Measurement of Residual Stress in Silicon Carbide Fibers of Tubular Composites Using Raman Spectroscopy. (15th September 2021)

• Record Type: Journal Article
• Authors: Nance, James; Subhash, Ghatu; Sankar, Bhavani; Haftka, Rafael; Kim, Nam Ho; Deck, Christian; Oswald, Sarah
• Is Part Of: Acta materialia. Volume 217(2021)
• Publication Date: 2021-09-15
• Subjects: Sic fiber -- Sic/sic composite -- Raman spectroscopy -- residual stress, graphite; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2021.117164
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Silicon carbide (SiC) fiber-reinforced ceramic matrix (SiCf /SiCm ) composites have been identified as potential materials for nuclear fuel cladding. These composites are fabricated by braiding the SiC fibers around a mandrel into a cylindrical tube and then densifying this preform with SiC matrix using chemical vapor infiltration (CVI). However, during this fabrication process residual stresses develop in the composite, either due to the mechanical braiding process or due to high temperature CVI deposition of the SiC matrix phase. Micro-Raman spectroscopy has been employed to measure the residual stress in the SiC fibers at various stages of the fabrication process. Samples of the composite were analyzed after mechanical braiding and at 33%, 66% and 100% CVI densification of the composites. Raman spectra obtained at the above stages revealed significant band shifts of the SiC peaks and these peak-shift corresponded to -716 MPa of residual stress following the braiding process and -1075 MPa after the densification process. Interestingly, the Raman spectra also revealed carbon bands whose origin was traced to the presence of nanoscale turbostratic graphite throughout the nanograined SiC microstructure. Graphical abstract: Image, graphical abstract