Ce对Mg-Gd-Y-Nd-Zr合金组织与性能的影响

Effects of Ce Addition on Microstructure and Properties of Mg-Gd-Y-Nd-Zr Alloy

采用金相显微镜、硬度测试、扫描电镜、透射电镜和X射线衍射仪,研究了Ce元素对Mg-Gd-Y-Nd-Zr合金组织与性能的影响。结果表明:Ce元素可细化铸态合金的晶粒,加速合金中亚稳相的析出过程,并增加合金中亚稳相的体积分数,提高合金的室温及高温力学性能;本实验条件下,Mg-5.5Gd-4.5Y-Nd-Zr-0.2Ce合金的综合力学性能最优,过量Ce的添加将形成粗大的Mg12Ce,易引起应力集中,降低合金的室温强度和伸长率;添加0.2Ce后,合金的室温抗拉强度提高25MPa,300℃时抗拉强度提高17MPa。

The effects of Ce addition on the microstructure and properties of Mg-Gd-Y-Nd-Zr alloy were investigated by optical microscopy （OM）, hardness test, scanning electron microscopy（SEM）, transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The results indicate that Ce can refine the grain of as-cast alloys, accelerate the precipitation process, increase the volume fraction of metastable phase and improve the mechanical properties of the alloy under both ambient and elevated temperatures. Mg-5.5Gd-4.5Y-Nd-0.2Ce-Zr alloy can exhibit the best properties. Excess Ce addition can lead to the formation of coarse MgzzCe particles, which can cause the stress concentration during the deformation, and reduce the strength and elongation at room temperature. Compared with Mg-5.5Gd-4.5Y-Nd-Zr alloy, the ultimate tensile strength of Mg-5. 5Gd-4.5Y-Nd-0.2Ce-Zr alloy at room temperature and 300 ~C increases by 25 MPa and 17 MPa, respectively.