Mg-6Y-7RE-0.4Zr镁合金的显微组织和力学性能  

Microstructure and Mechanical Properties of Mg-6Y-7RE-0.4Zr Alloys

作　　者：王海珍[1] 张奎[1] 李兴刚[1] 李永军[1] 马鸣龙[1] 何兰强[1] 

机构地区：[1]北京有色金属研究总院有色金属材料制备加工国家重点实验室

出　　处：《特种铸造及有色合金》2010年第5期472-475,共4页Special Casting & Nonferrous Alloys

基　　金：国家重点基础研究发展计划(973计划)资助项目(2007CB613704;2007CB613705)

摘　　要：利用光学显微镜、扫描电镜、X射线衍射、拉伸试验等方法,研究了固溶处理和挤压对Mg-6Y-7RE-0.4Zr合金显微组织和力学性能的影响,以及挤压后合金的高温力学性能。结果表明,铸态合金组织主要由α-Mg基体和Mg24Y5、Mg12RE相组成,经过固溶处理(500℃×8h)之后,Mg-Y相基本消失,Mg-RE相仍有部分存在于晶界处;室温条件下,挤压后合金塑性有了大幅度提高,抗拉强度由156MPa提高到260MPa,且出现了明显的屈服特征,屈服强度为220MPa,伸长率由0.5%提高到7.0%;高温条件下,低于250℃时挤压态合金仍保持与室温条件下相当的力学性能,300℃时强度有所降低,伸长率大幅度提高,σ=215MPa,σ=164MPa,δ=20.5%。Effects of solid solution treatment and hot extrusion on microstructure and mechanical properties of Mg-6Y-7RE-0.4Zr alloys at room temperature and high temperature were investigated by optical microscope (OM),SEM (scanning electron microscope),EDS (energy dispersive spectroscopy),XRD (X-ray diffraction) and tensile testing.The results reveal that as-cast microstructure of the alloy is composed of α-Mg matrix,Mg24Y5 and Mg12RE phases.After solid solution treatment at 500 ℃ for 5 hours,Mg-Y phase is mostly dissolved into the matrix,while part of Mg-RE phase still exists at the intergranular.Plasticity of as-extruded alloy at room temperature is greatly improved,and tensile strength is increased from 156MPa to 260MPa,and yield strength reach 220MPa,showing apparent yield plateau,and elongation is increased from 0.5% to 7%.In condition of high temperature,mechanical properties of extruded alloy are equivalent to those of one at room temperature below 250℃,while strength is slightly decreased with great increase of elongation at 300℃,where tensile strength,yield strength and elongation reach 215MPa,164 MPa and 20.5%,respectively.

关 键 词：Mg-6Y-7RE-0.4Zr镁合金 固溶处理 挤压 显微组织 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]