(1. 华南理工大学 材料科学与工程学院，广州 510640；
2. 广州金邦有色合金有限公司，广州 510340)
摘 要: 以A356-1.3%Fe再生铝合金为原材料，通过Mg-Si熔体直接反应制备20%Mg2Si/A356-1.3%Fe铝基复合材料，研究B和Cr对复合材料组织中初始Mg2Si和富Fe相变质行为以及研究变质处理对拉伸性能和耐磨性的影响。结果表明：B和Cr分别对复合材料中的初生Mg2Si相和β-Fe相具有较佳的变质效果，B-Cr复合能够实现初生Mg2Si相和β-Fe相的同步变质。针状Fe相全部转变成汉字状或骨骼状α-Fe相，长径比减小近90%，初生Mg2Si相由粗大的树枝晶状转变成细小的颗粒状，平均尺寸由70.2 μm减小到36.4 μm，约下降50%。与A356-1.3%Fe再生铝相比，复合材料的耐磨性提高约3倍，而经B-Cr变质的复合材料其抗拉强度提高27%，断裂应变提高73%。
关键字: 再生铝；复合材料；初生Mg2Si；富Fe相；变质
（1. School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China;
2. Guangzhou Jinbang Non-ferrous Alloy Limited Company, Guangzhou 510340, China）
Abstract:A356-1.3%Fe recycled aluminum alloy was chosen as raw material to prepare 20%Mg2Si/A356-1.3%Fe composites by direct melt reaction between Mg and Si. Modification behaviors of B and Cr elements on primary Mg2Si and Fe-rich phases in the composites and its influence on tensile properties and wear resistance were mainly investigated. The results show that the elements of B and Cr can effectively modify primary Mg2Si and Fe-rich phases, respectively. Simultaneous modification of primary Mg2Si and Fe-rich phases can be effectively achieved by the combination of B and Cr. All of the needle-like β-Fe phases are changed into α-Fe phase like Chinese-script characters or skeleton. The aspect ratio of Fe-rich phase is reduced by 90%. Morphologies of primary Mg2Si phase are changed from coarse dendrite to small granular. Its average size is reduced by about 50% from 70.2 μm to 36.4 μm. Compared with A356-1.3%Fe recycled aluminum, the wear resistance of the composites is improved by 3 times, and the tensile strength and elongation to failure of the composites modified by B and Cr are increased by 27% and 73%.
Key words: recycled aluminum alloy; composites; primary Mg2Si phase; Fe-rich phase; modification
