A synthesis of in situ formed TiC/Al composites utilizing the reaction between molten aluminum and preforms consisting of Ti, C, Al and TiC powder was studied. The addition of TiC powder as a dilution agent controlled the explosive exothermic reaction and played a key role in the homogeneous distribution of reinforcement. (C) 2002 Published by Elsevier Science Ltd. on behalf of Acta Materialia Inc.