(東南大學(xué) 機(jī)械工程系， 南京 210018)
摘 要: 研究了在Sr變質(zhì)的近共晶Al11.6%Si(質(zhì)量分?jǐn)?shù))合金中加入混合稀土(MM)對(duì)組織的影響。 Sr對(duì)二次枝臂間距(DAS)起著重要的作用， 隨著Sr含量的增加， DAS減小； 隨著MM加入量的增加，枝晶 α 的數(shù)量增加， 主干長度縮短， 存在等軸化趨向， 但同時(shí)導(dǎo)致DAS增加，也導(dǎo)致共晶硅尺寸增大。 MM的加入在某種程度上削弱了Sr的變質(zhì)作用。
關(guān)鍵字: AlSi合金； 鍶變質(zhì)； 混合稀土
（Department of Mechanical Engineering, Southeast University，Nanjing 210018, P.R.China）
Abstract:The effects of AlMM master alloy on the microstructures of neareutectic Al11.6%Si(mass fraction) alloys modified with Sr were investigated. Sr plays a crucial role in determining the DAS(second dendritic arm spacing) and the value of DAS decreases linearly with increasing Sr content in the melt. With the increase of MM addition, the amount of primary α increases, which inclines to become equiaxed, and DAS value and the size of eutectic silicon also increase. The addition of MM reduces the effectiveness of Sr modification to some extent.
Key words: AlSi alloy； Srmodification； mischmetal
