的相变特性
(陕西理工学院 材料科学与工程学院，汉中 723003)
摘 要: 用示差扫描量热仪研究了退火温度、退火时间和时效温度、时效时间对Ti-50.2Ni(摩尔分数)形状记忆合金丝相变特性的影响，给出了退火、时效工艺对该合金R、M相变温度和热滞的影响规律。结果表明：350~550℃退火态合金冷却/加热相变类型为A→R→M/M→A(A－母相，R－R相，M－马氏体)，600~800 ℃退火态为A→M/M→A，400 ℃长时间退火态相变类型为A→R→M/M→R→A；随时效时间延长，300 ℃时效态合金的相变类型经过A→M/M→A到A→R→M/M→A再到A→R→M/M→R→A的转变，400 ℃时效态相变类型经过A→M/M→A到A→R→M/M→A的转变，500 ℃时效态相变类型则保持A→M/M→A不变。
关键字: Ti-50.2Ni合金; 形状记忆合金; 相变温度; 热滞
Ti-50.2Ni shape memory alloy
heat-treated in different processes
（School of Materials Science and Engineering, Shaanxi
University of Technology,Hanzhong 723003, China）
Abstract:The effects of annealing temperature, annealing time, aging temperature, and aging time on the transformation characteristics of Ti-50.2Ni (atomic percentage) shape memory alloy wire were investigated by differential scanning calorimetry. The effect regularity of annealing and aging processes on the R, M transformation temperature and temperature hysteresis were given out. The results show that the cooling / heating transformation type of 350−550 ℃ annealed Ti-50.2Ni alloy is A→R→M/M→A (A is parent phase, R is R phase, M is martensite ), that of 600−800 ℃ annealed alloy is A→M/M→A, and that of the alloy annealed at 400 ℃ for long time is A→R→M/M→R→A. With increasing aging time, the transformation type of 300 ℃ aged alloy changes from A→M/M→A then A→R→M/M→A to A→R→M/M→R→A, the one of 400 ℃ aged alloy changes from A→M/M→A to A→R→M/M→A, and the one of 500 ℃ aged alloy keeps as A→M/M→A.
Key words: Ti-50.2Ni alloy; shape memory alloy; transformation temperature; temperature hysteresis
