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

Abstract

This research is focused on the production of aluminum matrix composites (AMCs) reinforced with various percentages of aluminum nitride (AlN). For this purpose, aluminum powder was milled at room temperature for a total time of 5 hours. The percentage of reinforcement is varied by milling under different periods of vacuum followed by ammonia gas flow. X-ray diffraction analysis showed the benefits of using a combined milling atmosphere to form, after the heat treatment of the powder, a higher amount of AlN. Results showed that the period in vacuum determines the greater or lesser capacity to absorb nitrogen during the ammonia gas period. Even using shorter vacuum milling periods, the AlN formed after sintering can be increased.