Numerical treatment of diffusional reactions in multicomponent alloys

Abstract This report describes a numerical method to treat diffusional reactions in alloys where a thermodynamic description, complete enough to represent phase equilibria, as well as diffusion coefficients is available. The method combines a rigorous treatment of the thermodynamic equilibrium locally at a moving phase interface with an ambitious treatment of the diffusion inside the one-phase regions. The method contains no formal restrictions on the number of components. Different kinds of phases, substitutional and interstitial solutions and phases, with stoichiometrie constraints, e.g. carbides and nitrides, can be handled. The implementation on computer is discussed in several appendices.