微量Y对AM50铸态合金组织及力学性能的影响

Effect of Y Addition on Microstructure and Mechanical Property of As-cast AM50 Alloy

利用光学显微镜、扫描电镜和X射线衍射仪，分析研究了微量Y对AM504铸态合金组织及其室温和高温（200℃）力学性能的影响。结果表明，在AM50合金中加入质量分数1％Y，晶粒细化，连续或半连续网状分布的β-Mg17Al12相呈骨骼状或颗粒状弥散分布，同时晶界附近有大量块状新相Al2Y生成；合金的室温和高温抗拉强度分别提高了18．9％和23．2％；屈服强度分别提高了16．1％和20．5％；合金伸长率分别提高9．1％和11．7％。

The microstructure and mechanical property of as-cast AM50 alloys with and without Y addition have been investigated by optical microscopy, scanning electron microscopy and energy dispersion X-ray analysis. The results show that with addition of 1%Y to AM50 alloy, the grain is refined, the continuous or semi-continuous network morphology of fl-Mg17Al^2 phase tends to be in the skeletal or granular shape, and a large number of blocky A12Y phase is formed nearby the grain boundaries. The ultimate tensile strength at room temperature and at elevated temperature are increased by 18.9 % and 23.2% respectively, while yield strength are increased by 16.1% and 20.5% respectively. Meanwhile, the values of elongation at room temperature and at elevated temperature are increased by 9.1% and 11.7% respectively.