Microstructure and properties of Al/Al2O3 composites fabricated by reaction between SiO2 and molten Al

Fused silica rods were dipped into molten Al. Al/Al2O3 composites were obtained as the reaction products. In this study, composites were fabricated at different reaction temperatures. Time variation of the reaction layer thickness was measured and microstructures were observed. For those specimens, the relationship between the mechanical properties and the microstructures were discussed. Growth rate of the reaction layer decreased between 1073K and 1273K, in which the produced alumina phase changed. Hardness of the high temperature phase was lower. Coarsening of the microstructure occurred as the reaction temperature increased. Al channels widened reamarkably above 1373K. This contributed to the increase in growth rate of the reaction layer and to the plastic deformation in Al. Bulging was observed around the indent.