Mechanochemical Synthesis of Mo-Doped Nickel Aluminides

The structure and thermal stability of Mo-doped Ni–Al intermetallic phases prepared by mechanical alloying were studied by x-ray diffraction and differential scanning calorimetry. The results demonstrate that mechanical processing of 50Ni + 45Al + 5Mo and 45Ni + 5Mo + 50Al powder mixtures yields nonstoichiometric aluminides and that a part of the Mo remains unreacted. The Mo introduced instead of Ni occupies some Ni sites in the structure of the forming aluminide, and this distribution persists during subsequent heating to 700°C. When Mo partially replaces Al, the Mo atoms also occupy some Ni sites, but subsequent heating to 700°C drives them to Al sites.