Effect of Cold Metal Transfer Parameters during Wire Arc Additive Manufacturing of Ti6Al4V Multi-layer Walls

Abstract This study analyzed the effect of process parameters on Ti6Al4V thin walls additively manufactured by cold metal transfer (CMT). An experimental procedure methodology was stablished to develop the process parameters with the most significance on the morphological aspects of the deposits. The maximum working temperature for Ti6Al4V multilayer deposits was defined using differential scanning calorimetry. A difference of 100°C was found between the maximum working temperature of the substrate plate and that of the deposited wall. The experimental results showed overheating above 450°C, which is the maximum recommended working temperature for Ti6Al4V, in the four previous layers during processing. The aspect ratio and metallurgical dilution were compared between single and multi-layer deposits; values of 1.5 and 20%, respectively, were ideal for obtaining continuous thin walls. Furthermore, a continuity factor along the construction walls was defined by 3D measurements, as 1.9 taking into account all deposited layers. In addition, it was observed that the oxygen concentration on the walls rises with increasing power regardless the interpass time used. Finally, microhardness measurements values showed more dispersion as the heat input increased.