Sliding Wear Behaviour of Al-B4C Cast Composites Under Dry Contact

Aluminium based composites containing 5, 7 and 9 wt.% B4C were synthesized with the help of Potassium Hexaflurotitanate (K2TiF6) following stir casting route. The technique results in good bonding of second phase with the matrix due to improved wettability and good dispersion. Dry sliding friction and wear test were carried out at 9.8N, 19.6 N,29.4 N, 39.2N load at a constant sliding speed of 1m/s and compared with pure Aluminium. The wear rate was observed to vary linearly with normal load following Archard's law. However, the wear rate shown by the composites was significantly lower than for the pure Aluminium. Both the wear rate and the average friction coefficient were found to decrease with increasing weight percentage of boron carbide. The wear mechanism appeared to be primarily oxidative for both pure Aluminium and composites under the given condition of load and sliding velocity as indicated by the presence of a well compacted transfer layer of wear debris on the sliding surface as revealed by the scanning electron microscopy of worn surfaces. The said layer inhibits metal-metal contact leading to reduction in both wear rate and friction coefficient. (C) 2018 Elsevier Ltd. All rights reserved.