Dislocations deflect and perturb dynamically propagating cracks.
We demonstrate that in single-crystal silicon short-range collisions of a dynamically propagating crack with stationary, intrinsic, "inclined" dislocations generate local crack deflections that grow to a large surface perturbation. Experiments show that when the crack collides with a single dislocation, the perturbation height is about 8 nm, but when it collides with a group of adjacent dislocations, the perturbation may extend to 80 nm in height (approximately 200/b/) and 250 microm in length, visible to the naked eye. A model was developed formulating the maximum velocity at which the crack climbs into the dislocation's core. The model predicts that when a dislocation's line is perpendicular to the crack surface, no interaction takes place.
Sherman
Dov
D
Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Be'ery
Ilan
I