热处理对砂型铸造Mg-Gd-Y合金微观组织和力学性能的影响
杨庆波1,2
吴迪
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陈荣石
1中国科学院金属研究所，沈阳110016）(2沈阳大学机械工程学院，沈阳110044）
牛建平2
文摘通过金相观察(OM)、扫描电镜(SEM)以及拉伸测试系统地表征和研究了热处理对砂型铸造Mg-Gd-Y合金微观组织和力学性能的影响。研究表明：固溶态GW94、CW74、CW44合金主要由α-Mg过饱和固溶体、铸态残留相Mgs（Gd,Y)以及固溶过程形成的方块相组成。随着Gd含量的增加，固溶态Mg-Gd-Y合金中方块相的体积分数不断增加；在同一时效温度下，合金达到时效峰值的时效时间缩短；室温下拉伸的固溶态、时效峰值态合金以及200和250℃下拉伸的时效峰值态合金的抗拉强度和屈服强度不断提高（围溶态合金层服强度先降低后升高），但是伸长率却是不断降低。时效峰值态GW94合金表现出优越的力学性能，室温时其抗拉强度和属服强度分别为300、247MPa，而伸长率仅为0.9%；200和250℃拉伸时，时效峰值态GW94合金抗拉强度、届服强度和伸长率分别为329、234MPa和2.6%以及312、233MPa和2.7%。时效峰值态GW94、 GW74合金出现抗拉强度随温度升高而升高的反常力学行为。
关键词热处理，砂型铸造，Mg-Gd-Y合金，微观组织，力学性能
中图分类号：TG146
D0I:10.3969/j.issn.10072330.2016.05.013
Effect of Heat Treatment on Microstructure and Mechanical Properties of
Sand Casting Mg-Gd-Y Magnesium Alloys
YANG Qingbo'-2
WUDi'
MAYuequn'
CHEN Rongshi'
NIU Jianping
(1Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016)(2 School of Mechanical Engineering, Shenyang University, Shenyang110044)
Abstract The effect of heat treatment on microstructure and mechanical properties of sand casting Mg-GdY system alloys were investigated systematically by optical microscopy(OM), scanning electron microscopy(SEM) and tensile tests. The results showed that the microstructure of solutionized GW94, CW74 and CW44 Mg alloys was main-ly composed of supersaturated αMg solid solution, residual phases of Mgs(Gd, Y) as well as square phases formed during solution treatment. As the content of Gd addition to MgGdY alloys increased, the volume fraction of square phases in the matrix increased. The time of reaching peak hardness decreased in the same aging temperature. The ul-timate tensile strength and yield strength increased gradually ( the yield strength of solutionized alloys firstly decreased and then increased) , while the elongation-to-failure decreased gradually from solution treated and peak-aged alloys at eeeeea cal properties. The ultimate tensile strength, yield strength and elongation-to-failure of the peak-aged CW94 Mg alloys
收稿日期：2016-02-14
基金项目：国家重点基础研究发展计划(973计划：2013CB632202）和国家自然科学基金(51301173)(51531001)
作者简介杨庆波，1987年出生，硕士，主要研究方向为高强耐热Mg-Gd-Y合金微观组织和力学性能的表征与调控。E-mail：813351739@qq.com 通讯作者：吴迪，副研究员。E-mail：dwu@imr.ac.cn
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2016年第5期