Mechanisms of dislocation multiplication at crack tips
Bitzek E, Gumbsch P (2013)
Publication Type: Journal article
Publication year: 2013
Journal
Book Volume: 61
Pages Range: 1394-1403
Journal Issue: 4
DOI: 10.1016/j.actamat.2012.11.016
Abstract
Whether a stressed material fractures by brittle cleavage or ductile rupture is determined by its ability to convert elastic strain energy to plastic deformation through the generation and motion of dislocations. Although it is known that pre-existing dislocations play a crucial role in crack tip plasticity, the involved mechanisms are unclear. Here it is demonstrated by atomistic simulations that individual pre-existing dislocations may lead to the generation of large numbers of dislocations at the crack tip. The newly generated dislocations are usually of different types. The processes involved are fundamentally different for stationary cracks and propagating cracks. Whereas local crack front reorientation plays an important role in propagating cracks, the multiplication mechanism at stationary cracks is connected with cross-slip in the highly inhomogeneous stress field of the crack. Analysis of the forces acting on the dislocations allows to determine which dislocations multiply and the slip systems they activate. These results provide the necessary physical link between pre-existing dislocations and the generation of dislocations at crack tips.
Authors with CRIS profile
Additional Organisation(s)
Exzellenz-Cluster Engineering of Advanced Materials (EAM)
Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)
Involved external institutions
Germany (DE)How to cite
APA:
Bitzek, E., & Gumbsch, P. (2013). Mechanisms of dislocation multiplication at crack tips. Acta Materialia, 61(4), 1394-1403. https://doi.org/10.1016/j.actamat.2012.11.016
MLA:
Bitzek, Erik, and Peter Gumbsch. "Mechanisms of dislocation multiplication at crack tips." Acta Materialia 61.4 (2013): 1394-1403.
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