Direct synthesis of NiAl intermetallic matrix composite with TiC and Al2O3 reinforcements by mechanical alloying of NiO–Al–Ti–C powder mixture

Abstract

NiAl intermetallic matrix nanocomposite with TiC and Al2O3 was directly fabricated by mechanical alloying of NiO, Al, graphite, and Ti as the starting powder mixture. The phase and morphological evaluations during mechanical alloying were characterized by X-ray diffraction and scanning electron microscopy equipped by energy-dispersive X-ray spectroscopy, respectively. The thermal behavior of the 40 h milled powder was obtained via differential thermal analysis. Followed by 10 h milling, no new phases were formed; but after 20 h milling, Al reduced a fraction of NiO, NiAl and Al2O3 were formed, and the released energy promoted TiC formation. When milling time reached 40 h, the remained raw materials were completely consumed and NiAl/TiC–Al2O3 nanocomposite was formed. Therefore, the main stage to synthesize NiAl/TiC–Al2O3 nanocomposite was the reduction of NiO by Al. The microstructural evaluation revealed formation of a homogeneously distributed composite and thermal analysis showed that the synthesized product was stable.