scholarly journals Welding Joints in High Entropy Alloys: A Short-Review on Recent Trends

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1411 ◽  
Author(s):  
Fabio C. Garcia Filho ◽  
Sergio N. Monteiro
Keyword(s):  
Short Review ◽  
Research Field ◽  
Future Perspective ◽  
High Entropy Alloys ◽  
Engineering Applications ◽  
High Entropy ◽  
Production Techniques ◽  
Recent Trends ◽  
Welding Joints ◽  
In The Beginning

High entropy alloys (HEAs) emerged in the beginning of XXI century as novel materials to “keep-an-eye-on”. In fact, nowadays, 16 years after they were first mentioned, a lot of research has been done regarding the properties, microstructure, and production techniques for the HEAs. Moreover, outstanding properties and possibilities have been reported for such alloys. However, a way of jointing these materials should be considered in order to make such materials suitable for engineering applications. Welding is one of the most common ways of jointing materials for engineering applications. Nevertheless, few studies concerns on efforts of welding HEAs. Therefore, it is mandatory to increase the investigation regarding the weldability of HEAs. This work aims to present a short review about what have been done in recent years, and what are the most common welding techniques that are used for HEAs. It also explores what are the measured properties of welded HEAs as well as what are the main challenges that researchers have been facing. Finally, it gives a future perspective for this research field.

Microstructure and Mechanical Properties of FeNiCrCuAl High Entropy Alloys

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.

Powder metallurgy of high-entropy alloys and related composites: A short review

2021 ◽  
Vol 28 (6) ◽  
pp. 931-943
Author(s):  
Bo-ren Ke ◽  
Yu-chen Sun ◽  
Yong Zhang ◽  
Wen-rui Wang ◽  
Wei-min Wang ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Short Review ◽  
High Entropy Alloys ◽  
High Entropy

scholarly journals Application of high-entropy alloys

2021 ◽  
Vol 64 (10) ◽  
pp. 747-754
Author(s):  
V. E. Gromov ◽  
Yu. A. Shlyarova ◽  
S. V. Konovalov ◽  
S. V. Vorob'ev ◽  
O. A. Peregudov
Keyword(s):  
Ammonia Oxidation ◽  
Sea Water ◽  
Protective Coatings ◽  
Stoichiometric Composition ◽  
Short Review ◽  
Wide Frequency Range ◽  
Soft Magnetic Materials ◽  
Muscular Tissue ◽  
High Entropy Alloys ◽  
High Entropy

From accumulated information on structure, properties, stability, and methods of manufacturing the high-entropy alloys (HEA) created early in the 21 century it follows that they possess a whole complex of useful properties that suggests their perspective application in different branches of industry. The authors have made a short review of scientific articles on analysis of possibilities of HEA application in specific science-consuming branches of the last 5 years. In biomedicine the protective coatings made of (TiZrNbHfTa)N and (TiZrNbHfTa)O HEAs possess biocompatibility, high level of mechanical properties, high wear- and corrosion resistance in physiological media, and excellent adhesion. Products made of (MoTa)χNbTiZr passed clinical tests successfully when being implanted to living muscular tissue. The developed HEAs based on rare-earth elements and metals of Fe group such as YbTbDyAlMe (Me = Fe, Co, Ni) possess magnetocaloric effect, have Curie temperature close to room one and may be used in modern refrigerator mechanisms. Changing in stoichiometric composition of CoCrFeNiTi HEAs, alloying them and performing thermal treatment, the researchers succeed in obtaining soft magnetic materials. Fields of HEA application are presented as following: catalysts of ammonia oxidation - (PtPdRhRuCe), ammonia decomposition - (RuRhCoNiIr), oxidation of aromatic alcohols - (Co0,2Ni0,2Cu0,2Mg0,2Zn0,2 ), electric catalysts of hydrogen extraction - (Ni20Fe20Mo10Cr15Co35 ), redox reactions (AlCuNiPtMn and AlNiCuPtPdAu), and oxidation of methanol/ethanol. HEAs can be used as electrodes - anodes and cathodes for Li-ion and Na-ion accumulators. Synthesized nanoporous HEA AlCoCrFeNi has high bulk density up to 700 F/cm3 and cyclic stability (>3000 cycles) and is used in supercapacitors. High-entropy oxides such as (MgNiCoCuZn)0.95Li0.05O with high dielectric properties in a wide frequency range may be used in electronic converters. Examples of HEA application are given: as coatings of ship parts being operated in sea water, various welded joints, parts of nuclear reactors. Perspectives of widening the fields of HEA application are indicated.

scholarly journals Agarose, Alginate and Chitosan Nanostructured Aerogels for Pharmaceutical Applications: A Short Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Mariangela Guastaferro ◽  
Ernesto Reverchon ◽  
Lucia Baldino
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Freeze Drying ◽  
Controlled Drug Delivery ◽  
Short Review ◽  
Research Field ◽  
Cross Linking ◽  
Promising Technique ◽  
Production Techniques ◽  
Traditional Production

In this short review, drug delivery systems, formed by polysaccharide-based (i.e., agarose, alginate, and chitosan) aerogels, are analyzed. In particular, the main papers, published in the period 2011–2020 in this research field, have been investigated and critically discussed, in order to highlight strengths and weaknesses of the traditional production techniques (e.g., freeze-drying and air evaporation) of bio-aerogels with respect to supercritical CO2 assisted drying. Supercritical CO2 assisted drying demonstrated to be a promising technique to produce nanostructured bio-aerogels that maintain the starting gel volume and shape, when the solvent removal occurs at negligible surface tension. This characteristic, coupled with the possibility of removing also cross-linking agent residues from the aerogels, makes these advanced devices safe and suitable as carriers for controlled drug delivery applications.

A review on laser cladding of high-entropy alloys, their recent trends and potential applications

2021 ◽  
Author(s):  
Zia Ullah Arif ◽  
Muhammad Yasir Khalid ◽  
Ehtsham ur Rehman ◽  
Sibghat Ullah ◽  
Muhammad Atif ◽  
...  
Keyword(s):  
Laser Cladding ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Potential Applications ◽  
Recent Trends

High-Entropy Alloys as Catalysts for the CO2 and CO Reduction Reactions

2019 ◽  
Author(s):  
Jack Pedersen ◽  
Thomas Batchelor ◽  
Alexander Bagger ◽  
Jan Rossmeisl
Keyword(s):  
Density Functional ◽  
Rational Design ◽  
Hydrogen Adsorption ◽  
Co Adsorption ◽  
Reduction Reaction ◽  
Supervised Machine Learning ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Co Reduction ◽  
Disordered Alloy

Using the high-entropy alloys (HEAs) CoCuGaNiZn and AgAuCuPdPt as starting points we provide a framework for tuning the composition of disordered multi-metallic alloys to control the selectivity and activity of the reduction of carbon dioxide (CO2) to highly reduced compounds. By combining density functional theory (DFT) with supervised machine learning we predicted the CO and hydrogen (H) adsorption energies of all surface sites on the (111) surface of the two HEAs. This allowed an optimization for the HEA compositions with increased likelihood for sites with weak hydrogen adsorption{to suppress the formation of molecular hydrogen (H2) and with strong CO adsorption to favor the reduction of CO. This led to the discovery of several disordered alloy catalyst candidates for which selectivity towards highly reduced carbon compounds is expected, as well as insights into the rational design of disordered alloy catalysts for the CO2 and CO reduction reaction.

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