РОЗРОБКА СКЛАДІВ ВИСОКОЕНТРОПІЙНИХ СПЛАВІВ ДЛЯ ОТРИМАННЯ НАДТВЕРДИХ КОМПОЗИТІВ НА ОСНОВІ КУБІЧНОГО НІТРИДУ БОРУ: Procesi littâ, 2025, Vol 4 (162), 62-73
This work explores the prospects of developing new composite materials based on cubic boron nitride (cBN) using high-entropy alloys (HEAs) as a binding matrix. The research is driven by the need for next-generation tool materials capable of efficiently machining modern structural materials under ext...
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| Datum: | 2025 |
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| Hauptverfasser: | , , , |
| Format: | Artikel |
| Sprache: | Ukrainian |
| Veröffentlicht: |
National Academy of Sciences of Ukraine, Physical-Technological Institute of Metals and Alloys of NAS of Ukraine
2025
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| Schlagworte: | |
| Online Zugang: | https://plit-periodical.org.ua/index.php/plit/article/view/301 |
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| Назва журналу: | Casting Processes |
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Casting Processes| Zusammenfassung: | This work explores the prospects of developing new composite materials based on cubic boron nitride (cBN) using high-entropy alloys (HEAs) as a binding matrix. The research is driven by the need for next-generation tool materials capable of efficiently machining modern structural materials under extreme conditions where the properties of traditional cBN-based composites are no longer sufficient. The unique properties of cBN make it a key enabling material for cutting tools. However, the consolidation of cBN presents fundamental challenges due to its strong covalent bonds, which require the application of extreme pressures and temperatures, thus necessitating the use of binding materials. Existing traditional metallic and ceramic binding agents have significant drawbacks: metallic binders have low softening temperatures, while ceramic binders are brittle and exhibit low thermal conductivity. In contrast, high-entropy alloys combine high strength, wear resistance, and, crucially, exceptional thermal stability inherent to their specific structure. Nevertheless, the successful development of HEA/cBN composites depends on overcoming a number of critical challenges: controlling interfacial interactions, managing porosity, and minimizing residual stresses. This necessitates predictive methods, including the application of thermodynamic modeling to forecast interactions across a wide temperature range. Given the fragmented and limited availability of specialized thermodynamic databases for HEA systems, this work proposes a combinatorial method of thermodynamic analysis. This approach is designed to predict optimal compositions of high-entropy alloys (HEAs) intended for the creation of composites based on cubic boron nitride (cBN). The developed model accounts for changes in the Gibbs free energy of the system during the formation of nitrides and borides at the HEA/cBN phase boundary, enabling assessment of the thermodynamic likelihood of their formation. The method is based on calculations of the mixing entropy of the HEA components and the formation energies of compounds of the AnBm type. A five-component system (Ni–Cr–Fe–Co–Al–Ti) was used for the analysis, where the contribution of each element to the change in Gibbs free energy upon interaction with cBN was taken into account. Calculations showed that aluminium, titanium, and zirconium are the most active elements that form stable nitrides and borides (AlN, TiB₂, ZrN) at temperatures up to 2000 °C. Results indicate that adding 5–10 at. % Al and Ti to the HEA promotes formation of a strong interfacial bond with cBN through the creation of thermally stable intermediate phases. Thermodynamic calculations also confirm that an excess of these elements can lead to undesirable delamination and failure of the composite. The proposed method makes it possible to reduce the number of experimental studies by pre-selecting promising systems via thermodynamic screening. |
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