High-temperature flexural strength of I-CVI processed Cf/SiC composites with variable interphases

• Published in: Journal of the European Ceramic Society Vol. 41; no. 1; pp. 130 - 135
• Main Authors: Singh, Sarabjit, Singh, Vajinder, Kumari, Sweety, Udayakumar, A., Bhanu Prasad, V.V.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2021
• Subjects: Composites; Electron microscopy; Interphase; SiC; Composites; SiC; Electron microscopy; Interphase
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2020.08.075

•The Cf/SiC composites having single layer PyC and multilayered [(PyC/SiC)n=4] interphases are processed by I-CVI method.•The effect of interphase type and SiC-CVD seal coating on the high temperature (1200oC) flexural properties is investigated.•Uncoated and seal coated Cf/SiC composites with multilayered interphase showed higher flexural strength and displacement.•The fractured surfaces of tested samples are analyzed in detail to study the fracture phenomena.•A mechanism is proposed for the increase of flexural properties of Cf/SiC composites having multilayered interphase. The effect of single-layer pyrocarbon (PyC) and multilayered (PyC/SiC)n=4 interphases on the flexural strength of un-coated and SiC seal-coated stitched 2D carbon fiber reinforced silicon carbide (Cf/SiC) composites was investigated. The composites were prepared by I-CVI process. Flexural strength of the composites was measured at 1200 °C in air atmosphere. It was observed that irrespective of the type of interphase, the seal coated samples showed a higher value of flexural strength as compared to the uncoated samples. The flexural strength of 470 ± 12 MPa was observed for the seal coated Cf/SiC composite samples with multilayered interphase. The seal coated samples with single layer PyC interphase showed flexural strength of 370 ± 20 MPa. The fractured surfaces of tested samples were analyzed in detail to study the fracture phenomena. Based on microstructure-property relations, a mechanism has been proposed for the increase of flexural properties of Cf/SiC composites having multilayered interphase.