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Molecular Dynamics Studies of Twist Boundaries in Ionic Materials

Published online by Cambridge University Press:  26 February 2011

Long-Qing Chen
Affiliation:
Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 77 Mass. Ave., Cambridge, MA 02139
Gretchen Kalonji
Affiliation:
Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 77 Mass. Ave., Cambridge, MA 02139
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Abstract

The technique of constant stress molecular dynamics (MD) has been used to study NaCI systems containing ⅀-5 [001] twist boundaries interacting with the rigid-ion model of Tosi and Fumi. While perfect coincidence ⅀-5 [001] twist boundaries were found to dissociate into free surfaces below 0. 125Tm, ⅀-5 [001] anticoincidence twist boundaries with Schottky defects on the boundaries were stable up to the bulk melting temperature. No grain boundary melting was observed below the bulk melting temperature. Grain boundary thermodynamic properties, including the excess entropy and excess free energy of stable boundaries with 464 and 944 ions were calculated by molecular dynamics from low temperatures to bulk melting.

Type
Research Article
Copyright
Copyright © Materials Research Society 1988

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References

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