重稀土Ho对Mg-3Zn-0.6Zr合金铸态组织及力学性能的影响
Effects of Ho on Microstructure and Mechanical Properties of Mg-3Zn-0.6Zr Alloy
刘娇娇，张 志，刘宝忠
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作者单位：（河南理工大学 材料科学与工程学院，河南 焦作 454000）
中文关键字：镁合金；钬；显微组织；力学性能
英文关键字： magnesium alloy; holmium; microstructure; mechanical property
中文摘要：采用金相显微分析、X射线衍射、扫描电镜以及显微硬度测试等方法，研究了稀土元素Ho对Mg-3Zn-0.6Zr合金显微组织及力学性能的影响。结果表明，Mg-3Zn-xHo-0.6Zr（x=3，5，7）合金系组织由α-Mg基体、Mg3Ho2Zn3相，以及少量的Mg24Ho5相组成。随着Ho含量的增加，Mg3Ho2Zn3相含量增多，起到强化晶界作用。由于Mg3Ho2Zn3相硬而脆，当Ho含量（质量分数）超过3%时，Mg3Ho2Zn3相使合金硬度提高的同时抗拉强度、屈服强度以及伸长率都有不同程度的降低。
英文摘要： The effects of Ho on the microstructure and mechanical properties of the as-cast Mg-3Zn-0.6Zr alloys were investigated by OM, XRD, SEM and hardness testing. The results show that the compositions of the as-cast alloys are α-Mg, Mg3Ho2Zn3 phase and a small amount of Mg24Ho5 phase. The Mg3Ho2Zn3 phase can strengthen the grain boundary which increase with the increase of Ho content. When the alloys containing more than 3wt% Ho, they exhibit larger hardness but lower ultimate tensile strength, yield strength and elongation due to the hard and crisp phase of Mg3Ho2Zn3.