Microstructure and mechanical property optimization of NiTi shape memory alloys fabricated by wire arc additive manufacturing with post-processing laser shock peening

NiTi shape memory alloys (SMAs) are widely used in biomedical and aerospace fields. Wire arc additive manufacturing (WAAM) provides an efficient route for fabricating NiTi components, but the process is prone to defects such as coarse grains, residual stress accumulation, and insufficient fatigue performance. In this study, the as-built WAAM-fabricated NiTi SMA was solution-treated at 950 °C for 2 hours and aged at 450 °C for 2 hours, promoting the formation of Ni 4 Ti 3 precipitates and improvi