Microstructure evolution and mechanical properties of cold metal transfer additive manufactured Ti-6Al-4V wall with trace MoSi₂ addition

The effects of trace MoSi2 addition on the microstructure evolution, mechanical properties and fracture behavior of Ti-6Al-4V wall via cold metal transfer additive manufacturing (CMTAM) were investigated. After the addition of trace MoSi2 powder, trace (beta-Ti, Mo) phase and SiO2 particles were obtained and partly prior-beta ->alpha' phase transformation was suppressed. Compared with the as-built Ti-6Al-4V wall, the prior-beta grains changed from columnar to the equiaxed or near-equiaxed after the addition of trace MoSi2. The tensile analysis result revealed that the addition of trace MoSi2 could improve the average strain while reduce anisotropy. All specimens showed dimples corresponding to ductile failure mode. The possible thermal cycles for the trace-MoSi2-addition speci-mens during the CMTAM process were analyzed.