Сoating of a multicomponent system Al–Cr–Ni–Co–Fe on a steel substrate obtained by laser

Author(s):  
R. Yu. Bystrov ◽  
D. A. Gerashchenkov

In recent years, the unique physical and mechanical properties of high-entropy alloys (HEAs) have been the subject of increased attention of researchers. The study of the thermodynamic characteristics of such materials may be of interest for formulating the principles of the formation of structures with the required functional characteristics. Since the processes of structure and phase formation, as well as the diffusion mobility of atoms, the mechanism for the formation of mechanical properties and thermal stability differ significantly from similar processes in traditional alloys, HEAs are singled out into a special group of materials.The article presents a brief overview of the results of obtaining a high-entropy alloy by the combined method. At the first stage, a precursor layer was deposited by сold gas dynamic spraying (CGDS), and at the second stage, it was subjected to high-energy action using a laser. An alloy of the Al-Cr-Ni-Co-Fe type has been studied. By varying the ratio of the components, it was possible to obtain an almost equimolar composition for this system. A prediction of properties and structure is made based on the phase composition of the system.

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 345 ◽  
Author(s):  
Lianzan Yang ◽  
Yongyan Li ◽  
Zhifeng Wang ◽  
Weimin Zhao ◽  
Chunling Qin

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.


Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 41
Author(s):  
Yin-Yu Chang ◽  
Cheng-Hsi Chung

Multi-element material coating systems have received much attention for improving the mechanical performance in industry. However, they are still focused on ternary systems and seldom beyond quaternary ones. High entropy alloy (HEA) bulk material and thin films are systems that are each comprised of at least five principal metal elements in equally matched proportions, and some of them are found possessing much higher strength than traditional alloys. In this study, CrVTiNbZr high entropy alloy and nitrogen contained CrVTiNbZr(N) nitride coatings were synthesized using high ionization cathodic-arc deposition. A chromium-vanadium alloy target, a titanium-niobium alloy target and a pure zirconium target were used for the deposition. By controlling the nitrogen content and cathode current, the CrNbTiVZr(N) coating with gradient or multilayered composition control possessed different microstructures and mechanical properties. The effect of the nitrogen content on the chemical composition, microstructure and mechanical properties of the CrVTiNbZr(N) coatings was investigated. Compact columnar microstructure was obtained for the synthesized CrVTiNbZr(N) coatings. The CrVTiNbZrN coating (HEAN-N165), which was deposited with nitrogen flow rate of 165 standard cubic centimeters per minute (sccm), exhibited slightly blurred columnar and multilayered structures containing CrVN, TiNbN and ZrN. The design of multilayered CrVTiNbZrN coatings showed good adhesion strength. Improvement of adhesion strength was obtained with composition-gradient interlayers. The CrVTiNbZrN coating with nitrogen content higher than 50 at.% possessed the highest hardness (25.2 GPa) and the resistance to plastic deformation H3/E*2 (0.2 GPa) value, and therefore the lowest wear rate was obtained because of high abrasion wear resistance.


2021 ◽  
Vol 812 ◽  
pp. 141147
Author(s):  
Xianzhe Zhong ◽  
Qingming Zhang ◽  
Jing Xie ◽  
Mingze Wu ◽  
Fuqing Jiang ◽  
...  

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 265
Author(s):  
Chun-Liang Chen ◽  
Sutrisna

Refractory high-entropy alloy (RHEA) is one of the most promising materials for use in high-temperature structural materials. In this study, the WMoNbTaV coatings on 304 stainless steel substrates has been prepared by mechanical alloying (MA). Effects of V addition and subsequent heat treatment on properties of the WMoNbTaV coatings were investigated. The results show that the RHEA coatings with nanocrystalline body-centered cubic (BCC) solid-solution phase were generated by the mechanical alloying process. The presence of the V element promotes a uniform microstructure and homogeneous distribution of composition in the RHEA coatings due to improving alloying efficiency, resulting in an increase of hardness. After the annealing treatment of the RHEA coatings, microstructure homogeneity was further enhanced; however, the high affinity of Ta for oxygen causes the formation of Ta-rich oxides. Annealing also removes strain hardening generated by high-energy ball milling and thus decreases the hardness of the RHEA coating and alters microstructure evolution and mechanical properties.


2017 ◽  
Vol 61 (1) ◽  
pp. 117-123 ◽  
Author(s):  
TianDang Huang ◽  
Li Jiang ◽  
ChangLiang Zhang ◽  
Hui Jiang ◽  
YiPing Lu ◽  
...  

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