Phase formation in irradiated thin metallic bilayer at 500 K temperature

Abstract

A theoretical description of the phase formation in a thin solid bilayer under heavy ion irradiation is developed. The mixing and reaction of particles is described through a mass transport equation defined in terms of a chemical potential which, after some manipulation, exhibits the form of a Fick's second law for diffusion. In this equation there is an effective diffusion coefficient put forward as a function of the point defect concentrations and the formation enthalpies of the growing phases. This effective transport coefficient is a space dependent function impregnated with all the dynamic aspects involved in the description of the phenomenon. Within the framework of the model it is possible to analyze the phase sequence evolution of metallic bilayer under irradiation and, through a transformation of the theoretical concentration profile into a Rutherford Backscattering spectrum, to compare results with the experimental data.