(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 针对不同晶粒尺寸的镁合金AZ31及添加稀土Ce或Nd的AZ31Ce/AZ31Nd的轧制变形行为， 探讨了滑移、 孪生和晶界滑动三种变形机制在镁合金塑性变形过程中的作用。 结果表明: 多种变形机制共同作用可提高镁合金在热变形时的塑性变形能力； 合金热变形及再结晶退火后， 在平均晶粒尺寸为50 μm以上的大晶粒中， 变形机制以滑移和孪生为主， 位错运动和增殖会使位错在变形过程中互相缠结、 钉扎以及受晶界的阻碍而终止运动； 孪生容易发生在不利于滑移的晶粒中促进塑性变形； 在5~20 μm的小晶粒中， 晶界滑动机制发挥了重要作用， 它可以协调大尺寸晶粒的变形而对提高镁合金变形能力起有益的补充作用。
关键字: 变形镁合金； 变形机制； 稀土
（ School of Materials Science and Engineering,
Central South University,Changsha 410083, China）
Abstract: The slipping, twinning and grain boundary sliding deformation mechanism were studied based on the investigation of rolling behaviors of AZ31 alloy with Ce or Nd addition. The results show that all the three mechanisms have great effects on the deformation ability of magnesium alloys. In a large size grain (diameter larger than 50 μm), the dislocation sliding and twinning are the main deformation mechanisms. But in a small size grain (about 10-20 μm), grain boundary sliding is another important mechanism to improve the ductility of magnesium alloy. AZ31(Ce) and AZ31(Nd) alloys having such fine grains obtain a better plastic deformation than commercial AZ31 alloy.
Key words: wrought magnesium alloy; deformation mechanism; rare earth
