原位自生AlB_(2)/6061复合材料的组织及耐磨性能

Microstructure and Wear Resistance of In-Situ Synthesized AlB_(2)/6061 Composites

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%。

3wt%AlB_(2)/6061 composites were in-situ synthesized by molten salt method using Al-KBF 4 as reaction system.Compared with 6061 matrix,effects of AlB_(2)particles on the hardness and wear resistance of the composites were studied.The results show that regular hexagonal AlB_(2)particles with the size of 0.5~2.0μm can be directly in-situ synthesized in 6061 matrix.After T6 heat treatment,the hardness of 3wt%AlB_(2)/6061 composites is HB 119.1,which is 26.57%higher than that of 6061 matrix.The specific wear rate of the composites is 1.83×10^(-8) kg·N^(-1)·m^(-1),which is 17.94%lower than that of 6061 matrix.Due to good enough wettability and high interface bonding strength between AlB_(2)particles and the matrix,and high hardness of the particles,the particles can play a bearing role,then reduce the contact area between the composites and the wear-resistant material during wear,thus wear resistance of the composites is improved.The wear mechanism of the composites is mainly abrasive wear and adhesive wear.The average friction coefficient of the composites is 0.235,which is 17.54%lower than that of 6061 matrix.