Matrix grain refinement in Al-TiAl composites by severe plastic deformation: influence of particle size and processing route

The microstructure and mechanical behaviour of Al-based composites reinforced with TiAl intermetallic particles has been examined in the as-extruded state and after processing by equal channel angular pressing (ECAP). The latter produces a grain size reduction in the aluminium matrix to values of 500 nm, using route A, and 750 nm, using route C. The ECAP produces up to a 75% increase in the yield stress of the composites, being more rapid when route A is used. The strengthening effect by ECAP is much larger than that obtained by increasing the volume fraction of reinforcement particles from 25 to 50% in these compositesThanks to the Spanish Ministry of Education and Science for financing this study under project number MAT2003-01540.Peer reviewe