The University of Tokyo Department of Mechanical Engineering,Fracture Mechanics Laboratory.SAKAI & IZUMI group.


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Investigation of activation Free energy for dislocation nucleation process by using accelerated molecular dynamics

The deformation and failure of materials are the results of stress-driven, thermally activated processes at the atomic level. Molecular dynamics (MD) simulations can only follow very limited time period which hinders one from gaining complete knowledge about the deformation physics. Here we present a strain-boost method for accelerating atomistic simulations, which can be more efficient and robust than the bond-boost hyperdynamics in tracking collective stress-driven events. We realize a direct access to the dynamical evolution of dislocation nucleation in compressed Cu nano-pillar over the time scale comparable to an experimental laboratory level. The method is able to provide the stress-dependent activation enthalpy, activation entropy and activation volume associated with dislocation nucleation from free surface.

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