OXIDATION BEHAVIOR OF ALUMINIUM 6061-HEMATITE PARTICULATE MMCs AT ELVATED TEMPERATURE

摘要

The oxidation behavior of an aluminium composite with 0, 2, 4, and 6 percent by weight of hematite at 200 to 500 deg C has been investigated With in the experimental temperature ranges a parabolic weight gain was observed. The weight gain as a function of oxidation time becomes linear after an initial period on oxidation formation, an oxide scale was found whose morphology depends on temperature, cooling rate and sub-scale formation at the interface between the matrix and reinforcement. The presence of hematite particulate reinforcement has very little effect on the oxidation behavior. The interface oxidization rate was found to be higher than that of other regions. The oxidation products were either metallic oxides or ceramic oxides. The exposure time of specimens to oxidation was 1000 minutes at various temperatures. In the present work key principles of alloy oxidation were discussed. Also the paper emphasizes various reactions taking place and the activation energies involved in the oxidation reactions.