Structural engineering and functional properties of vacuum-arc coatings of high-entropy (TiZrNbVHf)N and (TiZrNbVHfTa)N alloys nitrides

2019 ◽  
Vol 26 (2) ◽  
Keyword(s):  
Functional Properties ◽  
Structural Engineering ◽  
Vacuum Arc ◽  
High Entropy

scholarly journals Influence of Bias Potential Magnitude on Structural Engineering of ZrN-Based Vacuum-Arc Coatings

2021 ◽  
Vol 22 (1) ◽  
pp. 66-72
Author(s):  
O.V. Sobol’ ◽  
H.O. Postelnyk ◽  
N.V. Pinchuk ◽  
A.A. Meylekhov ◽  
M.A. Zhadko ◽  
...  
Keyword(s):  
Functional Properties ◽  
Structural Engineering ◽  
Preferred Orientation ◽  
Vacuum Arc ◽  
Negative Bias ◽  
Crystal Lattices ◽  
Bias Potential ◽  
The Creation ◽  
Modern Technologies

The creation of the scientific foundations for the structural engineering of ultrathin nanolayers in multilayer nanocomposites is the basis of modern technologies for the formation of materials with unique functional properties. It is shown that an increase in the negative bias potential (from -70 to -220 V) during the formation of vacuum-arc nanocomposites based on ZrN makes it possible not only to control the preferred orientation of crystallites and substructural characteristics but also changes the conditions for conjugation of crystal lattices in ultrafine (about 8 nm) nanolayers.

Structural Engineering of the Multilayer Vacuum Arc Nitride Coatings Based on Ti, Cr, Mo and Zr

2017 ◽  
Vol 9 (3) ◽  
pp. 03003-1-03003-6 ◽  
Author(s):  
O. V. Sobol ◽  
◽  
A. A. Postelnyk ◽  
A. A. Meylekhov ◽  
A. A. Andreev ◽  
...  
Keyword(s):  
Structural Engineering ◽  
Vacuum Arc ◽  
Nitride Coatings

scholarly journals In-Situ TEM Annealing Observation of Helium Bubble Evolution in Pre-Irradiated FeCoNiCrTi0.2 Alloys

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3727
Author(s):  
Huanhuan He ◽  
Zhiwei Lin ◽  
Shengming Jiang ◽  
Xiaotian Hu ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Vacuum Arc ◽  
In Situ Tem ◽  
Face Centered Cubic ◽  
Helium Bubble ◽  
High Entropy ◽  
Helium Bubbles ◽  
Transmission Electron ◽  
Bubble Evolution ◽  
Face Centered

The FeCoNiCrTi0.2 high-entropy alloys fabricated by vacuum arc melting method, and the annealed pristine material, are face centered cubic structures with coherent γ’ precipitation. Samples were irradiated with 50 keV He+ ions to a fluence of 2 × 1016 ions/cm2 at 723 K, and an in situ annealing experiment was carried out to monitor the evolution of helium bubbles during heating to 823 and 923 K. The pristine structure of FeCoNiCrTi0.2 samples and the evolution of helium bubbles during in situ annealing were both characterized by transmission electron microscopy. The annealing temperature and annealing time affect the process of helium bubbles evolution and formation. Meanwhile, the grain boundaries act as sinks to accumulate helium bubbles. However, the precipitation phase seems have few effects on the helium bubble evolution, which may be due to the coherent interface and same structure of γ’ precipitation and matrix.

Microstructure and Mechanical Properties of VTaTiMoAlx Refractory High Entropy Alloys

2017 ◽  
Vol 898 ◽  
pp. 638-642 ◽  
Author(s):  
Dong Xu Qiao ◽  
Hui Jiang ◽  
Xiao Xue Chang ◽  
Yi Ping Lu ◽  
Ting Ju Li
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
Dendrite Structure ◽  
X Ray ◽  
High Entropy ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Microstructure And Mechanical Properties

A series of refractory high-entropy alloys VTaTiMoAlx with x=0,0.2,0.6,1.0 were designed and produced by vacuum arc melting. The effect of added Al elements on the microstructure and mechanical properties of refractory high-entropy alloys were investigated. The X-ray diffraction results showed that all the high-entropy alloys consist of simple BCC solid solution. SEM indicated that the microstructure of VTaTiMoAlx changes from equiaxial dendritic-like structure to typical dendrite structure with the addition of Al element. The composition of different regions in the alloys are obtained by energy dispersive spectroscopy and shows that Ta, Mo elements are enriched in the dendrite areas, and Al, Ti, V are enriched in inter-dendrite areas. The yield strength and compress strain reach maximum (σ0.2=1221MPa, ε=9.91%) at x=0, and decrease with the addition of Al element at room temperature. Vickers hardness of the alloys improves as the Al addition.

Reproducibility of the single-phase structural state of the multielement high-entropy Ti-V-Zr-Nb-Hf system and related superhard nitrides formed by the vacuum-arc method

2012 ◽  
Vol 38 (7) ◽  
pp. 616-619 ◽  
Author(s):  
O. V. Sobol’ ◽  
A. A. Andreev ◽  
V. F. Gorban’ ◽  
N. A. Krapivka ◽  
V. A. Stolbovoi ◽  
...  
Keyword(s):  
Structural State ◽  
Single Phase ◽  
Vacuum Arc ◽  
High Entropy

scholarly journals Synthesis of Spherical V-Nb-Mo-Ta-W High-Entropy Alloy Powder Using Hydrogen Embrittlement and Spheroidization by Thermal Plasma

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1296 ◽  
Author(s):  
Won-Hyuk Lee ◽  
Ki Beom Park ◽  
Kyung-Woo Yi ◽  
Sung Yong Lee ◽  
Kwangsuk Park ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Thermal Plasma ◽  
Fine Powder ◽  
Hydrogen Atmosphere ◽  
Vacuum Arc ◽  
Cubic Phase ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Inductively Coupled ◽  
Arc Melting

V-Nb-Mo-Ta-W high-entropy alloy (HEA), one of the refractory HEAs, is considered as a next-generation structural material for ultra-high temperature uses. Refractory HEAs have low castability and machinability due to their high melting temperature and low thermal conductivity. Thus, powder metallurgy becomes a promising method for fabricating components with refractory HEAs. Therefore, in this study, we fabricated spherical V-Nb-Mo-Ta-W HEA powder using hydrogen embrittlement and spheroidization by thermal plasma. The HEA ingot was prepared by vacuum arc melting and revealed to have a single body-centered cubic phase. Hydrogen embrittlement which could be achieved by annealing in a hydrogen atmosphere was introduced to get the ingot pulverized easily to a fine powder having an angular shape. Then, the powder was annealed in a vacuum atmosphere to eliminate the hydrogen from the hydrogenated HEA, resulting in a decrease in the hydrogen concentration from 0.1033 wt% to 0.0003 wt%. The angular shape of the HEA powder was turned into a spherical one by inductively-coupled thermal plasma, allowing to fabricate spherical V-Nb-Mo-Ta-W HEA powder with a d50 value of 28.0 μm.

scholarly journals Microstructure and Mechanical Properties of Co-Cr-Mo-Si-Y-Zr High Entropy Alloy

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1456
Author(s):  
Karsten Glowka ◽  
Maciej Zubko ◽  
Paweł Świec ◽  
Krystian Prusik ◽  
Robert Albrecht ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Microstructure Analysis ◽  
Vacuum Arc ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Transmission Electron ◽  
Multi Phase ◽  
Principal Elements

Presented work was focused on obtaining new, up to our knowledge, non-described previously in the literature high entropy Co15Cr15Mo25Si15Y15Zr15 alloy to fill in the knowledge gap about the six-elemental alloys located in the adjacent to the center of phase diagrams. Material was obtained using vacuum arc melting. Phase analysis revealed the presence of a multi-phase structure. Scanning electron microscopy microstructure analysis revealed the existence of three different phases with partially dendritic structures. Chemical analysis showed that all phases consist of all six principal elements—however, with different proportions. Transmission electron microscopy microstructure analysis confirmed the presence of amorphous and nanocrystalline areas, as well as their mixture. For the studied alloy, any phase transformation and solid-state crystallization were not revealed in the temperature range from room temperature up to 1350 °C. Nanoindentation measurements revealed high nanohardness (13(2) GPa and 18(1) GPa for dendritic and interdendritic regions, respectively) and relatively low Young’s modulus (185(23) GPa and 194(9) GPa for dendritic and interdendritic regions, respectively) of the observed phases.

scholarly journals Phase Evolution and Microstructure Analysis of CoCrFeNiMo High-Entropy Alloy for Electro-Spark-Deposited Coatings for Geothermal Environment

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 406 ◽  
Author(s):  
Sigrun N. Karlsdottir ◽  
Laura E. Geambazu ◽  
Ioana Csaki ◽  
Andri I. Thorhallsson ◽  
Radu Stefanoiu ◽  
...  
Keyword(s):  
Bulk Material ◽  
Microstructural Analysis ◽  
Electrochemical Corrosion ◽  
High Hardness ◽  
Phase Evolution ◽  
Vacuum Arc ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
Σ Phase ◽  
High Entropy

In this work, a CoCrFeNiMo high-entropy alloy (HEA) material was prepared by the vacuum arc melting (VAM) method and used for electro-spark deposition (ESD). The purpose of this study was to investigate the phase evolution and microstructure of the CoCrFeNiMo HEA as as-cast and electro-spark-deposited (ESD) coating to assess its suitability for corrosvie environments encountered in geothermal energy production. The composition, morphology, and structure of the bulk material and the coating were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The hardness of the bulk material was measured to access the mechanical properties when preselecting the composition to be pursued for the ESD coating technique. For the same purpose, electrochemical corrosion tests were performed in a 3.5 wt.% NaCl solution on the bulk material. The results showed the VAM CoCrFeNiMo HEA material had high hardness (593 HV) and low corrosion rates (0.0072 mm/year), which is promising for the high wear and corrosion resistance needed in the harsh geothermal environment. The results from the phase evolution, chemical composition, and microstructural analysis showed an adherent and dense coating with the ESD technique, but with some variance in the distribution of elements in the coating. The crystal structure of the as-cast electrode CoCrFeNiMo material was identified as face centered cubic with XRD, but additional BCC and potentially σ phase was formed for the CoCrFeNiMo coating.

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