Effect of high hydrostatic pressure treatment of cememted carbides WC-3Co, WC-6Co, and WC-15Co on their Vickers hardness

DOI: 10.62564/M4-VS1330

Gennadiy Akimov¹, Vitalii Sheremet², Ihor Andreev³, Petro Loboda², Iryna Trosnikova<sup>2

1</sup>Donetsk Institute for Physics and Engineering named after O.O. Galkin of the National Academy of Sciences of Ukraine
²National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»
³V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine


The experimental study is devoted to the investigation of the influence of high hydrostatic pressure (HHP) compression of tungsten carbide and cobalt carbide-based cemented carbides on their properties. The samples WC-3 wt.% Co, WC-6 wt.% Co, and WC-15 wt.% Co were investigated. Vickers hardness was measured. The following results were obtained. Compression of HHP at 400MPa leads to a decrease in Vickers hardness of WC-3 wt.% Co by 8%, WC-6 wt.% Co by 5%, and WC-15 wt.% Co by 5%. Using SEM, cracking of large grains of tungsten carbide in Vickers indenter imprints was found in all samples treated with HHP. It is concluded that cracking and hardness decrease are mainly due to the well-known fact that the compressibility of Co is more than twice as high as that of WC [1]. It is suggested that the different compressibility of WC and Co could change the coherence fraction of the two materials at their boundary and cause residual stress along the boundary and in the regions of WC and Co adjacent to the boundary after HHP removal. These stresses could cause cracking of WC grains, and cracking of grains entailed a decrease in hardness.

Keywords
High Hydrostatic Pressure, Cemented Carbide, Hardness, Fracture

Acknowledgments
Not provided

References
[1] V. A. Mukhanov, O. O. Kurakevych, V. L. Solozhenko, The interrelation between hardness and compressibility of substances and their structure and thermodynamic properties, J. Superhard Mater., 2009, V. 30, No. 6, P. 368–378.