Processing,microstructure,and mechanical properties of (Al-Cu)/C composites synthesised using partial liquid phase casting process

Abstract

In the present study, an Al-Cu based metallic matrix was reinforced with graphite particles using an innovative partial liquid phase casting (rheocasting) technique. The results of microstructural characterisation studies revealed the presence of columnar-equiaxed grain morphology, afinite amount of porosity, interdendritic/intercellular Al-Cu phase, and predominantly grain boundary segregated distribution of graphite particles. Heat treatment studies conducted on rheocast composite specimens revealed accelerated ((Al-4.5Cu)/6.8C) and retarded ((Al-4.5Cu)/4.2C) aging kinetics when compared with unreinforced specimens. Ambient temperature tensile testing results, contrary to those reported by other investigators, revealed an increase in 0.2% yield stress and ultimate tensile strength of graphite reinforced specimens when compared with unreinforced specimens. The enhanced tensile properties realised by the graphite reinforced specimens are correlated with the processing influenced microstructural characteristics of these specimens.