稀土镁合金强韧性设计与开发

镁合金作为最轻质的结构材料,在电子产品及汽车工业领域具有广泛的应用前景。相比于非稀土镁合金,稀土镁合金具有强度高且高温性能好的优点,而成为研究热点之一。本文重点介绍了高稀土含量镁合金和低稀土含量镁合金的强韧化方法。高稀土含量的镁合金可以调控三角分布的棱柱面片状析出相β',阻碍位错滑移,提高合金强度。低稀土含量的镁合金可以采用表面机械研磨处理方法得到表面含有纳米晶中心含有孪晶的梯度组织,利用细晶强化和孪晶强化提高合金强度。

Strengthening and Toughening Design and Development of Mg-Rare Earth Alloys

Magnesium alloys are the lightest structural alloys developed so far and have a great potential for lightweight applications, ranging from portable electronic devices to automobile parts. Comparing to Mg alloys containing no rare earth ( RE) , Mg-RE alloys at-tracted more and more attentions due to the higher strengths at both room temperature and elevated temperature. Strengthening methods for Mg alloys with high RE contents and low RE contents were introduced respectively in this paper. For Mg alloys with high RE con-tents, precipitates ofβ′lying in the triangular prismatic plates can impede dislocation slip effectively to enhance the strength of the al-loy. For Mg alloys with low RE contents, the microstructure containing nano grains in the surface layer and twinning in the center can be obtained by surface mechanical attrition treatment. Thus the Mg alloy can be strengthened by both refinement strengthening of nano grains and twinning strengthening of RE segregated twin boundaries.