Effect of dopants on the phase formation in microwave processed Al–Al2O3 composites

Microwave processing of undoped and doped Al powder compacts was performed for the preparation of Al–Al2O3 composites. Mg, Mg–Si and Al2O3 were used as dopants to study their effects on the oxidation of Al powder and resultant Al–Al2O3 composites. The microwave heated undoped and doped Al powder compacts were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. XRD and EDX data of the microwave treated powder compacts confirmed the formation of Al–Al2O3 composites. Mg and Mg–Si doped Al powder compacts exhibited bulk composite growth. On the contrary, composite formation was restricted to the surface and near surface only in the undoped and Al2O3 doped Al powder compacts. SEM showed the microstructures of the microwave processed undoped and doped Al powder compacts.