冷轧对Cu-Al-Mn合金双程形状记忆效应及马氏体相变的影响

利用热膨胀仪、X射线衍射仪和示差扫描热分析装置等对冷轧Cu 18Al 10.5Mn合金的双程形状记忆效应的各向异性及其产生机制进行了研究·结果表明,冷轧可造成马氏体织构,且马氏体织构按最大程度缓和外加应力的方式产生,并在特定方向上产生形状记忆效应·通过对压下量的控制,可以在一定范围内任意获得正、负的自发形状变化和热膨胀性·随着加工量的增加,马氏体相变温度区间大幅度扩大·随着温度变化,具有择优取向的应力诱发马氏体晶核的生长和消失是导致可逆的自发形状变化各向异性的根本原因·

Influence of Cold Rolling on Two-way Shape Memory Effect and Martensite Transformation of Cu-18Al-10.5Mn Alloy

The cold-rolled Cu-18Al-10.5Mn alloy was investigated for its martensite transformation caused by cold rolling by means of dilatometer, X-ray diffraction and DSC. The results showed that cold rolling process can induce texture of stress-induced martensite and two-way shape memory effect in specific direction. The control of cold rolling reduction can change shapes freely and spontaneously to a certain extent, either forwardly or reversely, and realize the effect of low thermal expansion. The range of martensite transform temperature will be much wider if increasing the reduction. The results of X-ray diffraction in the three sections, i.e. normal to rolling direction (RD) and normal direction (ND), showed that the martensite texture is stress-induced to release the stress due to cold rolling to utmost extent. With the change in temperature, the optimization-oriented stress induces the nuclear growth/disappearance of martensites, which is just the root cause of the anisotropy of reversibly spontaneous change of shapes.