Nanostructure and nanoindentation study of pulse electric-current sintered TiB2-SiC-C-f composite

A carbon-fiber (C-f) doped TiB2-SiC composite was prepared and investigated to determine its densification behavior, micro/nanostructural properties, and mechanical characteristics. TiB2-25 vol% SiC-2 wt% C-f was prepared at 40 MPa and 1800 degrees C for 7 min using the pulsed electric-current sintering technique, and a relative density of 98.5% was realized. The as-sintered composite was characterized using advanced techniques, e.g., X-ray diffractometry, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, field-emission electron probe micro-analysis, and nanoindentation. The C-f additive could remove the surface oxide layers from the TiB2 and SiC domains, thus transforming them into TiB2 and SiC. According to micro/nanostructural studies, C-f could not retain its initial structure and was eventually converted into graphite nanosheets. In addition, the prepared composite was examined using the nanoindentation technique, and the following results were obtained for the calculated hardness, elastic modulus, and stiffness values: TiB2 > SiC > TiB2/SiC interface.

Automated summary

A carbon-fiber (C-f) doped TiB2-SiC composite was prepared and investigated, revealing its densification behavior, micro/nanostructural properties, and mechanical characteristics. The addition of C-f resulted in the removal of surface oxide layers, transformation of TiB2 and SiC, and eventual conversion into graphite nanosheets. Nanoindentation tests showed that the hardness, elastic modulus, and stiffness values followed the order of TiB2 > SiC > TiB2/SiC interface.