Nanoindentation and tribology of VC, NbC and ZrC refractory carbides

Balko, Ján; Csanádi, Tamás; Sedlák, Richard; Vojtko, Marek; Kovalčíková, Alexandra; Kováľ, Karol; Wyzga, Piotr; Naughton-Duszová, Annamária

doi:10.1016/j.jeurceramsoc.2017.04.064

Cited by 60 publications

(17 citation statements)

References 21 publications

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“…This led to densities of >96% in both the HfC and TaC samples. The other base ZrC and NbC monocarbides that are considered were fabricated using a similar SPS sintering route (powders from H.C. Starck, sintering at 2200 °C under 35 MPa for 30 min) in previous work involving the same authors 33 and hence they were subjected to an identical nanoindentation testing regime to that applied in the present work. Therefore, it is considered that any difference in mechanical behaviour observed between the four monocarbides (HfC, TaC, ZrC, NbC) derives only from their intrinsically different physical properties.…”

Section: Resultsmentioning

confidence: 99%

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Processing and Properties of High-Entropy Ultra-High Temperature Carbides

Castle

Csanádi

Grasso

et al. 2018

Sci Rep

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642

361

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Bulk equiatomic (Hf-Ta-Zr-Ti)C and (Hf-Ta-Zr-Nb)C high entropy Ultra-High Temperature Ceramic (UHTC) carbide compositions were fabricated by ball milling and Spark Plasma Sintering (SPS). It was found that the lattice parameter mismatch of the component monocarbides is a key factor for predicting single phase solid solution formation. The processing route was further optimised for the (Hf-Ta-Zr-Nb)C composition to produce a high purity, single phase, homogeneous, bulk high entropy material (99% density); revealing a vast new compositional space for the exploration of new UHTCs. One sample was observed to chemically decompose; indicating the presence of a miscibility gap. While this suggests the system is not thermodynamically stable to room temperature, it does reveal further potential for the development of new in situ formed UHTC nanocomposites. The optimised material was subjected to nanoindentation testing and directly compared to the constituent mono/binary carbides, revealing a significantly enhanced hardness (36.1 ± 1.6 GPa,) compared to the hardest monocarbide (HfC, 31.5 ± 1.3 GPa) and the binary (Hf-Ta)C (32.9 ± 1.8 GPa).

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Section: Resultsmentioning

confidence: 99%

“…The microstructure and indents on the ZrC and NbC samples can be found in the paper by Balko et al . 33 . The majority of the indents did not exhibit cracks on their walls.…”

Section: Resultsmentioning

confidence: 99%

Processing and Properties of High-Entropy Ultra-High Temperature Carbides

Castle

Csanádi

Grasso

et al. 2018

Sci Rep

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642

361

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“…All of the carbides were fabricated using the same SPS sintering route used in previous work involving the same authors or in the present work. [4,23,26,27] The mechanical testing was performed under identical nanoindentation testing conditions, and average hardness and Young's modulus were taken from the region of penetrations of 100-300 nm. The SEM images of the indents in HEC8-MoW ( Figure S6, Supporting Information,), as a typical example, show that the majority of the indents did not exhibit cracking, and the shape of the indents have a regular triangular shape, which suggests that no pile-up occurred around them and hence the measured nanoindentation data were correctly evaluated by the Oliver-Pharr method.…”

Section: Design and Synthesis Of Eight-cation Hecsmentioning

confidence: 99%

Enhanced Hardness in High‐Entropy Carbides through Atomic Randomness

Wang

Csanádi

Zhang

et al. 2020

Advcd Theory and Sims

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High‐entropy carbides (HECs) are of great interest as they are promising candidates for ultra‐high‐temperature and high‐hardness applications. To discover carbides with enhanced yield strength and hardness, mechanism‐based design approaches are needed. In this study, dislocation core atomic randomness as a mechanism for hardness enhancement is proposed, in which the random interactions between different elements at a dislocation core make it more difficult for the dislocation to slip. The Peierls stress of an a/2false⟨11¯0false⟩false{110false} edge dislocation is calculated based on density functional theory, in which atomic randomness is increased by increasing the number of elements at the dislocation core. The results show that the Peierls stress statistically increases with increasing number of elements, indicating that incorporating more elements is likely to produce higher hardness. Based on this guiding principle, three eight‐cation HECs are fabricated (Ti,Zr,Hf,V,Nb,Ta,X,Y)C (X,Y = Mo,W, Cr,Mo, or Cr,W), the composition of which is guided by ab initio calculations of their formation enthalpy and entropy forming ability. The single‐phase dense ceramics all show high nanoindentation hardness of around 40 GPa. The random interactions between different elements at a dislocation core provide a mechanism for improving the hardness of structural ceramics.

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“…It's can be mixed with other materials to get a better composite according to its usefulness [8]. Carbides of transition metals form an interesting class of materials in which anions and cations are held together by a mixture of strong ionic, covalent, and metallic bonds [9]. Different transition metal carbides showed good chemical stability andgood mechanical properties with high resistance against corrosion [10] The metal lattice expands and the metal-metal distance increases upon carbide formation, the increase in metal-metal distance causes contraction of the metal d-band and therefore would give a greater density of states (DOS) near the Fermi level [11].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Optical, Electronic and Spectroscopic properties of (Biopolymer-SiC) Nanocomposites For Electronics Applications

Hashim¹,

Abduljalil

2019

Egypt. J. Chem.

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I N THIS paper, studying the effect of increase the number of SiC nanoparticles atoms on the optimized geometrical parameters, electronic and spectroscopic properties of polyvinyl alcohol. The studied structures are (PVA)(43Atom), (PVA-SiC)(35 Atom) and (PVA-SiC)(51Atom) nanocomposites. The optimization parameters included both bonds and angles. The electronic and structural properties included the (energy gap, cohesive energy, ionization potential, electron affinity, chemical hardness, chemical softness, electronegativity, electrophilicity and density of states) as well as spectral properties, which included IR and UV-Visible. This study uses Gaussian 0.9 program with help of Gaussian View 0.5 using density function theory (DFT) with local spin density approximation B3LYP level and6-31Gbasis sets. The results showed that the number of atoms has a direct impact on all the properties of the molecules studied. The increase of number of atoms is caused changes in spectral of (PVA) which include shift in some bonds and change in the intensities. These changes attributed to interactions of nanoparticles (SiC) with (PVA). Also, from Ultra Violet and Visible spectrum observed that absorption increases by increasing the number of atoms, this is due to the excitations of donor level electrons to the conduction band at these energies. The energy gap of the nanocomposites reduces from 6.8568 eV for (PVA) to5.0715 eV for (PVA-SiC)(35Atom) and 4.5330 eV for (PVA-SiC)(51Atom). The total energies decreases with the increase the number of atoms forming the nanocomposites. The results showed that the nanocomposites can be used for different applications such as: solar cells, diodes, transistors, sensors, electronics gates, electronics devices.

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Nanoindentation and tribology of VC, NbC and ZrC refractory carbides

Cited by 60 publications

References 21 publications

Processing and Properties of High-Entropy Ultra-High Temperature Carbides

Processing and Properties of High-Entropy Ultra-High Temperature Carbides

Enhanced Hardness in High‐Entropy Carbides through Atomic Randomness

Analysis of Optical, Electronic and Spectroscopic properties of (Biopolymer-SiC) Nanocomposites For Electronics Applications

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