Microstructure and Mechanical Properties of Mg-4%Al-0.8%Sb-xRE Magnesium Alloy

A series of Mg-4%Al-0.8%Sb-xRE magnesium alloys added 0.8%Sb instead of some RE were prepared.Changes of the mechanical properties and microstructure of the alloys with RE content were investigated by SEM,XRD and universal tensile testing machine.The results indicate that the as-cast microstructure of AE42 alloy was composed of α matrix,some needle-shaped and granular Al11RE3 phase.With the decrease of RE content,the number of needle-shaped Al11RE3 phase decreased,and its shape became thinner and shorter,a small quantity of β-Mg17Al12 and dispersed RESb and RE2Sb particles appeared in the matrix at the same time,and the number of RESb particles increased while the shape of them became larger.The mechanical properties improved gradually with the increase of RE content,and achieved the level of AE42 alloy when the RE content was 1.3%.