On understanding the microstructure of SiC/SiC Ceramic Matrix Composites (CMCs) after a material removal process

Gavalda Diaz, O.; Axinte, D.A.; Butler-Smith, P.; Novovic, D.

Abstract

The unique material nature (e.g. hard, brittle, heterogeneous and orthotropic) of SiC-based Ceramic Matrix Composites (CMCs) highly affects the outcomes of machining process by inducing high thermo-mechanical loads during material removal. This can result in severe material damage which in turn causes a reduction of the in-service life of critical structural ceramic components (such as in aero-engines or nuclear reactors). In this study, the phenomenon by which the material removal mechanism during drilling influences the CMC surface integrity are discussed by characterising the fracture and deformation phenomena on the CMC's constituents - i.e. SiC and Si materials. Moreover, the strain induced to the surface, together with the changes in chemical composition are characterised via micro Raman spectroscopy and related to the principles of residual stresses upon cutting. This results in a novel understanding of the material removal process that governs cutting of SiC-based CMCs while emphasising how the different microstructure, morphology and nature of ceramics behave under the same cutting conditions. This study has therefore led to a comprehension of how the microstructure of complex hierarchical ceramic materials such as SiC/SiC CMCs is affected by a mechanical cutting process and opens avenues to understand the structure damage under other machining operations (e.g. milling, grinding).

Citation

Gavalda Diaz, O., Axinte, D., Butler-Smith, P., & Novovic, D. (2019). On understanding the microstructure of SiC/SiC Ceramic Matrix Composites (CMCs) after a material removal process. Materials Science and Engineering: A, 743, 1-11. https://doi.org/10.1016/j.msea.2018.11.037

• Journal Article Type: Article
• Acceptance Date: Nov 7, 2018
• Online Publication Date: Nov 14, 2018
• Publication Date: Jan 16, 2019
• Deposit Date: Nov 26, 2018
• Publicly Available Date: Nov 15, 2019
• Journal: Materials Science and Engineering: A
• Print ISSN: 0921-5093
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 743
• Pages: 1-11
• DOI: https://doi.org/10.1016/j.msea.2018.11.037
• Keywords: Ceramic Matrix Composites; Microstructure; Residual stresses; Material removal mechanism; Machining
• Public URL: https://nottingham-repository.worktribe.com/output/1308434
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0921509318315557?via%3Dihub
• Additional Information: This article is maintained by: Elsevier; Article Title: On understanding the microstructure of SiC/SiC Ceramic Matrix Composites (CMCs) after a material removal process; Journal Title: Materials Science and Engineering: A; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.msea.2018.11.037; Content Type: article; Copyright: © 2018 Elsevier B.V. All rights reserved.