The structure and properties of high-entropy alloys and nitride coatings based on them

Pogrebnjak, A.D.; Bagdasaryan, A. A.; Yakushchenko, I. V.; Береснев, В. М.

doi:10.1070/rcr4407

Cited by 245 publications

(84 citation statements)

References 211 publications

(139 reference statements)

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“…They can be used to solve the fundamental and applied problems, such as fabricating coatings, studying their structure and properties, or using the products covered with these coatings in practice [1][2][3][4][5]. The nitrides and carbides from HEAs significantly improve the characteristics of materials: radiation, wear, and corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

The influence of nitrogen pressure on the fabrication of the two-phase superhard nanocomposite (TiZrNbAlYCr)N coatings

et al. 2018

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a b s t r a c tThe multicomponent nitride coatings from TiZrNbAlYCr high entropy alloy (HEA) were fabricated using the vacuum-arc method. The effect of nitrogen pressure on the crystallite size, elemental and phase composition of (TiZrNbAlYCr)N coatings was investigated. A bias voltage applied to the substrate during the deposition process was À200 V. The partial nitrogen pressure was 0.05 Pa, 0.27 Pa, and 0.5 Pa. Bodycentered cubic (BCC) lattice with crystallites of 15 nm in size was formed at the lowest pressure. An increase in the pressure led to the formation of the two-phase structure: BCC phase with crystallite size of 15 nm and face-centered cubic (FCC) phase with crystallite size of about 3.5 nm. The same two-phase state was found in coatings fabricated at 0.5 Pa, while the mean crystallite size was 7 nm. The maximum hardness of the deposited coatings was about 47 GPa.

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Section: Introductionmentioning

confidence: 99%

The influence of nitrogen pressure on the fabrication of the two-phase superhard nanocomposite (TiZrNbAlYCr)N coatings

et al. 2018

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“…In many cases, refractory (with melting point above 2000˝C) HEAs are characterized by high hardness (600-900 HV): however, since their main components are Mo, Nb, Ta or Zr, their density equals or surpasses 10 g¨cm´3 [2][3][4], which limits their application. Conversely, only few alloys display micro-hardness values of 800 HV or more.…”

Section: Introductionmentioning

confidence: 99%

Formation and Disruption of W-Phase in High-Entropy Alloys

Riva

Fung

Searle³

et al. 2016

Metals

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High-entropy alloys (HEAs) are single-phase systems prepared from equimolar or near-equimolar concentrations of at least five principal elements. The combination of high mixing entropy, severe lattice distortion, sluggish diffusion and cocktail effect favours the formation of simple phases-usually a bcc or fcc matrix with minor inclusions of ordered binary intermetallics. HEAs have been proposed for applications in which high temperature stability (including mechanical and chemical stability under high temperature and high mechanical impact) is required. On the other hand, the major challenge to overcome for HEAs to become commercially attractive is the achievement of lightweight alloys of extreme hardness and low brittleness. The multicomponent AlCrCuScTi alloy was prepared and characterized using powder X-ray diffraction (PXRD), scanning-electron microscope (SEM) and atomic-force microscope equipped with scanning Kelvin probe (AFM/SKP) techniques. Results show that the formation of complex multicomponent ternary intermetallic compounds upon heating plays a key role in phase evolution. The formation and degradation of W-phase, Al 2 Cu 3 Sc, in the AlCrCuScTi alloy plays a crucial role in its properties and stability. Analysis of as-melted and annealed alloy suggests that the W-phase is favoured kinetically, but thermodynamically unstable. The disruption of the W-phase in the alloy matrix has a positive effect on hardness (890 HV), density (4.83 g¨cm´3) and crack propagation. The hardness/density ratio obtained for this alloy shows a record value in comparison with ordinary heavy refractory HEAs.

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“…A new class of materials -high-entropy alloys (HEA), which consist of at least 5 atoms with atomic content from 5 to 35 at% -are under great interest nowadays due to their exceptional wealth of physical-mechanical characteristics [8][9][10][11]13,12,[16][17][18][19][20][21][22]. Several works have been performed so far to obtain a comprehensive understanding of the effect of constitutive elements on the microstructure, phase composition and mechanical properties of HEA [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

“…The main advantages of ion implantation are preservation of sample sizes, locality (small projective path), high reproducibility, absence of problems with adhesion etc. [7][8][9][10][11][12][13][14][15]. In order to improve the properties of metals, alloys and ceramics, it is necessary to use high doses of ion implantation, from typically 5Á10 16 up to 5x10 17 cm À2 [16].…”

Section: Introductionmentioning

confidence: 99%

Nanostructured multielement (TiHfZrNbVTa)N coatings before and after implantation of N+ ions (1018cm−2): Their structure and mechanical properties

Pogrebnjak

Бондар

Borba

et al. 2016

Nuclear Instruments and Methods in Physics Research Section B:

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a b s t r a c tMultielement high entropy alloy (HEA) nitride (TiHfZrNbVTa)N coatings were deposited by vacuum arc and their structural and mechanical stability after implantation of high doses of N + ions, 10 18 cm À2 , were investigated. The crystal structure and phase composition were characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy, while depth-resolved nanoindentation tests were used to determine the evolution of hardness and elastic modulus along the implantation depth. XRD patterns show that coatings exhibit a main phase with fcc structure, which preferred orientation varies from (1 1 1) to (2 0 0), depending on the deposition conditions. First-principles calculations reveal that the presence of Nb atoms could favor the formation of solid solution with fcc structure in multielement HEA nitride. TEM results showed that amorphous and nanostructured phases were formed in the implanted coating sub-surface layer ($100 nm depth). Concentration of nitrogen reached 90 at% in the near-surface layer after implantation, and decreased at higher depth. Nanohardness of the as-deposited coatings varied from 27 to 38 GPa depending on the deposition conditions. Ion implantation led to a significant decrease of the nanohardness to 12 GPa in the implanted region, while it reaches 24 GPa at larger depths. However, the H/E ratio is P0.1 in the sub-surface layer due to N + implantation, which is expected to have beneficial effect on the wear properties.

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The structure and properties of high-entropy alloys and nitride coatings based on them

Cited by 245 publications

References 211 publications

The influence of nitrogen pressure on the fabrication of the two-phase superhard nanocomposite (TiZrNbAlYCr)N coatings

The influence of nitrogen pressure on the fabrication of the two-phase superhard nanocomposite (TiZrNbAlYCr)N coatings

Formation and Disruption of W-Phase in High-Entropy Alloys

Nanostructured multielement (TiHfZrNbVTa)N coatings before and after implantation of N+ ions (1018cm−2): Their structure and mechanical properties

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