Functional behaviour of a NiTi-welded joint: Two-way shape memory effect

The functional behaviour of NiTi-welded joints was investigated. In particular, the influence of Nd:YAG laser welding on the two-way shape memory effect (TWSME) of a Ni–51 at.% Ti alloy was analyzed through a systematic comparison between welded and unwelded materials. The TWSME was induced through a proper training procedure, which consists of the repetition of several thermo-mechanical cycles, and its characteristic hysteretic behaviour, strain versus temperature, was recorded. The effects of the number of cycles and plastic strain, which develop during the training process, were also investigated. The results show that the TWSME is partially preserved in the welded material, however, higher values of plastic strain with respect to the unwelded material, are observed.