Synthesis and tribological characterization of in situ cast Al-TiC composites

The Al-TiC composites containing three different volume fractions 0.07, 0.12 and 0.18 of TiC have been fabricated by in melt reaction method. Friction and wear characteristics of Al-TiC composites have been investigated under dry sliding and compared with those observed in pure aluminium. Dry sliding wear tests have been carried out using a pin-on-disk wear tester at normal loads of 9.8, 14.7, 19.6 and 24.5 N and at a constant sliding velocity of 1.0 m/s. Weight loss of the samples has been measured and the variation of cumulative wear loss with sliding distance has been found to be linear for both the pure aluminium and the composites. The wear rate varies linearly with normal load which is indicative of Archard's law and it is significantly lower in composites as compared to that in base material. The wear mechanism appears to be primarily oxidative for both pure aluminium and composites under the given conditions of load and sliding velocity as indicated by the scanning electron micrographs (SEM) of the worn surfaces which show a well compacted transfer layer of wear debris on the sliding surface. This layer inhibits metal-metal contact and the wear rate is reduced. The wear rate decreases linearly with increasing volume fraction of titanium carbide. Average coefficient of friction also decreases linearly with increasing normal load and volume fraction of TiC.