Interaction of an edge dislocation with a 〈110〉 tilt boundary in nickel: molecular dynamics simulation

Abstract

The interaction of a lattice edge dislocation with a 〈110〉 tilt boundary in nickel was studied by the molecular dynamics method in the case when the dislocation glide plane is parallel to the grain tilt axis. The dependence of the local threshold stress on the grain misorientation angle is obtained. It is found that with increasing misorientation angle, the local threshold stress increases, but the growth rate for low- and high-angle boundaries is different: for high-angle boundaries, this growth is slower. When studying the mechanism of overcoming the low-angle 〈110〉 tilt boundary by an edge dislocation in the considered orientation, it was found that the dislocation, in fact, does not pass through the boundary, but exchanges places with a grain-boundary dislocation, which are ordinary perfect edge dislocations in the low-angle 〈110〉 tilt boundaries. When studying the interaction of a dislocation with high-angle boundaries, a peculiarity was noticed, which consists in pushing two or three grain-boundary dislocations out of the boundary at once.