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Title: An atomistic investigation of the interaction of dislocations with Guinier-Preston zones in Al-Cu alloys

Abstract

The interaction between edge dislocations and Guinier-Preston zones in an Al-Cu alloy was analyzed by means of atomistic simulations. The different thermodynamic functions that determine the features of these obstacles for the dislocation glide were computed using molecular statics, molecular dynamics and the nudged elastic band method. It was found that Guinier-Preston zones are sheared by dislocations and the rate at which dislocations overcome the precipitate is controlled by the activation energy, Δ U, in agreement with the postulates of the harmonic transition state theory. Moreover, the entropic contribution to the Helmholtz activation free energy was in the range 1.3–1.8 k b, which can be associated with the typical vibrational entropy of solids. Finally, an estimation of the initial shear flow stress as a function of temperature was carried out from the thermodynamic data provided by the atomistic simulations. Furthermore, comparison with experimental results showed that the effect of the random precipitate distribution and of the dislocation character and dislocation/precipitation orientation has to be taken into account in the simulations to better reproduce experiments.

Authors:
 [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [2];  [3]
  1. IMDEA Materials Institute, Madrid (Spain); Polytechnic Univ. of Madrid/Univ. Politecnica de Madrid, Madrid (Spain); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. IMDEA Materials Institute, Madrid (Spain); Polytechnic Univ. of Madrid/Univ. Politecnica de Madrid, Madrid (Spain)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1482933
Report Number(s):
LA-UR-18-21773
Journal ID: ISSN 1359-6454
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 162; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Atomistic simulations, Al alloys, dislocations, precipitate strengthening, transition state theory

Citation Formats

Esteban-Manzanares, Gustavo, Martínez, Enrique Saez, Segurado, J., Capolungo, Laurent, and LLorca, Javier. An atomistic investigation of the interaction of dislocations with Guinier-Preston zones in Al-Cu alloys. United States: N. p., 2018. Web. doi:10.1016/j.actamat.2018.09.052.
Esteban-Manzanares, Gustavo, Martínez, Enrique Saez, Segurado, J., Capolungo, Laurent, & LLorca, Javier. An atomistic investigation of the interaction of dislocations with Guinier-Preston zones in Al-Cu alloys. United States. doi:10.1016/j.actamat.2018.09.052.
Esteban-Manzanares, Gustavo, Martínez, Enrique Saez, Segurado, J., Capolungo, Laurent, and LLorca, Javier. Mon . "An atomistic investigation of the interaction of dislocations with Guinier-Preston zones in Al-Cu alloys". United States. doi:10.1016/j.actamat.2018.09.052. https://www.osti.gov/servlets/purl/1482933.
@article{osti_1482933,
title = {An atomistic investigation of the interaction of dislocations with Guinier-Preston zones in Al-Cu alloys},
author = {Esteban-Manzanares, Gustavo and Martínez, Enrique Saez and Segurado, J. and Capolungo, Laurent and LLorca, Javier},
abstractNote = {The interaction between edge dislocations and Guinier-Preston zones in an Al-Cu alloy was analyzed by means of atomistic simulations. The different thermodynamic functions that determine the features of these obstacles for the dislocation glide were computed using molecular statics, molecular dynamics and the nudged elastic band method. It was found that Guinier-Preston zones are sheared by dislocations and the rate at which dislocations overcome the precipitate is controlled by the activation energy, ΔU, in agreement with the postulates of the harmonic transition state theory. Moreover, the entropic contribution to the Helmholtz activation free energy was in the range 1.3–1.8 kb, which can be associated with the typical vibrational entropy of solids. Finally, an estimation of the initial shear flow stress as a function of temperature was carried out from the thermodynamic data provided by the atomistic simulations. Furthermore, comparison with experimental results showed that the effect of the random precipitate distribution and of the dislocation character and dislocation/precipitation orientation has to be taken into account in the simulations to better reproduce experiments.},
doi = {10.1016/j.actamat.2018.09.052},
journal = {Acta Materialia},
number = C,
volume = 162,
place = {United States},
year = {2018},
month = {10}
}

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