Effects of Mg content on primary Mg_2Si phase in hypereutectic Al-Si alloys  

Mg含量对过共晶Al-Si合金中初生Mg_2Si相的影响（英文）

作　　者：黄治黎 王开[1] 张志明[1] 李波[1] 薛寒松[1] 杨大壮[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400044

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第10期3197-3203,共7页中国有色金属学报（英文版）

基　　金：Project(CDJZR12240056)supported by the Fundamental Research Funds for Central Universities,China;Project(cstc2013jcyj A50014)supported by the Foundational and Cutting-edge Research Plan of Chongqing,China

摘　　要：Hypereutectic Al-Si alloy with variant Mg contents were fabricated by casting,and the effects of Mg content on the microstructure of primary Mg2Si particles in hypereutectic Al-Si alloys were investigated.The results show that the volume fraction of primary Mg2Si particles increases linearly with raising the Mg content,but the average size of Mg2Si particles does not exhibit a corresponding change.When the Mg content is 3%,á1 0 0？ directions have the fastest growth velocity,so that Mg2Si particles are likely to form octahedron shape.When gradually increasing the Mg content,the distributions of Mg and Si atoms on the solid-liquid interface become inhomogeneous,which results in the formation of irregular octahedron structures.Finally,when the Mg content is about 10%,the morphology of primary Mg2Si particles changes from the octahedron shape into various complex structures with a large size.采用铸造方法制备不同Mg含量的过共晶Al-Si合金,并研究Mg含量对合金中初生Mg2Si显微组织的影响。结果表明:随着Mg含量的增大,Mg2Si的体积分数呈线性增加,但是平均晶粒尺寸没有呈线性增加。当Mg含量为3%时,Mg2Si晶粒的á1 0 0?晶向生长速度最快,Mg2Si易生长成八面体状。随着Mg含量的升高,晶粒固液界面溶质分布不均匀,合金形成不规则八面体结构。当Mg含量约为10%时,Mg2Si生长成尺寸较大的复杂结构。

关 键 词：hypereutectic Al-Si alloys primary Mg2Si particles growth pattern growth velocity 

分 类 号：TG292[金属学及工艺—铸造] TG146.21[一般工业技术—材料科学与工程]