Production of metalic matrix composites via oxidation of barium-aluminum metallic powder precursor at low temperature

In powder metallurgy and cast method used for production of metal matrix composites, there are some limitations such as cost, compatibility of matrix and reinforcement, wetting and problems at high temperature. To eliminate some of these limits, after mechanically alloying metallic barium and aluminium precursor powders for different duration, bariumaluminate (Ba3Al206 or BaAI2O6) refractor reinforcement was formed in Al matrix via oxidation of these powders at low temperature and controlled atmosphere. Effect of mechanical alloying time on density, reaction and composite microstructure has been determined. Fracture toughness and bend strength of this composite have been determined by using four-point bend test. It has been found that green and final density of the composite first increased then decreased with mechanical alloying time and also mechanical alloying time is rather effective on composite microstructure and reactions took place during oxidation. Production of aluminum matrix composite with bariumaluminate via solid state reaction is possible, however fracture toughness and bend strength of the composite are relatively low. Key Words : Composite Materials, Oxidation, Fracture toughness