采用低功率脉冲激光对0.2 mm厚的TiNi形状记忆合金/不锈钢异种材料进行焊接，对焊接接头的裂纹形态和元素分布进行了研究，分析裂纹的形成原因，提出裂纹控制的措施。结果表明，TiNi合金/不锈钢异种材料直接对接焊裂纹敏感性很大，仅通过调整激光焊接工艺参数无法避免裂纹的产生。裂纹产生的主要原因是不锈钢母材中的Fe元素大量进入焊缝，与Ti元素形成脆性金属间化合物导致焊缝变脆，在焊接应力作用下开裂。通过在TiNi合金与不锈钢之间预置纯Ni丝作为填充材料可以稀释焊缝中Fe和Ti元素的含量，对形成裂纹的脆性组织进行阻隔，避免裂纹的产生，焊接接头的平均抗拉强度达到580 MPa。

Low-power pulsed laser weld the 0.2 mm thickness of TiNi shape memory alloy /stainless steel welding dissimilar materials, the crack of the weld joint morphology and elemental distribution are studied, the reasons for crack formation are analyzed, and crack control measures are proposed. The results show that, TiNi alloy /stainless steel butt welding of dissimilar materials has large crack sensitivity. Only by adjusting the laser welding process parameters can′t avoid cracks. The main reason of cracks is the weld elements Fe, and Ti elements in the stainless steel base metal in the formation of brittle intermetallic compounds, resulting in welds brittle, cracking under sress in the weld. TiNi alloy and stainless steel by pure Ni wire between the pre-filling materials can be diluted as a weld in Fe, Ti element content, on the formation of brittle cracks organizations barrier to avoid cracks. The tensile strength of the welded joint with pure Ni wire as filler material is 580 MPa.