The temperature dependence of microhardness of the transition-metal carbides

Kohlstedt, D. L.

doi:10.1007/bf02397907

Cited by 72 publications

(17 citation statements)

References 28 publications

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“…Using the approach proposed by Tian, the calculated value (24.1 GPa) is in that range experimentally reported at room temperature. Similarly, calculated hardness for ZrC (23.2 GPa) and HfC (25.2 GPa) are in good agreement with the experimental measurements [125][126][127][128][129]. To the best of our knowledge, there are not too many experimental works which study the hardness of nitrides, however we have found that calculated values are slightly lower than the homolog carbides and are close to the reported values for TiN [130], ZrN [131] and HfN [77].…”

Section: Isotropic Mechanical Propertiessupporting

confidence: 87%

“…where Q, R, T , and t are the activation energy for creep, the gas constant, the temperature and loading time, respectively, and m and A are constants [132,133]. When Arrhenius plots are used to study hardness in a temperature range, different regions are identified for many UHTCs [116,119,123,125,134]. These regions are linked to a brittle-ductile transition and the different mechanisms that govern the deformation during the indentation at different temperatures [125].…”

Section: Isotropic Mechanical Propertiesmentioning

confidence: 99%

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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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Section: Isotropic Mechanical Propertiessupporting

confidence: 87%

Section: Isotropic Mechanical Propertiesmentioning

confidence: 99%

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

Nath¹,

Plata²,

Santana³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…Kohlstedt 87 noted that at lower temperatures, the highly directional covalent bonds on the close packed {111} planes inhibit slip and reduce dislocation mobility. However, at higher temperatures, sharp decreases in hardness were explained due to the increasing mobility of s electrons, with temperature screening the bonding orbitals that reduce the directionality of the covalent bonds, thereby reducing the hardness to that similar of a metal.…”

Section: Hardnessmentioning

confidence: 99%

Processing and properties of ZrC, ZrN and ZrCN ceramics: a review

Harrison

Lee

2016

Advances in Applied Ceramics

180

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ZrC and ZrN ceramics are of interest in the application of materials in extreme high temperature environments, particularly for nuclear applications in generation IV reactors. These materials demonstrate desirable characteristics such as high thermal and electrical conductivities along with high hardness and melting temperatures. Data reported in the literature often suffer from scatter due to differences in processing techniques and difficulty determining stoichiometry, which will significantly affect thermophysical properties. This article reviews the current available data for the properties of ZrC, ZrN and mixed carbonitrides phases and identifies causes of scatter in the literature and areas requiring further research.

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“… 59 , 60 These regions are linked to a brittle–ductile transition and the different mechanisms that govern the deformation during the indentation at different temperatures. 60 Activation energies for creep for borides and carbides have been reported to be around 80 kcal/mol and most of the experimental studies obtain values for m between 4 and 5. 59 , 60 These values can be combined with our predictions at room temperature to calculate the pre-exponential constant and obtain good trends for hardness below 1000 K.…”

Section: Resultsmentioning

confidence: 99%

“… 60 Activation energies for creep for borides and carbides have been reported to be around 80 kcal/mol and most of the experimental studies obtain values for m between 4 and 5. 59 , 60 These values can be combined with our predictions at room temperature to calculate the pre-exponential constant and obtain good trends for hardness below 1000 K.…”

Section: Resultsmentioning

confidence: 99%

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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The temperature dependence of microhardness of the transition-metal carbides

Cited by 72 publications

References 28 publications

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

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

Processing and properties of ZrC, ZrN and ZrCN ceramics: a review

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

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