Voronoi cell finite element modelling of the intergranular fracture mechanism in polycrystalline alumina

Wang, Z. and Li, P. (2017) Voronoi cell finite element modelling of the intergranular fracture mechanism in polycrystalline alumina. Ceramics International, 43(9), pp. 6967-6975. (doi: 10.1016/j.ceramint.2017.02.121)

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The mechanisms of fracture in polycrystalline alumina were investigated at the grain level using both the micromechanical tests and finite element (FE) model. First, the bending experiments were performed on the alumina microcantilever beams with a controlled displacement rate of 10 nm s–1 at the free end; it was observed that the intergranular fracture dominates the failure process. The full scale 3D Voronoi cell FE model of the microcantilever bending tests was then developed and experimentally validated to provide the insight into the cracking mechanisms in the intergranular fracture. It was found that the crystalline morphology and orientation of grains have a significant impact on the localised stress in polycrystalline alumina. The interaction of adjacent grains as well as their different orientations determines the localised tensile and shear stress state in grain boundaries. In the intergranular fracture process, the crack formation and propagation are predominantly governed by tensile opening (mode I) and shear sliding (mode II) along grain boundaries. Additionally, the parametric FE predictions reveal that the bulk failure load of the alumina microcantilever increases with the cohesive strength and total fracture energy of grain boundaries.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Li, Dr Peifeng
Authors: Wang, Z., and Li, P.
Subjects:T Technology > TJ Mechanical engineering and machinery
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Ceramics International
ISSN (Online):1873-3956
Published Online:24 February 2017
Copyright Holders:Copyright © 2017 Elsevier Ltd and Techna Group S.r.l.
First Published:First published in Ceramics International 43(9): 6967-6975
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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