Fabrication and Characterization of Al3003–Cu Functionally Graded Material Using Pre-Placed Powder Laser Processing

Fabrication and Characterization of Al3003–Cu Functionally Graded Material Using Pre-Placed Powder Laser Processing | 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 Fabrication and Characterization of Al3003–Cu Functionally Graded Material Using Pre-Placed Powder Laser Processing Yasika R, Vishnu Anandan, Jaisurya S, Harshinni S, Sohini Chowdhury, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9399300/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Functionally graded materials (FGMs) enable spatial variation of properties within a single component, making them suitable for tribological and structural applications. In this study, a five-layer Al3003–Cu FGMMC was fabricated using a pre-placed powder method followed by controlled laser scanning. Unlike conventional powder-fed additive manufacturing methods, this approach allows precise compositional control with minimum powder wastage, improving process efficiency and sustainability. The composition was gradually varied from Al - rich substrate layers to Cu-rich layers at the surface to achieve a tailored property gradient. Microstructural analysis confirmed gradual compositional transition and the formation of intermetallic phases across layers. Mechanical and tribological results indicated reduced tensile strength due to intermetallic phase development, along with a lower coefficient of friction in Cu-rich layers. These results highlight the effectiveness of the laser-assisted pre-placed powder technique for sustainable fabrication of Al–Cu FGMs. Functionally graded materials (FGMs) Al3003–Cu FGMMC Pre-placed powder technique Laser scanning Microstructural characterization Tribological behaviour Figures Figure 1 Figure 2 Figure 3 1. Introduction Functionally graded materials (FGMs) are engineered materials with gradual variation in composition and microstructure, enabling spatial control of mechanical, thermal, and tribological properties. This eliminates abrupt interfaces encountered in conventional composites, reducing thermal mismatch, stress concentration, and structural failure. Due to these advantages, FGMs have gained significant interest in aerospace, automotive, energy, and electronics applications for improved structural performance [ 1 – 3 ]. Amongst various material systems, aluminium–copper (Al–Cu) alloy combinations have gained interest due to their complementary physical and mechanical properties. Aluminium offers low density, excellent corrosion resistance, and good formability, while copper provides high thermal and electrical conductivity along with improved wear resistance. The graded architecture enables lightweight components with enhanced surface functionality. Previous studies have explored Al–Cu FGMs using powder metallurgy, hot pressing, and spark plasma sintering [ 4 – 6 ]. Conventional fabrication approaches are limited due to poor compositional control, longer processing times, and interfacial defects [ 7 – 9 ]. Recently, laser-based fabrication techniques have emerged as promising approaches due to precise microstructural control and rapid solidification. However, most studies focus on laser-assisted powder-fed methods, which involve high powder wastage and complex process control [ 10 – 12 ]. Therefore, alternative laser-based fabrication strategies with improved material utilization and simpler processing are of interest. Pre-placed powder laser scanning offers a promising route with reduced powder loss and better composition control. Despite recent advances in laser processing, studies on multi-layer Al3003-Cu FGMs using technique are absent [ 13 – 15 ]. In this study, a pre-placed powder laser scanning strategy is used to fabricate a five-layer Al3003–Cu FGMMC where the microstructural, mechanical, and tribological behaviour is analysed to evaluate its effectiveness. 2. Experimental Methodology The processing conditions for the development of FGM component are presented in Table 1 . The Al/Cu FGMMC was fabricated using Laser Directed Energy Deposition (L-DED), as shown in Fig. 1 (a). The composite was developed through layer-wise deposition of pre-placed Al/Cu slurry on an AA1100 substrate with increasing Cu content. A slurry-based pre-placement method was used to deposit five layers as shown in Fig. 1 (b). In this method, polyvinyl alcohol (PVA) solution was mixed with composite powders in a 3:1 ratio and deposited on the substrate to a thickness of 0.5–0.7 mm. This approach ensures near-complete material utilization with minimal powder loss. Each layer was oven-dried at 160°C for 20 minutes to remove binders and moisture. Table 1 Processing parameters for FGM development. Parameter Specification Laser Source 2 kW Ytterbium-Doped Fiber Laser Laser Mode Continuous Wave (CW) Beam Diameter 1.5 mm Wavelength 1080 nm Fiber Core Diameter 0.50 mm Shielding and Carrier Gas Flow Rate 12 LPM The laser scanning was performed at an optimized condition of 1000 W power and 10 mm/s scanning speed for each deposited layer, providing high linear energy density to ensure adequate thermal energy input for complete melting and metallurgical bonding. Figure 1 (c) illustrates the deposited FGMMC layer that exhibits uniform bead geometry with proper track overlap, indicating stable melt pool formation and sound metallurgical bonding without visible macro-defects. Figure 1 (d) represents the pyrometer-recorded average temperatures across the graded layers, measured as 1169°C, 830°C, 718°C, 1025°C, and 500°C for the 1st to 5th layers, respectively, indicating compositional variation and controlled thermal input during graded fabrication. 3. Results and Discussion Figure 2 shows the microstructural evolution of Al3003–Cu FGMMC with increasing Cu content (20–80 wt.%). In Fig. 2 (a) (80 wt.% Al3003–20 wt.% Cu), microstructure is dominated by a continuous α–Al3003 matrix with finely dispersed Al₂Cu intermetallic particles, indicating limited intermetallic formation at low Cu content. In Fig. 2 (b) (60 wt.% Al3003–40 wt.% Cu), the fraction and size of Al₂Cu particles increase with transition zones and localized Cu-rich regions, suggesting enhanced interdiffusion and partial segregation during solidification. In Fig. 2 (c) (40 wt.% Al3003–60 wt.% Cu), the microstructure becomes intermetallic–dominated with a reduced α–matrix and more interconnected submicron features indicating rapid solidification. In Fig. 2 (d) (20 wt.% 3003–80 wt.% Cu), the microstructure is primarily Cu-rich intermetallic with minimal α–phase, indicating Cu-dominated solidification. Overall, a systematic transition from Al-rich matrix with dispersed intermetallics to a Cu-rich intermetallic-dominated structure confirms successful composition grading and strong interlayer bonding. Figure 3 (c) displays the coefficient of friction (CoF) versus sliding time. It is observed that FGMMC has a lower and more stable value of CoF in comparison with AA1100 substrate, indicating improved wear resistance. This reduction is attributed to the presence of hard intermetallic phases that enhance hardness of FGMMC. Also, the thermal responses during laser scanning are presented in Fig. 3 (d). The peak temperature declines from first layer to fourth layer, representing variation in thermal absorption and conductivity with composition. This controlled thermal gradient promotes stable melt pool behaviour and effective metallurgical bonding during fabrication. Overall, results demonstrate that FGMMC exhibits enhanced hardness and wear resistance at the expense of ductility, with a well-defined thermal and compositional gradient. 4. Conclusions The present study demonstrates the feasibility of fabricating a five-layer Al3003-Cu FGMMC using a laser-assisted pre-placed powder process. This process enables accurate compositional control, near-complete material utilization and strong metallurgical bonding, thus overcoming limitations of conventional powder-fed processes. Microstructural analysis shows s smooth transition of Al3003-rich matrix to Cu-rich intermetallic- structure, confirming successful gradient formation. The composite exhibits improved hardness and tribological performance, particularly in Cu-rich layers while reduced tensile strength due to intermetallics indicates a trade-off for applications demanding superior surface durability. Overall, the study highlights the effectiveness of this approach for sustainable and efficient fabrication of FGMs. Declarations Author Contribution Yasika R: Experimentation, analysis, preparation of figures, Manuscript reviewingVishnu Anandan: Experimentation, analysis, preparation of figures, Manuscript reviewingJaisurya S: Experimentation, analysis, preparation of figuresHarshinni S: Experimentation, analysisSohini Chowdhury: Supervision, conceptualization, original manuscript writingA. Suresh Babu: ResourcesN. Arunachalam: Resources, supervision Acknowledgement The authors gratefully acknowledge Mr. Selvakumaram, Senior Head Lab Technician, Central Workshop for his dedicated technical support and valuable assistance during the experimental investigations. The authors further express sincere appreciation to the Department of Mechanical Engineering, Indian Institute of Technology Madras, and the Department of Manufacturing Engineering, College of Engineering Guindy (CEG), Anna University, Chennai, for providing access to laboratory facilities and characterization infrastructure essential for the completion of this research. References Liu Y, Yang Y, Wang D (2020) A review on additive manufacturing of functionally graded materials. Mater Design, 188, Art. 108358. Bandyopadhyay A, Bose S (2019) Additive manufacturing of functionally graded materials. Additive Manuf 28:1–20 Niendorf M, Niendorf T (2019) Functionally graded materials produced by additive manufacturing. Mater Sci Eng A, 764, Art. 138209. Zhang H, Liu L, Shen J (2019) Microstructure and mechanical properties of Al–Cu gradient materials fabricated by powder metallurgy. J Alloys Compd 792:1155–1163 Wang X, Zhang Z, Li Y (2019) Microstructural evolution and mechanical performance of Al–Cu functionally graded materials. Mater Sci Eng A 754:483–491 Chen Y, Zhao H, Wang J (2020) Interfacial reactions and microstructural evolution in Al3003–Cu dissimilar metal systems. Acta Mater 199:1–12 Li J, Liu Y, Wang Z (2019) Fabrication of Al–Cu graded materials by spark plasma sintering and their mechanical properties. J Alloys Compd 806:1520–1528 Kumar S, Bandyopadhyay A, Bose S (2020) Powder metallurgy processing of functionally graded materials: A review. J Mater Process Technol, 275, Art. 116380. Gupta R, Kumar A (2020) Fabrication of metal–metal functionally graded materials using powder metallurgy techniques, Materials Today: Proceedings , vol. 26, pp. 2205–2210 Mazumder J, Dutta D, Pinkerton A (2020) Laser directed energy deposition for additive manufacturing of graded materials. CIRP Ann 69(2):589–612 Guo S, Wang Z, Chen X (2020) Additive manufacturing of functionally graded metallic materials using laser directed energy deposition. Additive Manuf, 36, Art. 101556. Debroy H et al (2021) Additive manufacturing of metallic components – Process, structure and properties. Prog Mater Sci, 117, Art. 100741. Liu L, Zhang H, Liu Y (2020) Laser processing of Al–Cu dissimilar materials: Microstructure and mechanical properties. Surf Coat Technol, 403, Art. 126375. Zhao Y, Chen X, Zhang J (2021) Microstructural evolution in Al–Cu gradient materials fabricated by laser additive manufacturing. J Mater Process Technol, 298, Art. 117303. Singh M, Kumar R, Singh PK (2022) Laser-based fabrication of functionally graded metallic structures: A review. Opt Laser Technol, 149, Art. 107865. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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-9399300","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":633560836,"identity":"7fa9f137-ac49-4296-bdc1-208d8062f980","order_by":0,"name":"Yasika R","email":"","orcid":"","institution":"Anna University, Chennai","correspondingAuthor":false,"prefix":"","firstName":"Yasika","middleName":"","lastName":"R","suffix":""},{"id":633560837,"identity":"8e122d68-e981-4cdb-9181-9a942f821fa9","order_by":1,"name":"Vishnu Anandan","email":"","orcid":"","institution":"Anna University, Chennai","correspondingAuthor":false,"prefix":"","firstName":"Vishnu","middleName":"","lastName":"Anandan","suffix":""},{"id":633560839,"identity":"62e913d6-c9b1-443b-9c03-e7fa37a8b34f","order_by":2,"name":"Jaisurya S","email":"","orcid":"","institution":"Anna University, Chennai","correspondingAuthor":false,"prefix":"","firstName":"Jaisurya","middleName":"","lastName":"S","suffix":""},{"id":633560841,"identity":"6b89677c-7d66-431b-80e8-308033d7a430","order_by":3,"name":"Harshinni S","email":"","orcid":"","institution":"Anna University, Chennai","correspondingAuthor":false,"prefix":"","firstName":"Harshinni","middleName":"","lastName":"S","suffix":""},{"id":633560843,"identity":"77943b76-6660-4d52-ab46-0e7b2f07af39","order_by":4,"name":"Sohini Chowdhury","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuklEQVRIiWNgGAWjYHACwwdAggfKkSBKi7EBWAsbCVrMIMrYiHWVfPvhbdUFFfdk5Oc3MH74wWCRR1CLwZm0stszzhTzGBxjYJbsYZAoJqxFgsfsNm9bAo8B0GHSQL8kNhB02Awes2Lefwk88m0MzL+J0sJwg8eMmbchgYfhGAMbcbYA/VIszXMM6LBjiW2WPQbEOKz98MbPPDUJ9vLNhw/f+FFRR4TDEIARqNiABPWjYBSMglEwCnADALDEL+9iO2+7AAAAAElFTkSuQmCC","orcid":"","institution":"North Eastern Regional Institute of Science and Technology","correspondingAuthor":true,"prefix":"","firstName":"Sohini","middleName":"","lastName":"Chowdhury","suffix":""},{"id":633560847,"identity":"ffff5692-5ad8-4556-9161-daed72dd9585","order_by":5,"name":"Suresh Babu A.","email":"","orcid":"","institution":"Anna University, Chennai","correspondingAuthor":false,"prefix":"","firstName":"Suresh","middleName":"Babu","lastName":"A.","suffix":""},{"id":633560848,"identity":"46ad9ed3-37d5-4d2c-b727-a1ee0e6e1f5e","order_by":6,"name":"Arunachalam N.","email":"","orcid":"","institution":"Indian Institute of Technology Madras","correspondingAuthor":false,"prefix":"","firstName":"Arunachalam","middleName":"","lastName":"N.","suffix":""}],"badges":[],"createdAt":"2026-04-13 06:08:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9399300/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9399300/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108446638,"identity":"a8c4653b-53c9-411d-b833-ce88c284d4ed","added_by":"auto","created_at":"2026-05-04 18:03:13","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":336344,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Schematic of laser-assisted fabrication and pyrometric monitoring of Al3003/Cu FGMMC; (b) powder preparation; (c) printed layer; and (d) layer-wise average temperature variation.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9399300/v1/2515aa6ccf5343fec7cdf2c7.png"},{"id":108493276,"identity":"f9443a9c-3a64-4dd1-8511-7831a144cc63","added_by":"auto","created_at":"2026-05-05 09:59:50","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":475267,"visible":true,"origin":"","legend":"\u003cp\u003eMicrostructures of Al3003–Cu FGMMC at different compositions: (a) 80 wt.% 3003–20 wt.% Cu, (b) 60 wt.% 3003–40 wt.% Cu, (c) 40 wt.% 3003–60 wt.% Cu, and (d) 20 wt.% 3003–80 wt.% Cu.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9399300/v1/2bd5c780f17124b067be77c8.png"},{"id":108446640,"identity":"c89c3c5b-b235-41a7-a80d-c4f5723a2103","added_by":"auto","created_at":"2026-05-04 18:03:13","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":285352,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Stress–strain behaviour of AA1100 substrate and FGMMC specimens; (b) microhardness variation across graded layers; (c) coefficient of friction versus sliding time; (d) layer-wise temperature distribution during laser processing.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9399300/v1/749f7244903d1b2a835a7a48.png"},{"id":108494714,"identity":"4d981903-adf6-4f29-a55c-73d74cff6fc5","added_by":"auto","created_at":"2026-05-05 10:06:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1124562,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9399300/v1/ee978b63-b6c5-4f0d-b26b-b990c56a8b2c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Fabrication and Characterization of Al3003–Cu Functionally Graded Material Using Pre-Placed Powder Laser Processing","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eFunctionally graded materials (FGMs) are engineered materials with gradual variation in composition and microstructure, enabling spatial control of mechanical, thermal, and tribological properties. This eliminates abrupt interfaces encountered in conventional composites, reducing thermal mismatch, stress concentration, and structural failure. Due to these advantages, FGMs have gained significant interest in aerospace, automotive, energy, and electronics applications for improved structural performance [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Amongst various material systems, aluminium\u0026ndash;copper (Al\u0026ndash;Cu) alloy combinations have gained interest due to their complementary physical and mechanical properties. Aluminium offers low density, excellent corrosion resistance, and good formability, while copper provides high thermal and electrical conductivity along with improved wear resistance. The graded architecture enables lightweight components with enhanced surface functionality. Previous studies have explored Al\u0026ndash;Cu FGMs using powder metallurgy, hot pressing, and spark plasma sintering [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eConventional fabrication approaches are limited due to poor compositional control, longer processing times, and interfacial defects [\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Recently, laser-based fabrication techniques have emerged as promising approaches due to precise microstructural control and rapid solidification. However, most studies focus on laser-assisted powder-fed methods, which involve high powder wastage and complex process control [\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTherefore, alternative laser-based fabrication strategies with improved material utilization and simpler processing are of interest. Pre-placed powder laser scanning offers a promising route with reduced powder loss and better composition control. Despite recent advances in laser processing, studies on multi-layer Al3003-Cu FGMs using technique are absent [\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In this study, a pre-placed powder laser scanning strategy is used to fabricate a five-layer Al3003\u0026ndash;Cu FGMMC where the microstructural, mechanical, and tribological behaviour is analysed to evaluate its effectiveness.\u003c/p\u003e"},{"header":"2. Experimental Methodology","content":"\u003cp\u003eThe processing conditions for the development of FGM component are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The Al/Cu FGMMC was fabricated using Laser Directed Energy Deposition (L-DED), as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(a). The composite was developed through layer-wise deposition of pre-placed Al/Cu slurry on an AA1100 substrate with increasing Cu content. A slurry-based pre-placement method was used to deposit five layers as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(b). In this method, polyvinyl alcohol (PVA) solution was mixed with composite powders in a 3:1 ratio and deposited on the substrate to a thickness of 0.5\u0026ndash;0.7 mm. This approach ensures near-complete material utilization with minimal powder loss. Each layer was oven-dried at 160\u0026deg;C for 20 minutes to remove binders and moisture.\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\u003eProcessing parameters for FGM development.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSpecification\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLaser Source\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 kW Ytterbium-Doped Fiber Laser\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLaser Mode\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eContinuous Wave (CW)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBeam Diameter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.5 mm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWavelength\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1080 nm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFiber Core Diameter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.50 mm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eShielding and Carrier Gas Flow Rate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 LPM\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\u003eThe laser scanning was performed at an optimized condition of 1000 W power and 10 mm/s scanning speed for each deposited layer, providing high linear energy density to ensure adequate thermal energy input for complete melting and metallurgical bonding. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(c) illustrates the deposited FGMMC layer that exhibits uniform bead geometry with proper track overlap, indicating stable melt pool formation and sound metallurgical bonding without visible macro-defects. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(d) represents the pyrometer-recorded average temperatures across the graded layers, measured as 1169\u0026deg;C, 830\u0026deg;C, 718\u0026deg;C, 1025\u0026deg;C, and 500\u0026deg;C for the 1st to 5th layers, respectively, indicating compositional variation and controlled thermal input during graded fabrication.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"3. Results and Discussion","content":"\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the microstructural evolution of Al3003\u0026ndash;Cu FGMMC with increasing Cu content (20\u0026ndash;80 wt.%). In Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a) (80 wt.% Al3003\u0026ndash;20 wt.% Cu), microstructure is dominated by a continuous α\u0026ndash;Al3003 matrix with finely dispersed Al₂Cu intermetallic particles, indicating limited intermetallic formation at low Cu content. In Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(b) (60 wt.% Al3003\u0026ndash;40 wt.% Cu), the fraction and size of Al₂Cu particles increase with transition zones and localized Cu-rich regions, suggesting enhanced interdiffusion and partial segregation during solidification. In Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(c) (40 wt.% Al3003\u0026ndash;60 wt.% Cu), the microstructure becomes intermetallic\u0026ndash;dominated with a reduced α\u0026ndash;matrix and more interconnected submicron features indicating rapid solidification. In Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(d) (20 wt.% 3003\u0026ndash;80 wt.% Cu), the microstructure is primarily Cu-rich intermetallic with minimal α\u0026ndash;phase, indicating Cu-dominated solidification. Overall, a systematic transition from Al-rich matrix with dispersed intermetallics to a Cu-rich intermetallic-dominated structure confirms successful composition grading and strong interlayer bonding.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(c) displays the coefficient of friction (CoF) versus sliding time. It is observed that FGMMC has a lower and more stable value of CoF in comparison with AA1100 substrate, indicating improved wear resistance. This reduction is attributed to the presence of hard intermetallic phases that enhance hardness of FGMMC. Also, the thermal responses during laser scanning are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(d). The peak temperature declines from first layer to fourth layer, representing variation in thermal absorption and conductivity with composition. This controlled thermal gradient promotes stable melt pool behaviour and effective metallurgical bonding during fabrication. Overall, results demonstrate that FGMMC exhibits enhanced hardness and wear resistance at the expense of ductility, with a well-defined thermal and compositional gradient.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eThe present study demonstrates the feasibility of fabricating a five-layer Al3003-Cu FGMMC using a laser-assisted pre-placed powder process. This process enables accurate compositional control, near-complete material utilization and strong metallurgical bonding, thus overcoming limitations of conventional powder-fed processes. Microstructural analysis shows s smooth transition of Al3003-rich matrix to Cu-rich intermetallic- structure, confirming successful gradient formation. The composite exhibits improved hardness and tribological performance, particularly in Cu-rich layers while reduced tensile strength due to intermetallics indicates a trade-off for applications demanding superior surface durability. Overall, the study highlights the effectiveness of this approach for sustainable and efficient fabrication of FGMs.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eYasika R: Experimentation, analysis, preparation of figures, Manuscript reviewingVishnu Anandan: Experimentation, analysis, preparation of figures, Manuscript reviewingJaisurya S: Experimentation, analysis, preparation of figuresHarshinni S: Experimentation, analysisSohini Chowdhury: Supervision, conceptualization, original manuscript writingA. Suresh Babu: ResourcesN. Arunachalam: Resources, supervision\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors gratefully acknowledge Mr. Selvakumaram, Senior Head Lab Technician, Central Workshop for his dedicated technical support and valuable assistance during the experimental investigations. The authors further express sincere appreciation to the Department of Mechanical Engineering, Indian Institute of Technology Madras, and the Department of Manufacturing Engineering, College of Engineering Guindy (CEG), Anna University, Chennai, for providing access to laboratory facilities and characterization infrastructure essential for the completion of this research.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLiu Y, Yang Y, Wang D (2020) A review on additive manufacturing of functionally graded materials. Mater Design, 188, Art. 108358.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBandyopadhyay A, Bose S (2019) Additive manufacturing of functionally graded materials. Additive Manuf 28:1\u0026ndash;20\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNiendorf M, Niendorf T (2019) Functionally graded materials produced by additive manufacturing. Mater Sci Eng A, 764, Art. 138209.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang H, Liu L, Shen J (2019) Microstructure and mechanical properties of Al\u0026ndash;Cu gradient materials fabricated by powder metallurgy. J Alloys Compd 792:1155\u0026ndash;1163\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang X, Zhang Z, Li Y (2019) Microstructural evolution and mechanical performance of Al\u0026ndash;Cu functionally graded materials. Mater Sci Eng A 754:483\u0026ndash;491\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen Y, Zhao H, Wang J (2020) Interfacial reactions and microstructural evolution in Al3003\u0026ndash;Cu dissimilar metal systems. Acta Mater 199:1\u0026ndash;12\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi J, Liu Y, Wang Z (2019) Fabrication of Al\u0026ndash;Cu graded materials by spark plasma sintering and their mechanical properties. J Alloys Compd 806:1520\u0026ndash;1528\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKumar S, Bandyopadhyay A, Bose S (2020) Powder metallurgy processing of functionally graded materials: A review. J Mater Process Technol, 275, Art. 116380.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGupta R, Kumar A (2020) Fabrication of metal\u0026ndash;metal functionally graded materials using powder metallurgy techniques, \u003cem\u003eMaterials Today: Proceedings\u003c/em\u003e, vol. 26, pp. 2205\u0026ndash;2210\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMazumder J, Dutta D, Pinkerton A (2020) Laser directed energy deposition for additive manufacturing of graded materials. CIRP Ann 69(2):589\u0026ndash;612\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuo S, Wang Z, Chen X (2020) Additive manufacturing of functionally graded metallic materials using laser directed energy deposition. Additive Manuf, 36, Art. 101556.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDebroy H et al (2021) Additive manufacturing of metallic components \u0026ndash; Process, structure and properties. Prog Mater Sci, 117, Art. 100741.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu L, Zhang H, Liu Y (2020) Laser processing of Al\u0026ndash;Cu dissimilar materials: Microstructure and mechanical properties. Surf Coat Technol, 403, Art. 126375.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao Y, Chen X, Zhang J (2021) Microstructural evolution in Al\u0026ndash;Cu gradient materials fabricated by laser additive manufacturing. J Mater Process Technol, 298, Art. 117303.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSingh M, Kumar R, Singh PK (2022) Laser-based fabrication of functionally graded metallic structures: A review. Opt Laser Technol, 149, Art. 107865.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Functionally graded materials (FGMs), Al3003–Cu FGMMC, Pre-placed powder technique, Laser scanning, Microstructural characterization, Tribological behaviour","lastPublishedDoi":"10.21203/rs.3.rs-9399300/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9399300/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eFunctionally graded materials (FGMs) enable spatial variation of properties within a single component, making them suitable for tribological and structural applications. In this study, a five-layer Al3003\u0026ndash;Cu FGMMC was fabricated using a pre-placed powder method followed by controlled laser scanning. Unlike conventional powder-fed additive manufacturing methods, this approach allows precise compositional control with minimum powder wastage, improving process efficiency and sustainability. The composition was gradually varied from Al\u003cb\u003e-\u003c/b\u003erich substrate layers to Cu-rich layers at the surface to achieve a tailored property gradient. Microstructural analysis confirmed gradual compositional transition and the formation of intermetallic phases across layers. Mechanical and tribological results indicated reduced tensile strength due to intermetallic phase development, along with a lower coefficient of friction in Cu-rich layers. These results highlight the effectiveness of the laser-assisted pre-placed powder technique for sustainable fabrication of Al\u0026ndash;Cu FGMs.\u003c/p\u003e","manuscriptTitle":"Fabrication and Characterization of Al3003–Cu Functionally Graded Material Using Pre-Placed Powder Laser Processing","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-04 18:03:05","doi":"10.21203/rs.3.rs-9399300/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"bebd6d2c-7bc0-4ba9-9d70-0c85326da319","owner":[],"postedDate":"May 4th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-04T18:03:05+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-04 18:03:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9399300","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9399300","identity":"rs-9399300","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}