Development of ultrafine grain aluminium–graphite metal matrix composite by equal channel angular pressing

Al–5 vol% graphite particulate composite was subjected to equal channel angular pressing (ECAP) at room temperature up to four passes. A significant grain refinement, down to the submicron level of ∼300 nm was achieved. Hardness enhancement of more than two fold was observed with only a marginal difference along the perpendicular and parallel directions of pressing. Further, the strength of the composites was increased by more than two folds. ECAP at room temperature has resulted in a more rapid and significant grain refinement and strengthening in Al–graphite composite.