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 γ , θ , α - Al₂O₃ to the single phase of α - 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.