chemical heterogeneities across the weld. However, it should be noted that scanning did not significantly affect the width of the interlayer transition zones, which, due to their brittleness, have a decisive influence on the mechanical properties of the joints.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIt is evident that in the weld metal the concentrations of nickel and titanium vary from 0 to 100% across the fusion zone, from one fusion boundary to the other. However, except for the transition zones near the fusion boundaries, the weld metal microstructure in all specimens is relatively homogeneous, particularly in welds produced at low travel speeds. Overall, for all specimens, the weld metal microstructure at the given chemical composition corresponded to the Ti\u0026ndash;Ni equilibrium phase diagram (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Since three types of intermetallic compounds and three eutectic mixtures can form under equilibrium conditions in the Ti\u0026ndash;Ni system, local variations in chemical composition lead to significant structural changes, as confirmed by the observations.\u003c/p\u003e\u003cp\u003eAs an example, the microstructure of a weld produced at a travel speed of 1000 mm/min without beam offset and without scanning is considered. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e shows the weld structure near the titanium fusion boundary, where characteristic structural constituents can be clearly distinguished.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAlong the fusion boundary, a dark layer approximately 5 \u0026micro;m thick is observed, consisting of quenched titanium-based solid-solution structures. In fusion welding, dendritic growth from remelted grains of the base metal is typical; however, in the present case, dendrites of Ti-based solid solution are virtually absent at the fusion boundary, presumably due to suppression by a steep concentration gradient. Elongated white dendrites growing toward the fusion boundary are identified as Ti\u003csub\u003e2\u003c/sub\u003eNi intermetallic crystals. The interdendritic liquid solidifies as a eutectic mechanical mixture (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti). With increasing distance from the weld, the eutectic fraction decreases, giving way to a continuous layer composed solely of Ti\u003csub\u003e2\u003c/sub\u003eNi. Further from the fusion line, Ti\u003csub\u003e2\u003c/sub\u003eNi regions contain dendrites of TiNi mononickelide. Such a microstructure is characteristic of a substantial portion of the weld.\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e presents the weld metal microstructure near the fusion boundary with nickel. Dendritic growth of nickel-based solid solution is likewise absent, inhibited by the high concentration gradient. Instead, a thin layer (1\u0026ndash;5 \u0026micro;m) of solid solution is located directly at the fusion boundary, followed by a 1\u0026ndash;15 \u0026micro;m layer of TiNi\u003csub\u003e3\u003c/sub\u003e intermetallic, which transitions into a eutectic mechanical mixture TiNi\u003csub\u003e3\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;TiNi. At greater distances from the fusion boundary, the TiNi\u003csub\u003e3\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;TiNi eutectic is embedded between TiNi dendrites growing toward the fusion line. From the TiNi-only layer, TiNi dendrites also grow toward the weld center, while Ti\u003csub\u003e2\u003c/sub\u003eNi intermetallic crystallizes in the interdendritic spaces via a peritectic reaction, consistent with the decrease in nickel concentration away from the fusion boundary.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe microstructure of the weld central zone in joints produced without offset is predominantly composed of freely grown TiNi dendrites surrounded by the intermetallic Ti\u003csub\u003e2\u003c/sub\u003eNi. In regions with locally increased nickel concentration, rounded areas are observed from which TiNi dendrites emanate, with Ti\u003csub\u003e2\u003c/sub\u003eNi crystallizing in the interdendritic space (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e). Given the relatively wide homogeneity range of titanium nickelide at elevated temperatures (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), supersaturated solid solution formation is expected in nickel-enriched regions. Prolonged etching of the weld revealed contrast between TiNi dendrites of different chemical compositions, enabling differentiation between supersaturated and near-equilibrium titanium mononickelide. In Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, nickel-supersaturated titanium nickelide is denoted as \u0026ldquo;TiNi\u0026prime;\u0026rdquo; and appears darker. In the lower right corner of Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, dendrites of supersaturated TiNi are surrounded by a eutectic mixture of TiNi\u0026ndash;TiNi\u003csub\u003e3\u003c/sub\u003e. The homogeneity range towards titanium is an order of magnitude narrower according to the Ti\u0026ndash;Ni equilibrium diagram (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e); thus, TiNi dendrites growing towards regions of decreasing nickel concentration can be considered of near-equilibrium composition. These dendrites, denoted as \u0026ldquo;TiNi\u0026rdquo; in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, exhibit a lighter contrast.\u003c/p\u003e\u003cp\u003eMicrohardness measurements at a 10 g load for various structural constituents indirectly support the above assumptions. Absolute HV0.01 values often have large uncertainties due to proximity of other phase boundaries and indentation sizes exceeding the grain dimensions in some cases. Nevertheless, comparative evaluation provides insight into phase hardness levels. The hardness of equilibrium TiNi does not exceed 400 HV0.01, whereas Ni-supersaturated TiNi reaches\u0026thinsp;~\u0026thinsp;710\u0026ndash;730 HV0.01. The highest hardness is exhibited by a secondary Ni-rich phase within locally Ni-enriched regions (presumably nonequilibrium Ti\u003csub\u003e3\u003c/sub\u003eNi\u003csub\u003e4\u003c/sub\u003e or Ti\u003csub\u003e2\u003c/sub\u003eNi\u003csub\u003e3\u003c/sub\u003e), attaining 891 HV0.01. Microhardness assessment of Ti\u003csub\u003e2\u003c/sub\u003eNi is less reliable due to the narrowness of its interstitial veins between TiNi dendrites; its hardness is estimated to be not less than 560 HV0.01.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMicrostructural analysis of similar weld regions revealed that Ni-supersaturated TiNi may contain up to 55\u0026ndash;57 at.% Ni (spectrum 2, 3, and 6 in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e). Within these grains, secondary-phase precipitates are observed, likely representing nonequilibrium Ti\u003csub\u003e3\u003c/sub\u003eNi\u003csub\u003e4\u003c/sub\u003e or Ti\u003csub\u003e2\u003c/sub\u003eNi\u003csub\u003e3\u003c/sub\u003e. The secondary Ni-rich phases in locally enriched regions (bright areas in the left part of Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e, spectrum 1) are identified, based on chemical composition, as nonequilibrium intermetallics, since their Ni content is significantly lower than that of equilibrium TiNi\u003csub\u003e3\u003c/sub\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe beam offset towards titanium in the welding process initially results in an increase in the concentration of Ti\u003csub\u003e2\u003c/sub\u003eNi and a decrease in the number of TiNi dendrites. Subsequently, there is an appearance and increase in the proportion of the eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti). It is noteworthy that the microstructure comprising the eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti) and Ti\u003csub\u003e2\u003c/sub\u003eNi dendrites exhibits the presence of microcracks in any region of the weld (Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e). A further increase in the beam offset towards titanium leads to the appearance of β-Ti dendrites and localization of Ti\u003csub\u003e2\u003c/sub\u003eNi dendrites near the nickel fusion line. At the maximum beam offset, which ensures the formation of a welded joint devoid of non-welded regions, α'-Ti martensitic grains appear in the weld with a minimum amount of β-Ti. In such a scenario, the distribution of Ti\u003csub\u003e2\u003c/sub\u003eNi and the eutectic is confined to a narrow band along the fusion line of nickel. In this case, Ti\u003csub\u003e2\u003c/sub\u003eNi and eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti) dendrites are located in a narrow band along the nickel fusion line.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eBeam deflection toward the Ni side increases the regions of Ni-supersaturated TiNi, the TiNi\u0026ndash;TiNi\u003csub\u003e3\u003c/sub\u003e eutectic, and the formation of large TiNi\u003csub\u003e3\u003c/sub\u003e crystals. With further deflection toward Ni, the fraction of TiNi\u003csub\u003e3\u003c/sub\u003e intermetallic increases (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea). Continued deflection promotes a higher fraction of Ni-rich γ-phase.\u003c/p\u003e\u003cp\u003eTensile tests were conducted to determine the ultimate tensile strength (UTS) of the base metals and welds. The results for the welds are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The average UTS of titanium was 407 MPa, and for nickel, 506 MPa. Notably, the first six specimens were used to study the weld-metal formation process and were entirely sectioned into transverse metallographic samples. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, some specimens fractured prior to testing, most frequently during specimen extraction for tensile testing due to variable bending stresses.\u003c/p\u003e\u003cp\u003eThe maximum UTS was recorded for a specimen extracted from weld No. 49, reaching 384 MPa, corresponding to 95% of the UTS of titanium.\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e presents the ultimate tensile strength of the welds as a function of weld metal chemical composition at a welding speed of 2000 mm/min. The maximum tensile strength is achieved for Ni content of about 85\u0026ndash;90%, when the weld structure is represented by a supersaturated solid solution of Ti in Ni and a secondary excess phase along the grain boundaries. The local maximum is observed at a Ni concentration of about 10%, when the weld is formed by solid solutions based on titanium. When the titanium concentration in the weld is about 25\u0026ndash;30% and the structure is represented by Ti\u003csub\u003e2\u003c/sub\u003eNi and eutectic dendrites (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti), the welded joints are broken down before testing. The second local maximum is observed at a Ti concentration of 55%, when the weld metal structure consists mainly of a nickel-supersaturated solid solution of titanium nickelide. The decrease in strength at the extreme points is associated with the lack of fusion.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEBW parameters and tensile test results of the welded joints\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample №\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWelding speed, mm/min.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBeam current, mА\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBeam oscillation amplitude, mm\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eBeam oscillation frequency, Hz\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eBeam offset toward titanium, mm\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c9\" namest=\"c7\"\u003e\u003cp\u003eUltimate tensile strength \u003c/p\u003e\u003cp\u003eMPa\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25\u0026hellip;15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u0026hellip;1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" morerows=\"5\" nameend=\"c9\" namest=\"c7\" rowspan=\"6\"\u003e\u003cp\u003ewere used only for metallographic studies\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,1\u0026hellip;0,3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,3\u0026hellip;0,6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" morerows=\"1\" nameend=\"c9\" namest=\"c7\" rowspan=\"2\"\u003e\u003cp\u003ebroke down before testing\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e118\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e133\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e113\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e137\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e188\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e139\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e261\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e122\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c9\" namest=\"c7\"\u003e\u003cp\u003ebroke down before testing\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e123\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e227\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e145\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e156\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e132\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e179\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e142\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e132\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e227\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e210\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e500\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e179\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e142\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e500\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e170\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e168\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e132\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e215\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e500\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e198\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e189\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e91\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e247\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e46\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e150\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c9\" namest=\"c7\"\u003e\u003cp\u003ebroke down before testing\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e147\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" morerows=\"1\" nameend=\"c9\" namest=\"c7\" rowspan=\"2\"\u003e\u003cp\u003ebroke down before testing\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7..8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e133\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e338\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e276\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e193\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e204\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e158\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e226\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c9\" namest=\"c7\"\u003e\u003cp\u003ebroke down before testing\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e138\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e154\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e102\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e111\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e111\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e39\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e125\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e143\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e114\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e155\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e127\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e115\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0,2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e155\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e208\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e127\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e44\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e208\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e193\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e213\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e173\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e194\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e125\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e46\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e155\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e198\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e141\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e47\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e186\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e170\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e55\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e281\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e188\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e188\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e384\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e235\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e323\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e199\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e212\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e142\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0,4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e139\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e230\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e93\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe dependence of weld width on welding speed is well established and is consistent with the present observations. Increasing the welding speed reduces the volume of molten metal, thereby decreasing residual stresses and distortions in the welded structure. However, this simultaneously increases the thermal gradient around the weld pool and accelerates cooling, which promotes localized stress accumulation during electron-beam welding (EBW), formation of nonequilibrium phases, and enhanced structural and chemical heterogeneity across the weld cross-section.\u003c/p\u003e\u003cp\u003eWeld widening at the crown and root can be attributed to Marangoni convection, which is characteristic of all welds due to the high temperature gradient at the liquid-metal surface. Welding of nickel to titanium exhibits pronounced asymmetry, likely due to differences in thermophysical properties and the strong influence of composition on the solidification temperature. For instance, the flow of superheated equiatomic liquid toward the titanium side promotes heating and melting of titanium, reducing the nickel concentration in the melt. This reduction lowers the solidification temperature, reaching a eutectic minimum at 24% Ni, and prolongs the residence time of the metal in the liquid state. Consequently, the temperature difference between the center and the titanium side of the weld pool is amplified, enhancing Marangoni convection. The relatively low thermal conductivity of titanium further slows cooling, creating conditions for elongated widening on the titanium side. Conversely, on the nickel side, higher thermal conductivity and the smaller effect of nickel enrichment on the solidification temperature result in less pronounced widening. Variations in surface tension of liquid metal with different composition may also affect Marangoni convection under high concentration gradients.\u003c/p\u003e\u003cp\u003eBecause convective transport is inertial, the extent of crown and root widening decreases with reduced liquid residence time, as observed at higher welding speeds.\u003c/p\u003e\u003cp\u003eBeam deflection did not significantly reduce chemical heterogeneity or the width of the transition zones; therefore, achieving chemically and structurally homogeneous welds is more effective at lower welding speeds. However, low welding speeds negatively affect weld shape, making the selection of an optimal welding speed a compromise between chemical homogeneity and minimization of residual stress through shape optimization.\u003c/p\u003e\u003cp\u003ePost-weld microstructural analysis indicated that failure consistently occurred along the eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti) and Ti\u003csub\u003e2\u003c/sub\u003eNi intermetallic phases, irrespective of beam displacement or welding speed. Ti\u003csub\u003e2\u003c/sub\u003eNi and the eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti) solidify at temperatures over 300\u0026deg;C lower than TiNi and over 600\u0026deg;C lower than titanium, resulting in high deformation rates during solidification and elevated stress in these phases. This promotes microcrack formation and the development of mechanically weak structures, as confirmed by microstructural examination of the welds.\u003c/p\u003e\u003cp\u003eThe problem of rapid deformation of low-melting phases is further aggravated by differential thermal contraction during cooling due to the mismatch in thermal expansion coefficients among phases. For example, Ti\u003csub\u003e2\u003c/sub\u003eNi exhibits nearly twice the thermal expansion of titanium [30], generating tensile stress at Ti\u0026ndash;Ti\u003csub\u003e2\u003c/sub\u003eNi interfaces upon cooling. Additionally, the TiNi intermetallic exhibits a complex temperature-dependent thermal expansion due to phase transformations, and the discontinuous volume changes associated with phase transformations in TiNi may increase residual stress and promote microcracking [31]. Therefore, Ti\u003csub\u003e2\u003c/sub\u003eNi and the eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti) are the most susceptible to crack formation, being relatively low-melting phases with high thermal expansion coefficients. Consequently, when the titanium content in the weld is about 25\u0026ndash;30%, the welded joints break down brittlely even at the stage of machining under low loads.\u003c/p\u003e\u003cp\u003eFrom a weldability perspective, experimental conditions should limit the formation of these brittle phases. Functional welds formation can be achieved if the weld predominantly consists of TiNi intermetallic or nickel/titanium solid solutions, as can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eProducing a weld through nickel\u0026ndash;titanium solid solutions requires significant beam displacement and a \u0026ldquo;weld\u0026ndash;braze\u0026rdquo; approach. In such schemes, the lower-melting metal\u0026mdash;nickel in this system\u0026mdash;is melted first. Marangoni-driven transport of nickel toward titanium causes substantial melting of titanium at both root and crown, enriching the liquid in titanium and forming a solidified structure consisting mainly of grains of a supersaturated solid solution based on nickel, eutectic (TiNi\u0026thinsp;+\u0026thinsp;TiNi\u003csub\u003e3\u003c/sub\u003e) and TiNi\u003csub\u003e3\u003c/sub\u003e grains. However, it is with this weld structure that the maximum strength of the welded joint is achieved. This can be explained by the minimal width of the interlayer containing Ti\u003csub\u003e2\u003c/sub\u003eNi and the eutectic phase (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti). Additionally, the linear expansion coefficients of TiNi\u003csub\u003e3\u003c/sub\u003e and nickel phase are closely matched, so there are no significant stresses at the interface during cooling in the contact zone. Beam displacement toward titanium allows formation of a titanium-rich solid solution weld but demands precise positioning to avoid lack of fusion. Simultaneously, a transition layer of Ti\u003csub\u003e2\u003c/sub\u003eNi dendrites and eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti) forms at the nickel interface, limiting weld strength.\u003c/p\u003e\u003cp\u003eFormation of the weld metal mainly due to titanium nickelide provides a local maximum that is displaced towards nickel. This means that the maximum strength is not achieved with a chemical composition that corresponds to titanium nickelide, but rather with a nickel concentration of about 55%, when nickel-supersaturated TiNi is formed. This is due to the fact that elements distribution in the weld metal becomes uneven, as a result, with an equal content of nickel and titanium in the weld, areas with a reduced nickel content inevitably appear with an undesirable Ti\u003csub\u003e2\u003c/sub\u003eNi phase. A certain excess of nickel can minimize the proportion of this phase, but it also leads to TiNi solid solution saturation and eutectic (TiNi\u0026thinsp;+\u0026thinsp;TiNi\u003csub\u003e3\u003c/sub\u003e) formation, which do not have such a negative impact on the weld strength.\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eFrom a weld-metal microstructural perspective, functional Ni\u0026ndash;Ti joints can be achieved via two approaches: a \u0026ldquo;weld\u0026ndash;braze\u0026rdquo; scheme or formation of titanium mononickelide (TiNi) within the weld. The preferred strategy is to produce nickel-supersaturated TiNi rather than titanium-rich TiNi, due to the narrow homogeneity range on the titanium side and the risk of forming the brittle, low-melting Ti\u003csub\u003e2\u003c/sub\u003eNi intermetallic in the weld.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eAll welds exhibit a low-melting, brittle layer composed of Ti\u003csub\u003e2\u003c/sub\u003eNi and the eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti). This layer frequently contains microcracks, attributable to the high deformation rates of these phases and their limited ductility, particularly at elevated temperatures.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eMicrostructural analysis of the fracture region after tensile testing revealed that most specimens failed along the Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;eutectic (Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026thinsp;+\u0026thinsp;β-Ti) layer. The reduced tensile strength of the welds is thus evidently associated with residual welding stresses and the presence of microcracks in these brittle layers.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe ultimate tensile strength of Ni\u0026ndash;Ti welds can reach at least 384 MPa, corresponding to approximately 95% of the base metal strength.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eDeclaration of competing interest\u003c/h2\u003e\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e\u003cp\u003eThe research was carried out with the financial support of the Ministry of Science and Highter Education of the Russian Federation (project No. FSWF-2023-0016).\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData will be made available on request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBoyer RR (1996) An Overview on the Use of Titanium in the Aerospace Industry. 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J Phys Conf Ser 1089:012005. https://doi.org/10.1088/1742-6596/1089/1/012005\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"the-international-journal-of-advanced-manufacturing-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jamt","sideBox":"Learn more about [The International Journal of Advanced Manufacturing Technology](https://www.springer.com/journal/170)","snPcode":"170","submissionUrl":"https://submission.nature.com/new-submission/170/3","title":"The International Journal of Advanced Manufacturing Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Dissimilar joints, Electron beam welding, Titanium, Nickel, Titanium nickelide, Microstructure, Intermetallic compounds, Brittle interlayers, Mechanical properties","lastPublishedDoi":"10.21203/rs.3.rs-7659950/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7659950/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study presents the results of investigating the influence of welding parameters \u0026mdash; beam power, beam offset relative to the joint, welding speed, and scanning frequency \u0026mdash; on the formation of welded joints between commercially pure titanium grade VT1-0 and nickel grade NP2. It is shown that the weld metal structure consists of various types of intermetallic compounds, eutectics, and solid solutions based on nickel and titanium, with their ratio determined by the degree of penetration of the welded materials. The features of weld formation caused by the differences in the physical properties of the materials are described. The welding parameter ranges enabling high-quality weld formation have been identified. It is demonstrated that the presence in the weld metal of low-melting intermetallic Ti\u003csub\u003e2\u003c/sub\u003eNi and eutectic Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026ndash;Tiβ increases the tendency to crack formation and leads to brittle fracture of the welded joint. Almost all specimens fractured during tensile testing in zones containing a high proportion of Ti\u003csub\u003e2\u003c/sub\u003eNi and Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026ndash;Tiβ eutectic \u0026mdash; either near the fusion lines or within the weld metal. Welded joints whose weld metal predominantly consisted of Ti\u003csub\u003e2\u003c/sub\u003eNi and Ti\u003csub\u003e2\u003c/sub\u003eNi\u0026ndash;Tiβ eutectic failed before testing or within the elastic region of the tensile curve. A high content of titanium nickelide (NiTi) in the weld metal contributes to improving the strength of the welded joint. The maximum ultimate tensile strength of the welded joint reached 384 MPa, corresponding to 95% of the ultimate tensile strength of commercially pure titanium VT1-0.\u003c/p\u003e","manuscriptTitle":"Electron beam welding of pure titanium and nickel","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-20 18:33:24","doi":"10.21203/rs.3.rs-7659950/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major Revisions Needed","date":"2025-11-23T05:58:01+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-10-07T19:09:17+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-07T09:39:23+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-23T03:42:21+00:00","index":"","fulltext":""},{"type":"submitted","content":"The International Journal of Advanced Manufacturing Technology","date":"2025-09-22T04:10:34+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"the-international-journal-of-advanced-manufacturing-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jamt","sideBox":"Learn more about [The International Journal of Advanced Manufacturing Technology](https://www.springer.com/journal/170)","snPcode":"170","submissionUrl":"https://submission.nature.com/new-submission/170/3","title":"The International Journal of Advanced Manufacturing Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ecd45bdd-75bf-4fdb-8cc2-efbfd9783efd","owner":[],"postedDate":"October 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-02-02T16:02:27+00:00","versionOfRecord":{"articleIdentity":"rs-7659950","link":"https://doi.org/10.1007/s00170-026-17497-9","journal":{"identity":"the-international-journal-of-advanced-manufacturing-technology","isVorOnly":false,"title":"The International Journal of Advanced Manufacturing Technology"},"publishedOn":"2026-01-31 15:59:30","publishedOnDateReadable":"January 31st, 2026"},"versionCreatedAt":"2025-10-20 18:33:24","video":"","vorDoi":"10.1007/s00170-026-17497-9","vorDoiUrl":"https://doi.org/10.1007/s00170-026-17497-9","workflowStages":[]},"version":"v1","identity":"rs-7659950","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7659950","identity":"rs-7659950","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}