Microstructure-process-property relationship in Al/Al2O3 composites fabricated by reaction between SiO2 and molten Al

Fused silica rods were reacted with molten aluminum at different temperature and they were converted into Al/Al2O3 composite bodies. Their mechanical properties were investigated and discussed in comparison with the observed microstructures. As increase of the reaction temperature, microstructures of the composite bodies coarsened and the consisting Al2O3 phase changed from the mixed states of r, theta, alpha- Al2O3 to the single phase of alpha - Al2O3. Hardness of the composites fabricated below 1273K was almost twice as larger than that fabricated at higher temperature. Compressive fracture stress had highest value in the specimens fabricated at 1173K, however the data scattered. Bulging around the corner of indents indicated a little increase in ductility, which was observed in the specimens fabricated above 1273K. The coarsened composite structures had larger Al width, in which the larger amount of plastic deformation was considered to occur.