Assessment on heat treatment and machinability of DMLS-processed Ti64 alloy

The titanium alloy is developed through the direct metal laser sintering (DMLS) process to study the metallurgical quality, mechanical properties and machinability of the material. The titanium with aluminum and vanadium powder is used to develop the DMLS Ti64 alloy. To enhance the metallurgical quality, heat treatment plan is proposed. The DMLS Ti64 alloys are heat-treated for double aging process (720° and 620°) and their performance is compared with as-built DMLS Ti64 alloy. The results are surprising to infer that the heat-treated DMLS Ti64 alloy has metallurgical phase transformation in terms of grain refinement. The transformation of thin α-grain to a thick elongated is due to double aging process. Mechanical strength found increase to 965 MPa from 955 MPa for as-built DMLS Ti64 alloy. In terms of density and hardness for heat-treated DMLS Ti64 alloy, these are better when compared to the as-built DMLS Ti64 alloy. Further, the impact of heat-treated DMLS alloy with as-built DMLS alloy is studied with wire electro-spark machining process to identify the best process conditions.