微量Sr对Al-8Si-0.3Mg-0.5Mn铝合金铸态组织与拉伸性能的影响  

Effect of trace Sr on the microstructure and tensile properties of as-cast Al-8Si-0.3Mg-0.5Mn aluminum alloy

作　　者：王强 刘文君 杨琴 徐小敏 王志白 向多 马云峰 WANG Qiang;LIU Wenjun;YANG Qin;XU Xiaomin;WANG Zhibai;XIANG Duo;MA Yunfeng(School of Materials Science and Engineering,Chongqing University of Technology,Chongqing 400054,China;Chongqing Changan Automobile Co.,Ltd.,Chongqing 400030,China)

机构地区：[1]重庆理工大学材料科学与工程学院,重庆400054 [2]重庆长安汽车股份有限公司,重庆400030

出　　处：《重庆理工大学学报(自然科学)》2025年第1期171-176,共6页Journal of Chongqing University of Technology:Natural Science

基　　金：重庆市技术创新与应用发展专项重点项目(CSTB2022TIAD-DEX0011);重庆市教委科学技术研究项目(KJQN202201136);重庆理工大学研究生创新项目(gzlcx20233005);重庆理工大学研究生教育高质量发展项目(gzljd2024201)。

摘　　要：以汽车后地板用Al-8Si-0.3Mg-0.5Mn合金为基础,研究微量(质量分数为0.001%~0.008%)Sr添加对铝合金铸态组织与拉伸性能的影响。结果表明:微量Sr添加可有效改善铝合金组织中的共晶Si和含Fe相形貌,轻微细化α-Al组织,提高合金的塑性;随着Sr含量的增加,组织中的共晶Si形貌由粗大的针片状转变为细小纤维状,含Fe相形貌由骨骼状转变为无定形的细小块状;微量Sr添加对合金抗拉强度的影响较小,但极大提高了合金的延伸率,当Sr含量由0.001%增加到0.008%时,合金断后伸长率增加约41%。添加的Sr元素在凝固界面前沿的偏聚,不仅阻碍了共晶Si的长大,也抑制了含Fe相的生长,使合金组织细化,变形协调能力提高。此外,对不同Sr含量下的合金断口形貌进行分析,进一步研究了合金的力学性能。In this paper,based on the Al-8Si-0.3Mg-0.5Mn alloy used for automobile rear floor,the effect of trace Sr addition(0.001%~0.008%)on the microstructure and tensile properties of as-cast aluminum alloy is studied.The results show that the addition of trace Sr effectively improves the morphology of eutectic Si and Fe-containing phases in the microstructure of aluminum alloys,slightly refines the microstructure ofα-Al,and then enhances the plasticity of the alloys.As Sr increases,the morphology of eutectic Si changed from coarse needle sheet to fine fiber,and the morphology of Fe-containing phase changed from skeleton character to amorphous fine block.The addition of trace Sr had small effect on the tensile strength of the alloy,but greatly improved the elongation of the alloy.When the Sr content increased from 0.001%to 0.008%,the elongation of the alloy after fracture increased by about 41%.The segregation of added Sr element at the front edge of the solidification interface not only hinders the growth of eutectic Si,but also inhibits the growth of Fe-containing phases,thereby refining the microstructure and improving the deformation coordination ability of the alloy.In addition,the fracture morphology of the alloy with different amount of Sr was analyzed,and the mechanical properties of the alloy were further verified.

关 键 词：Al-Si系铝合金 SR 共晶Si 含Fe相 塑性 

分 类 号：TG146.21[一般工业技术—材料科学与工程]