挤压铸造(SiC_(w)+CNTs)/2024Al复合材料高温摩擦磨损性能

High Temperature Friction and Wear Properties of Squeeze Cast(SiC_(w)+CNTs)/2024Al Composites

铝基复合材料因具有低密度、高硬度、高强度以及耐磨损等特点,是制备轻量化制动零部件的理想材料。本研究采用挤压铸造法和热挤压工艺制备了具有优异耐磨性的(SiC_(w)+CNTs)/2024Al复合材料。利用干滑动摩擦磨损实验研究了复合材料在高温条件(200℃)不同载荷(5~20N)下的耐磨性。研究表明,相较于2024Al,复合材料在高温低载荷条件下具有高且稳定的摩擦系数以及低的磨损率,而在高载荷条件下,其摩擦系数显著降低且出现明显的波动。通过增加载荷使得SiC_(w)和CNTs被拔出,CNTs自润滑能力及硬质SiC_(w)的表面强化作用得到充分发挥,大幅度降低了材料的摩擦系数。高温下2024Al被软化,发生粘着磨损,而复合材料中混杂增强体的存在有效提高了材料的高温耐磨性。

Aluminum matrix composites are ideal materials for lightweight brake components due to their low density,high hardness,high strength and wear resistance.In this study,(SiC_(w)+CNTs)/2024Al composites with excellent wear resistance were prepared by squeeze casting and hot extrusion.The wear resistance of the composites was investigated under different loads(5~20 N)at high temperature(200 C)using dry sliding friction and wear experiments.The results show that compared with 2024Al,the composites have a high and stable friction coefficient and low wear rate at low loads and high temperatures,while the friction coefficient of composites decreases significantly and fluctuates at high loads.With increasing load,SiC_(w)and CNTs are extracted,fully utilizing the self-lubricating ability of CNTs and the surface strengthening effect of hard SiC_(w),which significantly reduce the friction coefficient of 2024Al.Additionally,2024Al is sofened at high temperatures and adhesive wear occurres,while the presence of reinforcements in the composites effectively improves the high-temperature wear resistance.