Monte Carlo study of ordering processes in fcc-based Ni-Mo alloys

The Monte Carlo simulations were carried out to clarify the ordering mechanisms in fee-based Ni-Mo alloys of Ni4Mo, Ni3Mo and Ni2Mo. When the pairwise atomic interactions up to the eighth coordinate shells are taken into account, the simulation results are consistent with the experimental changes in electron diffraction pattern during the ordering processes in Ni4Mo, Ni3Mo and Ni2Mo alloys. In the early stage of ordering, subunit cell clusters of D1(a), D0(22) and Pt2Mo structures are first generated to form the short range ordered (SRO) state. The selective growth of stable D1(a) and/or Pt2Mo-type ordered domains is involved in the transition to the long range ordered (LRO) state in the following stage.