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Title: Modal analysis of dislocation vibration and reaction attempt frequency

Transition state theory is a fundamental approach for temporal coarse-graining. It estimates the reaction rate for a transition processes by quantifying the activation free energy and attempt frequency for the unit process. To calculate the transition rate of a gliding dislocation, the attempt frequency is often obtained from line tension estimates of dislocation vibrations, a highly simplified model of dislocation behavior. This work revisits the calculation of attempt frequency for a dislocation bypassing an obstacle, in this case a self-interstitial atom (SIA) loop. First, a direct calculation of the vibrational characteristics of a finite pinned dislocation segment is compared to line tension estimates before moving to the more complex case of dislocation-obstacle bypass. The entropic factor associated with the attempt frequency is calculated for a finite dislocation segment and for an infinite glide dislocation interacting with an SIA loop. Lastly, it is found to be dislocation length independent for three cases of dislocation-self interstitial atom (SIA) loop interactions.
Authors:
 [1] ; ORCiD logo [2] ;  [3] ; ORCiD logo [2]
  1. Georgia Inst. of Technology, Metz (France)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Georgia Inst. of Technology, Atlanta, GA (United States)
Publication Date:
Report Number(s):
LA-UR-16-26394
Journal ID: ISSN 1359-6454
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 134; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; dislocation; thermal activation; attempt frequency; modal analysis
OSTI Identifier:
1343712