scholarly journals Electrodeposition of high entropy alloy coating from water bath

2018 ◽  
Vol 62 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. Bárta ◽  
S. Ivanová ◽  
M. Pazderová
Keyword(s):  
Alloy Coating ◽  
Thin Layers ◽  
Water Bath ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Accelerated Corrosion ◽  
Metallic Substrates ◽  
High Entropy ◽  
Arc Melting ◽  
Accelerated Corrosion Tests

Abstract High entropy alloys (HEAs) have been in focus of scientist for past few years owing to their predicted scratch, corrosion and temperature resistance and also to interesting magnetic properties. They are usually prepared by arc melting of at least 5 pure elements. This article deals with electrodeposition of such five-element alloy from water bath, which have not been yet reported. The HEA coating consisting of Fe, Co, Ni, Mn and Mo or Zn was successfully electrodeposited on steel, copper and other metallic substrates. Substrates were polished and treated by sonication in acetone prior to electrodeposition. Obtained thin layers were documented by optical microscopy and SEM techniques. Their exact composition was determined by EDS and XRF analysis. Scratch and accelerated corrosion tests were performed to asses their resistance properties. Electrochemical properties were determined by measurements of polarization curves.

Synthesis and Characterization of NiCoFeCrAl3 High Entropy Alloy Coating by Laser Cladding

2010 ◽  
Vol 97-101 ◽  
pp. 1408-1411 ◽  
Author(s):  
Hui Zhang ◽  
Yi Zhu He ◽  
Ye Pan ◽  
Yin Sheng He ◽  
Kee Sam Shin
Keyword(s):  
Laser Cladding ◽  
Alloy Coating ◽  
Synthesis And Characterization ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Arc Melting ◽  
Melting Technique

The NiCoFeCrAl3 high entropy alloy coating with a little addition of C, Si, Mn, Mo has been succesively synthesized by laser cladding. The results show that simple solution phases of ordered BCC and a small fraction of FCC are obtained with fine equaixed dendrites morphology. Because the fine grain strengthening obtained by rapid solidification and the additived small atomic elements like C, Si further increase the distortion of the solid solution lattice, The microhardness of the coating reached above 800 HV and is 50 % higher than previous study on the similar composition by arc melting technique.

Microstructure and Mechanical Properties of High-Entropy Alloys CoCrFeNiAl by Welding

2014 ◽  
Vol 936 ◽  
pp. 1635-1640 ◽  
Author(s):  
Lang Cui ◽  
Bing Ma ◽  
Sheng Qiang Feng ◽  
Xiu Ling Wang
Keyword(s):  
Mechanical Properties ◽  
Spot Welding ◽  
Dendritic Morphology ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Common Elements ◽  
High Entropy ◽  
Grain Sizes ◽  
Arc Melting ◽  
Microstructure And Mechanical Properties

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.

scholarly journals Design and Fabrication of New High Entropy Alloys for Evaluating Titanium Replacements in Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3001 ◽  
Author(s):  
Prashant Sarswat ◽  
Taylor Smith ◽  
Sayan Sarkar ◽  
Arun Murali ◽  
Michael Free
Keyword(s):  
Corrosion Current ◽  
Cost Comparison ◽  
High Entropy Alloys ◽  
Accelerated Corrosion ◽  
Powder Bed ◽  
High Entropy ◽  
Accelerated Corrosion Tests ◽  
Hardness Tests ◽  
Before And After ◽  
And Performance

High entropy alloys (HEAs) were prepared using the powder bed fusion (PBF) technique. Among titanium free alloys AlCoCrFeNiMn, CoCr1.3FeMnNi0.7, AlCoCrFeNi1.3, and AlCoCr1.3FeNi1.3 have been further investigated. A cost comparison was done for these four alloys as well as the titanium-based alloys AlCoCrFeNiTi and AlCo0.8CrFeNiTi. Such a comparison was done in order to evaluate the performance of the titanium-free alloys as the estimated cost of these will be less than for Ti-based HEAs. Hence, we have chosen four titanium free alloys and two titanium-based alloys for further processing. All these alloys were fabricated and subsequently characterized for phase, purity and performance. Scanning electron microscopy-based images were captured for microstructure characterization. EIS-based tests and potentiodynamic scans were performed to evaluate corrosion current. Hardness tests were performed for mechanical properties evaluation. Additional testing using factorial design tests was performed to evaluate the effects of various parameters to create better PBF-based HEA samples. EBSD tests, accelerated corrosion tests (mass loss), chemical analysis after degradation, microstructure analysis before and after degradation, and mechanical property comparison for finalized samples and other similar tests were executed. The details about all these HEAs and subsequent laser processing as well as behavior of these HEAs have been included in this study. It has been observed that some of the selected alloys exhibit good performance compared to Ti-based alloys, especially with respect to improvements in elastic constant and hardness relative to commercially pure Ti.

FABRICATION AND WEAR BEHAVIOR ANALYSIS ON AlCrFeNi HIGH ENTROPY ALLOY COATING UNDER DRY SLIDING AND OIL LUBRICATION TEST CONDITIONS

2016 ◽  
Vol 23 (04) ◽  
pp. 1650018 ◽  
Author(s):  
YIPIN TANG ◽  
SHOUREN WANG ◽  
BIN SUN ◽  
YAN WANG ◽  
YANG QIAO
Keyword(s):  
Hot Pressing ◽  
Solution Structure ◽  
Wear Behavior ◽  
Alloy Coating ◽  
High Entropy Alloy ◽  
Dry Sliding ◽  
High Entropy Alloys ◽  
Oil Lubrication ◽  
High Entropy ◽  
Hot Pressing Sintering

In this paper, AlCrFeNi high entropy alloy coating was fabricated on the surface of Q235 steel using hot pressing sintering process. The coating has the controlled thickness size and excellent mechanical properties. Scanning electron microscopy (SEM), XRD and hardness testing method were used to study the morphology, phase structure and hardness of high entropy alloys coating. The lattice distortion plays a significant role in increasing the hardness. Coating formation mechanism caused by the element diffusion under the hot pressing effect is also discussed in the paper. Simultaneously, the dry sliding and oil lubrication wear tests, wear morphology observation and wear mechanism discussion were completed. As the result shows, AlCrFeNi high entropy alloys coating exhibits superior wear resistance either at dry sliding or oil lubrication tests owing to its hard high entropy solid solution structure.

Microstructure and Properties of MoFeCrTiW High-Entropy Alloy Coating Prepared by Laser Cladding

2013 ◽  
Vol 820 ◽  
pp. 63-66 ◽  
Author(s):  
Bo Zheng ◽  
Qi Bin Liu ◽  
Ling Yan Zhang
Keyword(s):  
Laser Cladding ◽  
Alloy Coating ◽  
Lattice Parameter ◽  
Alloy Layer ◽  
Middle Part ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Q235 Steel ◽  
High Entropy ◽  
Microstructure And Properties

To obtain high-entropy alloys (HEAS) coating with excellent properties on Q235 steel, a kind of HEAS powders was designed. The HEAS coating was prepared uniformly on Q235 steel by laser cladding. By means of OM, XRD and microhardness tester, the microstructure and properties of the high-entropy alloy layer were investigated. The experimental results indicate that the phases in the high-entropy alloy coating is mainly MoFeCrTiW with simple BCC, whose lattice parameter is a-3.1256Å. The microstructure in the coating is mainly cellular crystal, on which dispersion precipitates exist. And in the near bottom of the coating, there is few precipitates, in the middle part of coating, the precipitates are larger than that of bottom coating, while in near top of coating, dispersion precipitates become largest. The maximum microhardness value of coating reaches 800HV0.98.

scholarly journals Effect of Copper Addition on the AlCoCrFeNi High Entropy Alloys Properties via the Electroless Plating and Powder Metallurgy Technique

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 540
Author(s):  
Mohamed Ali Hassan ◽  
Hossam M. Yehia ◽  
Ahmed S. A. Mohamed ◽  
Ahmed Essa El-Nikhaily ◽  
Omayma A. Elkady
Keyword(s):  
Compressive Strength ◽  
Powder Metallurgy ◽  
Atomic Radius ◽  
The Other ◽  
High Entropy Alloy ◽  
Coating Process ◽  
High Entropy Alloys ◽  
Powder Metallurgy Technique ◽  
Copper Metal ◽  
High Entropy

To improve the AlCoCrFeNi high entropy alloys’ (HEAs’) toughness, it was coated with different amounts of Cu then fabricated by the powder metallurgy technique. Mechanical alloying of equiatomic AlCoCrFeNi HEAs for 25 h preceded the coating process. The established powder samples were sintered at different temperatures in a vacuum furnace. The HEAs samples sintered at 950˚C exhibit the highest relative density. The AlCoCrFeNi HEAs model sample was not successfully produced by the applied method due to the low melting point of aluminum. The Al element’s problem disappeared due to encapsulating it with a copper layer during the coating process. Because the atomic radius of the copper metal (0.1278 nm) is less than the atomic radius of the aluminum metal (0.1431 nm) and nearly equal to the rest of the other elements (Co, Cr, Fe, and Ni), the crystal size powder and fabricated samples decreased by increasing the content of the Cu wt%. On the other hand, the lattice strain increased. The microstructure revealed that the complete diffusion between the different elements to form high entropy alloy material was not achieved. A dramatic decrease in the produced samples’ hardness was observed where it decreased from 403 HV at 5 wt% Cu to 191 HV at 20 wt% Cu. On the contrary, the compressive strength increased from 400.034 MPa at 5 wt% Cu to 599.527 MPa at 15 wt% Cu with a 49.86% increment. This increment in the compressive strength may be due to precipitating the copper metal on the particles’ surface in the nano-size, reducing the dislocations’ motion, increasing the stiffness of produced materials. The formability and toughness of the fabricated materials improved by increasing the copper’s content. The thermal expansion has increased gradually by increasing the Cu wt%.

A review on phase prediction in high entropy alloys

2021 ◽  
pp. 095440622110089
Author(s):  
Vinay Kumar Soni ◽  
S Sanyal ◽  
K Raja Rao ◽  
Sudip K Sinha
Keyword(s):  
Solid Solution ◽  
Phase Formation ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Modeling Tools ◽  
High Entropy ◽  
Recent Developments ◽  
Phase Prediction ◽  
The Stability

The formation of single phase solid solution in High Entropy Alloys (HEAs) is essential for the properties of the alloys therefore, numerous approach were proposed by many researchers to predict the stability of single phase solid solution in High Entropy Alloy. The present review examines some of the recent developments while using computational intelligence techniques such as parametric approach, CALPHAD, Machine Learning etc. for prediction of various phase formation in multicomponent high entropy alloys. A detail study of this data-driven approaches pertaining to the understanding of structural and phase formation behaviour of a new class of compositionally complex alloys is done in the present investigation. The advantages and drawbacks of the various computational are also discussed. Finally, this review aims at understanding several computational modeling tools complying the thermodynamic criteria for phase formation of novel HEAs which could possibly deliver superior mechanical properties keeping an aim at advanced engineering applications.

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