Kinetics of "order-order" relaxations in Ni3Al studied by Monte Carlo simulation

Atomic migration in L1(2)-ordered A(3)B-type alloys during "order-order" relaxations was studied by Monte Carlo computer simulations. The configuration energy of the system was approximated by an Ising formula with six pair-interaction energy parameters evaluated with reference to the experimental reality of Ni3Al. An experimental result of two simultaneous processes differing in rates (Kozubski 1997) was reproduced by the simulation. The obtained curves fitted well a weighted sum of two exponentials. It was found that the weight factor of the fast relaxation process depended on the dynamics of minority atom jumps. We proved that the distribution of A- and B- anti-sites played a very important role while disordering and ordering the system.