Gd含量对Mg-Gd-Sm-Zr合金组织和性能影响

Effect of Gd content on microstructure and mechanical properties of Mg-Gd-Sm-Zr alloy

通过光学显微镜(OM)、透射电镜(TEM)、X射线衍射(XRD)及室温到300℃的拉伸试验,研究了Mg-(6,9,12,15)Gd-1Sm-0.5Zr镁合金显微组织和力学性能的影响。结果表明:时效态Mg-Gd-Sm-Zr系镁合金由α-Mg基体和Mg5Gd相组成。适量Gd元素的添加能够细化合金组织、提高合金室温和高温的力学性能。在Gd含量达到和超过9 mass%后,合金出现抗拉强度反常温度效应,本文初步探讨了出现这种现象的微观机理。合金伸长率在200℃以下时,随Gd添加量的增加而减小;超过200℃后,伸长率随Gd添加量的增大而增大。

Effect of Gd content on microstructure and mechanical properties of Mg-Gd-Sm-Zr alloys was investigated by optical microscope（OM）,transmission electron microscopy（TEM）,X-ray diffraction（XRD） and mechanical tensile test.The results show that the aged MgGd-Sm-Zr magnesium alloys consist of α-Mg matrix and Mg5Gd phase.A moderate amount of Gd element addition can refine microstructure and increase mechanical properties of the alloy at room and high temperature.The abnormal temperature effect for tensile strength occurs in the alloys when the Gd content is equal to and high than 9 mass%,for which the microscopic mechanism is discussed.Elongation of the alloy decreases with the increase of Gd content under 200 ℃,and increases with the increase of Gd content above 200 ℃.