Search academic texts

Information × Registration Number 0224U000112, 0123U104070 , R & D reports Title Structure and properties of reactively sintered high-entropy metal diborides popup.stage_title Head Popov Oleksii Yu., Доктор фізико-математичних наук Registration Date 02-01-2024 Organization Taras Shevchenko National University of Kyiv popup.description2 The purpose of the project: studying the possibility of creating monolithic non-porous high-entropy ceramics based on diborides of transition metals of the systems (Ti, Zr, Hf, Nb, V)B2, (Ti, Zr, Hf, W)B2 and (Ti, Zr, Hf, Nb)B2 by the reaction hot pressing method and their investigation physical and mechanical characteristics. The object of the study: the kinetics of densification of multiphase polycarbide powders during heat treatment under pressure and the connection of densification with the formation of new phases of diborides of transition metals. Research methods: X-ray diffractometry, electron and optical microscopy, energy dispersive analysis, analysis of powder body compaction curves, determination of density by hydrostatic weighing, indentation, determination of thermal conductivity by the method of quasi-stationary heat flow. High-entropy materials of TiZrHfVNbTaB12-C, TiZrHfVNbB10-C, TiZrHfVNbB10-C and TiZrHfNbB8-C systems were obtained by hot pressing of powder mixtures TiC-ZrC-HfC-VC-NbC-TaC-B4C, TiC-ZrCHfC-NbC-TaC-B4C, TiC- ZrC-HfC-NbC-B4C and TiC-ZrC-HfC-B4C at a temperature of 1900°C for 4 min at a pressure of 30 MPa. It is shown that the flow of in-situ reactions leads to a significant intensification of the compaction of the material, which made it possible to obtain non-porous samples of the specified high-entropy systems for the first time. The structure, phase composition, microhardness, crack resistance and thermal conductivity of the obtained ceramics were studied. A comparison of the characteristics of high-entropy composites with similar materials based on binary diborides of titanium and zirconium was carried out.  Product Description popup.authors Kuryliuk Alla M. Ovcharenko Anton О. popup.nrat_date 2024-01-02 Close