MONTE-CARLO STUDY OF ORDERING PROCESSES IN FCC-BASED NI-MO ALLOYS

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