在所有工程用金属结构材料中,镁合金的密度最低,具有较高的比强度和比刚度.然而,镁合金在一定的塑性变形条件下会出现明显的"塑性不稳定"现象,也被称作锯齿屈服(流变)现象或Portevin-Le Chatelier(PLC)效应,主要表现为应力-应变曲线上的锯齿状波动.近年来,关于镁合金PLC效应的研究报道逐年增加.本文将重点介绍镁合金中存在塑性不稳定现象相关的研究进展,叙述并归纳镁合金PLC效应发生的条件、 锯齿屈服的特征、 合金元素对锯齿屈服现象的影响及对应的理论机制等.最后,指出目前研究中尚存在的问题,提出将来的研究重点和发展方向.%Among all the structural metallic materials, magnesium alloys have the lowest density, relatively high specific strength and rigidity. However, under plastic deformation conditions, magnesium alloys can exhibit the phenomenon of plastic instability, i. e. serrated flow or Portevin-Le Chatelier ( PLC) effect, showing serrated waves on the stress-strain curves. Recently, research works about the PLC effects of magnesium alloys are widely carried out and increase annually. This paper is mainly concentrated on the research progress on PLC effect of magnesium alloys. The occurring conditions of PLC effect, characteristics of serration, effect of alloying elements on the PLC effect and relevant mechanisms are reviewed. Finally, the existing problems in current studies, research emphasis and direction in the future are also pointed out.
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