退火温度和应力-应变循环对Ti-Ni-Cr形状记忆合金超弹性的影响

来源期刊：金属学报2010年第7期

论文作者：王启 贺志荣 王永善 杨军

文章页码：800 - 804

关键词：Ti-Ni-Cr合金； 形状记忆合金； 退火温度； 应力-应变循环； 超弹性

Key words：Ti-Ni-Cr alloy； shape memory alloy； annealing temperature； stress-strain cycle； superelasticity

摘    要：用拉伸实验研究了退火温度(θ_an)和应力应变循环对Ti-50.8Ni-0.3Cr合金超弹性(SE)的影响.结果表明,随θ_an升高,应力诱发马氏体(M)相变的临界应力σM先降低后升高,随后趋于稳定,分别在450和600℃达到最小值(311 MPa)和最大值(583 MPa).残余应变在θ_an=350—590℃之间变化不大,始终保持在较低的水平;当θ_an高于590℃时,残余应变则急剧升高.随着应力-应变循环次数(N)增加,350和590℃退火态合金由部分非线性超弹性逐渐转变为完全非线性超弹性,而650℃退火态合金由部分非线性超弹性逐渐转变为线性超弹性.此外,随N增加,590和650℃退火态合金的能耗作用逐渐下降,并趋于稳定,而350℃退火态合金的能耗作用基本保持不变.要使Ti-50.8Ni-0.3Cr合金获得良好的SE,退火温度应低于再结晶温度.

Abstract: Effects of annealing temperature (θ_an) and stress-strain cycle on superelasticity (SE) of Ti-50.8Ni-0.3Cr alloy were investigated by tensile test.The results show that with increasingθ_an, critical stress for stress-induced martensite (σ_m) descends firstly and then rise.The σ_m reaches its minimum value (311 MPa) and maximum value(583 MPa)when annealing temperature is 450 and 600℃, respectively.When θ_an=350-590℃,the residual strain (ε_r) has no obvious change,keeps at a low value all the time.When θ_an>590℃,the ε_r rises rapidly.With increasing stress-strain cycle number (N),the alloy annealed at 350 and 590℃ transform from incompletely nonlinear superelasticity to completely nonlinear superelasticity.The alloy annealed at 650℃ transform from incompletely superelasticity to linear-like superelasticity.Moreover,with increasing N,the energy dissipation ability of the alloy annealed at 590 and 650℃ descend gradually,and tend to stability.The energy dissipation ability of the alloy annealed at 350℃ nearly keeps constant.In order to get excellent SE,the annealing temperature of Ti-50.8Ni-0.3Cr alloy should be below recrystallization temperature.