均匀化退火对Al-8Zn-1.2Mg-1.5Cu合金显微组织和力学性能的影响  

Effect of homogenization annealing on microstructure and mechanical properties of Al-8Zn-1.2Mg-1.5Cu alloy

作　　者：刘文义[1] 王永善[1] 李亚鹏[1] 张会[1] LIU Wen-yi;WANG Yong-shan;LI Ya-peng;ZHANG Hui(School of Materials Science and Engineering,Shaanxi University of Technology,Hanzhong 723000,China)

机构地区：[1]陕西理工大学材料科学与工程学院,陕西汉中723000

出　　处：《材料热处理学报》2024年第12期75-83,共9页Transactions of Materials and Heat Treatment

基　　金：陕西省科技厅项目(2024GX-YBXM-361,2024GX-YBXM-376,2024CY2-GJHX-37);陕西省秦创原“科学家+工程师”队伍建设项目(2024QCY-KXJ-013)。

摘　　要：通过半固态电磁搅拌铸造法制备了Al-8Zn-1.2Mg-1.5Cu合金,并对其进行均匀化退火处理。采用光学显微镜、X射线衍射仪、扫描电镜、金属涡流电导仪和维氏硬度计等对合金组织和性能进行分析与测试。结果表明:铸态Al-8Zn-1.2Mg-1.5Cu合金的组织主要由α-Al基体和MgZn_(2)相组成,并存在严重的枝晶偏析;随着均匀化退火温度从400℃升高到460℃,粗大的网状枝晶组织逐渐消失,MgZn_(2)和非平衡共晶相逐渐溶入α-Al基体中,合金的硬度和电导率先增大后减小,在440℃退火保温12 h后硬度达到最大值,为134.8 HV0.3;在460℃均匀化退火时,随着保温时间从6 h增加到24 h,合金中的共晶组织不断溶解,硬度先增大后减小,在保温时间为18 h时达到最大值,为131.7 HV0.3,合金的电导率则是呈先下降再上升随后下降的趋势。Al-8Zn-1.2Mg-1.5Cu alloy was prepared by semi-solid electromagnetic stirring casting technology and subjected to homogenization annealing treatment.Microstructure and properties of the alloy were analyzed and tested using optical microscope,X-ray diffraction,scanning electron microscopy,metal eddy current conductivity tester and Vickers hardness tester.The results show that the microstructure of the as-cast Al-8Zn-1.2Mg-1.5Cu alloy is mainly composed ofα-Al matrix and MgZn_(2) phase,and there is severe dendritic segregation.As the homogenization annealing temperature increases from 400℃to 460℃,the coarse network dendritic structure gradually disappears,the MgZn_(2) and non-equilibrium eutectic phases gradually dissolve into theα-Al matrix,and the hardness and conductivity of the alloy first increase and then decrease.After annealing at 440℃for 12 h,the hardness reaches its maximum value,which is 134.8 HV0.3.When homogenizing annealing at 460℃,as the holding time increases from 6 h to 24 h,the eutectic structure in the alloy continuously dissolves,the hardness first increases and then decreases,which reaches its maximum value of 131.7 HV0.3 at the holding time of 18 h,and the conductivity of the alloy shows a trend of first decreasing,then increasing,and then decreasing.

关 键 词：AL-ZN-MG-CU合金 均匀化退火 显微组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]