Effect of rolling on the thermo-physical properties of SiCp/Al composites fabricated by plasma spraying

Aluminum (Al) matrix composites reinforced by SiC particulates (SiCp/Al) were fabricated by the atmospheric plasma spraying. The composite powder, as a feedstock for plasma spraying, was prepared by ball milling of pure Al powders with 55 vol.% SiC particles. The feedstock was deposited into a freestanding bulk composite sheet on a graphite substrate by atmospheric plasma spraying. As-sprayed composites had a great amount of porosity, which deteriorates the thermo-physical properties, especially the thermal conductivity. In order to reduce the porosity of the plasma-sprayed SiCp/Al composite sheets, rolling processes were carried out at the room and elevated temperature with the thickness reduction of about 20%. The thermal conductivities of the rolled composites were considerably enhanced with the decrease of the porosity in the composites, while the coefficients of thermal expansion (CTEs) of the composites were slightly affected by the rolling process.