| Autor: |
Kutran, T. M., Zamula, M. V., Pokhylko, B. A., Shyrokov, O. V., Kolesnichenko, V. G., Kovalchuk, V. V., Stepanenko, A. V., Borodianska, H. Yu. |
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| Zdroj: |
Powder Metallurgy & Metal Ceramics; Jan2023, Vol. 61 Issue 9/10, p522-540, 19p |
| Abstrakt: |
The reactive synthesis of heterophase refractory ultrahard B4C-based composites by spark plasma sintering (SPS) was examined. To produce heterophase B4C + TiB2 + CrB2 ceramics, the chemical reaction between boron carbide and chromium oxide and between boron carbide and titanium carbide resulting in boron carbide–chromium diboride and boron carbide–titanium diboride composites was previously studied. The reactive sintering of B4C + Cr2O3 + C and B4C + TiC mixtures using boron carbide powders obtained from the Zaporizhzhya Abrasive Plant and Donetsk Chemical Reagent Plant (Ukraine) was compared. The boron carbide powders differed in the ratio of B13C2 and B4C phases and particle sizes. The reactively synthesized TiB2, CrB2, and CrTiB2 boride phases positively influenced the SPS consolidation and properties of the boron carbide composites. The B4C–CrB2 and B4C–TiB2 ceramics subjected to Vickers hardness testing under a load of 98 N showed HV levels of 23–29 GPa and 26–28 GPa. The ceramics demonstrated brittle fracture according to the Half-penny model, with a fracture toughness of 3 MPa∙m1/2 for B4C–CrB2 and 4.4 MPa∙m1/2 for B4C–TiB2. The 90 vol.% B4C–5.5 vol.% TiCrB2–4.5 vol.% C ceramics with ~33 GPa hardness and ~ 4 MPa∙m1/2 fracture toughness were produced by reactive SPS from a mixture of B4C (Zaporizhzhya Abrasive Plant), 6.6 wt.% TiC, and 11 wt.% Cr2O3. The high strength of TiCrB2 ceramics was attributed to the stress–strain state, where the matrix phase of boron carbide was subjected to compressive stresses. The high hardness and fracture toughness allow the B4C–TiCrB2 composite to be classified as an ultrahard ceramic material. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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