In situ prepared Al-Si alloy matrix composites reinforced by γ-Al_2O_3p

A γ-Al2O3 particles reinforced Al-Si alloy matrix composite was fabricated by adding NH4Al（SO4）2 to molten aluminum alloy. TEM observation shows that in-situ γ-Al2O3 particles are generally spherical and uniformly distributed in the matrix. The results of dry sliding wear tests show that the wear resistance of the composites increases with increasing mass fraction, and the volume loss is considerably lesser than that of the matrix and is lesser than that of the composites by adding γ-Al2O3 particles directly.

原位自生AlB_(2)/6061复合材料的组织及耐磨性能

以Al-KBF 4为反应体系,采用熔盐反应法制备了原位自生3%AlB_(2)/6061复合材料(质量分数),对比6061基体材料,研究了AlB_(2)颗粒对复合材料组织、硬度和耐磨性能的影响。结果表明,在6061基体材料中原位自生了六边形AlB_(2)颗粒,颗粒尺寸为0.5~2.0μm。经T6热处理后,3%AlB_(2)/6061复合材料的硬度为HB 119.1,较6061基体提高了26.57%。复合材料比磨损率为1.83×10^(-8) kg·N^(-1)·m^(-1),较6061基体下降了17.94%。AlB_(2)颗粒与基体材料之间的润湿性好,界面结合强度高,且其本身硬度高,在磨损时能够起到承载作用,有效地减少了复合材料与对磨材料间的接触面积,提高了复合材料的耐磨性。复合材料的磨损机制主要为磨粒磨损和粘着磨损,其平均摩擦系数为0.235,相较于6061基体材料降低了17.54%。