钆对Mg-8Li-4Zn-xGd合金铸态组织与力学性能的影响  

Effects of Gd on microstructures and mechanical properties of as-cast Mg-8Li-4Zn-xGd alloys

作　　者：徐春杰[1,2] 徐信锋 马涛 孟令楠[1,2] 张忠明[1,2] SHECHTMAN Dan XU Chun-jie;XU Xin-feng;MA Tao;MENG Ling-nan;ZHANG Zhong-ming;SHECHTMAN Dan(School of Materials Science and Engineering,Xi'an University of Technology,Xi’an 710048,China;Xi’an Shechtman Nobel Price New Materials Institute,Xi'an 710048,China;Department of Electrical and Mechanical Engineering,Shaanxi Railway Institute,Weinan 714099,China;Shanghai Spaceflight Precision Machinery Institute,Shanghai 201600,China)

机构地区：[1]西安理工大学材料科学与工程学院,西安710048 [2]西安谢赫特曼诺奖新材料研究院,西安710048 [3]陕西铁路工程职业技术学院机电工程系,渭南714099 [4]上海航天精密机械研究所,上海201600

出　　处：《中国有色金属学报》2020年第4期793-800,共8页The Chinese Journal of Nonferrous Metals

基　　金：陕西省重点研发计划资助项目(2017GY-135);国家自然科学基金资助项目(U1502274)。

摘　　要：采用锂盐熔剂保护熔铸Mg-8Li-4Zn-xGd(x=1,3,5)合金铸锭,研究钆含量对铸态合金组织和力学性能的影响。结果表明:Mg-8Li-4Zn-xGd合金基体由α-Mg(HCP)和β-Li(BCC)双相构成。随着钆含量的增加,Mg5Gd共晶相和Zn12Gd化合物相逐渐连成网状,将基体α+β双相隔离成20~40μm的等轴状或类似于铸铁中的共晶团状,可有效细化α-Mg相和连续的β-Li相;组织中大颗粒Mg2Zn11相弥散分布在β-Li相内,Mg51Zn20相分布在α-Mg晶界处;锌元素还可以在β-Li相中析出细小弥散分布的MgZn相,其数量随钆含量的增加而增加,可直接弥散强化β-Li相。此外,锌和钆对合金硬度的影响较大,随着钆含量的增加,合金的抗拉强度提高,但伸长率降低。As-cast ingots of Mg-8Li-4Zn-xGd(x=1,3,5)alloys were prepared by lithium flux protection in an electric-resistance furnace.The effects of Gd addition on microstructures and mechanical properties of as-cast Mg-8Li-4Zn-xGd alloys were investigated.The results show that the matrix of as-cast Mg-8Li-4Zn-xGd alloys is consisted ofα-Mg(HCP)andβ-Li(BCC)phase.With the content of Gd increasing,the Mg5Gd eutectic and Zn12Gd compound are gradually connected into network,isolatingαandβeutectic into equiaxed with a dimension from 20μm to 40μm or eutectic-cell similar to those in the cast iron,which can refineα-Mg and the continuousβ-Li phase effectively.The large Mg2Zn11 particles are dispersed inβ-Li phase and the Mg51Zn20 phases are distribution at the grain boundary ofα-Mg phase.Zn can also precipitate the fine dispersed MgZn phases in theβ-Li phase and the quantity increases with the increase of Gd content,which can directly dispersion strengtheningβ-Li phase.In addition,Zn and Gd have a great influence on the hardness of as-cast alloy,and with the Gd content increasing,the tensile strength of Mg-8Li-4Zn-xGd alloys increases,while the elongation decreases.

关 键 词：MG-LI合金 钆 显微组织 相组成 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]