Effect of Hot Working on Structure and Tribological Properties of Aluminium Reinforced with Aluminium Oxide Particulates

Al-Al2O3 (18%) composite was prepared by stir-cast melt technique. The microstructures showed uniform distribution of particulates, dispersed in the matrix. There exists discontinuity (similar to 0.25 mu m) in the interface between particulates and matrix. The composite was hot forged. Hot working resulted in fine recrystallized microstructure with particulates dispersed along grain boundaries. Formation of pancake microstructure with some inhomogeneity in the microstructure along three faces of the forged composite was observed. The discontinuity across the interface between Al-Al2O3 was reduced to 0.125 mu m after forging. The as-cast and forged Al-Al2O3 composites showed higher wear resistance than pure Al. In lubricant media, there was no significant wear observed for either the as-cast or forged composite, whereas Al had shown higher wear at 50 N load.