| Nanocrystalline powders with stoichiometric Ni3Al composition were prepared by ball milling of Al3Ni intermetallic compound or Ni-4%Al solid solution with addition of Ni powder and Al powder respectively. The thermal stability of the milled powders was investigated using differential scanning calorimetry. The phase and structural transformations occurring in the samples during mechanical alloying and during subsequent heating in the calorimeter were investigated using X-ray diffraction. In the cases of both starting powders compositions, small zones of supersaturated Ni(Al) solid solution were formed during the first step of milling. Upon further milling, the Ni(Al) solid solution was formed in the whole content of the milled material. During heating of the milling products in the calorimeter, the Ni(Al) solid solution transformed into an ordered Ni3Al intermetallic compound. The powders after milling as well as after subsequent heating were nanocrystalline. |
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