Formation of Ni-Al and Ni-Al-X phases by mechanical alloying

The Ni-Al phases were synthesized in the composition range 40-85 at. % Ni by mechanical alloying (MA) of elemental component mixtures. MA of Ni-Al powders produces the B2 phase in the range 40 - 61 at. % Ni and a solid solution Ni(Al) - in the range 65-85 at. % Ni. Milling of Ni62.5Al37.5 composition results in formation of the B2 and Ni(Al) phases mixture. Formation of a supersaturated solid solution for 65-75 at. % Ni were accompanied by appearance of B2 phase at the intermediate MA stage. Ball milling of Ni and Al powder mixtures of the compositions corresponded to intermetallics NiAl and Ni3Al, with a 5 at. % addition of X=Ti, Mo or Nib, where the third element was substituted for Ni (Ni45Al50X5 and Ni70Al25X5), Al (Ni50Al45X5 and Ni75Al20X5) or both (Ni47.5Al47.5X5 and Ni71.25Al23.75X5) was performed. The regularities of influence of the third components on the final structure of the as-milled and annealed alloys were observed. The preferred sublattices for X additions in B2 and L1(2) intermetallic phases were determined.