混合稀土对超轻Mg-Li合金微观组织和力学性能的影响（英文）  

Effect of Mischmetal on Microstructure and Mechanical Properties of Superlight Mg-Li Alloys

作　　者：李杨敏[1] 彭晓东[1,2] 胡发平[1] 魏国兵[1] 谢卫东[1,2] 刘军威[1] 杨艳[1] 李孟孪 王雪梅 

机构地区：[1]重庆大学材料科学与工程学院,重庆400044 [2]国家镁合金材料工程技术研究中心,重庆400044 [3]上汽依维柯红岩商用车有限公司,重庆401122

出　　处：《稀有金属材料与工程》2017年第7期1775-1781,共7页Rare Metal Materials and Engineering

基　　金：Fundamental Research Funds for the Central Universities(CDJZR14130007,106112015CDJXY130011)

摘　　要：对La/Ce混合稀土的Mg-9Li-3Al-xRE(x=0,0.5,1,1.5,2,质量分数,%)合金,利用光学显微镜,带能谱(EDS)的扫描电子显微镜(SEM)和X射线衍射(XRD)研究了微观组织对其力学性能的影响。结果表明,在加入混合稀土的铸态合金中,形成了Al_4RE相,并且Mg_(17)Al_(12)相的含量和α-Mg相的体积分数均被减少。此外,细化了α-Mg相并提高了合金的力学性能。但是,随着La/Ce混合稀土含量的增加,Al_4RE相的尺寸增大,降低了合金的力学性能。在加入混合稀土的挤压态合金中,合金中Al_4RE相挤压破碎至1~3μm,分布于β-Li基体中和α/β相之间。Mg-9Li-3Al-1.5RE合金获得最好的力学性能,最大抗拉强度和延伸率分别为228.3 MPa和20.8%,同铸态Mg-9Li-3Al相比分别提高了88.6%和197.4%。The influence of mischmetal（lanthanum and cerium） on the microstructure and mechanical properties of Mg-9Li-3Al-x RE（x=0, 0.5, 1, 1.5, 2, wt%） alloys was investigated by optical microscope, scanning electron microscope（SEM） with an energy dispersive spectroscope（EDS）, and X-ray diffraction（XRD）. In as-cast alloys, Al_4RE phase is formed, the content of Mg_（17）Al_（12） phase and the volume fraction of α-Mg phase decrease. In addition, α-Mg phase is refined and the mechanical properties of Mg-9Li-3Al-x RE alloys are improved. However, with increasing mischmetal content, the size of Al_4RE phase increases and the mechanical properties decrease. In extruded alloys, Al_4RE phase is broken into the particles of 1~3 μm in the β-Li matrix phase and α/β interphase. And the best mechanical properties are obtained for Mg-9Li-3Al-1.5RE alloy with a tensile strength of 228.3MPa and elongation of 20.8%, increased by 88.6% and 197.4%, respectively, compared with as-cast Mg-9Li-3Al alloy.

关 键 词：MG-LI合金 混合稀土 挤压 微观组织 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]