FRICTION AND WEAR BEHAVIOUR OF Al6061Alloy (SiCP +Al2O3P) HYBRID COMPOSITES

摘要

Aluminum-base hybrid composites reinforced with mixtures of SiC and Al2O3 particles have been fabricated on an Al6061alloy by stir casting method and their wear resistance and Co-efficient of Friction has been investigated as a function of applied load and Volume fraction of the particles. The dry sliding wear properties of the hybrid composites and that of Al6061 unreinforced alloy at room temperature were investigated by using Pin-on-disk wear testing machine at a constant sliding velocity of 2.09 m/s and sliding distance of 1884m over a various loads of 29.43N, 39.24 N and 49.05N (3, 4 and 5 kgf) for particle volume fraction ranging from 5-25%. The results show that, the reinforcement of the metal matrix with SiC and Al2O3 particulates upto a volume fraction of 25% reduces the wear rate at room temperature. The results also show that the wear of the test specimens increase with the increasing load and sliding distance. The coefficient of friction slightly decreases with increasing volume content of reinforcements. Micro hardness of the specimens at the room temperature was also measured before and after the wear tests by Vickers hardness testing machine. The micro hardness of the hybrid composite test specimens increases with increasing volume fraction of particulates reinforcement. The optical micrographs taken for the micro structure analysis of the hybrid composite specimens show that the SiC and Al2O3 particulates are uniformly distributed in the matrix. The wear surfaces were examined by scanning electron microscopy, which showed that the large grooved regions and cavities with ceramic particles were found on the worn surface of the composite alloy. This indicates an abrasive wear mechanism which is essentially a result of hard ceramic particles exposed on the worn surface.