Mechanical and tribological properties of AA7075-TiC metal matrix composites under heat treated (T6) and cast conditions

The sliding friction and wear behavior of aluminum matrix composites (AA7075-TiC) have been investigated under dry sliding wear conditions. The aluminum metal matrix composites (AMMCs) are produced as AA7075 matrix metal and TiC particulates of an average size of 2 μm as reinforced particles through stir casting. AMMCs studied are contained 2-10 wt.% of TiC particles in both as cast and heat treated (T6) conditions. All the composites exhibited better mechanical properties (hardness, tensile strength and percentage of elongation) than the matrix metal in both the conditions. The wear tests were carried out at a sliding velocity of 2 m/s, sliding distance 2 km and at normal load of 20 N. The wear resistance of the composites increased with increasing weight percentage of TiC particles, and also the wear rate was notably less for the composite material compared to the matrix material. A detailed analysis in as-cast condition and T6 condition of the AMMCs was carried out using SEM in order to find out the influence of TiC particles in the AMMCs formed. It has been observed that under T6 heat treatment condition, matrix as well as composite shown significant improvement in mechanical and tribological properties when compared in as cast condition.