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In this paper, in situ high-resolution electron backscattered diffraction (EBSD) is combined with concurrent atomistic-continuum (CAC) simulations to study the interactions between dislocation-mediated slip and grain boundaries (GBs) in Ni. It is found that the local stress associated with slip-GB intersections first increases upon the pileup of dislocations, then remains high even after the nucleation of dislocations in the neighboring grain, only relaxing after the nucleated dislocations propagate away from the GB due to more incoming dislocations participating in the pileup. The local stress relaxation is accompanied by an atomic-scale GB structure reconfiguration, which affects not only the subsequent dislocation transmission, but also the configuration of those dislocations away from the GB. These findings demonstrate the importance of incorporating local stress history at higher length scale models, such as crystal plasticity finite element.
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Coarse-grained atomistic modeling of dislocations and generalized crystal plasticity
Recent developments in generalized continuum modeling methods ranging from coarse-grained atomistics to micromorphic theory offer potential to make more intimate physical contact with dislocation field problems framed at length scales on the order of microns. We explore a range of discrete dynamical and continuum mechanics approaches to crystal plasticity that are relevant to modeling behavior of populations of dislocations. Predictive atomistic and coarse-grained atomistic models are limited in terms of length and time scales that can be accessed; examples of the latter are discussed in terms of interactions of multiple dislocations in heterogeneous systems. Generalized continuum models alleviate restrictions to a significant extent in modeling larger scales of dislocation configurations and reactions, and are useful to consider effects of dislocation configuration on strength at characteristic length scales of sub-micron and above; these models require a combination of bottomup models and top-down experimental information to inform parameters and model form. The concurrent atomistic-continuum (CAC) method is extended to model complex multicomponent alloy systems using an average atom approach. Examples of CAC are presented, along with potential to assist in informing parameters of a recently developed micropolar crystal plasticity model based on a set of sub-micron dislocation field problems. Prospects for further developments are discussed.
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- Award ID(s):
- 1761553
- PAR ID:
- 10377271
- Date Published:
- Journal Name:
- Journal of Micromechanics and Molecular Physics
- Volume:
- 07
- Issue:
- 02
- ISSN:
- 2424-9130
- Page Range / eLocation ID:
- 103 to 125
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1142/S2424913021420133
