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采用光学显微镜、透射电子显微镜和电阻率测量技术,研究回复加热速度对上淬后Cu-8.8Al-10.27Mn合金的形状记忆效应的影响。结果表明:材料形状回复率随回复加热速度的减小而减小。当回复加热速度为20°C/min时,形状回复率可达75%;而当回复加热速度为1°C/min时,其形状回复率仅为8%。原位金相观察表明:材料的形状记忆效应是由马氏体逆转变后的残余孪晶形变马氏体的稳定性引起的。电阻率分析结果表明:残余孪晶形变马氏体的稳定性与其界面处空位与位错在慢速加热时形成的复合缺陷相关。而复合缺陷的形成会阻碍孪晶形变马氏体的逆转变。
The effects of heating rate on the shape memory effect of Cu-8.8Al-10.27Mn alloy after quenching were investigated by optical microscope, transmission electron microscopy and resistivity measurement. The results show that the shape recovery rate decreases with the decrease of the heating rate. The shape recovery rate was 75% when the heating rate was 20 ° C / min, and only 8% when the heating rate was 1 ° C / min. In-situ metallographic observation shows that the shape memory effect of the material is caused by the stability of the residual twin-deforming martensite after the martensitic transformation. The results of resistivity analysis show that the stability of residual twin deforming martensite is related to the composite defects formed when the vacancy and dislocation at the interface are slowly heated. The formation of composite defects hinders the reverse transformation of twinned martensite.