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Title: Mechanisms of intergranular fracture

Abstract

The authors present a study of the atomistic mechanisms of crack propagation along grain boundaries in metals and alloys. The failure behavior showing cleavage crack growth and/or crack-tip dislocation emission is demonstrated using atomistic simulations for an embedded-atom model. The simulations follow the quasi-equilibrium growth of a crack as the stress intensity applied increases. Dislocations emitted from crack tips normally blunt the crack and inhibit cleavage, inducing ductile behavior. When the emitted dislocations stay near the crack tip (sessile dislocations), they do blunt the crack but brittle cleavage can occur after the emission of a sufficient number of dislocations. The fracture process occurs as a combination of dislocation emission/micro-cleavage portions that are controlled by the local atomistic structure of the grain boundary. The grain boundary is shown to be a region where dislocation emission is easier, a mechanism that competes with the lower cohesive strength of the boundary region.

Authors:
 [1]
  1. Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Materials Science and Engineering
Publication Date:
Sponsoring Org.:
National Science Foundation, Washington, DC (United States)
OSTI Identifier:
364079
Report Number(s):
CONF-981104-
Journal ID: ISSN 0272-9172; TRN: IM9934%%104
Resource Type:
Book
Resource Relation:
Conference: Fall meeting of the Materials Research Society, Boston, MA (United States), 30 Nov - 4 Dec 1998; Other Information: PBD: 1999; Related Information: Is Part Of Fracture and ductile vs. brittle behavior -- Theory, modeling and experiment; Beltz, G.E. [ed.] [Univ. of California, Santa Barbara, CA (United States)]; Selinger, R.L.B. [ed.] [Catholic Univ., Washington, DC (United States)]; Kim, K.S. [ed.] [Brown Univ., Providence, RI (United States)]; Marder, M.P. [ed.] [Univ. of Texas, Austin, TX (United States)]; PB: 345 p.; Materials Research Society symposium proceedings, Volume 539
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRACK PROPAGATION; GRAIN BOUNDARIES; METALS; ALLOYS; CLEAVAGE; DISLOCATIONS; MATHEMATICAL MODELS; STRESS INTENSITY FACTORS; FRACTURE MECHANICS; THEORETICAL DATA

Citation Formats

Farkas, D. Mechanisms of intergranular fracture. United States: N. p., 1999. Web.
Farkas, D. Mechanisms of intergranular fracture. United States.
Farkas, D. 1999. "Mechanisms of intergranular fracture". United States.
@article{osti_364079,
title = {Mechanisms of intergranular fracture},
author = {Farkas, D},
abstractNote = {The authors present a study of the atomistic mechanisms of crack propagation along grain boundaries in metals and alloys. The failure behavior showing cleavage crack growth and/or crack-tip dislocation emission is demonstrated using atomistic simulations for an embedded-atom model. The simulations follow the quasi-equilibrium growth of a crack as the stress intensity applied increases. Dislocations emitted from crack tips normally blunt the crack and inhibit cleavage, inducing ductile behavior. When the emitted dislocations stay near the crack tip (sessile dislocations), they do blunt the crack but brittle cleavage can occur after the emission of a sufficient number of dislocations. The fracture process occurs as a combination of dislocation emission/micro-cleavage portions that are controlled by the local atomistic structure of the grain boundary. The grain boundary is shown to be a region where dislocation emission is easier, a mechanism that competes with the lower cohesive strength of the boundary region.},
doi = {},
url = {https://www.osti.gov/biblio/364079}, journal = {},
issn = {0272-9172},
number = ,
volume = ,
place = {United States},
year = {1999},
month = {8}
}

Book:
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