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Atomistic Aspects of Crack Propagation Along High Angle Grain Boundaries

Published online by Cambridge University Press:  15 February 2011

Diana Farkas
Diana Farkas*
Affiliation:
Department of Materials Science and Engineering, Virginia Polytechnic Institute, Blacks-burg, VA 24061.
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Abstract

We present atomistic simulations of the crack tip configuration near a high angle Σ= 5 [001](210) symmetrical tilt grain boundary in NiAl. The simulations were carried out using molecular statics and embedded atom (EAM) potentials. The cracks are stabilized near a Griffith condition involving the cohesive energy of the grain boundary. The atomistic configurations of the tip region are different in the presence of the high angle grain boundary than in the bulk. Three different configurations of the grain boundary were studied corresponding to different local compositions. It was found that in ordered NiAl, cracks along symmetrical tilt boundaries show a more brittle behavior for Al rich boundaries than for Ni-rich boundaries. Lattice trapping effects in grain boundary fracture were found to be more significant than in the bulk.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 460: Symposium Z – High-Temperature Ordered Intermetallic Alloys VII , 1996 , 399
Copyright
Copyright © Materials Research Society 1997

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References

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