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Title: A phase field dislocation dynamics model for a bicrystal interface system: An investigation into dislocation slip transmission across cube-on-cube interfaces

In this study, we present a phase field dislocation dynamics formulation designed to treat a system comprised of two materials differing in moduli and lattice parameters that meet at a common interface. We apply the model to calculate the critical stress τcrit required to transmit a perfect dislocation across the bimaterial interface with a cube-on-cube orientation relationship. The calculation of τcrit accounts for the effects of: 1) the lattice mismatch (misfit or coherency stresses), 2) the elastic moduli mismatch (Koehler forces or image stresses), and 3) the formation of the residual dislocation in the interface. Our results show that the value of τcrit associated with the transmission of a dislocation from material 1 to material 2 is not the same as that from material 2 to material 1. Dislocation transmission from the material with the lower shear modulus and larger lattice parameter tends to be easier than the reverse and this apparent asymmetry in τcrit generally increases with increases in either lattice or moduli mismatch or both. In efforts to clarify the roles of lattice and moduli mismatch, we construct an analytical model for τcrit based on the formation energy of the residual dislocation. We show that path dependence inmore » this energetic barrier can explain the asymmetry seen in the calculated τcrit values.« less
Authors:
 [1] ;  [2] ;  [2] ;  [1]
  1. Purdue Univ., West Lafayette, IN (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
1246364
Report Number(s):
LA-UR--15-25049
Journal ID: ISSN 0749-6419; PII: S0749641915001473
Grant/Contract Number:
FG02-07ER46398; 20130745ECR; 20140348ER; AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
International Journal of Plasticity
Additional Journal Information:
Journal Volume: 79; Journal Issue: C; Journal ID: ISSN 0749-6419
Publisher:
Elsevier
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 97 MATHEMATICS AND COMPUTING; 77 NANOSCIENCE AND NANOTECHNOLOGY A. Dislocations; B. Crystal plasticity; B. Metallic material