NiTi合金爆炸焊接试验分析

Experimental analysis of explosive welding of NiTi alloy

采用下限法,并通过设计刚性缓冲层结构,对非退火态NiTi形状记忆合金的爆炸焊接技术进行了试验研究.通过光学显微镜、SEM及EDS对焊缝的微观组织、抗剪强度和成分进行了分析.结果表明,通过改进传统爆炸焊接工艺方法,采用刚性缓冲板代替常规柔性防护层,配合刚性砧座,可实现非退火态NiTi合金的爆炸焊接特殊应用要求;爆炸焊接对基材基体组织的影响较小,仅在距焊缝100μm的过渡区内,有一定的晶粒细化.化学成分分布比较均匀,且基本接近基材成分,这对保持NiTi合金的形状记忆功能具有重要意义.

The explosive welding technology for unannealed NiTi shape memory alloy is studied by means of the lower limit method and the design of structure of rigid buffering layer.The chemical composition and structure of welding materials are analyzed with optical microscopy,scanning electron microscope and energy disperse spectroscopy.The results show that the explosive welding of unannealed NiTi shape memory alloy is possible by replacing the flexible buffering layer with the rigid buffering layer and using rigid anvil.The explosive welding has little effect on the chemical composition of welding materials,only a few grain refinement in transition region which is 100 μm from the weld joint.The chemical compositions of the weld joint and the base material are basic identical.It has an important significance that keeps the shape memory function of the NiTi alloy.