多粒径TiB2颗粒增强铜基复合材料的制备与载流摩擦磨损性能

采用粉末冶金工艺分别制备了单一粒径TiB₂颗粒和多粒径TiB₂颗粒增强铜基复合材料，对比研究了非载流和载流条件下多粒径（2 μm+50 μm）TiB₂/Cu复合材料的摩擦磨损行为。微观组织观察表明:不同粒径的TiB₂颗粒在Cu基体中分布均匀。与单一粒径TiB₂/Cu复合材料相比，多粒径TiB₂/Cu复合材料具有更高的相对密度、硬度和导电率。摩擦磨损实验结果表明:多粒径TiB₂/Cu复合材料抗摩擦磨损性能明显高于单一粒径TiB₂/Cu复合材料，当2 μm与50 μmTiB₂颗粒配比为1:2时，多粒径TiB₂/Cu复合材料的抗摩擦磨损性能最佳。相对于2 μm单一粒径TiB₂/Cu复合材料，电流为0 A时，（2 μm+50 μm）TiB₂/Cu复合材料的摩擦系数和磨损率分别降低了17.3%和62.5%；电流为25 A时，（2 μm+50 μm）TiB₂/Cu复合材料的摩擦系数和磨损率分别降低了6%和45.8%，同时载流效率和载流稳定性得到明显提高，磨损表面更加平整。磨损机制分析表明:多粒径TiB₂颗粒合理配比有利于提高复合材料载流质量，同时摩擦过程中大粒径的TiB₂颗粒起到支撑作用，小粒径的TiB₂颗粒弥散强化Cu基体，二者的协同作用使TiB₂/Cu复合材料具有更好的抗载流摩擦磨损性能。 

Preparation and electrical wear characteristics of copper matrix composites reinforced with mixing sized TiB2 particles

Copper matrix composites reinforced with single sized TiB₂ particles and mixing sized TiB₂ particles were prepared by powder metallurgy, respectively. Effects of mixing sized TiB₂ particles (2 μm+50 μm) on the friction behavior under non-current and current of the TiB₂/Cu composites were studied. Microstructure observation shows that the different TiB₂ particles are evenly distributed in the copper matrix. The higher relative density, the hardness and electrical conductivity of mixing sized TiB₂/Cu composite are obviously better than those of TiB₂/Cu composites reinforced with single sized TiB₂ particles. The results of friction and wear tests show that:The friction and wear properties of mixing sized TiB₂/Cu composites are significantly higher than those of single sized TiB₂/Cu composites. When the mixed ratio of 2 μm and 50 μm TiB₂ particles is 1:2, the TiB₂/Cu composite has the best wear resistance, when the current is 0 A, compared to the composites with 2 μm single sized, its friction coefficient and wear rate decrease by 17.3% and 62.5%, respectively, when the current is 25 A, compared to TiB₂/Cu composites with 2 μm single sized, its friction coefficient and wear rate decrease by 6% and 45.8%, respectively. Meanwhile, its wear surface is more flat and the stability of the current carrying and efficiency of the current carrying capacity are obviously improved. The analysis of wear mechanism shows that:The mixed TiB₂ particles are favorable for improving the current carrying quality of TiB₂/Cu composites. The mixed TiB₂ particles play a supporting role in the friction process, and the small TiB₂ particles disperse and strengthen the Cu matrix. The synergistic effect of that makes the TiB₂/Cu composites have better current-carrying friction and wear resistance.