Title: Multiscale Concurrent Atomistic-Continuum (CAC) modeling of multicomponent alloys

Abstract

We report strengthening in complex multicomponent systems such as solid solution alloys is controlled primarily by the dynamic interactions between dislocation lines and heterogeneously distributed solute species. Modeling of extended defect length scales in such multicomponent systems becomes prohibitively expensive, motivating the development of reduced order approaches. This work explores the application of the Concurrent Atomistic-Continuum (CAC) method to model dislocation mobility in random alloys at extended length scales. By employing recently developed average-atom interatomic potentials, the average “bulk” material response in coarse-grained regions interacts with true random solute species in the atomistic-scale domain. We demonstrate that spurious stresses in domain resolution transition regions are eliminated entirely due to the CAC formulation. Simultaneously, the key details of local stress fluctuation due to randomness in the dislocation core region are captured, and fluctuating stress smoothly decays to the long-range dislocation stress field response. Dislocation mobility calculations, for line lengths over 400 nm, are computed as a function of alloy composition in the model FeNiCr system and compared to full molecular dynamics (MD). The results capture the composition-dependent trends, while reducing degrees of freedom by nearly 40%. This approach can be readily extended to any system described by an EAM potential andmore » facilitates the study of large-scale defect dynamics in complex solute environments to support computational alloy design.« less

Authors:

Chu, Kevin ^[1]; Diaz, Adrian ^[2]; Chen, Youping ^[3]; Zhu, Ting ^[1]; McDowell, David L. ^[1]

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+ Show Author Affiliations

1. Georgia Institute of Technology, Atlanta, GA (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. Univ. of Florida, Gainesville, FL (United States)

Publication Date:

Mon Sep 20 00:00:00 EDT 2021

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); US Department of the Navy, Office of Naval Research (ONR); National Science Foundation (NSF); Georgia Institute of Technology

OSTI Identifier:

1865012

Report Number(s):

LA-UR-21-25737
Journal ID: ISSN 0927-0256

Grant/Contract Number:  

89233218CNA000001; N00014-18-2784; CMMI-176512; 1828187

Resource Type:

Accepted Manuscript

Journal Name:

Computational Materials Science

Additional Journal Information:

Journal Volume: 201; Journal ID: ISSN 0927-0256

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; multiscale simulation; dislocation dynamics; atomistic modeling; alloys; random alloys; concurrent atomistic-continuum; molecular dynamics; average atom