Microwave processing of undoped and doped Al powder compacts was performed for the preparation of Al–Al 2 O 3 composites. Mg, Mg–Si and Al 2 O 3 were used as dopants to study their effects on the oxidation of Al powder and resultant Al–Al 2 O 3 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–Al 2 O 3 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 Al 2 O 3 doped Al powder compacts. SEM showed the microstructures of the microwave processed undoped and doped Al powder compacts.