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Title: A novel method for calculating the energy barriers for carbon diffusion in ferrite under heterogeneous stress

A novel method for accurate and efficient evaluation of the change in energy barriers for carbon diffusion in ferrite under heterogeneous stress is introduced. This method, called Linear Combination of Stress States, is based on the knowledge of the effects of simple stresses (uniaxial or shear) on these diffusion barriers. Then, it is assumed that the change in energy barriers under a complex stress can be expressed as a linear combination of these already known simple stress effects. The modifications of energy barriers by either uniaxial traction/compression and shear stress are determined by means of atomistic simulations with the Climbing Image-Nudge Elastic Band method and are stored as a set of functions. The results of this method are compared to the predictions of anisotropic elasticity theory. It is shown that, linear anisotropic elasticity fails to predict the correct energy barrier variation with stress (especially with shear stress) whereas the proposed method provides correct energy barrier variation for stresses up to ∼3 GPa. This study provides a basis for the development of multiscale models of diffusion under non-uniform stress.
Authors:
 [1] ;  [2] ; ;  [3] ;  [1] ;  [4]
  1. IRSN, PSN, SEMIA, LPTM, Saint-Paul-Lez-Durance (France)
  2. (France)
  3. Univ. Lyon, INSA Lyon, MATEIS, UMR CNRS 5510, Villeurbanne (France)
  4. IRSN, PSN, SAG, LETR, Saint-Paul-Lez-Durance (France)
Publication Date:
OSTI Identifier:
22419886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON; COMPARATIVE EVALUATIONS; ELASTICITY; FERRITE; FERRITES; SIMULATION; STRESSES