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MM: Fachverband Metall- und Materialphysik

MM 20: Topical Session: Interface-dominated phenomena - Diffusion

MM 20.2: Vortrag

Dienstag, 17. März 2020, 10:45–11:00, IFW A

Influence of atomic interaction on grain boundary self-diffusion in binary solid solutions — •Vladimir A. Esin — Centre des Matériaux, MINES ParisTech, PSL University, France

Atomic interaction of solute atoms with solvent ones has been considered to be of the major responsibility for the effect of solute on grain boundary self-diffusion. It is supposed that during diffusion process the diffusing solvent atoms form atomic complex with solute atoms at grain boundary with the formation of chemical bonds [1,2]. A description of solvent GB diffusion is then given for both B- and C-regimes.

Using such an approach, a new equation for the dependence of solvent GB diffusion coefficient on solute bulk concentration is derived for the systems with simple atomic attraction in GB. Theoretical results predict non-linear dependence of solvent GB diffusion coefficient on solute bulk content, which is in agreement with earlier published experimental data regarding the ease of grain boundary diffusion in alloys of different chemical compositions. More importantly, the equation deduced permits to evaluate, on one hand, the characteristics of solute GB segregation from solvent GB diffusion measurements and, one the other hand, GB diffusion coefficient in pure solvent. Such a numerical data analysis for Fe-Sn system is in agreement with experimental results.

[1] V. Esin, B. Bokstein and A. Rodin, Defect Diffus. Forum 309-310 (2011) p. 29.

[2] V.A. Esin and B.S. Bokstein, Acta Mater. 60 (2012) p. 5109.