scholarly journals Review of Recent Research on AlCoCrFeNi High-Entropy Alloy

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1302
Author(s):  
Marzena Tokarewicz ◽  
Małgorzata Grądzka-Dahlke

High-entropy alloys (HEAs) have gained significant interest in recent years because of their outstanding properties. The AlCoCrFeNi alloy is one of the most studied HEAs. The effect of the manufacturing methods and heat treatment on the properties of the high-entropy AlCoCrFeNi alloy is under intense scrutiny. The effect of varying component content on properties of the alloy is frequently analysed. Aluminium is most popular due to its impact on alloy microstructure and occurrence of phases. Research is also conducted on the influence of alloying additives, such as boron and titanium, on the properties of the AlCoCrFeNi alloy. High-entropy alloys also have excellent mechanical properties at high temperatures. Excellent structural and functional properties make them suitable for application in the most demanding conditions. The research conducted on HEAs still provides a lot of new and valuable information on the properties and structures of these alloys. This article summarizes the most important information about HEAs, specifically the AlCoCrFeNi alloy.

2021 ◽  
Vol 11 (6) ◽  
pp. 2832
Author(s):  
Haibo Liu ◽  
Cunlin Xin ◽  
Lei Liu ◽  
Chunqiang Zhuang

The structural stability of high-entropy alloys (HEAs) is closely related to their mechanical properties. The precise control of the component content is a key step toward understanding their structural stability and further determining their mechanical properties. In this study, first-principle calculations were performed to investigate the effects of different contents of each component on the structural stability and mechanical properties of Co-Cr-Fe-Ni HEAs based on the supercell model. Co-Cr-Fe-Ni HEAs were constructed based on a single face-centered cubic (FCC) solid solution. Elemental components have a clear effect on their structure and performance; the Cr and Fe elements have an obvious effect on the structural stability and equilibrium lattice constant, respectively. The Ni elements have an obvious effect on stiffness. The Pugh ratios indicate that Cr and Ni addition may increase ductility, whereas Co and Fe addition may decrease it. With increasing Co and Fe contents or decreasing Cr and Ni contents, the structural stability and stiffness of Co-Cr-Fe-Ni HEAs are improved. The structural stability and mechanical properties may be related to the strength of the metallic bonding and covalent bonding inside Co-Cr-Fe-Ni HEAs, which, in turn, is determined by the change in element content. Our results provide the underlying insights needed to guide the optimization of Co-Cr-Fe-Ni HEAs with excellent mechanical properties.


Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1017
Author(s):  
Yang Shao ◽  
Huan Ma ◽  
Yibing Wang

In order to reveal the effect of Mo addition on the microstructure and mechanical properties, (CoCuFeNi)100-xMox (x = 0, 10, 15, 19, and 25, x values in atomic ratio) high entropy alloys were prepared by vacuum arc-melting. The results showed that with Mo addition, the μ phase formed and serious separation occurred in the high entropy alloys. The content of μ phase increased with the increase in Mo content. The microstructure of the alloys changed from an initial single-phase face-center-cubic (FCC) solid solution structure (x = 0) to a hypoeutectic microstructure (x = 15), then to a full eutectic microstructure (x = 19), and finally to a hypereutectic microstructure (x = 25). Coherent interface between μ phase and FCC phase was observed. The (CoCuFeNi)81Mo19 alloy with fully eutectic microstructures exhibited the highest yield strength of 557 MPa and fracture strength of 767 MPa in tensile tests at room temperature. The fracture surface revealed that the formation of great amounts of the μ phase resulted in the loss of ductility of (CoCuFeNi)100-xMox alloys.


Author(s):  
Gen Lin ◽  
Jianwu Guo ◽  
Pengfei Ji

As a novel alloy material with outstanding mechanical properties, high-entropy alloys have a wide range of promising applications. By establishing individual Au, Ag, Cu, Ni, and Pd nanolaminates with faced-centered-cubic...


2014 ◽  
Vol 936 ◽  
pp. 1635-1640 ◽  
Author(s):  
Lang Cui ◽  
Bing Ma ◽  
Sheng Qiang Feng ◽  
Xiu Ling Wang

Five common elements Co, Cr, Fe, Ni and Al were selected, and CoCrFeNiAl was prepared by arc-melting. The microstructure and mechanical properties after spot welding were studied. The results show that the cast microstructure of high entropy alloy CoCrFeNiAl is relatively uniform with a dendritic morphology. The heat is inversely proportional with the alloy grain sizes. The greater the heat is, the smaller the grain size is, which leads to the higher hardness and more uniform tissue. But there is a critical value of the heat(Hcrit) in spot welding. When Hactu(actual heat) exceeds Hcrit, it will adversely affect the performance, resulting in crack, splash and other defects.


Entropy ◽  
2018 ◽  
Vol 20 (9) ◽  
pp. 646 ◽  
Author(s):  
Anna Manzoni ◽  
Sebastian Haas ◽  
Haneen Daoud ◽  
Uwe Glatzel ◽  
Christiane Förster ◽  
...  

Compositionally complex alloys, or high entropy alloys, are good candidates for applications at higher temperatures in gas turbines. After their introduction, the equiatomic Al17Co17Cr17Cu17Fe17Ni17 (at.%) served as a starting material and a long optimization road finally led to the recently optimized Al10Co25Cr8Fe15Ni36Ti6 (at.%) alloy, which shows promising mechanical properties. Investigations of the as-cast state and after different heat treatments focus on the evolution of the microstructure and provide an overview of some mechanical properties. The dendritic solidification provides two phases in the dendritic cores and two different ones in the interdendritic regions. Three of the four phases remain after heat treatments. Homogenization and subsequent annealing produce a γ-γ’ based microstructure, similar to Ni-based superalloys. The γ phase is Co-Cr-Fe rich and the γ’ phase is Al-Ni-Ti rich. The understanding of the mechanical behavior of the investigated alloy is supported and enhanced by the study of the different phases and their nanohardness measurements. The observations are compared with mechanical and microstructural data from commercial Ni-based superalloys, Co-based alloys, and Co-Ni-based alloys at the desired application temperature of ~800 °C.


2017 ◽  
Vol 750 ◽  
pp. 34-38
Author(s):  
Gheorghe Buluc ◽  
Romeu Chelariu ◽  
Gabriela Popescu ◽  
Mihail Sârghi ◽  
Ioan Carcea

Traditional alloys is based on a single element called matrix and to improve some mechanical properties (strength, ductility, strength) are added and other metallic elements in the system. High entropy alloys have become a field of increasingly explored in the world of materials. Excellent mechanical properties obtained of the high entropy alloys recommend them to be from year to year as investigated. In the last decade more than 500 high entropy alloys journal and conference papers have been published [1]. High entropy alloys are alloys who have in their composition 5 to 13 metal elements and the concentration of each component is between 5% and 35%. These elements in the composition of high entropy alloys are divided into elements of minority and majority elements. They are called minority elements because their molar fraction is less than 5%. High entropy alloys have mixing entropy higher than traditional alloys, ΔScons≥1.61R (R = 8.314 J / (mol • K)) [1]. High entropy alloy have been obtained in the laboratory of Science and Materials Engineering faculty from Iasi using a medium frequency induction furnace with 8000 Hz. Because they have excellent mechanical properties high entropy alloys can be used in various fields with high wear and corrosion degree or electronic, magnetic applications [1]. In this work we selected pure metallic elements like: Fe, Ni, Cr, Mn and Al. The quantity of alloy developed varied between 0.5 and 1.5 kg. Metal load necessary for the preparation of metal alloys were formed technical grade, industrial accessible prices and satisfying. Friction and wear rezistance were studies by using a reciprocating sliding test machine , in a pin on disk configuration, using aluminum as counter face.In this paper it investigated the wear resistance of high entropy alloys obtained, microstructure and their mechanical properties.


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