Phenomenological Investigation of Disorder-L1_0 Phase Equilibria for Au-Pd and Ni-Pt Alloy Systems

摘要

A phenomenological investigation is performed on the dis-order-L1_0 phase equilibria for Au-Pd and Ni-Pt alloy systems based on the Lennard-Jones type pair potential combined with thermal vibration effects and the Cluster Variation Method. The phase diagrams are calculated and relevant thermodynamic quantities such as long range order parameters and thermal expansion coefficients are derived. It is revealed that the thermal vibration effects decrease the order-disorder transition temperature, which is attributed to the destabilization of the L1_0 ordered phase due to the enhancement of the disordering reaction caused by the lattice softening.