硅酸铝短纤维增强Al-12Si合金复合材料的磨损行为

WEAR BEHAVIOR OF Al 12Si ALLOY METAL MATRIX COMPOSITES REINFORCED WITH ALUMINOSILICATE SHORT FIBRE

用挤压铸造法制备了低体积分数（３％～７％）的硅酸铝短纤维增强Ａｌ１２Ｓｉ合金复合材料，并利用销盘磨损试验机研究了材料在干摩擦条件下的磨损行为。磨损试验结果表明：硅酸铝短纤维加入到Ａｌ１２Ｓｉ合金明显提高抗磨损能力，随纤维体积分数的增加该复合材料的耐磨性逐渐增强。金相观察和测试表明：基体合金和复合材料的磨损区由硬化层和变形层组成，断裂的ＡｌＳｉ共晶相沿滑动方向重新分布排列形成了硬化层；而复合材料硬化层由于破断的硅酸铝纤维和破碎的ＡｌＳｉ共晶相的共同作用，使该硬化层硬度高于基体合金硬化层的硬度，从而使复合材料表现出优异的耐磨性。

Al 12Si alloy metal matrix composites reinforced with aluminosilicate short fibre were prepared by the squeeze casting process. The wear behavior of the metal matrix composites (MMCs) and that of Al 12Si alloy were investigated using a pin on disk tests at room temperature under dry condition. The results showed that the addition of aluminosilicate short fibre is beneficial to increasing the wear resistance of the Al 12Si alloy, with increasing fiber content, the mass loss of MMCs appears to decrease.Metallographic examinations revealed that the wear zone of the Al 12Si alloy consists of hardened and deformation layers. The formation of the hardened layer is related to the alignment and redistribution of fragmented eutectic phase to the surface region during sliding wear. However such layer exhibites higher hardness and wear resistance than that developed in the unreinforced alloy by the incorporation of fragmented aluminosilicate fibre.Finally,the schematic model of wear mechanisms of unreinforced alloy and composites was made.