(上海交通大學(xué) 金屬基復(fù)合材料國(guó)家重點(diǎn)實(shí)驗(yàn)室， 上海 200030)
摘 要: 研究了Sr以及Ce-Sr復(fù)合添加劑對(duì)Al/Mg2Si/Si自生復(fù)合材料凝固組織的影響規(guī)律。當(dāng)Ce、 Sr的加入量分別為1.0%和0.7%（質(zhì)量分?jǐn)?shù)）時(shí)， Mg2Si增強(qiáng)體以細(xì)小短棒狀形態(tài)出現(xiàn)， 其平均粒徑為12μm， 這比未經(jīng)細(xì)化處理的Mg2Si增強(qiáng)體的平均粒徑降低52%。 同時(shí)， 單位面積Mg2Si晶粒平均數(shù)量為未經(jīng)細(xì)化處理時(shí)的4~6倍。 單獨(dú)加入Sr時(shí)， 復(fù)合材料的組織細(xì)化則不如Ce-Sr復(fù)合處理時(shí)的穩(wěn)定。 對(duì)相關(guān)機(jī)制的研究表明，上述細(xì)化元素對(duì)Mg、 Si原子在合金熔體中擴(kuò)散的不同程度的抑制是微觀組織得以細(xì)化的根本原因。
關(guān)鍵字: Al基復(fù)合材料；自生復(fù)合材料; Mg2Si; 組織細(xì)化
（State Key Laboratory of Metal Matrix Composites,
Shanghai Jiaotong University, Shanghai 200030, China）
Abstract: The effect of Sr and Ce-Sr refiners on the microstructure of as-cast Al/Mg2Si/Si in-situ composite was investigated. When the addition contents of element Ce and Sr are 1.0% and 0.7%(mass fraction) respectively, Mg2Si reinforcements exist in short rod-like shape, and the average size of Mg2Si reinforcements can be reduced to 12μm, which is 48% of that without refiners. Moreover, the average number per unit area of Mg2Si reinforcements can increase by 4-6 times compared with the untreated one. The microstructure refinement effect of composites by Sr addition is less stable than that by Ce-Sr addition. Based on the mechanism analyses, it is concluded that the suppression of the diffusion of Mg and Si element by refiners contributes highly to the microstructure refinement.
Key words: Al-base composites; in-situ composites; Mg2Si; microstructure refinement
