铸态Mg-5Sn-(0～3)Sr合金的组织和性能  

Effects of Different Sr Addition on Microstructure and Mechanical Properties of As-cast Mg-5Sn Alloy

作　　者：李世成[1] 陈云贵[1] 肖素芬[1] 唐永柏[1] 王卿[1] 赵源华[1] 丁武城[1] 

机构地区：[1]四川大学材料科学与工程学院

出　　处：《特种铸造及有色合金》2011年第4期369-372,398-399,共4页Special Casting & Nonferrous Alloys

基　　金：四川省科技厅重点攻关项目(03GG009-007-4)

摘　　要：利用SEM、EDS和XRD等研究了Mg-5Sn-xSr(x=0、0.3、1.0、1.5、2.0、3.0)镁合金的铸态显微组织,测试和分析了合金的室温力学性能。同时研究了Mg-5Sn-xSr合金在载荷为35MPa和温度为175℃下的蠕变性能。结果表明,Sr的加入使得Mg-5Sn合金中生成一种新的MgSnSr耐热相,其形貌呈棒状和针状,随着Sr含量的增加,MgSnSr相的数量逐渐增多而Mg2Sn相的数量却逐渐减少。少量的Sr能细化晶粒,同时由于MgSnSr相的弥散强化作用,使得Mg-5Sn合金的室温力学性能得到改善,其中Sr含量为0.3%时,合金具有最优室温力学性能,抗拉强度达到165MPa,伸长率达到10.4%;并且Sr含量的增加能不断改善Mg-5Sn合金的耐热性能,当Sr含量达到3%时,合金的稳态蠕变速率降低近50%。As-cast microstructure and ambient mechanical properties of Mg-5Sn with different Sn additions(as 0,0.3%,1.0%,1.5%,2.0% and 3.0%) were investigated by SEM(scanning electron microscope),EDS(energy dispersive spectrometer) and XRD(X-ray diffraction) as well as tensile testing,meanwhile,the creep behavior of the alloy was examined with loading of 35 MPa at 175℃.The results reveal that with Sr addition,MgSnSr heat resistant phase with rod and acicular shape can be observed in the Mg-5Sn alloy.With increasing in Sn addition,numbers of MgSnSr phase are increased,and Mg2Sn phase content is decreased.Ambient mechanical properties of the Mg-5Sn alloy can be improved with Sr addition,which is attributed to the refining effects of minor Sr on grain size and dispersed strengthening effects of MgSnSr phase.When Sr addition is 0.3%,tensile strength and elongation of the Mg-5Sn alloy reach 165MPa and 10.4%,respectively,exhibiting desirable mechanical behavior.In addition,heat resistance of the Mg-5Sn alloy can be greatly improved with increasing in Sr contents.Steady creep rate of the alloy with 3% Sr addition is decreased by approximately 50%.

关 键 词：镁合金 Mg-Sn-Sr合金 MgSnSr相 压缩蠕变 

分 类 号：TG113[金属学及工艺—物理冶金]