Microstructure and properties of a shape memory alloy Ti-Ni-Al-V fabricated by double-wire arc additive manufacturing

In this study, a novel heterogeneous double-wire arc additive manufacturing method was used for the in-situ synthesis of a novel Ti-Ni-Al-V alloy wall. The results indicated that the synthesis wall was composed of the NiTi2, B-2, and Ni4Ti3 phases from the bottom to the top. With an increase in deposition layers, the Ti2Ni content decreased. The hardness at the bottom was similar to 685.4 HV0.2, while that of the middle and stable regions was 553 HV0.2. The maximum compressive strength was 2100 MPa. The fracture morphology was brittle. After cyclic compression, the recoverable and unrecoverable strains were 4.79 % and 1.21 %, respectively, indicating excellent recovery characteristics.