Simulation of dislocation penetration through a general low-angle grain boundary

The interaction of dislocations with low-angle grain boundaries (LAGBs) is considered one important contribution to the mechanical strength of metals. Although LAGBs have been frequently observed in metals, little is known about how they interact with free dislocations that mainly carry the plastic deformation. Using discrete dislocation dynamics simulations, we are able to quantify the resistance of a LAGB—idealized as three sets of dislocations that form a hexagonal dislocation network—against lattice dislocation penetration, and examine the associated dislocation processes. Our results reveal that such a coherent internal boundary can massively obstruct and even terminate dislocation transmission and thus make a substantial contribution to material strength.