(1. 陕西理工学院 材料科学与工程学院，汉中 723003；
2. 陕西理工学院 图书馆，汉中 723003)
摘 要: 用示差扫描热分析仪、光学显微镜、X射线衍射仪和拉伸实验研究退火态Ti-50.8Ni-0.5V(摩尔分数，%)形状记忆合金的相变行为、显微组织和循环形变特性。结果表明：400、500和600 ℃退火态合金的相变类型分别为A→R/R→A、A→R→M/M→R→A和A→M/M→A(A—母相B2，R—R相，M—马氏体)，合金的室温组成相为B2和R相。400、500和600 ℃退火态合金的显微组织形态分别呈纤维状、纤维状和等轴状。Ti-50.8Ni-0.5V合金在室温下呈超弹性特性，600 ℃退火态合金的应力诱发M临界应力(σM)高于400和500 ℃退火态合金的。400 ℃退火态合金的应力—应变的循环特性稳定，超弹性特性优异，经一次循环后合金即可呈现完全非线性超弹性；500和600 ℃退火态合金的应力—应变的循环稳定性较差。随循环次数增加，合金的σM降低，循环耗能减小。随循环应变量增大，合金的循环耗能增加，而循环稳定性有所降低。
关键字: Ti-Ni-V合金；形状记忆合金；循环形变；超弹性
（1. School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723003, China;
2. Library, Shaanxi University of Technology, Hanzhong 723003, China）
Abstract:The transformation behavior, microstructure and cyclic deformation characteristics of annealing Ti-50.8Ni-0.5V (mole fraction, %) alloy were investigated by differential scanning calorimetry, optical microscopy, XRD and tensile test. The results show that the transformation types of the 400, 500 and 600 ℃ annealed alloys are A→R/R→A, A→R→M/M→R→A and A→M/M→A (A—parent phase, R—rhombohedral phase, M—martensite phase) upon cooling/heating, respectively. The constituent phases of the alloy at room temperature are B2 and R phases. The microstructure morphology of the 400, 500 and 600 ℃ annealed alloys are fibrous, fibrous and equiaxed, respectively. Ti-50.8Ni-0.5V alloy shows superelasticity at room temperature. The critical stress for inducing martensitic transformation (σM) of the 600 ℃ annealed alloy is higher than those of the 400 and 500 ℃ annealed alloys. The stress—strain cycling characteristics of the 400 ℃ annealed alloy is stable, the superelasticity is excellent, and the alloy shows completely nonlinear superelasticity after one stress—strain cycle. The stress—strain cycling stability of the 500 and 600 ℃ annealed alloys are poor. With increasing cyclic number, the σM and the cyclic energy dissipation of the alloy decrease. With increasing cyclic strain, the cyclic energy dissipation increases, while the cyclic stability decreases in the alloy.
Key words: Ti-Ni-V alloy; shape memory alloy; cyclic deformation; superelasticity
