Microstructure evolution, densification behavior and mechanical properties of nano-HfB2 sintered under high pressure

Liang, Hao; Guan, Shixue; Li, Xin; Liang, Akun; Zeng, Yan; Liu, Chuanqi; Chen, Haihua; Lin, Weitong; He, Duanwei; Wang, L.; Peng, Fang

doi:10.1016/j.ceramint.2019.01.099

Cited by 24 publications

(9 citation statements)

References 53 publications

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“…The driving force of this crushing is derived from the heterogeneous stress distributions between the particle edges and corners, , which makes the strength of HfC gradually decrease as the temperature increases, that is, the crystallinity worsens. Previous studies suggested that the recrystallization temperatures of hard and brittle materials under high pressure are just one-third of those under normal pressure . The recrystallization temperature of the HfC sample is 1400 °C at 15 GPa, which was verified by XRD analysis and SEM micrographs (see later section).…”

Section: Resultssupporting

confidence: 55%

“…Previous studies suggested that the recrystallization temperatures of hard and brittle materials under high pressure are just one-third of those under normal pressure. 44 The recrystallization temperature of the HfC sample is 1400 °C at 15 GPa, which was verified by XRD analysis and SEM micrographs (see later section). At a temperature higher than 1300 °C, the recrystallization of HfC begins to occur, causing plastic deformations with the release of partial strains and increased diffraction intensities.…”

Section: ■ Results and Discussionmentioning

confidence: 60%

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Achieving Dislocation Strengthening in Hafnium Carbide through High Pressure and High Temperature

et al. 2021

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Dislocations profoundly impact the mechanical behavior of materials. High dislocation density induced strengthening is easily achieved in metallic materials, but it is a challenge in ceramics. Here, we highlight the dislocation engineering of an ultrahigh-temperature ceramic, hafnium carbide (HfC), by high-pressure and high-temperature (HPHT) consolidation. The microstructure and temperature-dependent high-pressure consolidation behaviors were systematically investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Our results reveal that pressure-induced intergranular strains promote the generation of high-density dislocations in multiple orientations near grain boundaries and finally enhance the hardness and oxidation resistance of the HfC ceramic. These findings elucidate that dislocation strengthening can be achieved in ultra-high-temperature ceramic HfC, which offers crucial insights for the design and synthesis of advanced ceramic materials.

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Section: Resultssupporting

confidence: 55%

Section: ■ Results and Discussionmentioning

confidence: 60%

Achieving Dislocation Strengthening in Hafnium Carbide through High Pressure and High Temperature

et al. 2021

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“…In eq 26 , the constants are adjusted to obtain H V in GPa units. At room temperature, borides seem to be the most overestimated values obtaining 47, 41, and 42 GPa for TiB 2 , ZrB 2 , and HfB 2 when experimental values range between 34–22, 48 39–20, 56 , 57 and 33–31.4 GPa, 58 respectively ( Figure 5 ). TiC stands as a good example of the different values that can be obtained for hardness, depending on the plane and orientation of the crystal.…”

Section: Resultsmentioning

confidence: 98%

High-Throughput Screening of the Thermoelastic Properties of Ultrahigh-Temperature Ceramics

Nath

Plata

Santana-Andreo

et al. 2021

ACS Appl. Mater. Interfaces

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Ultrahigh-temperature ceramics (UHTCs) are a group of materials with high technological interest because of their applications in extreme environments. However, their characterization at high temperatures represents the main obstacle for their fast development. Obstacles are found from an experimental point of view, where only few laboratories around the world have the resources to test these materials under extreme conditions, and also from a theoretical point of view, where actual methods are expensive and difficult to apply to large sets of materials. Here, a new theoretical high-throughput framework for the prediction of the thermoelastic properties of materials is introduced. This approach can be systematically applied to any kind of crystalline material, drastically reducing the computational cost of previous methodologies up to 80% approximately. This new approach combines Taylor expansion and density functional theory calculations to predict the vibrational free energy of any arbitrary strained configuration, which represents the bottleneck in other methods. Using this framework, elastic constants for UHTCs have been calculated in a wide range of temperatures with excellent agreement with experimental values, when available. Using the elastic constants as the starting point, other mechanical properties such a bulk modulus, shear modulus, or Poisson ratio have been also explored, including upper and lower limits for polycrystalline materials. Finally, this work goes beyond the isotropic mechanical properties and represents one of the most comprehensive and exhaustive studies of some of the most important UHTCs, charting their anisotropy and thermal and thermodynamical properties.

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“…28, the constants are adjusted to obtain H V in GPa units. At room temperature, borides seem to be the most overstimated values obtaining 47 GPa, 41 GPa and 42 GPa for TiB 2 , ZrB 2 and HfB 2 when experimental values range between 34-22 GPa [100,[115][116][117], 39-20 GPa [118][119][120] and 33-31.4 GPa [121,122], respectively (Fig. 4).…”

Section: Isotropic Mechanical Propertiesmentioning

confidence: 95%

High-throughput screening of the thermoelastic properties of ultra-high temperature ceramics

Nath¹,

Plata²,

Santana³

et al. 2020

Preprint

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Ultra-high temperature ceramics, UHTCs, are a group of materials with high technological interest because their use in extreme environments. However, their characterization at high temperatures represents the main obstacle for their fast development. Obstacles are found from a experimental point of view, where only few laboratories around the world have the resources to test these materials under extreme conditions, and also from a theoretical point of view, where actual methods are extremely expensive. Here, a new theoretical high-throughput framework for the prediction of the thermoelastic properties of materials is introduced. This approach can be systematically applied to any kind of crystalline material, drastically reducing the computational cost of previous methodologies. Elastic constants for UHTCs have been calculated at a wide range of temperatures with excellent agreement with experimentally reported values. Moreover, other mechanical properties such a bulk modulus, shear modulus or Poisson ration have been also explored. Other frameworks with similar computational cost have been used only for predicting isotropic or averaged properties, however this new approach opens the door to the calculation of anisotropic properties at a very low computational cost.

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Microstructure evolution, densification behavior and mechanical properties of nano-HfB2 sintered under high pressure

Cited by 24 publications

References 53 publications

Achieving Dislocation Strengthening in Hafnium Carbide through High Pressure and High Temperature

Achieving Dislocation Strengthening in Hafnium Carbide through High Pressure and High Temperature

High-Throughput Screening of the Thermoelastic Properties of Ultrahigh-Temperature Ceramics

High-throughput screening of the thermoelastic properties of ultra-high temperature ceramics

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