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 attracted 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 contents, precipitates of β' lying in the triangular prismatic plates can impede dislocation slip effectively to enhance the strength of the alloy. 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