Synthesis and characterization of in situ-reinforced Al-AlN composites produced by mechanical alloying

This research focuses on the production of Al matrix composites (AMCs) reinforced with various percentages of AlN. For this purpose, Al powder was milled at room temperature for a total time of 5 h. The percentage of the reinforcement phase was varied by milling under different periods of vacuum and ammonia (NH3) gas flow. X-ray diffraction analysis showed the benefits of the combined milling atmosphere in forming higher amounts of AlN after powder heat-treatment. Results showed that the period milled in vacuum determined the capacity of the powder to adsorb N during the NH3 gas period. Even under shorter vacuum milling periods, the amount of AlN formed after sintering can be increased.