稀土Y及固溶处理对AM60镁合金组织和力学性能的影响

Effects of Y addition and solid solution treatment on microstructure and mechanical properties of AM60 magnesium alloys

研究了添加少量稀土Y及固溶处理对AM60合金显微组织和室温力学性能的影响。结果表明:稀土Y的加入能显著提高合金的抗拉强度σb、屈服强度σ0.2、伸长率δ。AM60铸造合金中加入Y后,与Al形成颗粒状的稀土化合物Al2Y,使合金中的γ相Mg17Al12数量减少,合金组织得到细化。固溶处理(T4)后,-γMg17Al12相基本溶解,热稳定性较高的稀土化合物相未溶解,使合金的抗拉强度进一步提高。AM60-0.4%Y合金的拉伸试样断口为带有局部韧窝的解理断裂和韧性断裂的混合特征。

Effects of Y addition and solid solution treatment on the microstructure and mechanical properties of cast AM60 magnesium alloys at room temperature were studied. The results show that the ultimate tensile strength σb, yield strength σ0.2 and elongation δ of AM60 alloy increase remarkably by addition of Y. New phase Al2Y forms after the addition of yttrium in the AM60 alloys. The size and amount of Mg17Al12 (γ) phase are decreased because of the Al2Y formation. After solid solution treatment (T4), the γ-Mg17Al12 phase dissolves and the rare earth phase with heat stability remains leading to further improving of the mechanical properties of the alloys. Ductile fracture features are observed at the tensile fracture surfaces of the AM60-0.4%Y alloys.