In situ aluminum matrix composites fabricated from Al–Ni2O3 system through microwave synthesis

• The (α-Al2O3 + Al3Ni + Al3Ni2)/Al can be fabricated by microwave heating synthesis.
• The reaction ignition temperature is lower than that in the conventional heating.
• The microstructures are finer than that by conventional heating method.
• The fabrication time is much shorter than that by conventional heating method.
• Some intermediate compounds can be remained in the final composites.

Aluminum matrix composites reinforced with α-Al2O3, Al3Ni and Al3Ni2 particulates were fabricated from Al and Ni2O3 powders by microwave synthesis. The reaction processes and resulting microstructures were analyzed by using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The results showed that the ignition temperatures of the reactions generated by microwave and conventional methods were approximately 695 °C and 735 °C, respectively. The time of microwave heating synthesis was about 8 min, which was much shorter than the time (more than 60 min) consumed by conventional heating method. It was found that the microstructure prepared by microwave heating was finer than that by conventional methods. The densities of the composites fabricated by microwave heating and conventional heating were 2.433 g/cm3 and 2.622 g/cm3, respectively. Some intermediate compounds were also observed in the final composites prepared by microwave heating synthesis.

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