In Situ Synthesis of Polycrystalline Cubic Boron Nitride Reinforced by Different Morphologic TiB2

Autor: Yang Liu, Zhi-Kai Li, Chuan Chen, Yi Wu, Shenglin Zhong, Bingsai Liu
Rok vydání: 2020
Předmět:
Zdroj: Journal of Materials Engineering and Performance. 29:3784-3791
ISSN: 1544-1024
1059-9495
DOI: 10.1007/s11665-020-04896-6
Popis: Polycrystalline cubic boron nitride (PcBN) reinforced by different morphologic titanium diboride (TiB2) was in situ synthesized in the temperature range of 1100-1600 °C under an ultra-high pressure of 5.5 GPa in cBN-Ti-Al system. The composition and microstructure of PcBN composites were investigated by x-ray diffractometry, scanning electron microscopy and energy-dispersive spectroscopy. The mechanism and influencing factors of TiB2 microstructure formation with different morphologies were analyzed. The mechanical properties of PcBN were also tested and analyzed. The results showed that the microstructure of TiB2 evolves from whisker to plate and rod to granular as the temperature increases. Under the combined effects of phase composition, relative density and TiB2 morphology, the microhardness of PcBN increased continuously, while the flexural strength first increased and then decreased. The high flexural strength was obtained at 1300 and 1400 °C, which were 840.39 and 823.32 MPa, respectively.
Databáze: OpenAIRE