Solute Diffusion in Grain Boundaries – Outside the Scope of Fisher Model

Alexey Rodin; Leonid Klinger; Boris S. Bokstein

doi:10.4028/www.scientific.net/DDF.289-292.711

Paper Titles

Essay on Techniques & Physics of Some Diffusion-Controlled Processes in Materials: Relevance to Nanofabrication Applications
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Impact of Carbon on the Diffusion of Donor Atoms in Germanium
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Diffusion in Isotope Heterostructures Investigated by Neutron Reflectometry
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Atomic Diffusion and its Relation to Thermodynamic Forces in Al-Ni Melts
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Solute Diffusion in Grain Boundaries – Outside the Scope of Fisher Model
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Concentration Characteristics of Diffusion-Induced Recrystallization
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Jump Frequencies of Cd Tracer Atoms in L1₂ Lanthanide Gallides
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Computer Simulation of Diffusion in Dilute Al-Fe Alloys
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Following the First Steps of UV Degradation of High Density Polyethylene by Fluorescence Spectroscopy
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Solute Diffusion in Grain Boundaries – Outside the Scope of Fisher Model

Abstract:

Thermodynamic and kinetic models are developed for grain boundary segregation and diffusion with regards to the possible complexes formation in grain boundary. The equilibrium state for ideal solutions can be described by the equilibrium constants b and K. The first corresponds to the pure segregation, i.e. the exchange A and B atoms between grain boundary and the bulk. The second represents the equilibrium of the reaction of the complexes formation in grain boundary. The segregation isotherm and diffusion profiles are calculated. It is shown that both b and K equilibrium constants define completely dependence of the total grain boundary concentration of B atoms on the bulk concentration and distribution of B atoms between two states: free (pure exchange) and tied (in the complexes). Segregation in both forms (free B atoms and tied B atoms) decreases grain boundary diffusivity in comparison with the absence of segregation.