Y和混合稀土对Mg-Li-Al合金力学性能的影响

Influence of Y and RE on Mechanical Properties of Mg-Li-Al Magnesium Alloy

研究了少量Y和镧镨铈混合稀土对Mg-Li-Al合金铸态及热处理态微观组织和力学性能的影响。结果表明,Mg-Li-Al合金中加入0.5%Y,形成球状共晶组织,枝晶很少被熔断,α-Mg相连在一起,组织粗大,力学性能较低。经过均化处理和淬火后,力学性能提高不明显;Mg-Li-Al合金中加入0.5%镧镨铈混合稀土,组织中出现稳定的铝稀土化合物,这些铝稀土化合物在均化处理的时候,能减缓原子的扩散运动,降低了均化效果。淬火后,组织细化,α-Mg相变小,由于固溶强化和细晶强化的共同作用,力学性能提高了30%。

The effects of trace elements rare Y and La-rich mischmetal on microstructure and mechanical properties of Mg-Li-Al magnesium alloy as-cast and as-hcat-treatment were studied. The results show that the spheric eutectic structure is formed, treelike crystal is little brokcn adding 0.5%Y to Mg-Li-Al alloy. The α-Mg phases link each other, the microstructure of magnesium ingot is coarser, and the mechanical properties reduces. After the homogenizing and quenching treatment, the mechanical properties have no improvement obviously. After adding 0.5%La-rich mischmetal to Mg-Li-Al alloy, stable rare earth compound is formed. The rare earth phase can make atom diffusion slow and weaken the effect of homogenizing heat-treatment. The microstructure of magnesium ingot and α-Mg phase are refined after quenching. The mechanical properties of Mg-Li-Al-LPC alloy increases by 30% owing to the effect of solution strengthing and grain strengthing.