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Title: Specific features of defect and mass transport in concentrated fcc alloys

Abstract

We report that diffusion and mass transport are basic properties that control materials performance, such as phase stability, solute decomposition and radiation tolerance. While understanding diffusion in dilute alloys is a mature field, concentrated alloys are much less studied. Here, atomic-scale diffusion and mass transport via vacancies and interstitial atoms are compared in fcc Ni, Fe and equiatomic Ni-Fe alloy. High temperature properties were determined using conventional molecular dynamics on the microsecond timescale, whereas the kinetic activation-relaxation (k-ART) approach was applied at low temperatures. The k-ART was also used to calculate transition states in the alloy and defect transport coefficients. The calculations reveal several specific features. For example, vacancy and interstitial defects migrate via different alloy components, diffusion is more sluggish in the alloy and, notably, mass transport in the concentrated alloy cannot be predicted on the basis of diffusion in its pure metal counterparts. Lastly, the percolation threshold for the defect diffusion in the alloy is discussed and it is suggested that this phenomenon depends on the properties and diffusion mechanisms of specific defects.

Authors:
ORCiD logo [1];  [1];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1260074
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 115; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; diffusion; concentrated alloys; Ni-Fe alloys; tracer diffusion coefficient

Citation Formats

Osetsky, Yuri N., Béland, Laurent K., and Stoller, Roger E. Specific features of defect and mass transport in concentrated fcc alloys. United States: N. p., 2016. Web. doi:10.1016/j.actamat.2016.06.018.
Osetsky, Yuri N., Béland, Laurent K., & Stoller, Roger E. Specific features of defect and mass transport in concentrated fcc alloys. United States. doi:10.1016/j.actamat.2016.06.018.
Osetsky, Yuri N., Béland, Laurent K., and Stoller, Roger E. 2016. "Specific features of defect and mass transport in concentrated fcc alloys". United States. doi:10.1016/j.actamat.2016.06.018. https://www.osti.gov/servlets/purl/1260074.
@article{osti_1260074,
title = {Specific features of defect and mass transport in concentrated fcc alloys},
author = {Osetsky, Yuri N. and Béland, Laurent K. and Stoller, Roger E.},
abstractNote = {We report that diffusion and mass transport are basic properties that control materials performance, such as phase stability, solute decomposition and radiation tolerance. While understanding diffusion in dilute alloys is a mature field, concentrated alloys are much less studied. Here, atomic-scale diffusion and mass transport via vacancies and interstitial atoms are compared in fcc Ni, Fe and equiatomic Ni-Fe alloy. High temperature properties were determined using conventional molecular dynamics on the microsecond timescale, whereas the kinetic activation-relaxation (k-ART) approach was applied at low temperatures. The k-ART was also used to calculate transition states in the alloy and defect transport coefficients. The calculations reveal several specific features. For example, vacancy and interstitial defects migrate via different alloy components, diffusion is more sluggish in the alloy and, notably, mass transport in the concentrated alloy cannot be predicted on the basis of diffusion in its pure metal counterparts. Lastly, the percolation threshold for the defect diffusion in the alloy is discussed and it is suggested that this phenomenon depends on the properties and diffusion mechanisms of specific defects.},
doi = {10.1016/j.actamat.2016.06.018},
journal = {Acta Materialia},
number = C,
volume = 115,
place = {United States},
year = 2016,
month = 6
}

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Free Publicly Available Full Text
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  • A long-standing objective in materials research is to understand how energy is dissipated in both the electronic and atomic subsystems in irradiated materials, and how related non-equilibrium processes may affect defect dynamics and microstructure evolution. Here we show that alloy complexity in concentrated solid solution alloys having both an increasing number of principal elements and altered concentrations of specific elements can lead to substantial reduction in the electron mean free path and thermal conductivity, which has a significant impact on energy dissipation and consequentially on defect evolution during ion irradiation. Enhanced radiation resistance with increasing complexity from pure nickel tomore » binary and to more complex quaternary solid solutions is observed under ion irradiation up to an average damage level of 1 displacement per atom. Understanding how materials properties can be tailored by alloy complexity and their influence on defect dynamics may pave the way for new principles for the design of radiation tolerant structural alloys.« less
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