TiNi形状记忆合金丝在约束态热循环后的力学特性

Mechanical Behavior of TiNi Shape Memory Alloy in Constrained Thermal Cycles

研究了TiNi形状记忆合金丝在约束态热循环后的应力-应变特性。结果表明,如果停止加热并加载,或者在母相状态下冷却但是尚未发生正相变时加载,加载应力-应变曲线首先呈线弹性关系,然后才出现应力平台。如果在冷却过程中发生正相变的时候停止冷却并加载,则加载应力-应变曲线只出现应力平台。与之相似,如果在约束态冷却过程中停止冷却并卸载,卸载应力-应变曲线首先呈线弹性关系,然后才出现应力平台。如果在加热过程中停止加热并卸载,则卸载应力-应变曲线立即出现应力平台。

The mechanical behavior of TiNi shape memory alloy wires in constrained thermal cycles were studied. The results showed that if the thermal cycle stopped during heating, or stopped during cooling before the forward martensitic transformation started, the loading stress strain curves of the wire exhibited a linear elastic response and then followed by a stress plateau. If the constrained thermal cycle stopped upon cooling while the forward martensitic transformation was in progress, the loading stress strain curves exhibited the stress plateau immediately. Similarly, the unloading stress-strain curves exhibited a linear elastic response followed by a stress plateau if the constrained thermal cycle stopped upon cooling. loading stress strain curves exhibit a If the constrained thermal cycle stopped upon heating, the un plateau immediately.