A study was made of quasi-cleavage processes that were driven by dislocation pile-up against a dislocation-free zone. The nanoscopic growth of the main crack consisted of sequences of nano-crack formation in the dislocation-free zone, and subsequent linking with the main crack. Under mode-I loading, the equilibrium locations of individual dislocations, and the equilibrium number of dislocations, were determined by invoking a minimum energy requirement. Three responses were identified. These were cleavage without dislocation emission, cleavage after emitting a certain number of dislocations, and cleavage which was suppressed by incessant dislocation emission. Accurate dislocation calculations indicated the emergence of a density stress peak, ahead of the crack tip, as the dislocations piled up against the dislocation-free zone.

Quasi-Cleavage Processes Driven by Dislocation Pile-Ups. T.Zhu, W.Yang, T.Guo: Acta Materialia, 1996, 44[8], 3049-58