Fe3Al bulk nanocrystalline intermetallic composites were prepared by microwave-assisted combustion synthesis technology under air atmosphere. The bulk Fe3Al intermetallic composites mainly consist of nanocrystalline matrix and inclusions of micro-scale acicular and granular Fe3Al phases. The acicular Fe3Al phases are presented at the grain boundary of original alpha-Fe solid solution phase, while the granular phases surround the intragranular Al2O3 particles. The formation of nanocrystalline matrix composites is mainly attributed to the high superheat in the process of microwave-assisted combustion synthesis and the rapid cooling effects of copper mold. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.