Mg-7Zn-0.3La-xCu镁合金半固态组织演变  

Semi-solid Microstructure Evolution of Mg-7Zn-0.3La-xCu Magnesium Alloy

作　　者：黄晓锋[1,2] 陈宣宇 贺光亮 张鑫涛 陶伟 何丹丹 HUANG Xiaofeng;CHEN Xuanyu;HE Guangliang;ZHANG Xintao;TAO Wei;HE Dandan(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050;Key Laboratory of Nonferrous Metal Alloys and Processing,Ministry of Education,Lanzhou University of Technology,Lanzhou 730050)

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,兰州730050 [2]兰州理工大学有色金属合金及加工教育部重点实验室,兰州730050

出　　处：《特种铸造及有色合金》2024年第10期1416-1422,共7页Special Casting & Nonferrous Alloys

基　　金：甘肃省科技重大专项资助项目(22ZD6GA008)。

摘　　要：采用等温热处理法制备了Mg-7Zn-0.3L_(a-x)Cu(x=0,0.5,1.0,1.5,质量分数,%,下同)镁合金半固态浆料。利用光学显微镜、扫描电镜和EDS等设备观察Cu含量、等温温度和等温时间对Mg-7Zn-0.3La镁合金半固态组织演变的影响。结果显示,Mg-7Zn-0.3La-1Cu镁合金的铸态组织组成主要由白色α-Mg基体和黑色共晶组织(α-Mg+MgZn_(2)+Mg_(4)Zn_(7)+CuMgZn)组成。该合金在等温热处理初始阶段,Cu起着加速非枝晶颗粒分离和球化的作用;随着等温温度的升高或等温时间的延长,非枝晶颗粒尺寸和形状因子呈先减小后增大的趋势,其中等温温度为580℃,等温时间为30 min时,Mg-7Zn-0.3La-1Cu镁合金的非枝晶组织呈现理想状态,此时的非枝晶颗粒的平均尺寸、形状因子和固相率分别为43.51μm、1.32和64.38%。在半固态组织的演变过程中,合金组织主要经历了初始粗化、组织分离、球化及最后的粗化4个阶段。A Mg-7Zn-0.3La-xCu(x=0,0.5,1.0,1.5,%)magnesium alloy semisolid slurry was prepared using iso⁃thermal heat treatment method.The influence of Cu content,isothermal temperature,and isothermal time on the evo⁃lution of semi-solid microstructure of Mg-7Zn-0.3La magnesium alloy was observed using optical microscopy,scan⁃ning electron microscopy,and EDS analysis.The experimental results reveal that the as-cast microstructure of Mg7Zn-0.3La-1Cu magnesium alloy mainly consists of a whiteα-Mg matrix and a black eutectic structure(α-Mg+MgZn2+Mg4Zn7+CuMgZn).During the initial stages of isothermal heat treatment,Cu plays a role in accelerating the sepa⁃ration and spheroidization of non-dendritic grains.With increasing in isothermal temperature or extension of isothermal time,the non-dendritic grain size and shape factor exhibit a trend of first decrease and then increase.Specifically,with the isothermal heat treatment parameters set at 580℃for 30 min,the non-dendritic microstructure of Mg-7Zn-0.3La1Cu magnesium alloy reaches desirable,where the average non-dendritic grain size,shape factor,and solid fraction reach up to 43.51μm,1.32,and 64.38%,respectively.The evolution of semisolid microstructure mainly undergoes four stages:initial coarsening,structure separation,spheroidization,and final coarsening.

关 键 词：CU含量 镁合金 半固态 演变机理 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG249.2[金属学及工艺—金属材料]