The deformation mechanism of slips and twins has a considerable influence on the plasticity of magnesium alloys. However, the roles of slips and twins in the room-temperature deformation of Mg-rare earth (Mg-RE) alloys with high contents of rare earth elements is rarely investigated. Here, the microstructural evolution and deformation mechanism of an aged Mg-5Y-2Nd-3Sm-0.5Zr alloy during uniaxial compression at room temperature were systematically investigated using in-situ electron-backscattered diffraction and transmission electron microscopy. The results indicated that in the early stage of deformation, the Mg-RE alloy was mainly controlled by the slip of <a> dislocations in the basal plane and the coordinated c-axis strain of the {10-12} twin. With an increase in the strain, the grain orientation became more suitable for the initiation of pyramidal II <c + a> dislocations in the later stage of deformation; these dominated the deformation mechanism. In the twin evolution of the Mg-RE alloy, there were three types of twin-twin interaction behaviors: (i) single twin variant ‘parallel’ structure, (ii) single twin variant ‘cross’ structure, and (iii) multi twin variant ‘cross’ structure. In addition, three types of twin-grain boundary interaction behaviors were summarized: (i) twin ‘refracting through’ grain boundary, (ii) twin ‘parallel through’ grain boundary, and (iii) twin ‘fusing through’ grain boundary, which are expected to act as new means and solutions for the twin strengthening of magnesium alloys.

滑移和孪晶的变形机理对镁合金的塑性有相当大的影响。但是，很少研究滑移和孪晶在稀土元素含量高的镁稀土（Mg-RE）合金室温变形中的作用。在这里，使用原位电子背散射衍射和透射电子显微镜系统研究了老化的Mg-5Y-2Nd-3Sm-0.5Zr合金在室温下的单轴压缩过程中的组织演变和变形机理。结果表明，在变形初期，所述Mg-RE合金主要由<滑移控制一>在基底面位错和协调Ç{10-12}双胞胎的轴向应变。随着应变的增加，晶粒取向变得更适合于锥形II < c + a的引发>在变形后期错位；这些主导了变形机制。在Mg-RE合金的孪生演化过程中，存在三种类型的孪生孪生相互作用行为：（i）单孪生变体“平行”结构，（ii）单孪生变体“交叉”结构和（iii）多孪生变体“交叉”结构。此外，总结了三种类型的双晶边界相互作用行为：（i）双晶“折射穿过”晶界，（ii）双晶“平行穿过”晶界，和（iii）双晶“熔融穿过”晶界，它们有望成为镁合金双强化的新手段和解决方案。