Preparation and characterization of aluminum matrix composites based on Al-WO3 system

The (WAl12 + Al2O3)/Al composites were fabricated by powder metallurgy based on the in situ reaction between WO3 and Al powders in this paper. The microstructure and properties of the composite were investigated and the reaction mechanism was determined. The produced reinforcements including WAl(12)p and W precipitated Al2O3 clusters are distributed mainly by a network in the matrix, where the majority of reinforcements lied within the wall of network with a thickness of 5-10 pin, and while a small part of fine reinforcements in the interior of network. The results show that the WAl12 and Al2O3 clusters were formed by the reaction between WO3 and Al during the sintering process, and WAl12 has the orientation relationship with Al: [1 1 0](Al)vertical bar vertical bar[0 0 1](WAl12), (1- 1 1)(Al)vertical bar vertical bar(3 1 0)(WAl12), meanwhile, nanosized W precipitates was formed and embedded in Al2O3 particles. The mechanical properties of (WAl12 + Al2O3)/Al composites were improved as compared with Al matrix due to the introduction of reinforcement particles, which is due to Orowan strengthening mechanism of reinforcements. The WAl12 and Al2O3 containing nanosized W precipitates reinforcement phases possess an outstanding hybrid effect on the mechanical properties of the composite, including strength and plasticity. (c) 2012 Elsevier B.V. All rights reserved.