热处理对Mg-6Zn-1.5Cu合金组织及性能的影响  

Effects of Heat Treatment on the Microstructure and Mechanical Properties of Mg-6Zn-1.5Cu Magnesium Alloy

作　　者：张玉[1] 黄晓锋[1,2] 马振铎[1] 李雅[1] 马颖[1,2] 郝远[1,2] 

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室 [2]兰州理工大学有色金属合金及加工教育部重点实验室

出　　处：《特种铸造及有色合金》2017年第10期1045-1049,共5页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51464032);国家高技术研究发展计划(973计划)资助项目(2010CB635106)

摘　　要：利用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)和力学万能试验机等手段研究了铸造Mg-6Zn-1.5Cu合金在不同状态下的组织,性能及断裂行为。结果表明,合金的铸态组织主要由α-Mg相,在晶界处呈连续或半连续分布的(α-Mg+MgZn_2+Mg_2Cu+CuMgZn)共晶相和晶内呈孤立的颗粒状相组成。合金在450℃固溶12~36h和180℃时效12~36h范围内,随着保温时间延长,固溶效果和时效强化效应逐渐增加;当固溶和时效时间超过28h后,固溶残余的共晶化合物和时效析出强化相均有粗化现象。合金在时效28h后获得了良好的组织,最大抗拉强度达265 MPa,最大伸长率达5.90%。铸态合金的断裂方式呈解理和沿晶断裂特征,时效处理后合金的断裂方式以沿晶和穿晶断裂混合模式存在。The microstructure,mechanical properties and fracture behaviors of Mg-6Zn-1.5Cu alloy at ascast,solution and aging treatment were investigated by OM,SEM,TEM,XRD and mechanical tests,respectively.The experimental results indicate that the microstructure of the as-cast alloy is composed ofα-Mg,semi-continuously or continuously distributed intermetallics（α-Mg＋MgZn2＋Mg2Cu＋CuZnMg）at grain boundaries and isolated particles in the grain.With the increase of holding time,solution effects and aging strengthening effects of the alloy are increased gradually with solution treatment at 450℃ for 12,20,28 and 36 h,and then aged at 180℃ for 12,20,28 and 36 h.With the solution and aging time more than 28 h,residual eutectic compounds and aging strengthening precipitation present coarsening phenomenon.With aged at 180℃ for 28 h,the alloy with desirable structure presents tensile strength and elongation of 265 MPa and 15.90%,respectively.The fracture morphology of the as-cast alloy is characterized by cleavage and inter-granular fracture,while the fracture behavior of the alloy aged is dominated by the mixture of inter-granular and trans-granular modes.

关 键 词：Mg-6Zn-1.5Cu镁合金 显微组织 热处理工艺 力学性能 断裂行为 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG166.4[金属学及工艺—金属材料]