Research Progress of NiTi Shape Memory Alloy Laser Welding

Abstract

NiTi shape memory alloys have been widely used in biomedical, aerospace and automotive fields due to their shape memory effect, superelasticity, good corrosion resistance and biocompatibility. Laser welding is one of the most important technologies in the field of material connection, and its application in NiTi shape memory alloys has attracted wide attention in recent years. The research progress on the microstructure, mechanical properties, corrosion resistance and biocompatibility of NiTi shape memory alloy laser welded joints at home and abroad is summarized and analyzed in detail. Meanwhile, the measures and mechanism of how to improve the quality of NiTi shape memory alloy laser welding are also analyzed. The evaporation of nickel in fusion zone and the precipitation of nickel-containing intermetallic in heat-affected zone are the basic reasons for the quality reduction of welded joints during laser welding. Although the quality of welded joints can be improved by process control, weld alloying or post-weld heat treatment, there is still room and demand for further improvement from the present results. Finally, the possible future research directions of laser welding of NiTi shape memory alloys are given based on the current research progress and the practical work of the research group in order to provide some reference for the follow-up research.