由于TiNi合金与钛合金的物理和化学性能差异较大，故其焊接性较差，焊缝区易形成大量的金属间化合物并产生裂纹。为实现上述材料的良好连接、提高接头性能，本文对采用激光焊连接0.2 mm厚TiNi形状记忆合金和TC4钛合金异种材料进行了探索。分别采用直接对接焊和手工填丝焊的方法，研究了焊接接头的微观组织和力学性能。结果表明，直接对接焊时焊缝中心产生了纵向裂纹；手工填丝焊则通过合适的焊接工艺，改善了焊缝成形，避免了裂纹的产生。较优的焊接工艺参数为功率百分比18%、脉冲宽度3 ms、脉冲频率3 Hz；在界面区，Ni与TC4形成的过渡层宽度约为2 μm，Ni与TiNi形成的过渡层宽度约为0.5 μm。接头最大抗拉强度为332 MPa，断裂位置发生在靠近TiNi侧的熔合线附近。

The physical and chemistry properties of TiNi shape memory alloy and TC4 titanium alloy are quite different, so the weldability is poor and a number of intermetallic compounds and cracks will produce in the weld seam. To achieve good joining of TiNi shape memory alloy and TC4 titanium alloy and improve the welded joint properties, this paper explores the micro laser welding of dissimilar materials between TiNi shape memory alloy and titanium alloy. The butt welding method and manual welding filler wire method are carried out for 0.2 mm thick TiNi shape memory alloy and TC4 titanium alloy to obtain the microstructure and mechanical properties. The results show that longitudinal cracks are brought out in butt welding, however, the appropriate welding process for manual welding filler wire improves weld forming and avoids cracks. The optimum welding parameters are the power percentage 8%, pulse width of 3 ms, and the pulse frequency of 3 Hz. Moreover, the transition width formed by Ni and TC4 is about 2 μm, and that formed by Ni and TiNi is about 0.5 μm. In the combined surface,transition is relatively weak link connector, the hardness is up to 650 HV with the maximum tensile strength of 332 MPa, and the fracture location occurs near TiNi side by the fusion line.