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Description
Aaron Kohnert1 Laurent Capolungo1

1, Los Alamos National Laboratory, Los Alamos, New Mexico, United States


In mean field rate theory (RT) based models for predicting the microstructural response of materials to radiation exposure, dislocation sinks are typically represented as a homogeneous absorbing medium, and the rate of defect point defect capture at them is based on simplified solutions from assumed defect profiles for ideal dislocation configurations. Recent advances in discrete dislocation dynamics (DDD) have allowed the efficient calculations of the strain field generated by arbitrary dislocation microstructures using the fast Fourier transform. This work presents a coupling of spatially resolved RT to DDD, utilizing the strain fields produced by the latter to inform defect interaction energies for a high fidelity solution of the drift-diffusion problem in the former. In the RT, defect capture rates are computed locally, based on the defect concentrations in the immediate vicinity of dislocations rather than globally or homogeneously. This approach enables explicit calculations of the sink strengths, biases, and spatially dependent point defect super-saturations caused by heterogeneous arrangements of dislocations and the interacting strain fields they produce. Additionally, the rates of point defect capture can be used in DDD simulations to produce climb rates which include with the effect of strain interactions, defect kinetics, and spatial correlations in the microstructure.

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