(1. 陕西理工大学 材料科学与工程学院，汉中 723001；
2. 陕西理工大学 图书馆，汉中 723003)
摘 要: 用XRD、光学显微镜、示差扫描量热仪和拉伸实验研究退火温度(ta)对冷拉Ti-50.8Ni-0.1Nb(摩尔分数，%)合金组织、相变和形状记忆行为的影响。结果表明：350~700 ℃退火态Ti-50.8Ni-0.1Nb合金由马氏体M(B19′，单斜结构)和母相A(B2，CsCl型结构)组成。随ta升高，合金组织形貌由纤维状变为等轴状，再结晶温度约为580 ℃；合金冷却/加热相变类型由A→R→M/M→R→A型向A→R→M/M→A型向A→M/M→A型转变(R-R相，菱方结构)，R相变温度降低，M相变温度和热滞先升高后降低，R相变热滞为6.7~9.8 ℃。350~550 ℃退火态合金的抗拉强度高于600~700 ℃退火态合金的，伸长率则远低于后者的。400~550 ℃退火态合金呈形状记忆效应，350 ℃退火态和600 ℃及以上温度退火态合金呈超弹性。随应力-应变循环次数增加，合金应力-应变曲线的平台应力下降。400~550 ℃退火态合金的形状记忆效应和600 ℃及以上温度退火态合金的超弹性稳定性良好。
关键字: Ti-Ni-Nb合金；形状记忆合金；退火；相变；形状记忆行为
（1. School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723001, China;
2. Library, Shaanxi University of Technology, Hanzhong 723003, China）
Abstract:The effects of annealing temperature (Ta) on the microstructure, phase transformation and shape memory behavior of cold drawing Ti-50.8Ni-0.1Nb (mole fraction, %) shape memory alloy were investigated by XRD, optical microscopy, differential scanning calorimetry and tensile test. The results show that the phase compositions of Ti-50.8Ni-0.1Nb alloy annealed at 350-700 ℃ are martensite M (B19′, monoclinic) and parent phase A (B2, CsCl). With increasing Ta, the microstructure morphology of the alloy changes from fibrous to equiaxed grain, the recrystallization temperature is about 580 ℃; the transformation types of the alloy change from A→R→M/M→R→A to A→R→M/M→A to A→M/M→A (A-parent phase B2, CsCl; R-R phase, rhombohedral; M-martensite B19′, monoclinic) upon cooling/heating, the R transformation temperature of the alloy decreases, the M transformation temperature and temperature hysteresis increases firstly and then decreases, the R transformation temperature hysteresis is 6.7-9.8 ℃. The tensile strength of the alloy annealed at 350-550 ℃ is higher than that of the alloy annealed at 600-700 ℃, while the percentage elongation of the former is lower than that of the latter. The alloy annealed at 400-550 ℃ shows shape memory effect, and the alloys annealed at 300 ℃ and 600-700 ℃ show superelasticity. With increasing stress-strain cycling number, the platform stress in the stress-strain curve of the alloy decreases. The stability of the shape memory effect in the alloy annealed at 400-550 ℃ and the superelasticity in the alloy annealed at 600-700 ℃ are well.
Key words: Ti-Ni-Nb alloy; shape memory alloy; annealing; transformation; shape memory behavior
