高强Mg-Gd-Y-Zn-Zr合金的微观组织和力学性能  

Microstructures and mechanical properties of high-strength Mg-Gd-Y-Zn-Zr alloy

作　　者：王振东[1] 房灿峰[1] 孟令刚[1] 李乃朴[1] 吴友芳[1] 张兴国[1] 

机构地区：[1]大连理工大学材料科学与工程学院,大连116024

出　　处：《中国有色金属学报》2012年第1期1-6,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(50875031)

摘　　要：通过金属模铸、热挤压和时效处理(T5)工艺过程制备出高强Mg-7Gd-4Y-1.6Zn-0.5Zr合金,并利用光学显微镜、XRD、SEM及TEM分析研究Mg合金不同状态下的显微组织和力学性能。结果表明:Mg-7Gd-4Y-1.6Zn-0.5Zr合金的铸态组织主要由α-Mg基体和沿晶界分布的片层状第二相Mg12Zn(Gd,Y)组成,经过热挤压变形后,合金晶粒显著细化,时效处理过程中Mg12Zn(Gd,Y)相上析出少量细小的颗粒状Mg3Zn3(Gd,Y)2相。时效态合金的抗拉强度、屈服强度和伸长率分别达到446 MPa、399 MPa和6.1%,其强化方式主要为细晶强化和第二相强化。High-strength Mg-7Gd-4Y-1.6Zn-0.5Zr alloy was prepared by conventional metal mold casting,subsequently hot extrusion and T5 heat treatment were conducted.The microstructures and mechanical properties of this Mg alloy under different states were studied by using OP,XRD,SEM and TEM.The results show that the as-cast microstructures of Mg-7Gd-4Y-1.6Zn-0.5Zr alloy consists of α-Mg matrix and lamellar second-phase Mg12Zn（Gd,Y） phase which distributes around α-Mg matrix.After hot extrusion,the grain size of this alloy can be refined dramatically.Tiny little particle Mg3Zn3（Gd,Y）2 phase is precipitated out of the Mg12Zn（Gd,Y） phase during the process of T5 heat treatment.The tensile strength,yield strength and elongation of alloys under T5 condition reach 446 MPa,399 MPa and 6.1%,respectively.The main strengthening methods are considered as fine grain strengthening and second-phase strengthening.

关 键 词：高强镁合金 稀土 热挤压 时效处理 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]