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Title: Modelling of monovacancy diffusion in W over wide temperature range

The diffusion of monovacancies in tungsten is studied computationally over a wide temperature range from 1300‚ÄČK until the melting point of the material. Our modelling is based on Molecular Dynamics technique and Density Functional Theory. The monovacancy migration barriers are calculated using nudged elastic band method for nearest and next-nearest neighbour monovacancy jumps. The diffusion pre-exponential factor for monovacancy diffusion is found to be two to three orders of magnitude higher than commonly used in computational studies, resulting in attempt frequency of the order 10{sup 15} Hz. Multiple nearest neighbour jumps of monovacancy are found to play an important role in the contribution to the total diffusion coefficient, especially at temperatures above 2/3 of T{sub m}, resulting in an upward curvature of the Arrhenius diagram. The probabilities for different nearest neighbour jumps for monovacancy in W are calculated at different temperatures.
Authors:
; ;  [1]
  1. Department of Physics, University of Helsinki, P.O. Box 43, 00014 Helsinki (Finland)
Publication Date:
OSTI Identifier:
22271167
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPUTERIZED SIMULATION; DENSITY FUNCTIONAL METHOD; DIFFUSION; MELTING POINTS; MOLECULAR DYNAMICS METHOD; PROBABILITY; TEMPERATURE DEPENDENCE; TUNGSTEN; VACANCIES