热处理对Ti-Ni-Cr低温超弹性合金相变行为的影响

来源期刊：金属学报2010年第3期

论文作者：贺志荣 王芳

文章页码：329 - 333

关键词：Ti-50.8Ni-0.3Cr合金； 形状记忆效应； 超弹性； 相变

Key words：Ti-50.8Ni-0.3Cr alloy； shape memory effect； superelasticity； transformation

摘    要：用示差扫描量热仪研究了退火和时效工艺对Ti-50.8Ni-0.3Cr（原子分数,%）低温超弹性合金相变行为的影响.结果表明.350—450℃退火态Ti-50.8Ni-0.3Cr合金冷却/加热时发生A→R/R→A型可逆相变,500℃退火态合金发生A→R→M/M→R→A型相变,550—600℃退火态合金发生A→R→M/M→A型相变,650℃以上退火态合金不发生相变.退火时间对合金相变行为影响不大.随时效时间t_ag延长,300℃时效态合金的相变类型保持为A→R/R→A,400℃时效态合金发生由A→R/R→A向A→R→M/M→R→A转变,500℃时效态合金发生由A→R→M/M→R→A向A→R→M/M→A转变.随退火温度升高,合金的R相变温度θ_R先升高后降低,M相变温度θ_M升高,M相变热滞△θ_M降低.合金经300—500℃时效后,θ_R⁴⁰⁰>θ_R³⁰⁰>θ_R⁵⁰⁰.随t_ag延长,θ_R和θ_M先快速升高后趋于稳定,△θ_M先快速降低后趋于稳定.退火和时效态合金的R相变热滞均在4℃左右.

Abstract: The effects of annealing and aging processes on transformation behavior of thelow-temperature superelasticity alloy Ti-50.8Ni-0.3Cr(atomic fraction,%) were investigated withdifferential scanning calorimetry.The A→R/R→A(A-parent phase,R-R phase) type reversibletransformation occurred in the 350-450℃annealed alloy upon cooling/heating,the A→R→M/M→R→A(M-martensite) type occurred in the 500℃annealed alloy,the A→R→M/M→A typeoccurred in 550-600℃annealed alloy,and no transformation occurred in the above 650℃annealedalloy.The effect of the annealing time on transformation behavior of the alloy is not serious.Withincreasing aging time t_ag,the transformation type of 300℃ aged alloy still is A→R/R→A,the one of 400℃ aged alloy changes from A→R/R→A to A→R→M/M→R→A,and the one of 500℃ aged alloychanges from A→R→M / M→R→A to A→R→M/M→A.With increasing annealing temperature,the R transformation temperature(θ_R) of the alloy increases first and then decreases,the Mtransformation temperature (θ_M) increases,and the M temperature hysteresise (△θ_M) decreases.After aging at 300-500℃.theθ_R⁴⁰⁰>θ_R³⁰⁰>θ_R⁵⁰⁰.With increasing t_ag,theθ_R andθ_M increase fast firstand then tend to stable,and the△θ_M decreases fast first and then tends to stable.The R temperaturehysteresises in both the annealed and aged alloys are about 4℃.