Microstructure and role of outermost coating for tensile strength of SiC fiber

S. Q. Guo, Y. Kagawa*, Y. Tanaka, C. Masuda

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)


The detailed microstructure of the SiC fiber surface and the outermost coating of SiC(SCS-6) fiber are observed using transmission electron microscopy (TEM) and high resolution electron microscopy (HREM). The tensile strengths of the SiC fibers: uncoated fiber (SCS-0), coated fiber (SCS-6) and extracted fiber from fatigue-loaded SiC(SCS-6) fiber-reinforced Ti-15-3 composite are determined. Fractographic analysis is done on these fibers and the mirror radius is compared with the tensile strength. Thickness of the outermost coating is ≈3.6 μm and it consists of three different layers (i.e. sublayers I, II and III). Basically, these sublayers consist of a carbon matrix in which β-SiC crystallites are dispersed. The fracture toughness of the SiC fiber is ≈3.3 MPa m1/2. The outermost coating increases the fiber strength twofold because it reduces stress concentration at the surface of the SiC fiber. The tensile strength of the extracted fiber (SCS-6) from fatigue-loaded specimens shows a reduced strength which is attributed to the debonding of the outermost coating while the composite is loaded.

Original languageEnglish
Pages (from-to)4941-4954
Number of pages14
JournalActa Materialia
Issue number14
Publication statusPublished - 1998 Sept 1
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Electronic, Optical and Magnetic Materials
  • Metals and Alloys


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