过热时效对铜基形状记忆合金工程元件微观组织的影响

Overheat aging effect on microstructures for copper-based shape memory alloy engineering parts

对含有混合稀土Re的形状记忆合金Cu-26．4Zn-4Al工程元件做了过热时效效应实验，观察了记忆合金在不同时效温度下，显微图像中可逆马氏体和母相等微观组织的变化。环境温度的升高和时效时间的延长，促使亚稳定热弹性马氏体向平衡态转变，且温度越高、保温时间越长，冷却时发生的共析反应越强，析出α＋γ相越多或转成贝氏体，均使可逆马氏体的数量减少，马氏体内的有序度降低，导致记忆效应衰减。

The overheat aging have been investigated for Cu-26.4Zn-4Al shape memory alloy engineering parts. In micro-images the microstructures reversible martensite and basic phase were changed under different overheat aging temperatures. High temperature and long aging time improved metastable heat-elastic reversible translating to equilibrium. The higher temperature and the longer of heat preservation, the better cooling eutectoid reaction. The reversible martensite were decreased, order-producing lowed, more α＋γ phases or translating to bainite, would resulted memory effect turned to attenuation.