不同固溶处理对亚共晶Al-Si合金组织和性能的影响  

Effect of Different Solution Treatments on Microstructure and Properties of Hypoeutectic Al-Si Alloys

作　　者：丁万武[1,2] 陈建超 田旭东[1,2] 王昊 安家志[1,2] 余海存 DING Wanwu;CHEN Jianchao;TIAN Xudong;WANG Hao;AN Jiazhi;YU Haicun(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

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]兰州理工大学材料科学与工程学院,兰州730050

出　　处：《有色金属工程》2024年第9期8-17,共10页Nonferrous Metals Engineering

基　　金：国家自然科学基金资助项目(52161006);甘肃省教育厅产业支持计划项目(2021CYZC-23);有色金属产业研究院成果转化项目;甘肃省中央引导地方科技发展资金项目(23ZYQB309)。

摘　　要：铸态的亚共晶Al-Si合金中,粗大的α-Al晶粒和针片状共晶Si是造成其性能降低的主要原因。通过对Al-Ti-La和Nd细化变质后的Al-7Si合金进行了不同条件的固溶处理,研究了不同固溶温度和时间对其微观组织及性能的影响。结果表明:铸态Al-7Si合金随着固溶温度的升高,二次枝晶臂间距(SDAS)逐渐增大,共晶Si尺寸逐渐减小,并且共晶Si由长条状和纤维状向短棒状转变。随着固溶时间的延长,共晶Si的演变过程为:长条状→短棒状→粒状→粗化长大。当固溶温度为535℃、固溶时间为3 h时,合金的显微硬度为62.5 HV,相比于铸态提升了10.5%,极限抗拉强度(UTS)和断裂延伸率(El)由铸态的170.2 MPa和11.1%提升至174.0 MPa和13.1%,分别提升2.2%和18.0%,断口的解理平台小且出现大面积韧窝,由脆性断裂转变为韧性断裂。In the as-cast hypoeutectic Al-Si alloy,the coarse α-Al grains and needle-like eutectic Si are the main reasons for its reduced performance.In this study,the Al-7Si alloy refined by Al-Ti-La and Nd was subjected to different conditions of solution treatment to investigate the influence of different solution temperatures and times on its microstructure and properties.The results show that with the increase of solution temperature,the secondary dendrite arm spacing(SDAS) of the as-cast Al-7Si alloy gradually increases,while the size of eutectic Si decreases,and the eutectic Si transforms from a long strip-like and fibrous shape to a short rod-like shape.With the prolongation of solution time,the evolution process of eutectic Si changes from long strip-like to short rod-like,then to granular,and finally to coarsening and growth.When the solution temperature is 535 ℃ and the solution time is three hours,the alloy′s microhardness is 62.5 HV,which is 10.5% higher than that of the as-cast state.The ultimate tensile strength(UTS) and elongation(El) increase from 170.2 MPa and 11.1% in the as-cast state to 174.0 MPa and 13.1%,respectively,representing 2.2% and 18.0% improvement.The fracture surface exhibits a small cleavage plane and a large area of ductile dimples,indicating a transition from brittle fracture to ductile fracture.

关 键 词：Al-7Si合金 固溶处理 SDAS 共晶Si 

分 类 号：TG146[一般工业技术—材料科学与工程]