Sn对正挤压Mg-Al-Sn-Zn-Y合金组织和力学性能的影响  

Effect of Sn on Microstructure and Mechanical Properties of Forward Extruded Mg-Al-Sn-Zn-Y Alloys

作　　者：孙尧 杨文朋[1,2] 王诗蒙 郭学锋[1,2] SUN Yao;YANG Wenpeng;WANG Shimeng;GUO Xuefeng(School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;Henan International Joint Research Laboratory for High-Performance Light Metallic Materials and Numerical Simulations,Henan Polytechnic University,Jiaozuo 454000,China)

机构地区：[1]河南理工大学材料科学与工程学院,河南焦作454000 [2]河南理工大学河南省高性能轻金属材料及其数值模拟国际联合实验室,河南焦作454000

出　　处：《有色金属工程》2020年第10期16-22,共7页Nonferrous Metals Engineering

基　　金：国家自然科学基金资助项目(51571086)。

摘　　要：在275~400℃对Mg-6Al-2Sn-0.5Zn-0.5Y和Mg-5Al-4Sn-0.5Zn-0.5Y合金正挤压,利用光学金相显微镜(OM)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)分析显微组织,并测试了其室温拉伸性能。结果表明,铸态合金主要由α-Mg、β-Mg17Al12相和Mg2Sn相组成。Sn含量由2%增加到4%后,Mg2Sn相和离异共晶β-Mg17Al12相体积分数增加,层片状共晶β-Mg17Al12相体积分数减少。挤压温度相同时,Mg-5Al-4Sn-0.5Zn-0.5Y合金挤压试样力学性能均优于Mg-6Al-2Sn-0.5Zn-0.5Y合金,275℃挤压试样抗拉和屈服强度最高,分别为329.9和254.4MPa。两种合金的室温拉伸断裂方式均为准解理断裂。Sn的添加可有效促进挤压过程中动态再结晶的形核,并抑制再结晶晶粒长大,从而同时提高挤压态合金的强度和塑性。The microstructures of forward extruded Mg-6Al-2Sn-0.5Zn-0.5Y and Mg-5Al-4Sn-0.5Zn-0.5Y alloys at a temperature range of 275-400℃were investigated by OM,XRD and SEM,and the tensile properties of as-extruded samples were tested at room temperature.The results show that the two alloys are mainly composed ofα-Mg,eutecticβ-Mg 17 Al 12 phase and Mg 2 Sn phase.With the increase of Sn content from 2%to 4%,the volume fractions of the Mg 2 Sn phase and the divorced eutecticβ-Mg 17 Al 12 phase increased,meanwhile,the volume fraction of the lamellar eutecticβ-Mg 17 Al 12 phase decreased.At the same extrusion temperature,Mg-5Al-4Sn-0.5Zn-0.5Y sample shows better mechanical properties than that of Mg-6Al-2Sn-0.5Zn-0.5Y sample.Mg-5Al-4Sn-0.5Zn-0.5Y alloy extruded at 275℃shows high ultimate tensile strength of 329 MPa and yield strength of 254.4 MPa.The room temperature tensile fracture mode of the two alloys is quasi-cleavage fracture.The addition of Sn effectively promotes the nucleation of dynamic recrystallization and suppresses the growth of recrystallized grains during extrusion process.Therefore,the strength and plasticity of the extruded alloy are improved simultaneously.

关 键 词：镁合金 正挤压 显微组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]