Microstructure and mechanical properties of SiC fiber/Si-CoSi₂ matrix composites fabricated by carbon chemical vapor infiltration and Si alloy melt infiltration process

Abstract

For this study, orthogonal three dimensional (3D) woven silicon carbide (SiC) fiber (Hi-Nicalon, Hi-Nicalon Type S) -reinforced Si-CoSi₂ matrix composites (SiC fiber/Si-CoSi₂ composites) were fabricated and the microstructures and mechanical properties were characterized. The SiC fibers (28% fiber volume fraction) woven into orthogonal 3D fabrics and used as reinforcement were coated with chemical vapor infiltration (CVI)-carbon to control the fiber–matrix interface. The composite material infiltrated with Si-CoSi₂ was produced using a melt-infiltration process. Four-point bending tests conducted at room temperature showed bending strength exceeding 300 MPa and tensile fracture strain exceeding 0.7%. Furthermore, bending strength greater than 400 MPa was found from a high-temperature four-point bending test under an Ar atmosphere. The failure mode was quasi-ductile. Fiber pull-out and fiber cross-linking were observed clearly. Melt infiltration of the Si-Co alloy caused little damage to the SiC fibers, confirming CVI-C layer protection of the fibers during melt infiltration and confirming that the layer can control mechanical properties at the fiber–matrix interface.

Keywords:

• SiC fiber
• Si-Co alloy
• melt-infiltration (MI)
• ceramic matrix composites

Acknowledgements

This work is supported by Adaptable and Seamless Technology transfer Program through Target-driven R&D (A-STEP) from Japan Science and Technology Agency (JST) Japan Grant Number JPMJTR202M.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Japan Science and Technology Agency [JPMJTR202M].