Structural energetics and the order-disorder transition

An investigation is made of the roles of the structural contributions to the Helmholtz free energy in the order-disorder transition that occurs in certain binary alloys. Detailed calculations of the transient temperature T _c in the CuZn (A2 to or from B2), AuCu₃ (A1 to or from L12) and Mg₃Cd ( epsilon to or from DO₁₉) transitions are presented. In these calculations the static lattice approximation is employed which ignores any effects due to lattice vibrations and only considers configurational disorder.