Effect of stannum addition on microstructure of as-cast and as-extruded Mg-5Li alloys  

Sn对Mg-5Li合金铸态和挤压态组织的影响(英文)

作　　者：蒋斌[1,2] 殷恒梅[1] 杨青山[1,2] 李瑞红[1,2] 潘复生[1,2] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400044 [2]国家镁合金材料工程技术研究中心,重庆400044

出　　处：《Transactions of Nonferrous Metals Society of China》2011年第11期2378-2383,共6页中国有色金属学报（英文版）

基　　金：Projects (51171212, 50725413) supported by the National Natural Science Foundation of China;Project (2007CB613706) supported by the National Basic Research Program of China;Project (2009AA03Z507) supported by the National High-tech Research Program of China;Projects (2010CSTC-BJLKR, CSTC2010AA4048) supported by Chongqing Science and Technology Commission, China

摘　　要：Mg-5Li-xSn （x=0.15, 0.25 and 0.65, mass fraction） alloys were prepared. The microstructures of these alloys were investigated through optical microscope （OM）, scanning electron microscope （SEM）, X-ray diffractometer （XRD） and energy dispersive spectrometer （EDS）. The results indicate that Sn additions produce a strong grain refinement effect on Mg-5Li alloy. The mean grain size of as-cast Mg-Li alloys with Sn is reduced remarkably from 556 μm to 345 μm, and that of the as-extruded alloys is reduced from 33 μm to 23 μm when the Sn content increases from 0.15% to 0.65%. The near net-like Mg2Sn phase in the as-cast alloys is verified at the grain boundaries. After extrusion, the granular Mg2Sn phase mainly exists inside the grains and thus can act as nucleation sites of α-Mg grains during the dynamic recrystallization and make the microstructure finer.在氩气保护气氛下熔炼,得到Mg-5Li-xSn(x=0.15,0.25和0.65,质量分数)系列合金。通过光学显微镜、扫描电镜、X射线衍射仪和能谱仪分析合金的显微组织。结果表明,Mg-5Li合金中添加的Sn元素可以起到明显的晶粒细化作用,当Sn含量从0.15%增加到0.65%时,铸态合金的平均晶粒尺寸从556μm细化到345μm,相应的挤压态合金的晶粒从33μm减小到23μm。近似网状的第二相Mg2Sn分布在铸态合金的晶界上,挤压之后,颗粒状的Mg2Sn主要分布在晶粒内部。这些金属间化合物在挤压动态再结晶中可以作为有效的形核质点,从而起到细化晶粒的作用。

关 键 词：Mg-Li alloys grain refinement intermetallic compound Sn 

分 类 号：TG146.22[一般工业技术—材料科学与工程]