摘要
通过光学显微镜对铸态Mg-11Gd-2Y-x Sm-0.5Zr(x=0,1,3,5)合金微观组织进行观察,使用X射线衍射仪研究合金的物相组成,同时通过扫描电镜和能谱仪对合金微观形貌及成分进行观察,最后利用拉伸实验测试合金的力学性能。研究结果表明:铸态Mg-11Gd-2Y-0.5Zr合金组织由固溶有稀土元素的粗大枝晶状α-Mg基体和沿晶界析出的稀土化合物Mg_5Gd和Mg_(24)Y_5组成。Sm的加入增加了Mg_(41)Sm_5相,使基体由粗大的树枝晶逐渐转变为枝晶细小的等轴晶。随着Sm含量的增加,第二相形态由不连续分布向连续网状分布转变。Sm的加入明显提高合金的强度,使合金室温强度先升高后降低,伸长率由2.39%下降至0.47%,在本研究范围内,Sm加入量为3%时合金抗拉强度为220 MPa,伸长率为1.19%,综合力学性能最优。
The microstructure of as cast Mg-llGd-2Y-xSm-0.5Zr （x=0,1,3,5） alloy was studied by optical microscope（OM）, the composition of alloy phase was studied by X- ray diffraction（XRD）, the micro morphology and element composition were observed by scanning electron microscope （SEM） and energy dispersive spectroscopy（EDS）. Finally, tensile test was used to test the mechanical properties of the alloy. The results show that the as cast Mg-11Gd-2Y-0.5Zr（x=0） alloy mainly consisted ofet-Mg matrix which is a solid solution of rare earth elements with coarse dendrite morphology while MgsGd and Mg24Y5 precipitates along grain boundaries. Besides a new phase Mg4~Sm5 appeared, the addition of Sm change the growth front of solid liquid interface which gradually change the matrix microstructure from coarse dendrite into fine equiaxed grains. With the increase of Sm content the morphology of second phase transformed from discontinuous mesh distribution to continuous network distribution. The addition of Sm improve the strength of the alloy significantly, with the increase of Sm, the tensile strength of alloy increase first and then decrease, while the elongation decrease from 2.39% to 0.47%. Within the scope of this study, the alloy has optimal mechanical properties when 3% Sm was added, which the tensile strength is 220 MPa, elongation is 1.19%.
作者
周耀
李全安
付三玲
张兴渊
陈晓亚
严景龙
ZHOU Yao LI Quan-an FU San-ling ZHANG Xing-yuan CHEN Xiao-ya YAN Jing-long(Department of Material, Henan University of Science and Technology, Luoyang 471023, Henan, China Collaborative innovation center of Henan Province, the common technology of nonferrous metals, Luoyang 471023, Henan, China)
出处
《铸造》
CAS
CSCD
北大核心
2017年第2期178-181,共4页
Foundry
基金
国家自然科学基金(51171059
51571084)
河南省重点科技攻关项目(152102210072)
关键词
SM
镁合金
微观组织
力学性能
Sm
magnesium alloy
microstructure
mechanical properties
