Study of the phase transitions b2-a2 and B32-A2 in alloys using the modified Kirkwood method

The modified Kirkwood method gives an improved treatment of the problem because both intraphase and heterophase fluctuations in the alloy can be taken into account. In other methods of the theory of ordering each superstructure must be treated as a separate case, whereas the advantage of the modified method is that the resulting expression for the free energy of the alloy describes the ordering in both the B2 and B32 phases, as well as the decomposition of the alloy. The reduced B2-A2 transition temperature obtained here agrees more closely with the asymptotic estimates from series expansions than the results of other approximations.