Order–disorder transition in nanocrystalline Ni3Al prepared by a chemical route

Ni3Al alloys of nanometer dimensions in the range 10–38 nm could be synthesized by reaction sintering of sol–gel-derived Ni/SiO2 nanocomposite and commercially available micrometer-sized aluminum powder. The sintering was carried out at a temperature of 923 K and a pressure of 2.4 MPa. By a suitable choice of sintering conditions a disordered phase of Ni3Al was stabilized. The disordered phase could be converted to an ordered one by an increase of heat treatment temperature.