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制备了不同Sc和Y含量的A356合金,通过金相显微分析和拉伸性能测试等,研究了复合添加稀土Sc和Y对A356合金组织与性能产生的影响.结果表明,复合添加微量Sc和Y后,A356合金组织中形成了Al3Sc、Al3Y强化相,α-Al基体得到明显细化,大部分共晶Si形态由片状向颗粒状转变,合金的抗拉强度和塑性得到明显提高.当添加0.2％的Sc和0.2％的Y时,效果最佳.Y和Sc含量过多时,导致合金组织成分偏聚,综合力学性能变差.“,”A356 aluminum alloys with different amount of Sc and Y were prepared.Through metallographic analysis and tensile testing,influences of trace Sc and Y on the properties and microstructure of A356 aluminum alloy were investigated.The results indicate that after compound addition of trace Sc and Y,Al3Y and Al3Sc strengthening phase can be generated in the microstructure of A356 aluminum alloy,so α-Al matrix is refined apparently and morphologies of most of eutectoid silicon are transformed from lamellar structure into granulate,which are responsible for improvement of tensile properties and plasticity.With 0.2％ Sc+0.2 ％ Y addition,mechanical properties of the alloy exhibit desirable.With excessive Y and Sc addition,the comprehensive performance of the alloy is deteriorated as a result of composition segregation.