Wear and mechanical characteristics of Al 7075/graphite composites

This work investigates 7075 aluminium alloy-graphite composites for its tribological and mechanical behaviour under dry sliding conditions. The conventional liquid casting technique was used for the fabrication of composite material and subjected to T6 heat treatment. The reinforcement content was chosen as 5, 10, 15 and 20 wt.% of graphite to identify its potential for self-lubricating property under dry sliding conditions. Wear tests were conducted by using pin on disc apparatus to evaluate the tribological behaviour of the composite and to determine the optimum content of graphite for its minimum wear rate. The wear rate decreases with addition of graphite content and reaches its minimum at 5 wt.% graphite. The wear mass loss was found to decrease with increasing sliding distance. The average coefficient of friction decreases with addition of graphite content and was found to be minimum at 5 wt.% graphite. The mechanical properties of the composites and base alloy were tested. The mechanical properties decrease with increasing graphite content as compared to base alloy. The worn surfaces were examined through SEM. The presence of 5 wt.% graphite in the composites can exhibit superior wear property as compared to base alloy.