固溶时间对Sr/Ce复合变质A357合金组织和性能的影响  

Influence of solution time on microstructure and properties for A357 alloy with Sr/Ce complex modification

作　　者：王波[1] 李青 刘让贤[1] 陈胜迁[1] Wang Bo;Li Qing;Liu Rangxian;Chen Shengqian(Department of Aviation Maintenance Engineering,Zhangjiajie Institute of Aeronautical Engineering,Zhangjiajie 427000,China;School of Liberal Arts Education,Guangzhou College of Technology and Business,Guangzhou 510850,China)

机构地区：[1]张家界航空工业职业技术学院航空维修工程系,湖南张家界427000 [2]广州工商学院通识教育学院,广东广州510850

出　　处：《锻压技术》2022年第8期200-207,共8页Forging & Stamping Technology

基　　金：湖南省自然科学基金资助项目(2020JJ7074);广东省金属强韧化技术与应用重点实验室开放课题。

摘　　要：采用金相显微镜、扫描电子显微镜、拉伸试验机和显微硬度仪,研究了不同固溶时间下Sr/Ce复合变质A357合金的组织和性能,并讨论了第二相特征的演变过程及其对合金性能的影响。研究结果表明:T6热处理后,共晶硅和Mg_(2)Si的面积分数均显著的降低,并随着固溶时间的延长而呈现先降低后增加的趋势。共晶硅的等效直径随着固溶时间的延长而增大,但相应的形状系数逐渐提高。合金的抗拉强度、屈服强度和显微硬度均显著提高,但伸长率大幅降低。随着固溶时间的延长,合金的强度和显微硬度均呈现先增加后降低的趋势,而伸长率则逐渐降低。当固溶时间为4 h时,合金中残留的Mg_(2)Si含量最少,共晶硅的尺寸较小且球形度较高,合金的综合力学性能达到最佳。合金的抗拉强度、屈服强度、伸长率和显微硬度分别达到350 MPa、290 MPa、6.5%和125 HV。The microstructure and properties of A357 alloy with Sr/Ce complex modification under different solution time were studied by metallurgical microscope,scanning electron microscope,tensile testing machine and microhardness tester,and the evolution process of the second phase characteristics and their effects on the properties of the alloy were discussed.The research results show that the area fractions of eutectic silicon and Mg_(2)Si both decrease significantly after T6 heat treatment and show a trend of first decrease and then increase with the extending of solution time.However,the equivalent diameter of eutectic silicon increases with the extending of solution time,and the corresponding shape factor gradually increases.The tensile strength,yield strength and microhardness of the alloy are significantly improved,but the elongation is greatly reduced.With the extending of solution time,the strength and microhardness of the alloy show a trend of first increase and then decrease,while the elongation gradually decreases.When the solution time is four hours,the residual Mg_(2)Si content in the alloy is the least,the size of eutectic silicon is smaller and the sphericity is higher,and the comprehensive mechanical properties of the alloy are the best.The tensile strength,yield strength,elongation and microhardness of the alloy reach 350 MPa,290 MPa,6.5%and 125 HV,respectively.

关 键 词：A357合金 固溶时间 Mg_(2)Si 共晶硅 富铁相 

分 类 号：TG292[金属学及工艺—铸造]