Effect of Heat Treatment on the Hardness and Electrical Connectivity of an Aluminum Composite Reinforced with Al.sub.2O.sub.3 Nanoparticles

The effect of heat treatment modes on the microstructure, microhardness and electrical conductivity of an aluminum metal matrix composite (MMC) reinforced with Al.sub.2O.sub.3 nanoparticles in an amount of 2.5 wt.% is studied. The MMC is treated by quenching from 510, 530 or 550°C and subsequent artificial aging at 140, 160, 180, 200 or 220°C. The cast composite has a Vickers microhardness of 36 HV and an electrical conductivity of 45% IACS. The heat treatment raises the hardness and the conductivity of the composite. Quenching from 530°C and aging at 200°C produce the highest microhardness (46 HV ); quenching from 530°C and aging at 180°C produce the highest conductivity (50% IACS).