Improved thermodynamic treatment of vacancy-mediated diffusion and creep

0464081 - ÚFM 2017 RIV GB eng J - Journal Article
Fischer, F. D. - Hackl, K. - Svoboda, Jiří
Improved thermodynamic treatment of vacancy-mediated diffusion and creep.
Acta Materialia. Roč. 108, APR (2016), s. 347-354. ISSN 1359-6454. E-ISSN 1873-2453
R&D Projects: GA ČR(CZ) GA15-06390S
Institutional support: RVO:68081723
Keywords : Thermodynamics * Non-equilibrium * Diffusion * Vacancies * Thermodynamic extremal principle
Subject RIV: BJ - Thermodynamics
Impact factor: 5.301, year: 2016

Approximately a decade ago a new concept to describe the kinetics of one-phase solid state systems evolving by diffusion and activity of vacancies has been published by the authors. The concept is based on the Onsager-Ziegler Thermodynamic Extremal Principle (TEP). In course of the last decade several improvements and corrections have been performed, which justify an overworking of the concept. A short introduction of the TEP is followed by a detail investigation of the Gibbs energy and its rate as well as of dissipation and dissipation function due to multicomponent diffusion process coupled with vacancy activity provoking swelling/shrinkage and creep and thus internal stress state development. The application of TEP allows an exact derivation of driving forces for the coupled processes. The Manning theory of diffusion is applied and the derivation of evolution equations for all system parameters (site fractions, swelling/shrinkage and creep strain tensor) is provided.
Permanent Link: http://hdl.handle.net/11104/0263138