Investigation of Mechanical Properties and Dry Sliding Wear Behaviour of Graphite Reinforced Al7068 Alloy

Abstract

The aim is to study the mechanical property and dry sliding wear behaviour of Al7068/graphite composite with various weight fractions (5%, 10%, 15%) were prepared by liquid metallurgy route was investigated. The average particle size of graphite is 40 μm. In addition, Al7068 alloys were cast for comparison purposes. The alloys and composites were given a T6 heat treatment process (solution treatment at 540 oC, water quenching at room temperature and artificial ageing at 170 oC) .Microstructure, hardness and tensile properties of these composites were evaluated and compared with as-cast alloy and the composites without T6 heat treatment. In addition, tribological properties of these composites were evaluated using a Pin-on-Disc apparatus with different parameters (constant velocity of 2m/s and varying loads as follows 10N, 15N, 20N, 25N, 30N) .The microstructure of the composites shows homogenous distribution of graphite particles in the Al matrix except in the Al7068/15% graphite composite. The wear and mechanical properties of composites improve with increasing the weight fraction of graphite upto 10% and then decreases gradually. This study provides an alternative way to enhance the tribological behaviour of Al7068/graphite composite. The study also highlights the different contribution of different input process parameters (like: composition of Al-graphite, molding technique and particle size of reinforcement material) on wear properties of Al-graphite MMCs.