Al_2O_3和C短纤维混杂增强铝基复合材料高温耐磨性能的研究

STUDY ON WEAR RESISTANCE OF ALUMINA AND CARBON SHORT FIBRES REINFORCED ALUMINUM ALLOY HYBRID COMPOSITES AT ELEVATED TEMPERATURE

利用预制体挤压浸渗法制备了Al_2O_3+C/ZL109短纤维混杂金属基复合材料,并探讨了该混杂复合材料的高温(≤400℃)摩擦磨损性能。结果表明:在试验温度范围内,混杂复合材料的磨损率低于基体合金及单一增强的复合材料。12％Al_2O_3+4％C /ZL109混杂复合材料从轻微磨损到急剧磨损的临界转变温度比基体合金提高了一倍。当环境温度低于临界转变温度时,混杂复合材料的摩擦因数随着Al_2O_3体积分数的升高而不断增大,而磨损率在12％时取得最低值。在此阶段,基体及复合材料的磨损机制主要为犁沟磨损和轻微的粘着磨损,而随着试验温度的进一步升高并超过临界温度时,主要磨损机制转变为严重的粘着磨损。

Alumina and carbon short fibers reinforced ZL109 aluminum alloy hybrid composites are fabricated by preform squeeze-infiltrated route. The friction and wear properties of the hybrid composites at elevated temperature (≤400 ℃) are investigated. The results show that wear rate of the hybrid composites is less than that of ZL109 matrix and composites reinforced with only alumina or carbon fibre. The critical transition temperature from mild wear to severe wear of the hybrid composites was improved one time than that of monolithic ZL109 alloy because of mutual effect of alumina and carbon short fibers. The friction coefficient of the hybrid composites increases with the increase of alumina fiber volume fraction when test temperature is below the critical transition temperature. However, there exists critical value of alumina fiber volume fraction which influences wear property of the hybrid composites with the lowest wear rate at the volume fraction of 12%. The wear mechanisms of metal matrix and composites are ploughing groove and slight adhesion when test temperature is below the critical transition temperature. Whereas the wear mechanisms of matrix and composites will be shifted to severe adhesion with the increase of test temperature and beyond transition temperature.