Diffusion in Transition Metal Diborides - An Overview

Schmidt, Harald; Borchardt, Günter; Weber, S.; Scherrer, H.

doi:10.4028/3-908451-35-3.219

Cited by 3 publications

(3 citation statements)

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“…Such alloys, with a small lattice mismatch, but a strong driving force for clustering are of particular interest for age-hardening potential. They are likely to form fully coherent interfaces and display spinodal decomposition with large composition fluctuations even when diffusion is limited, a concern for phase transitions in diborides 31 . The resulting nanostructure in the lattice can decrease dislocation mobility and increase hardness.…”

Section: Resultsmentioning

confidence: 99%

A theoretical investigation of mixing thermodynamics, age-hardening potential and electronic structure of ternary M11–xM2xB2 alloys with AlB2 type structure

Alling

Högberg

Armiento

et al. 2015

Sci Rep

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Transition metal diborides are ceramic materials with potential applications as hard protective thin films and electrical contact materials. We investigate the possibility to obtain age hardening through isostructural clustering, including spinodal decomposition, or ordering-induced precipitation in ternary diboride alloys. By means of first-principles mixing thermodynamics calculations, 45 ternary M11–xM2xB2 alloys comprising MiB2 (Mi = Mg, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta) with AlB2 type structure are studied. In particular Al1–xTixB2 is found to be of interest for coherent isostructural decomposition with a strong driving force for phase separation, while having almost concentration independent a and c lattice parameters. The results are explained by revealing the nature of the electronic structure in these alloys, and in particular, the origin of the pseudogap at EF in TiB2, ZrB2, and HfB2.

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Section: Resultsmentioning

confidence: 99%

A theoretical investigation of mixing thermodynamics, age-hardening potential and electronic structure of ternary M11–xM2xB2 alloys with AlB2 type structure

Alling

Högberg

Armiento

et al. 2015

Sci Rep

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“…Modification by boriding has been known to increase the hardness of some metals, and it has been reported to form a robust and hard boride surface layer on CoCrMo [29][30][31][32]. We used nanoindentation to evaluate the hardness and elastic vs. plastic depth for both unborided (but polished) CoCrMo and borided CoCrMo (Figure 4).…”

Section: Cocrmo-boride Nanoindentation Hardnessmentioning

confidence: 99%

Plasma boriding of a cobalt–chromium alloy as an interlayer for nanostructured diamond growth

Johnston

Jubinsky

Catledge

2015

Applied Surface Science

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“…Increasing the density of high-entropy ceramics can also elevate their mechanical properties, such as hardness (14). However, it is difficult to rapidly densify these ceramics because of the high covalent bond content and extremely low elemental diffusion coefficients (e.g., 10 −20 m 2 /s, even at 2200 K) (15)(16)(17)(18). As a result, long exposure times to a temperature range of 2000 to 2200 K along with the introduction of sintering additives are required to achieve densified borides by conventional ambient-pressure sintering approaches (16,17).…”

Section: Introductionmentioning

confidence: 99%

Rapid liquid phase–assisted ultrahigh-temperature sintering of high-entropy ceramic composites

et al. 2022

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High-entropy ceramics and their composites display high mechanical strength and attractive high-temperature stabilities. However, properties like strong covalent bond character and low self-diffusion coefficients make them difficult to get sintered, limiting their mass popularity. Here, we present a rapid liquid phase–assisted ultrahigh-temperature sintering strategy and use high-entropy metal diboride/boron carbide composite as a proof of concept. We use a carbon-based heater to fast-heat the composite to around 3000 K, and a small fraction of eutectic liquid was formed at the interface between high-entropy metal diborides and boron carbide. A crystalline dodecaboride intergranular phase was generated upon cooling to ameliorate the adhesion between the components. The as-sintered composite presents a high hardness of 36.4 GPa at a load of 0.49 N and 24.4 GPa at a load of 9.8 N. This liquid phase–assisted rapid ultrahigh-temperature strategy can be widely applicable for other ultrahigh-temperature ceramics as well.

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Diffusion in Transition Metal Diborides - An Overview

Cited by 3 publications

References 0 publications

A theoretical investigation of mixing thermodynamics, age-hardening potential and electronic structure of ternary M11–xM2xB2 alloys with AlB2 type structure

A theoretical investigation of mixing thermodynamics, age-hardening potential and electronic structure of ternary M11–xM2xB2 alloys with AlB2 type structure

Plasma boriding of a cobalt–chromium alloy as an interlayer for nanostructured diamond growth

Rapid liquid phase–assisted ultrahigh-temperature sintering of high-entropy ceramic composites

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