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A multiscale framework for coupling dislocation dynamics with vacancy diffusion theory

A. Amine Benzerga (Texas A&M University), Shyam Keralavarma (EPFL)

From Atomistics to Reality: Spanning Scales in Simulations and Experiments Symposium A

Mon 10:45 - 12:15

CIT 165

At low homologous temperatures, plastic deformation of metals is controlled by dislocation glide. At temperatures greater than about 1/3 of the melting point, dislocation climb becomes important leading to phenomena such as creep. Current discrete dislocation dynamics codes do not account for that. The modeling of climb as a non-conservative motion requires the concurrent modeling of dislocation motion and point defect diffusion into the cores of dislocations. Here we report on a formulation of high-temperature discrete dislocation plasticity in finite bodies, which accounts for the above couplings. An adaptive multi-time stepping algorithm is used in the numerical implementation of the theory. We then present a series of deformation analyses at constant applied stress in single crystals. We show that two regimes of power-law creep naturally emerge in the simulations, as affected by the applied stress and test temperature. We also systematically quantify the power law exponent in either regime.