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用示差扫描量热仪(DSC),光学显微镜和拉伸试验研究了退火温度对形变处理态Ti-51.1Ni(原子分数,%)形状记忆合金相变和低温形变特性的影响。结果表明,随退火温度升高,合金冷却/加热时相变类型由A→R/M→R→A型向A→R→M/M→R→A型再向A→R→M/M→A(A-母相B2,R-R相,M-马氏体相)型转变,R相变温度和M相变热滞降低,M相变温度升高,R相变热滞变化不大,保持在6.5℃左右。在10℃变形时,400~550℃退火态合金呈现形状记忆效应(SME)+超弹性(SE)特性,600~700℃退火态合金呈现SE特性,随退火温度升高,合金由SME+SE向SE特性转变。合金的退火再结晶温度为590℃,在590~650℃退火后合金可获得50.83%的断裂应变值,塑变性能优良,成型加工温度可选定在590~650℃之间。在使用该合金制作能耗阻尼器及相关缓冲减震装置时退火处理温度可选择大于550℃;制作超弹性器件时,退火处理温度可选择低于400℃或高于600℃。
The effect of annealing temperature on the phase transformation and deformation at low temperature of Ti-51.1Ni (atomic fraction,%) shape memory alloy was studied by differential scanning calorimeter (DSC), optical microscope and tensile test. The results show that with the annealing temperature increasing, the type of phase transformation from A → R / M → R → A to A → R → M / M → R → A and then A → R → M / M → A (A-mother phase B2, RR phase and M-martensite phase) type transition, R phase transition temperature and M phase transition hysteresis decreases, M phase transition temperature increases, R phase transition hysteresis does not change much, Keep at about 6.5 ℃. When annealed at 10 ℃, the shape-memory effect (SME) + superelasticity (SE) was observed in the as-annealed alloys at 400-550 ℃. The as-annealed alloys exhibited SE characteristics at 600-700 ℃. Change to SE features. The annealing recrystallization temperature of the alloy is 590 ℃. After annealing at 590 ~ 650 ℃, the fracture strain value of 50.83% can be obtained, and the plastic deformation property is excellent. The molding temperature can be selected between 590 and 650 ℃. In the use of the alloy damping energy consumption when the damper and related devices when the annealing temperature can be selected greater than 550 ℃; the production of hyperelastic devices, the annealing temperature can be selected below 400 ℃ or above 600 ℃.