Microstructure and mechanical properties of Ti₂Ni alloy fabricated by direct energy deposition

Abstract

It is difficult to prepare Ti2Ni alloys using traditional single-wire arc additive manufacturing. In this study, a Ti2Ni alloy wall was fabricated in situ by double-wire arc additive manufacturing with pure Ti and Ni wires, and the resulting material has the potential to be applied to spacecraft and ground armor protection. In the stable region, the Ti: Ni content ratio was close to 2:1 after stabilization, indicating that the as-built wall was very close to the designed composition (Ti2Ni). From the top of the wall to the substrate, the microstructure evolved as follows: Ti2Ni + NiTi → Ti2Ni + NiTi + α-Ti → α-Ti + Ti2Ni. In the stable region, the hardness remained stable at approximately 660 HV0.5.