Structural and chemical characterization of precipitates in Al-2024/TiC composites

Structural characterizations based on transmission electron microscopy observations were carried out on as-fabricated and heat-treated Al2024/TiC composites. These composites types reinforced with TiC particles were produced with a pressureless melt infiltration route at 1200 degreesC for 2 h under argon atmosphere. The composites were heat-treated at 530 degreesC during 150 min, cold-water quenched and subsequently artificial and natural aged at 190 degreesC for 12 h in an argon environment and at room temperature for 96 h, respectively. Different precipitate types were obtained and they were identified as CuAl2, Al3Ti, Ti3AlC and Ti3Al. Most of the precipitates were found to be uniformly distributed in the matrix and some regions show precipitates which have a cubic morphology (Ti3Cu). High-resolution electron microscopy images were partially used for the characterization of the precipitates in these composites. (C) 2002 Elsevier Science Ltd. All rights reserved.