(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 針對不同晶粒尺寸的鎂合金AZ31及添加稀土Ce或Nd的AZ31Ce/AZ31Nd的軋制變形行為， 探討了滑移、 孿生和晶界滑動三種變形機制在鎂合金塑性變形過程中的作用。 結(jié)果表明: 多種變形機制共同作用可提高鎂合金在熱變形時的塑性變形能力； 合金熱變形及再結(jié)晶退火后， 在平均晶粒尺寸為50 μm以上的大晶粒中， 變形機制以滑移和孿生為主， 位錯運動和增殖會使位錯在變形過程中互相纏結(jié)、 釘扎以及受晶界的阻礙而終止運動； 孿生容易發(fā)生在不利于滑移的晶粒中促進(jìn)塑性變形； 在5~20 μm的小晶粒中， 晶界滑動機制發(fā)揮了重要作用， 它可以協(xié)調(diào)大尺寸晶粒的變形而對提高鎂合金變形能力起有益的補充作用。
關(guān)鍵字: 變形鎂合金； 變形機制； 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
