Highly wear resistant dual-phase (Ti-Zr-Nb-Hf-Ta)C/(Ti-Zr-Nb-Hf-Ta) B₂ high-entropy ceramics

ABSTRACT

Wear characteristics of a fine-grained dual-phase high-entropy (Ti_0.14Zr_0.2Nb_0.2Hf_0.2Ta_0.26)C + (Ti_0.38Zr_0.18Nb_0.22Hf_0.115Ta_0.105)B₂ were investigated using the ball-on-flat technique/dry sliding in air. The experimental material showed very high density with a value of 8.72 g/cm³ and a small grain size of HEC and HEB grains with values of 0.95 ± 0.30 and 0.99 ± 0.27 μm, respectively. The nano-hardness of the HEC and HEB grains is very high with mean values of 37.4 ± 2.3 and 43.0 ± 2.9 GPa, respectively with the micro-hardness of the dual system HV1 29.4 ± 2.0 GPa. The friction coefficient values during the test with 5 and 10 N increased from a value of 0.4 and reached the values 0.65 and 0.77 at the sliding distances of approximately 1500 and 1000 m, respectively. The specific wear rate decreased with increasing sliding distance at 5 N load, from 4.75 × 10⁻⁷ mm³/Nm to 4.2 × 10⁻⁷ mm³/Nm and at 10 N from 2.1 × 10⁻⁷ to 1.7 × 10⁻⁷ mm³/Nm. The dominant wear mechanisms in both cases were an oxidation-driven tribo-chemical reaction and tribo-layer formation in boride grains and mechanical wear in carbide grains.

KEYWORDS:

• Dual-phase high-entropy ceramics
• wear
• wear mechanisms

Acknowledgements

‘Funding from the European Union’s Horizon 2020 Research and Innovation Programme was used for this Project on the basis of a Grant agreement under the Marie Skłodowska-Curie funding scheme No. 945478.’ and Slovak Grant Agency for Science by projects: VEGA 2/ 0118/20, VEGA 2/0174/21, VEGA 2/0144/21 and APVV-17-0328, APVV-19-0497, APVV-21-0402. This work was performed during the implementation of the project Building-up Centre for advanced material application of the Slovak Academy of Sciences, ITMS project code 313021T081 supported by Research and Innovation Operational Programme funded by the ERDF. The authors thank Martin Kusý for the help with wear volume measurement. J.D. gratefully acknowledges the support of ESET and Alexander von Humboldt Foundations.

Disclosure statement

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

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by Agentúra na Podporu Výskumu a Vývoja [grant number 17-0328, 21-0402, 9-0497]; European Regional Development Fund [grant number 313021T081]; H2020 Marie Skłodowska-Curie Actions [grant number 945478]; Vedecká Grantová Agentúra MŠVVaŠ SR a SAV [grant number 2/0174/21, 2/0118/20].