The formation of typical dislocation patterns in copper under cyclic loading is closely associated with cross slip of screw dislocations.
Typical dislocation structures including straight prismatic slip lines, curved dislocation lines, dislocation tangles and twins can be discovered in fatigued specimens with two different microstructures.
Detailed analysis of the atomic processes allowed correlation of the stress signature of slip events with typical dislocation processes related to nucleation and propagation.
First, a typical dislocation distribution near the microvoid is presented and the void growth mechanism is revealed by dislocation shear loop expansion for each of three typical fcc slip systems.
When either of these length scales is decreased below roughly 1 μm, the typical dislocation wall and cell structures found in fatigued coarse-grained bulk materials no longer develop and are replaced by individual dislocations.
At low strain amplitudes, the prevailing dislocation structure in the [345] component crystal is loop patches, while the typical dislocation structure in the [117] component crystal consists of labyrinth-like loop patches and less orderly persistent slip band (PSB) ladder structures.
