Fabrication of nanostructured nickel and titanium aluminides starting from elemental nanopowders

The current paper investigates the fabrication of nanostructured aluminide intermetallics (Ni3Al, NiAl and Ti3Al) starting from elemental nanopowders Ni, Al, and Ti under a more simplified experimental setup as compared to other techniques. The in situ processing involves the reaction synthesis (RS) of the nanopowder green compacts in an air-furnace from which nanostructured aluminides were successfully produced. The data revealed that in the case of both Ni3Al and NiAl processing, the nanopowders were completely reacted to form the intended single phase Ni3Al and NiAl, respectively, with no remaining nanopowders, while, in the case of Ti3Al processing, small amount of Ti3Al5 was found after the in situ fabrication. The hardness was increased sharply due to nanostructure grain formation (110-140 nm). Microalloying additions of Nb and B elements induced considerable ductility in the case of Ni3Al and NiAl compared to Ti3Al. Both scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS)-analysis and X-ray powder diffractometer (XRD) were used to examine the phase composition after the RS-process.