High strength magnesium alloy with α-Mg and W-phase processed by hot extrusion  

热挤压高强度Mg-6Zn-4Y合金(英文)

作　　者：杨文朋[1] 郭学锋[2] 

机构地区：[1]西安理工大学材料科学与工程学院,西安710048 [2]河南理工大学材料科学与工程学院,焦作454003

出　　处：《Transactions of Nonferrous Metals Society of China》2011年第11期2358-2364,共7页中国有色金属学报（英文版）

基　　金：Project (50271054) supported by the National Natural Science Foundation of China;Project (20070700003) supported by the Doctorate Programs Foundation of Ministry of Education of China;Project (102102210031) supported by the Science and Technologies Foundation of Henan Province, China;Project (2010A430008) supported by the Natural Science Foundation of Henan Educational Committee of China

摘　　要：Fine-grained Mg-6Zn-4Y alloy was prepared by an ingot metallurgy process with hot extrusion at 300 ℃.The microstructure was studied by XRD,OM,SEM and TEM,and the tensile properties were tested at room temperature.The results show that the alloy is composed of α-Mg and W-phase.The microstructure of the as-extruded alloy has a bimodal grain size distribution.The fine grains with the mean size of 1.2 μm are formed by dynamic recrystallization.The coarse grains（about 23% in area fraction） are unrecrystallized regions which are elongated along extrusion direction.The engineering stress—strain curve shows a pronounced yield point.The ultimate tensile strength,yield strength,and elongation are（371±10） MPa,（350±5） MPa and（7±2）%,respectively.The high strengths are attributed to the fine-grained matrix structure enhanced by W-phase particles,nano-scaled precipitates,and strong basal plane texture.通过铸造和300℃热加压制备细晶Mg-6Zn-4Y合金,利用XRD、OM、SEM和TEM研究合金组织,并测试其室温拉伸性能。结果表明,合金主要由α-Mg和W相两相组成,挤压态合金具有双峰晶粒尺寸分布;细小晶粒为动态再结晶晶粒,平均尺寸为1.2μm;粗大晶粒(占面积分数的23%)为未再结晶区域,并沿挤压方向被拉长。合金的极限抗拉强度、屈服强度和伸长率分别为(371±10)MPa,(350±5)MPa和(7±2)%,其工程应力—应变曲线有明显的屈服点。合金高强度归因于晶粒细化和W相、纳米沉淀颗粒及强基面织构的增强作用。

关 键 词：Mg-6Zn-4Y alloy EXTRUSION W-phase high strength yield phenomenon 

分 类 号：TG379[金属学及工艺—金属压力加工]