Molecular dynamics simulations of the effect of the composition of intergranular films on grain growth

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Molecular dynamics simulations were performed to study the effect of the composition of the intergranular film (IGF) on grain growth in α-Al 2O 3 and β-Si 3N 4 In each case, the IGF is formed while in contact with two differently oriented crystals. Results show preferential growth along the [11̄20] direction of the (11̄20) surface in comparison to growth along the surface normal on the (0001) surface for certain calcium alumino-silicate compositions in the alumina system. However, in the silicon nitride system, preferential growth occurred along the surface normal on the (0001) surface in comparison to that in the (10̄10) surface. Such preferential growth in each system is consistent with experimentally observed anisotropic grain growth in each of the different systems. Platelets form in the alumina system because of faster outward growth of the prism orientations than the basal orientation, while the more rapid growth along the basal surface normal in the nitride system causes anisotropic growth to manifest itself as whisker growth. In the alumina system, the simulations show the mechanism by which Ca ions in the IGF inhibit growth on the basal surface and the Ca/Al ratio in the IGF plays an important role in the change from isotropic to anisotropic grain growth. At compositions with high or low Ca/Al ratios, growth along each surface normal is equivalent, indicating isotropic grain growth. The simulations provide an atomistic view of attachment onto crystal surfaces, affecting grain growth in alumina.

Original languageEnglish
Title of host publicationInterfaces in Heterogeneous Ceramic Systems - Proceedings of the 6th Pacific Rim Conference on Ceramic and Glass Technology, PacRim6
Pages19-30
Number of pages12
Publication statusPublished - Jul 24 2006
Event6th Pacific Rim Conference on Ceramic and Glass Technology, PacRim6 - Maui, HI, United States
Duration: Sep 11 2005Sep 16 2005

Publication series

NameCeramic Transactions
Volume191
ISSN (Print)1042-1122

Other

Other6th Pacific Rim Conference on Ceramic and Glass Technology, PacRim6
CountryUnited States
CityMaui, HI
Period9/11/059/16/05

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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    Garofalini, S. H. (2006). Molecular dynamics simulations of the effect of the composition of intergranular films on grain growth. In Interfaces in Heterogeneous Ceramic Systems - Proceedings of the 6th Pacific Rim Conference on Ceramic and Glass Technology, PacRim6 (pp. 19-30). (Ceramic Transactions; Vol. 191).