In-situ processing of AlN-Al alloy composites

Experimental study of in-situ formation of AIN reinforced aluminum alloy composites was carried out by bubbling nitrogen gas into aluminum alloy melts. AIN particulate reinforcement was synthesized in the aluminum alloy melts at 1473K. Mg3N2 was not found in the composites when the aluminum alloy contained magnesium. The experimental products were characterized using X-ray diffraction, SEM and EDX analyses. Equilibrium compositions of the system were calculated using Gibbs energy minimization method, indicating that the AIN is thermodynamically stable in Al-N binary and Al-Mg-N ternary systems in a wide temperature range. In addition, the effect of oxygen on the formation of nitrides was discussed.