Multiphase field modeling of grain boundary migration mediated by emergent disconnections

Abstract

Knowledge about grain boundary migration is a prerequisite for understanding and ultimately modulating the properties of polycrystalline materials. Evidence from experiments and molecular dynamics (MD) simulations suggests that the formation and motion of disconnections is a mechanism for grain boundary migration. Here, grain boundary migration is modeled using a multiphase field model based on the principle of minimum dissipation potential with nonconvex boundary energy, along with a stochastic model for thermal nucleation of disconnection pairs. In this model, disconnections arise spontaneously in the presence of an elastic driving force, and that their motion mediates boundary migration. The effect is due to the fact that the formation of the disconnections pairs results in a stress concentration, causing the elastic driving force to exceed the threshold value and driving the propagation of the disconnection along the interface. The model is applied to study the propagation/annihilation of single disconnection pairs, the relaxation of a perturbed interface, and shear coupling at various temperatures. The results are consistent with the current understanding of disconnections, and capture the effect of thermal softening.

References in corpus (6)

• Massively parallel finite difference elasticity using block-structured adaptive mesh refinement with a geometric multigrid solver
• Initiation and stagnation of room temperature grain coarsening in cyclically strained gold films
• Block structured adaptive mesh refinement and strong form elasticity approach to phase field fracture with applications to delamination, crack branching and crack deflection
• The driving force governing room temperature grain coarsening in thin gold films
• Optimal transportation of grain boundaries: A forward model for predicting migration mechanisms
• A crystal symmetry-invariant Kobayashi--Warren--Carter grain boundary model and its implementation using a thresholding algorithm

Cited by in corpus (8)

• Polycrystal plasticity with grain boundary evolution: A numerically efficient dislocation-based diffuse-interface model
• Atomistic-informed phase field modeling of magnesium twin growth by disconnections
• Grain boundary network plasticity: reduced-order modeling of deformation-driven microstructure evolution
• Robust, strong form mechanics on an adaptive structured grid: efficiently solving variable-geometry near-singular problems with diffuse interfaces
• The Alamo multiphysics solver for phase field simulations with strong-form mechanics and block structured adaptive mesh refinement
• Comparison of evolving interfaces, triple points, and quadruple points for discrete and diffuse interface methods
• Facet and energy predictions in grain boundaries: lattice matching and molecular dynamics
• Mechanics of incompatible asymmetric grain boundary migration