不同退火温度热机械处理对Fe-Mn-Si-Cr-Ni合金记忆效应的影响

Influence of thermo-mechanical treatment with different annealing temperature on shape memory effect of a Fe-Mn-Si-Cr-Ni alloy

采用OM、TEM和XRD方法研究了不同退火温度的热机械处理对Fe-14Mn-5Si-8Cr-4Ni合金中α′马氏体逆转变及合金形状记忆效应的影响。结果表明:当在773～1173 K之间退火时,Fe-14Mn-5Si-8Cr-4Ni合金的形状回复率随退火温度的升高先增加后降低,在923 K达到最大值88%;当退火温度低于923 K时,变形引入的α′马氏体仍大量残留在奥氏体基体中;当退火温度高于1073 K时,α′马氏体消失;热机械处理引入的α′马氏体能有效阻止再次变形过程中不同方向和不同区域应力诱发ε马氏体的交叉碰撞,使应力诱发马氏体以区域化的方式形成,进而显著提高合金的形状记忆效应。

Effect of thermo-mechanical treatment with different annealing temperatures on reverse transformation of α′ martensite and its influence on shape memory effect of a Fe-14Mn-5Si-8Cr-4Ni alloy was investigated by means of optical microscope（OM）,TEM and XRD.The results show that when the annealing temperature is between 773 K and 1173 K for the thermo-mechanical treatment,shape recovery ratio of the alloy increases with increasing annealing temperature first and reaches the maximum of 88% at 923 K and then decreases with further increasing the temperature up to 1173 K.When the annealing temperature is below 923 K,lots of α′ martensite introduced by the thermo-mechanical treatment remains inside austenite and the α′ martensite disappears at the annealing temperature higher than 1073 K.α′ martensite introduced by thermo-mechanical treatment can prevent the different stress-induced ε martensite bands from intersecting with each other and makes the stress-induced martensite to form in a domain-specific manner.The shape memory effect of the alloy is remarkably enhanced due to the formation of stress-induced martensite in a domain-specific manner.