Mode I and Mode II interfacial fracture energy of SiC/BN/SiC CMCs
File(s)
Accepted version
Supporting information
Author(s)
Type
Journal Article
Abstract
Quantifying the mixed mode fracture toughness of interfaces in ceramic matrix composites (CMCs) is crucial for understanding their failure. In this work we use in situ micromechanical testing in the scanning electron microscope to achieve stable interfacial crack propagation in Mode I (Double Cantilever Beam) and Mode II (Push out) and measure the corresponding fracture resistances. We use this approach to measure the interfacial fracture resistance in SiC/BN/SiC CMCs and compare it to the fracture energy of the fibres. During in-situ testing, fracture paths can be observed while data is acquired simultaneously. We clearly observe debonding at the BN-fibre interface (i.e. inside adhesive debonding). The critical energy release rate of the BN-fibre interface for Mode I and II (GIc ≈ 2.1 ± 1.0 J/m2 and GIIc ≈ 1.2 ± 0.5 J/m2) are equivalent and is lower than that measured for the fibre using microscopic DCB tests (GIc ≈ 6.0 ± 2.0 J/m2). These results explain the generalized fibre debonding and pull out observed in the fracture of these CMCs. By enabling direct observation of crack paths and quantifying the corresponding fracture energies, we highlight possible routes for the optimisation and modelling of the new generation of CMC interphases.
Date Issued
2021-08
Date Acceptance
2021-06-21
Citation
Acta Materialia, 2021, 215, pp.1-11
ISSN
1359-6454
Publisher
Elsevier BV
Start Page
1
End Page
11
Journal / Book Title
Acta Materialia
Volume
215
Copyright Statement
© 2021 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Rolls-Royce Plc
Identifier
https://www.sciencedirect.com/science/article/pii/S135964542100505X?via%3Dihub
Grant Number
PO1500-00014993
Subjects
0204 Condensed Matter Physics
0912 Materials Engineering
0913 Mechanical Engineering
Materials
Publication Status
Published
Article Number
117125
Date Publish Online
2021-06-24