铸造Mg-3Zn-0.5Cu-0.6Zr镁合金的时效析出行为研究  

A study of precipitation behabior of cast Mg-3Zn-0.5Cu-0.6Zr magnesiym alloy

作　　者：李爱文[1] 刘江文[1] 伍翠兰[2] 罗承萍[1] 焦东玲[1] 朱红梅[1] 

机构地区：[1]华南理工大学材料科学与工程学院,广州510640 [2]湖南大学材料科学与工程学院,长沙410082

出　　处：《材料科学与工艺》2010年第6期883-888,共6页Materials Science and Technology

基　　金：广东省自然科基金项目资助(070006483);国家重点基础研究"973"项目资助(2009CB623704;2008CB617608)

摘　　要：利用金相显微镜、显微硬度计、X射线衍射仪、扫描和透射电镜研究了铸造Mg-3Zn-0.5Cu-0.6Zr镁合金铸态和固溶时效后的显微组织,初步确定了时效Mg-3Zn-0.5Cu-0.6Zr镁合金中主要合金相的种类和形态.合金铸态组织主要由初晶Mg基体和(Mg+Mg2Cu,CuMgZn)共晶组成.固溶后,晶界处大部分非平衡共晶组织溶解;180℃/20h时效后达到合金时效硬度峰值,此时晶内析出相主要有三类:(1)轴线垂直于(0001)Mg,板条状或棱柱状β2'-MgZn2,长度50nm～200nm,该相是合金的主要时效硬化相;(2)较粗大的、其轴线仍与基面垂直的六棱柱状β2'-MgZn2;(3)轴线平行于(0001)Mg,板条状或针状β-MgZn,长度50nm～150nm.The types and nature morphologies of precipitates in as-cast and aged Mg-3Zn-1.5Cu-0.6Zr magnesium alloy were studied.The microstructure of the as-cast alloy was composed of Mg matrix and nonequilibrium eutectic（Mg＋Mg2Cu,CuMgZn） formed at grain boundaries,and most of the nonequilibrium eutectic were dissolved after solution treatment at 440 ℃.Three types of precipitates were found after aging at 180 ℃ for 20 h.The first type（lath-like） was MgZn2 with length of 50200nm and very high density,which was perpendicular to the base plane of the Mg matrix and primarily responsible for the hardening of the alloy.The second type（lath-like or neddle-like） was MgZn with length of about 50150 nm,which was parallel to the base plane.The third one（plate-like） was MgZn2 with length of about 50100nm,which was also parallel to the base plane

关 键 词：Mg-Zn-Cu镁合金 显微组织 CuMgZn MgZn2 MgZn 

分 类 号：TB34[一般工业技术—材料科学与工程]