采用激光冲击强化技术对初始相为奥氏体的NiTi形状记忆合金进行强化处理,研究了NiTi形状记忆合金力学性质的变化。实验发现激光冲击强化后NiTi合金的影响层深度在300μm左右,表面硬度提高了约10%。通过数字图像相关技术从拉伸过程拍摄的照片中得到材料的应变,从而获得NiTi合金的应力-应变关系的变化。激光冲击强化后NiTi样品的超弹性应力应变曲线表明相变应力几乎没有变化,马氏体的屈服应力下降了约100MPa,最大相变应变减少了13%。激光冲击强化产生的超高应变率的塑性变形导致材料硬度提高,超弹性应变减少。 The NiTi shape memory alloy with initial phase of austenite was strengthened by laser shock-enhanced technology, and the change of mechanical properties of NiTi shape memory alloy was studied. The experimental results show that the impact depth of NiTi alloy is about 300μm after laser shock and the surface hardness is increased by about 10%. The strain of the material was obtained from the photographs taken during the stretching process by digital image correlation techniques to obtain the change in the stress-strain relationship of the NiTi alloy. The hyper-elastic stress-strain curves of NiTi samples after laser shock-strengthening show that there is almost no change in phase transformation stress, the yield stress of martensite decreases about 100MPa, and the maximum transformation strain decreases by 13%. The plastic deformation of the ultrahigh strain rate produced by laser shock hardening results in an increase in the hardness of the material and a decrease in the superelastic strain.