稀土元素Y对AZ91D镁合金显微组织和力学性能的影响

Effects of Yttrium on microstructure and mechanical properties of AZ91D magnesium alloy

试验研究了在AZ91D镁合金中添加不同质量分数的稀土元素Y(w(Y)=0.4%、0.8%、1.2%、1.6%、2.0%)对其组织和力学性能的影响。结果表明,添加适量的稀土元素Y能改善AZ91D镁合金的组织并提高其力学性能。当w(Y)=1.2%时,对AZ91D镁合金的晶粒细化作用效果最佳,此时,晶粒尺寸为46.15μm,相比未加入稀土元素Y的AZ91D镁合金细化幅度为27.85%。稀土元素Y的加入还能提高AZ91D镁合金的硬度、抗拉强度、伸长率等性能,当w(Y)=1.2%时,AZ91D镁合金的各项力学性能最佳:维氏硬度为99.7 HV,室温抗拉强度为299 N/mm^2,伸长率为9.5%;200℃的抗拉强度为161.75 N/mm^2,伸长率为5.8%。

The experiment investigated the microstructure and mechanical properties of AZ91D magnesium alloy with different contents of Yttrium（ w（ Y） = 0. 4%,0. 8%,1. 2%,1. 6%,2. 0%,respectively）. The results show that the microstructure and mechanical properties of AZ91D magnesium alloy are improved with suitable content of rare earth element Y. When w（ Y） = 1. 2%,the grain size is 46. 15 μm and the refining extent is27. 85% compared with the alloy without Y,thus reaching the best effect of grain refinement. Rare earth Y also improves hardness,tensile strength,elongation and other properties of the alloy. The mechanical properties reach the best when w（ Y） = 1. 2%,where Vickers hardness is 99. 7 HV,tensile strength 299 N/mm2 and elongation 9. 5% at room temperature; tensile strength 161. 75 N/mm2 and elongation 5. 8% at 200℃.