Processing, microstructure, and properties of co-continuous alumina-aluminum composites

A novel co-continuous composite of Al2O3 and Al has been developed, consisting of approximately 65% (by volume) of the ceramic phase. It is formed by a liquid phase displacement reaction, involving the displacement of Si from SiO2 and its replacement by Al. A model for the formation mechanism is presented, based on the reaction thermodynamics and the associated experimentally determined transformation kinetics. It is shown that the process is essentially near-net shape, in which the features of the SiO2 precursors are faithfully reproduced in the composite product. Various physical and mechanical properties that are exhibited by this composite have been determined and are presented.