Effects of Deposition Current on the Microstructure and Pseudoelasticity of Wire-Arc Additively Manufactured Ni-rich NiTi Alloys

The evolution of microstructure, phase transformation, nanohardness, and pseudoelasticity of a Ni-rich NiTi alloy in-situ processed by wire arc additive manufacturing (WAAM) with different deposition current was assessed. As the deposition current increased, the size of the B2 grains and Ni4Ti3 precipitates coarsened and the characteristic phase transformation temperatures increased. Furthermore, by increasing the deposition current, the nanohardness decreased while the pseudoelastic recovery of the matrix improved to some extent. These findings can be used to further optimize the process of fabricating NiTi alloys by WAAM with acceptable microstructure and mechanical response.