Research on Electromagnetic Properties of High Entropy Alloys

In 1995, Yeh suggested the formation of an alloy made up of at least five metallic elements which have large mixing entropy solutions with many elements forming solide alloys. This alloy appeared because traditional alloys are characteised by high fragility and are difficult to process. High entropy alloys are alloys which have approximately equal concentrations, formed by a group of 5 to 11 elements majority in composition, mole fraction of each major metallic element in the alloy is between 5% and 30%. During the research it has been proved that this alloy has a high hardness and it is also corrosion proof and also resistance and good thermal stability It should be mentioned that High Entropy Alloys are characterized as alloys consisting of roughly equal concentrations of at least five metallic elements and are claimed to favor close-packed, disordered structures due to high configurational entropy. Such crystal structures, e.g. face-centered cubic (FCC), are advantageous in that they should offer multiple active slip systems usually observed in ductile metals and alloys. This opens the door to a large number of rich chemistries which would otherwise contain unacceptable volume fractions of intermetallic compounds to be useful in structural applications That way in this paper will carry out research to one specific high entropy alloy, we analyze the physical, chemical, electrical, magnetic, corrosion resistance of these materials, heat treatments corresponding and plastic deformation. This paper is divided into several chapters which will present application domains, and also a number of conclusions. Key words : high entropy alloys, properties of alloys, application domains, corrosion proof, thermal stability

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Emergence of machine learning in the development of high entropy alloy and their prospects in advanced engineering applications

Emergent Materials ◽

10.1007/s42247-021-00249-8 ◽

2021 ◽

Author(s):

Nirmal Kumar Katiyar ◽

Gaurav Goel ◽

Saurav Goel

Keyword(s):

Machine Learning ◽

High Entropy Alloy ◽

High Entropy Alloys ◽

Learning Approaches ◽

Metallic Elements ◽

Materials Synthesis ◽

High Entropy ◽

Structural Applications ◽

Electromagnetic Shield ◽

The Right

AbstractThe high entropy alloys have become the most intensely researched materials in recent times. They offer the flexibility to choose a large array of metallic elements in the periodic table, a combination of which produces distinctive desirable properties that are not possible to be obtained by the pristine metals. Over the past decade, a myriad of publications has inundated the aspects of materials synthesis concerning HEA. Hitherto, the practice of HEA development has largely relied on a trial-and-error basis, and the hassles associate with this effort can be reduced by adopting a machine learning approach. This way, the “right first time” approach can be adopted to deterministically predict the right combination and composition of metallic elements to obtain the desired functional properties. This article reviews the latest advances in adopting machine learning approaches to predict and develop newer compositions of high entropy alloys. The review concludes by highlighting the newer applications areas that this accelerated development has enabled such that the HEA coatings can now potentially be used in several areas ranging from catalytic materials, electromagnetic shield protection and many other structural applications.

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

Coatings ◽

10.3390/coatings9060406 ◽

2019 ◽

Vol 9 (6) ◽

pp. 406 ◽

Cited By ~ 4

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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High Strength and Deformation Mechanisms of Al0.3CoCrFeNi High-Entropy Alloy Thin Films Fabricated by Magnetron Sputtering

Entropy ◽

10.3390/e21020146 ◽

2019 ◽

Vol 21 (2) ◽

pp. 146 ◽

Cited By ~ 7

Author(s):

Wei-Bing Liao ◽

Hongti Zhang ◽

Zhi-Yuan Liu ◽

Pei-Feng Li ◽

Jian-Jun Huang ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Magnetron Sputtering ◽

High Hardness ◽

Deformation Mechanisms ◽

High Entropy Alloy ◽

Alloy Thin Film ◽

Face Centered Cubic ◽

High Entropy ◽

Strength And Deformation

Recently, high-entropy alloy thin films (HEATFs) with nanocrystalline structures and high hardness were developed by magnetron sputtering technique and have exciting potential to make small structure devices and precision instruments with sizes ranging from nanometers to micrometers. However, the strength and deformation mechanisms are still unclear. In this work, nanocrystalline Al0.3CoCrFeNi HEATFs with a thickness of ~4 μm were prepared. The microstructures of the thin films were comprehensively characterized, and the mechanical properties were systematically studied. It was found that the thin film was smooth, with a roughness of less than 5 nm. The chemical composition of the high entropy alloy thin film was homogeneous with a main single face-centered cubic (FCC) structure. Furthermore, it was observed that the hardness and the yield strength of the high-entropy alloy thin film was about three times that of the bulk samples, and the plastic deformation was inhomogeneous. Our results could provide an in-depth understanding of the mechanics and deformation mechanism for future design of nanocrystalline HEATFs with desired properties.

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Generalized Stacking Fault Energy of Al-Doped CrMnFeCoNi High-Entropy Alloy

Nanomaterials ◽

10.3390/nano10010059 ◽

2019 ◽

Vol 10 (1) ◽

pp. 59 ◽

Cited By ~ 5

Author(s):

Xun Sun ◽

Hualei Zhang ◽

Wei Li ◽

Xiangdong Ding ◽

Yunzhi Wang ◽

...

Keyword(s):

Interfacial Energy ◽

Stacking Fault ◽

Stacking Fault Energy ◽

High Entropy Alloy ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Al Content ◽

Generalized Stacking Fault ◽

Generalized Stacking Fault Energy

Using first-principles methods, we investigate the effect of Al on the generalized stacking fault energy of face-centered cubic (fcc) CrMnFeCoNi high-entropy alloy as a function of temperature. Upon Al addition or temperature increase, the intrinsic and extrinsic stacking fault energies increase, whereas the unstable stacking fault and unstable twinning fault energies decrease monotonously. The thermodynamic expression for the intrinsic stacking fault energy in combination with the theoretical Gibbs energy difference between the hexagonal close packed (hcp) and fcc lattices allows one to determine the so-called hcp-fcc interfacial energy. The results show that the interfacial energy is small and only weakly dependent on temperature and Al content. Two parameters are adopted to measure the nano-twinning ability of the present high-entropy alloys (HEAs). Both measures indicate that the twinability decreases with increasing temperature or Al content. The present study provides systematic theoretical plasticity parameters for modeling and designing high entropy alloys with specific mechanical properties.

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Ultrastrong Al0.1CoCrFeNi high-entropy alloys at small scales: effects of stacking faults vs. nanotwins

Nanoscale ◽

10.1039/c8nr03573c ◽

2018 ◽

Vol 10 (28) ◽

pp. 13329-13334 ◽

Cited By ~ 19

Author(s):

Xiaobin Feng ◽

Jinyu Zhang ◽

Kai Wu ◽

Xiaoqing Liang ◽

Gang Liu ◽

...

Keyword(s):

Stacking Faults ◽

Maximum Strength ◽

High Entropy Alloy ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Small Scales ◽

Face Centered

The present stacking faulted and nanotwinned Al0.1CoCrFeNi high-entropy alloy pillars achieved the maximum strength among face-centered cubic structured metals.

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Microstructure and Mechanical Properties of FeNiCrCuAl High Entropy Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1036.101 ◽

2014 ◽

Vol 1036 ◽

pp. 101-105

Author(s):

Gheorghe Buluc ◽

Iulia Florea ◽

Oana Bălţătescu ◽

Costel Roman ◽

Ioan Carcea

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

High Hardness ◽

High Strength ◽

High Entropy Alloys ◽

Engineering Applications ◽

High Entropy ◽

Good Thermal Stability ◽

Microstructure And Mechanical Properties ◽

Wide Range

This paper presents the microstructure and the mechanical properties of FeNiCrCuAl high entropy alloys. The microstructure and mechanical properties of the annealed FeNiCrCuAl high entropy alloys were investigated using scanning electron microscopy, and X-ray diffraction. High entropy alloys have been known as a new type of materials and have been defined as having five or more principal elements, each one having a concentration between 5 and 35 at.%. Previous researches show that HEAs can be processed to form simple solid solution structures instead of intermetallics and other complicated compounds. This phenomenon is commonly attributed to the high configurational entropy in the solid solution state of HEAs. Furthermore, HEAs have also exhibited interesting properties such as high hardness and high strength, good thermal stability outstanding wear and oxidation resistance which offer great potential for engineering applications. The HEA systems explored in the past decade show that metallic elements are the most commonly used, e.g. Al, Cr, Fe, Co, Ni, Cu,Ti, etc. A wide range of HEAs exhibit high hardness, high strength, distinctive electrical and magnetic properties, high-temperature softening resistance, as well as favorable combination of compression strength and ductility. This combination of properties and the particular structures of HEAs are attractive for a number of potential engineering applications.

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MICROSTRUCTURE AND PROPERTIES OF COATING OF AlFeCrNiMo HIGH-ENTROPY ALLOY

Surface Review and Letters ◽

10.1142/s0218625x18501639 ◽

2019 ◽

Vol 26 (03) ◽

pp. 1850163 ◽

Cited By ~ 2

Author(s):

DAN DOU ◽

KUN DENG ◽

JIANCHEN LI

Keyword(s):

Materials Science ◽

High Hardness ◽

Good Combination ◽

High Entropy Alloy ◽

High Entropy Alloys ◽

High Entropy ◽

Direct Current Magnetron Sputtering ◽

Science Community ◽

Significant Attention ◽

Better Than

High-entropy alloys (HEAs) have recently received significant attention in the materials science community. Some of these alloys can display a good combination of mechanical properties. The perfect dense and smooth coatings of AlFeCrNiMo HEA have been deposited by direct current magnetron sputtering method. The coatings possess single BCC crystal structure. The thickness of the coatings increases with increasing deposited time and plasma power. The coatings display excellent high hardness and Young’s modulus. The corrosion resistance of all coatings in acidic and salt media is better than that of 201 stainless steel. It is expected that the HEA coatings have very broad application prospects.

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A Short Review on Welding and Joining of High Entropy Alloys

Metals ◽

10.3390/met10020212 ◽

2020 ◽

Vol 10 (2) ◽

pp. 212 ◽

Cited By ~ 8

Author(s):

João G. Lopes ◽

João Pedro Oliveira

Keyword(s):

Solid State ◽

Mechanical Performance ◽

High Entropy Alloy ◽

High Entropy Alloys ◽

Specific System ◽

Science Field ◽

High Entropy ◽

Starting Point ◽

Structural Applications ◽

Alloy Systems

High entropy alloys are one of the most exciting developments conceived in the materials science field in the last years. These novel advanced engineering alloys exhibit a unique set of properties, which include, among others, good mechanical performance under severe conditions in a wide temperature range and high microstructural stability over long time periods. Owing to the remarkable properties of these alloys, they can become expedite solutions for multiple structural and functional applications. Nevertheless, like any other key engineering alloy, their capacity to be welded, and thus become a permanent feature of a component or structure, is a fundamental issue that needs to be addressed to further expand these alloys’ potential applications. In fact, welding of high entropy alloys has attracted some interest recently. Therefore, it is important to compile the available knowledge on the current state of the art on this topic in order to establish a starting point for the further development of these alloys. In this article, an effort is made to acquire a comprehensive knowledge on the overall progress on welding of different high entropy alloy systems through a systematic review of both fusion-based and solid-state welding techniques. From the current literature review, it can be perceived that welding of high entropy alloys is currently gaining more interest. Several high entropy alloy systems have already been successfully welded. However, most research works focus on the well-known CoCrFeMnNi. For this specific system, both fusion and solid-state welding have been used, with no significant degradation of the joints’ mechanical properties. Among the different welding techniques already employed, laser welding is predominant, potentially due to the small size of its heat source. Overall, welding of high entropy alloys is still in its infancy, though good perspectives are foreseen for the use of welded joints based on these materials in structural applications.

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Microstructure and Wear Resistance of FeNiCrMnCu High Entropy Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1143.3 ◽

2017 ◽

Vol 1143 ◽

pp. 3-6 ◽

Cited By ~ 1

Author(s):

Gheorghe Buluc ◽

Iulia Florea ◽

Romeu Chelariu ◽

Oana Rusu ◽

Ioan Carcea

Keyword(s):

Solid Solution ◽

Wear Resistance ◽

Materials Science ◽

Microstructural Analysis ◽

Main Element ◽

High Entropy Alloy ◽

Test Machine ◽

High Entropy Alloys ◽

Metallic Elements ◽

High Entropy

In this paper it is presented the microstructure and wear resistance of FeNiCrMnCu high entropy alloy. High entropy alloys are composed by at least five metallic elements in equimolar or non-equimolare proportions. High entropy alloys a brand new category of metallic materials, appeared to be a new effort in materials science and engineering, which attracted great interest. To obtain FeNiCrMnCu high entropy alloy we used an 8000 Hz induction furnace. The chemical composition was determined by EDAX. Microstructural analysis was performed using optical microscopy and SEM (scanning electron microscopy), which showed that the FeNiCrMnCu high entropy alloy has a dentritic structure and form a solid solution. Choosing copper as the main element (copper tends to segregate in interdentritic region due to its positive enthalpy of mixing with many common elements) [1], along with the iron, nickel, chromium and manganese, led to obtaining a dentritic structure specify for solid solution, which, however, did not lead to a significant hardness for FeNiCrMnCu high entropy alloy. In this work we selected pure metallic elements like: Fe, Ni, Cr, Mn and Cu. The quantity of alloy developed has 1.5 kg. Friction and wear resistance were the studied by using a reciprocating sliding test machine, in a pin on disk configuration, using aluminum as counter face. Hardness value regarding FeNiCrMnCu high entropy alloy was 184 HV and medium friction coefficient value for FeNiCrMnCu high entropy alloys was 0.86 for 28 minutesc and 1.13 for the first 20 seconds.

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Wear Behavior and Tribological Evolution of High Entropy Alloys

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b1409.0982s1119 ◽

2019 ◽

Vol 8 (2S11) ◽

pp. 3143-3146

Keyword(s):

Wear Behavior ◽

Research Work ◽

Review Article ◽

High Entropy Alloy ◽

Chemical Compositions ◽

High Entropy Alloys ◽

Multicomponent Alloys ◽

High Entropy ◽

Mechanical And Tribological Properties ◽

Structural Applications

High entropy alloy are equiatomic and nonequiatomic complex concentrated/ multicomponent alloys which are recognized due to their distinctive mechanical and triboligical properties. A unique combination of excellent mechanical and tribological properties of high entropy alloys makes them promising candidate for variety of industrial and structural applications. The wear resistance needs to be examined for these complex concentrated alloys as only few numbers of reports and investigation are available in the field of new advanced HEAs materials. In the current research work, we identified the crucial achievements and breakthrough in the wear and tribological investigations of high entropy alloy and HEA based composites in recent years. This review article investigates the tribological behaviors of multicomponent alloys /high entropy alloys and HEA based composites which play an important role and draw a considerable attention in the present era. In view of recent developments on tribological and wear related mechanisms of HEAs for different type of industrial and structural applications, microstructure, chemical compositions, and mechanical properties are explained and reviewed in this review article.

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