镧镨铈混合稀土对Mg-Li-Al合金组织及力学性能的影响
Effect of La-Pr-Ce RE on Microstructure and Mechanical Property of Mg-Li-Al Alloy
马洪波1, 赵 平2, 尚桂凡2
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作者单位：1. 西华大学 机械工程与自动化学院, 四川 成都 610039; 2. 西华大学 材料科学与工程学院, 四川 成都 610039
中文关键字：镁锂铝合金； 镧镨铈混合稀土； 显微组织； 力学性能
英文关键字：Mg-Li-Al alloy; La-Pr-Ce miscible-RE; microstructure; mechanical properties
中文摘要：采用光学显微镜、带能谱仪的扫描电镜、 X射线衍射仪以及电子万能试验机，研究了镧镨铈混合稀土对Mg-Li-Al合金显微组织和力学性能的影响。结果表明：加入镧镨铈混合稀土能显著细化合金组织， 起到细晶强化和提高塑性的作用；同时Al和La生成稀土化合物Al11La3，大量富集在晶界上，能阻止晶界滑移和基体变形，有强化晶界的作用。随着稀土加入量增大，Mg与La生成Mg3La，消耗了部分Mg，使得强度略为降低，塑性提高，相对于未加入混合稀土的Mg-Li-Al合金，其抗拉强度和伸长率分别提高了27.3%和1248.1%；当混合稀土含量为3%时合金强度最高，含量为4%时塑性最好。
英文摘要：The effects of La-Pr-Ce miscible-RE on microstructure and mechanical properties of Mg-Li-Al alloy were investigated by optical microscope, scanning electron microscope with energy spectrometer attached, X-ray diffractometer and electronic universal testing machine. The results show that adding La-Pr-Ce miscible-RE to Mg-Li-Al can fine the microstructure of magnesium ingot. Owing to the improvement of microstructure, the mechanical properties of the alloy also increase. It indicates that adding rare earth can prevent grain boundary from slip and matrix from deformation due to stable rare earth compound Al11La3 formed at grain boundaries, so ultimate tensile strength of the alloy improves. With the increase of La, Al and La create Mg3La and consume a part of Mg, which makes strength decrease and elongation increase. Compared with Mg-Li-Al alloy, the ultimate tensile strength and elongation is increased by 27.3% and 1248.1%, respectively. The Mg-Li-Al alloy with 3.0% miscible-RE addition has the best ultimate tensile strength, and with 4.0% miscible-RE addition has the best plasticity.