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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 microstructure of Mg-9Li-3Al-xRE (x = 0,0.5,1,1.5,2, mass fraction,%) alloy of La / Ce mischmetal was characterized by optical microscope, EDS (scanning electron microscope) ) And X-ray diffraction (XRD) were used to investigate the effect of microstructure on the mechanical properties. The results show that Al_4RE phase is formed in the as-cast alloy containing rare earth elements and the content of Mg_ (17) Al_ (12) phase and the volume fraction of α-Mg phase are reduced. In addition, the α-Mg phase is refined and the mechanical properties of the alloy are improved. However, with the increase of La / Ce mixed rare earth content, the size of Al_4RE phase increases, which decreases the mechanical properties of the alloy. In the mixed rare earth alloy, the Al_4RE phase in the alloy is crushed to 1 ~ 3μm and distributed in the β-Li matrix and α / β phase. The best mechanical properties were obtained for Mg-9Li-3Al-1.5RE alloy with the maximum tensile strength and elongation of 228.3 MPa and 20.8%, respectively, which increased by 88.6% and 197.4% respectively compared with that of as-cast Mg-9Li-3Al.