稀土元素Gd对Mg-Y-Zr合金组织和高温力学性能的影响  

Effect of Gd on Microstructure and High Temperature Mechanical Properties of Mg-Y-Zr Alloys

作　　者：董丽君[1] 夏长清[2] 周岩[1] 

机构地区：[1]湖南工程学院机械学院,湖南湘潭411101 [2]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《铸造》2014年第11期1149-1152,共4页Foundry

基　　金：湖南省科技厅科技计划项目(2012FJ3032);工程车辆轻量化与可靠性技术湖南省高校重点实验室开放基金资助项目(2012KFJJ0)

摘　　要：采用光学显微镜、扫描电镜、透射电镜、X射线衍射、高温力学性能测试等对3种合金的显微组织与力学性能进行了分析,研究了Gd元素对合金显微组织及高温力学性能的影响。稀土元素Gd和Y以Mg5Gd、Mg3Gd和Mg24Y5相存在于铸态组织晶界,这些相均具有很好的耐热性,是主要的强化相。试验合金经挤压+T6时效峰值处理后,合金中会析出弥散强化相β′(cbco)和β(Mg5Gd,fcc),且随Gd含量的提高,弥散析出相增多,在时效过程中形成的析出相对位错运动和变形产生很大的阻力。1#、2#、3#合金在300℃拉伸时强度分别为192.7 MPa、245.3 MPa、252.8 MPa。高温力学性能测试表明,Gd元素添加量的增加,使合金高温抗拉强度得到了较大提高。The microstructure and mechanical properties of the three alloys were investigated through optical microscopy,scanning electron microscopy,transmission electron microscopy,X-ray diffraction analysis and high temperature tensile test.The effects of Gd elements on the alloys＇ the microstructure and high temperature tensile properties were investigated.The element Gd and Y as Mg5Gd,Mg3Gd and Mg24Y5 in the grain boundaries with cast structure in the alloys.These phases are the main strengthening phase because of their good thermal stability.Dispersion strengthening phases β＇ （cbco） and β（Mg5Gd,fcc） would be precipitated from the alloy after extrusion T6 aging peak value treatment and the precipitation increased with the increase of Gd contents.The precipitated phase presented strong resistance to dislocation movement and deformation.The strength of 1#,2# and 3# alloys at 300 ℃ was 192.7 MPa,245.3 MPa and 252.8 MPa.The results of high temperature tensile test revealed that the increase of Gd addition improved the alloys＇ tensile strength under high temperatures.

关 键 词：MG-GD-Y-ZR镁合金 显微组织 高温力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]