Sc微合金化对Al-Zn-Mg-Cu-Zr合金组织性能的影响  

Effect of microalloying of Sc on microstructure and properties of Al-Zn-Mg-Cu-Zr alloys

作　　者：戴晓元[1] 喻井萍[2] 寇莉莉[1] 

机构地区：[1]长沙理工大学汽车与机械工程学院,湖南长沙410114 [2]中南勘测设计研究院,湖南长沙410014

出　　处：《材料热处理学报》2010年第6期89-94,共6页Transactions of Materials and Heat Treatment

基　　金：湖南省教育厅资助科研项目(08C093);国家重点基础研究发展规划项目(2005CB623706)

摘　　要：采用铸锭冶金法制备了Al-8.0Zn-2.0Mg-1.2Cu-0.15Zr-xSc合金,对合金进行了固溶、时效处理,测试了不同状态下合金的力学性能和电导率,利用光学显微镜、扫描电镜和透射电子显微镜研究了合金不同状态的显微组织。结果表明:添加微量钪形成的一次Al3(Sc,Zr)相可作为异质形核核心,细化合金铸态组织;均匀化退火过程中析出的二次Al3(Sc,Zr)粒子强烈钉扎位错和亚晶界,有效阻碍固溶处理过程中合金的再结晶;含0.30%Sc的Al-Zn-Mg-Cu-Zr合金的抗拉强度和伸长率显著高于不加钪的铝合金,经一般固溶及回归再时效(RRA)处理后含0.30%Sc合金的抗拉强度提高36 MPa、屈服强度提高30 MPa、伸长率提高3.0%;采用470℃×60 min+485℃×60 min强化固溶处理,降低合金固溶态的电导率,将合金固溶态以及T6态的抗拉强度分别提高了79.6 MPa、55.8 MPa。Al-8.0Zn-2.0Mg-1.2Cu-0.15Zr-xSc alloys were produced by ingot-metallurgy processing.The mechanical properties and electric conductivity of the alloys after solution and aging treatment were tested.Microstructure of the alloys after different heat treatment was investigated by means of optical microscope,scanning electron microscopy and transmission electron microscopy.The results indicate that trace Sc can fine grains of the as-cast alloy by precipitating of primary Al3（Sc,Zr） phase from the melt during solidification as heterogeneous nuclei.Secondary Al3（Sc,Zr） particles precipitated during homogenization treatment are coherent with the matrix and can strongly pin dislocation and subgrain boundaries,which can effectively restrain recrystallization of the alloys during solid solution treatment.Compared with the alloy without Sc addition,the Al-Zn-Mg-Cu-Zr alloy with 0.30% Sc exhibits remarkable higher tensile strength and ductility.After conventional solution and retrogression and reaging（RRA） treatment,the increase of tensile strength,yield strength and elongation for the alloy contain 0.30% Sc are 36 MPa,30 MPa,3.0%,respectively.After enhanced solution treatment,470 ℃ × 60 min ＋ 485 ℃ × 60 min,the electric conductivity of the Al-Zn-Mg-Cu-Zr-Sc alloy decreases,and its tensile strength increase 79.5 MPa and 55.8 MPa compared with that after solution and T6 treatment,respectively.

关 键 词：超高强铝合金 SC 晶粒细化 强化固溶处理 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG166.3[金属学及工艺—金属材料]