The radiation-induced order-disorder transformation in Cu3Au

A model for ordered alloys is presented which describes the combined effects of radiation disordering and radiation-enhanced ordering. The model uses the assumptions of Bragg-Williams ordering in a kinetic form in which the ordering energy is a linear function of order. Point-defect concentrations are introduced into the ordering kinetics so that the effect of the radiation (through enhancement of such concentrations) can be described. Both time-dependent and steady-state solutions to the resulting ordering rate equation are presented. All the available data on irradiation of Cu3Au with fast and thermal neutrons are reviewed and presented as functions of long-range order parameters versus dose. All the curves at a wide variety of temperatures are fitted successfully with the model using the same diffusion parameters throughout. The implications and predictions of the model for future experiments are discussed. (author)