Structure and mechanical characteristics of high pressure sintered ZrB2, HfB2 and ZrB2- TiB2, ZrB2-SiC composite materials. Tetiana Prikhna1; Anastasia Lokatkina2; Viktor Moshchil3; Pavlo Barvitskiy3; Olexandr Borymskyi4; Florian Kongoli5; Fernand Marquis6; 1V. BAKUL INSTITUTE NASU, Kiev, Ukraine; 2INSTITUTE FOR SUPERHARD MATERIALS OF THE NATIONAL ACADEMY OF SCIENCES OF UKRAINE, Kyiv, Ukraine; 3INSTITUTE FOR SUPERHARD MATERIALS, Kiev, Ukraine; 4V. BAKUL INSTITUTE FOR SUPERHARD MATERIALS OF THE NATIONAL ACADEMY OF SCIENCES OF UKRAINE, Kyiv, Ukraine; 5FLOGEN TECHNOLOGIES, Mont-Royal, Canada; 6SAN DIEGO STATE UNIVERSITY, San Diego, United States; PAPER: 286/AdvancedMaterials/Regular (Oral) SCHEDULED: 12:45/Mon. 28 Nov. 2022/Saitong ABSTRACT: The ZrB<sub>2</sub> and HfB<sub>2</sub> materials are promising for application in hypersonic aerospace, cutting tools, metallurgy, microelectronics and refractory industries. The structure and properties of sintered under high pressure (4GPa) - high temperature (1800 <sup>o</sup>C) or HP-HT conditions ZrB<sub>2</sub>, HfB<sub>2</sub>, ZrB<sub>2</sub>+30%TiB<sub>2</sub> and ZrB<sub>2</sub>-20% SiC refractory materials are under consideration. HP-HT sintered HfB<sub>2</sub> (a=0.3141, c=0.3473 nm γ=10.42 g/cm<sup>3</sup>) demonstrated hardness HV(9.8 N)=21.27±0.84 GPa, HV(49 N)=19.29±1.34 GPa, and HV(98 N)=19.17±0.5 GPa and fracture toughness K1C(9.8 N)=6.47 MN×m0.5. High pressure sintered ZrB<sub>2</sub> (a=0.3167 , c=0.3528 nm, γ=6.1 g/cm<sup>3</sup>) demonstrated HV(9.8N)= 17.66±0.60 GPa, HV(49 N)= 15.25±1.22 GPa, and HV(98 N)= 15.32±0.36 GPa and K1C(9.8 N)=3.64 MN×m0.5. Addition of 30 wt.% of TiB<sub>2</sub> to ZrB<sub>2</sub> did not allow to increase hardness of the material essentially (HV(9.8 N)=17.75±2.36 GPa, γ=5.29 g/cm<sup>3</sup> ). Addition of 20 wt.% of SiC to ZrB<sub>2</sub> and sintering under high pressure allowed essential increase of hardness to HV(9.8 N)=24.18±0.7 GPa, HV(49 N)=16.68±0.5 GPa, and HV(98 N)=17.59±0.4 GPa and fracture toughness (K1C(9.8 N)=6.49 ± 0.25 MN×m<sup>0.5</sup>, K1C(49 N)=7.06± 1.55 MN×m<sup>0.5</sup> , K1C(98 N)=6.18± 1.24 MN×m<sup>0.5</sup>) of composite ZrB<sub>2</sub>- SiC material (γ=5.03 g/cm<sup>3</sup>). |