Phase, microstructure and tensile strength of Al–Al 2 O 3 –C hybrid metal matrix composites

The aim of the present study is to investigate the effect of alumina (Al 2 O 3 )–carbon (C) reinforcement on the properties of aluminium matrix. Aluminium matrix reinforced with Al 2 O 3 –carbon (2.5, 5, 7.5 and 10 wt.%) in equal proportion was prepared by stir casting. Phase, microstructure, EDS, density, hardness, impact strength and tensile strength of prepared samples have been investigated. X-ray diffraction reports the intermediate phase formation between the matrix and reinforcement phase due to interfacial bonding between them. Scanning electron microscopy shows that Al matrix has uniform distribution of reinforcement particles, i.e. Al 2 O 3 and carbon. Density decreases due to variation of reinforcement because ceramic reinforcement has low density. Hardness decreases due to variation of carbon since it has soft nature. Impact strength was found to increase with addition of reinforcement. Hybrid composite of Al and 5% Al 2 O 3 + 5% carbon reinforcement has maximum engineering and true ultimate tensile strength. It is expected that the present hybrid metal matrix composites will be useful for fabricating stock screws.