Simulation of diffusion with non-equilibrium vacancies, Kirkendall shift and porosity in single-phase alloys

In an alloy subject to vacancy-mediated diffusion, differences in intrinsic diffusivities tend produce vacancy excess and deficit. These are accommodated by mechanisms such as dislocation climb pore formation. This is of concern high temperature alloy-coating systems used industrial applications, pores may develop at the interface between coating, which undesired. paper presents a multicomponent diffusion model with two types sinks/sources: one associated generates lattice shift, other porosity increase/decrease. The designed toward 1D implementation, described local average volume fraction. Thermodynamic properties mobility modeled according Calphad method allow future application engineering materials. Finite-difference simulations run on binary systems, NiCr NiSi, illustrate role sinks interdiffusion development. Diffusion found be more sensitive sink strengths NiSi system, where have stronger composition dependence. work provides basis for evaluation parameters involved generation/annihilation (e.g. density) from experimental data, concentration profiles obtained couple experiments, prediction