【摘要】 以高温固溶时效和中温退火处理过的Ti-50.7at%Ni合金为研究对象,考察了合金在试验温度为20 ℃,加载速率分别为3 mm/min、15 mm/min、30 mm/min、50 mm/min作用下的轴向压缩应力-应变行为。结果表明:2种热处理方式处理过的Ti-50.7at%Ni合金具有约4.5%～5.0%的非线性超弹性,高温固溶时效处理的合金由于析出相强化提高了合金母相强度,因而相变超弹性能比中温退火的合金要好,在相同试验条件下,高温固溶时效处理合金的加载—卸载曲线包围面积比中温退火的大,但随着加载速率的增加而减小;在较高加载速率下,中温退火的合金表现出近乎线性超弹性。更多还原

【Abstract】 The pseudoelasticity of Ti-50.7at%Ni alloy under axial compression dynamic load was investigated by MTS 858Mini Bionix test machine. Before experiments, Ti-50.7at%Ni alloy was treated by two kinds of heat-treatment methods, i.e. solution at 1000℃followed by ageing at 450℃ and anneal at 500℃. The experiments were conducted at 20℃ and the variety of dynamic loads were controlled by the velocity of compression displacement, which was 3mm/min, 15mm/min, 30mm/min and 50mm/min respectively. The experimental results indicate that both aged and annealed alloys show good nonlinear pseudoelasticity resulted from stress-induced martensitic transformation. The nonlinear pseudoelasticity of aged alloy with the recoverable strain up to 5.0% is superior to that of annealed alloy, which is about 4.5%. Under the same experimental conditions, the area enclosed by loading-curve and unloading-curve of aged alloy is larger than that of annealed alloy, and the areas of both kinds of alloys become smaller with the velocity of loading increasing. At higher velocity of loading, the alloys exhibit approximate linear pseudoelasticity, especially for the case of annealed alloy.更多还原