HOT-ROLL BONDING OF ALUMINUM-MATRIX COMPOSITES WITH DIFFERENT VOLUME FRACTIONS OF ALUMINA

Metal matrix composites (MMC) with volume fractions of 0.08, 0.11 and 0.14 alumina (Al2O3) were fabricated by roll bonding. This low-cost ap proach to MMC manufacture has the flexibility of controlling the volum e fraction of the MMCs by varying the oxide thickness on the anodized aluminium foil, and the number of layers of these foils to be sandwich ed between plain aluminium sheet as the matrix metal. The fragmentatio n of the laminate alumina is achieved by a series of hot- and cold-rol ling operations. The resulting reinforcing alumina particles have plat elet shape measuring approximately 20 mu m x 11 mu m x 5 mu m instead of a stringer shape as expected. It is found that the improvement in m odulus and strength did follow very closely with the rule of mixtures. A small scatter of measured data, especially the resistivity of the M MCs, was observed. This can be explained by the inefficient bonding be tween the reinforcing alumina and the matrix metal as demonstrated lat er in this study.