Mechanochemical synthesis of (Fe,Ti)3Al–Al2O3 nanocomposite

Formation mechanism of (Fe,Ti)3Al–Al2O3 nanocomposite prepared by mechanical alloying of Fe, Al and TiO2 with molar ratio of 6:7:3 was studied. The structural changes of powder particles during mechanical alloying were investigated by X-ray diffractometery. Morphology and microstructure of powder particles were characterized by scanning electron microscopy. It was found that during mechanical alloying Al first reacts with TiO2 leading to the gradual formation of crystalline Ti and amorphous Al2O3 phases. In the second stage Ti and remaining Al diffuse into the Fe lattice and as a result a Fe(Al,Ti) solid solution develops. This structure transformed to (Fe,Ti)3Al intermetallic compound at longer milling times. Heat treatment of this structure led to the crystallization of Al2O3 and ordering of (Fe,Ti)3Al phases.