以纯镍丝为填充材料，采用精密脉冲激光实现了厚度为0.2 mm的TiNi形状记忆合金/不锈钢异种材料的焊接，研究了熔化区（焊缝和熔合区）的组织形貌和微观结构。结果表明，焊缝中心晶粒呈外延连续生长的特征。连续生长的枝晶可以跨越3~5个脉冲激光形成的鱼鳞纹，长度可以达到约200 μm。焊缝与两侧母材的熔合区呈现完全不同的形貌，在不锈钢母材与焊缝的接合界面，枝晶沿着不锈钢母材的熔合线生长，在枝晶间有二次晶轴；在TiNi合金与焊缝的熔合区，有一层宽度约为5 μm的过渡层将焊缝与母材隔开。

Pure nickel wire is added into the butt joint of 0.2 mm thick TiNi alloy/stainless steel, and they are welded by pulsed laser. The morphological image and the interface microstructures of the fusion area are investigated. The results show that the characteristics of the welded joint center is extension of the continuous growth grain. The length of the fern-leaf crystal can reach about 200 μm which may span several fish-scales lines formed by pulsed laser. The morphological image of welded joint with both sides of base material fusion is completely different. In the joint interface of stainless steel base material, the branch crystal grows along fusion line of stainless steel base material, and there have second crystal axis between the branch crystals. In the fusion area between TiNi alloy and welded joint, there is a transition layer between TiNi alloy and welded joint, whose width is about 5 μm.