Predicting dislocation climb and creep from explicit atomistic details.

Predicting dislocation climb: Classical modeling versus atomistic simulations

Dislocation Creep: Climb and Glide in the Lattice Continuum

A continuum theory for high temperature creep of polycrystalline solids is developed. It includes the relevant deformation mechanisms for diffusional and dislocation creep: elasticity with eigenstrains resulting from vacancy diffusion, dislocation climb and glide, and the lattice growth/loss at the boundaries enabled by diffusion. All the deformation mechanisms are described with respect to the...

Pure climb creep mechanism drives flow in Earth’s lower mantle

At high pressure prevailing in the lower mantle, lattice friction opposed to dislocation glide becomes very high, as reported in recent experimental and theoretical studies. We examine the consequences of this high resistance to plastic shear exhibited by ringwoodite and bridgmanite on creep mechanisms under mantle conditions. To evaluate the consequences of this effect, we model dislocation cr...

Dislocation climb models from atomistic scheme to dislocation dynamics

We develop a mesoscopic dislocation dynamics model for vacancy-assisted dislocation climb by upscalings from a stochastic model on the atomistic scale. Our models incorporate microscopic mechanisms of (i) bulk diffusion of vacancies, (ii) vacancy exchange dynamics between bulk and dislocation core, (iii) vacancy pipe diffusion along the dislocation core, and (iv) vacancy attachment-detachment k...

Modeling the creep threshold stress due to climb of a dislocation in the stress field of a misfitting precipitate

A model for creep threshold stresses in alloys strengthened by coherent, misfitting precipitates is developed for the case where the precipitate is not sheared, and where there are elastic interactions between a dislocation and the precipitate over which it climbs. Calculations of the particle stress field due to a positive stiffness and lattice parameter mismatch between precipitate and matrix...