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利用INSTRON5985电子材料万能试验机和分离式Hopkinson压杆冲击加载装置对Ni-Ti形状记忆合金棒材进行准静态和动态力学性能研究,并通过XRD、OM、SEM等微观分析方法对不同状态下的微观组织结构进行分析。结果表明:Ni-Ti合金原始组织存在B2奥氏体相、B19’马氏体相、Ni_4Ti_3相,晶粒细小且呈等轴分布;准静态压缩和动态压缩均发生应力诱发马氏体相变,但动态压缩应力-应变曲线无屈服平台出现,存在应变率硬化效应;在一定的应变率范围内,随着应变率的提高,晶粒内部平行条纹状组织增多,应力诱发马氏体相变程度增大。
The static and dynamic mechanical properties of Ni-Ti shape memory alloy rods were investigated by INSTRON 5985 electronic material universal testing machine and separate Hopkinson pressure bar impact loading device. The microstructures of Ni-Ti shape memory alloy rods were studied by XRD, OM and SEM. Microstructure analysis. The results show that there are B2 austenite, B19 ’martensite and Ni_4Ti_3 phases in the original structure of Ni-Ti alloy. The grain size is small and equiaxed. The stress-induced martensitic transformation occurs in quasi-static compression and dynamic compression , But the dynamic compression stress-strain curve appeared without yielding platform, and there was a hardening effect of strain rate. Within a certain strain rate range, with the increase of strain rate, the number of parallel striped grains increased, and the stress-induced martensitic transformation Increased degree.