Effect of particle cracking on the strength and ductility of Al-SiCp powder metallurgy metal matrix composites

The effects of particle cracking on the strength and ductility of Al-SiCp metal matrix composite material (MMC) was investigated. The composite was manufactured using a simple powder metallurgy (PM) technique of hot pressing followed by hot extrusion. Also, the effects of reinforcement weight fraction and strain rate variations on the strength and ductility of the same composite were examined. It was found that particle cracking plays a significant role in controlling the mechanical properties of the composite. It was shown that particle cracking is possible in an MMC material made with a low strength matrix (commercially pure aluminum), and increases with the increase of reinforcement weight fraction, applied strain rate, and amount of plastic deformation. The yield strength increases as a function of reinforcement weight fraction and to a lesser extent as the strain rate increases. The tensile strength increases at low SiCp weight fractions, then remains constant or decreases as more particles are added to the matrix.