关键词: NiTi形状记忆合金, 激光焊接, 金属间化合物, 力学性能

Abstract: The laser welding of NiTi shape memory alloy with dissimilar materials（stainless steel and titanium alloy） in recent years is summarized and analyzed. Due to the great difference in chemical composition of materials, brittle intermetallic compounds easily generated in joints of direct laser welding. Which led to serious deterioration of mechanical properties and limited the application of heterogeneous materials. At home and abroad, the methods to optimize the mechanical properties of laser welded joints of NiTi shape memory alloy and dissimilar materials mainly included adding intermediate layer and laser bias. Their common point was that they can reduce the generation of brittle intermetallic compounds. The difference is that the method of adding intermediate layer can inhibit the generation of intermetallic compounds while introducing new intermetallic compounds into the weld. The mechanical properties of the joint depended on the brittleness of the new intermetallic compounds, and the mechanical properties of the joint are better if the brittleness is lower. In addition, the amount of intermediate layer should not be too much, otherwise it will deteriorate the mechanical properties. For laser bias welding, the position and distance of laser offset are very important. The advantage of this method is that filling materials can be saved, but the assembly accuracy is high. Compared with the laser bias method, the mechanical properties of the joint are better by adding an intermediate layer. In addition to the above two methods, post-weld heat treatment can also improve the mechanical properties of joints. Finally, the possible future research direction of laser welding between NiTi shape memory alloy and dissimilar materials is proposed to provide reference for subsequent research.

Key words: Ni Ti shape memory alloy, laser welding, intermetallic compound, mechanical properties