Transient dislocation emission from a crack tip

摘要

Transient nature of dislocation emission from a crack tip gives a new twist to the study of brittle-to-ductile transition. In a class of materials, only the dislocations traveling at high speed may escape from the crack tip. The nucleation of a fast moving dislocation, however, requires a higher level of activation energy, as supported by many experimental data. The present paper explores this scenario under the restriction that the dislocation moves along the crack extension plane.