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Published November 2014 | public
Journal Article

Stress-dependent solute energetics in W–Re alloys from first-principles calculations

Abstract

We present a systematic study of Re solute transport energetics in W using density functional theory calculations. The study focuses on substitutional solute diffusion in the presence of dislocation strain fields as a first step toward capturing the essential physics of solid solution hardening/softening in W–Re alloys. We calculate the heat of solution, the vacancy formation energy and the solute migration energy as functions of both hydrostatic and shear strains. Our results show that the vacancy formation energy scales with hydrostatic deformation, whereas it decreases with increasing shear strain. The migration energy decreases with hydrostatic deformation, whereas it displays path-length-dependent behavior under shear deformation. In addition, we compute the binding energies of an Re solute atom to the cores of 1/2〈111〉 screw and edge dislocations, and find the binding energy to be highest in the tensile lobe of the edge core. Finally, we obtain the dilatational stress due to a solute atom as a function of distance. Our calculations are then used to parameterize the jump rate of Re atoms in W as a function of the underlying stress state.

Additional Information

© 2014 Acta Materialia Inc. Published by Elsevier Ltd. Received 8 January 2014; received in revised form 1 July 2014; accepted 11 July 2014; Available online 24 August 2014. This work was carried out under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. M.Z.H. is very grateful to Prof. Kaushik Bhattacharya and the PSAAP-Caltech program. J.M. acknowledges support from DOE/OFES Early Career Program.

Additional details

Created:
August 22, 2023
Modified:
October 18, 2023