scholarly journals Re-Melting Behaviour and Wear Resistance of Vanadium Carbide Precipitating Cr27.5Co14Fe22Mo22Ni11.65V2.85 High Entropy Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1871
Author(s):  
Kai Treutler ◽  
Swenja Lorenz ◽  
Volker Wesling
Keyword(s):  
Vanadium Carbide ◽  
Wear Behavior ◽  
Base Alloy ◽  
Cast Alloy ◽  
Early Stage ◽  
Welding Process ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Vanadium Carbides

High entropy alloys (HEAs) are among of the most promising new metal material groups. The achievable properties can exceed those of common alloys in different ways. Due to the mixture of five or more alloying elements, the variety of high entropy alloys is fairly huge. The presented work will focus on some first insights on the weldability and the wear behavior of vanadium carbide precipitation Cr27.5Co14Fe22Mo22Ni11.65V2.85 HEA. The weldability should always be addressed in an early stage of any alloy design to avoid welding-related problems afterwards. The cast Cr27.5Co14Fe22Mo22Ni11.65V2.85 HEA has been remelted using a TIG welding process and the resulting microstructure has been examined. The changes in the microstructure due to the remelting process showed little influence of the welding process and no welding-related problems like hot cracks have been observed. It will be shown that vanadium carbides or vanadium-rich phases precipitate after casting and remelting in a two phased HEA matrix. The hardness of the as cast alloy is 324HV0.2 and after remelting the hardness rises to 339HV0.2. The wear behavior can be considered as comparable to a Stellite 6 cobalt base alloy as determined in an ASTM G75 test. Overall, the basic HEA design is promising due to the precipitation of vanadium carbides and should be further investigated.

scholarly journals Effect of V and Ti on the Oxidation Resistance of WMoTaNb Refractory High-Entropy Alloy at High Temperatures

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 41
Author(s):  
Shuaidan Lu ◽  
Xiaoxiao Li ◽  
Xiaoyu Liang ◽  
Wei Yang ◽  
Jian Chen
Keyword(s):  
Oxidation Resistance ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Early Stage ◽  
Mass Gain ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Entropy

Alloying with V and Ti elements effectively improves the strength of WMoTaNb refractory high entropy alloys (RHEAs) at elevated temperatures. However, their effects on the oxidation resistance of WMoTaNb RHEAs are unknown, which is vitally important to their application at high temperatures. In this work, the effect of V and Ti on the oxidation behavior of WMoTaNb RHEA at 1000 °C was investigated using a thermogravimetric system, X-ray diffraction and scanning electron microscopy. The oxidation of all alloys was found to obey a power law passivating oxidation at the early stage. The addition of V aggravates the volatility of V2O5, MoO3 and WO3, and leads to disastrous internal oxidation. The addition of Ti reduces the mass gain in forming the full coverage of passivating scale and prolongs the passivation duration of alloys.

scholarly journals Application of Nano High-Entropy Alloys to Reduce Energy Consumption and Wear of Copper Oxide and High-Grade Iron Ores in Heavy Mining Industries—A Case Study

Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 16
Author(s):  
Mohammadreza Heydartaemeh ◽  
Mohammad Karamoozian ◽  
Herman Potgieter
Keyword(s):  
Copper Oxide ◽  
Alloy Steel ◽  
Base Alloy ◽  
International Markets ◽  
Work Piece ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
High Grade ◽  
Iron Ores ◽  
High Entropy

Problems relating to the abrasion of equipment is one of the most important issues in mining and associated industries. Hardening is a method of protecting metal equipment, metal tools, or important components against erosion, corrosion, and abrasion. This can be achieved by welding a thin layer of abrasion-resistant metal onto the surface of the work piece. The useful life of a piece of equipment or parts can be significantly increased by applying abrasion-resistant coatings, thereby reducing repair or replacement costs associated with damaged parts. This process is inexpensive in the production of parts and is often economically justifiable. This study focuses on measuring the abrasion resistance of a nano high-entropy alloy against copper oxide and high-grade iron ores. When a base alloy was coated with the nano high-entropy alloy, the abrasion indexes of iron and copper ores decreased from 0.0001647 kg to 0.0000908 kg and from 0.0001472 kg to 0.0000803 kg, respectively. The standard deviation, repeatability, and reproducibility were calculated for the alloy steel blade covered with nano high entropy alloy (N-HEA), producing values of 0.00016, 0.00047, and 0.00040, respectively, while a standard alloy steel blade exhibited values of 0.0003, 0.00047, and 0.00042, respectively. High-entropy alloys and high-entropy nano-alloys have not been used as practical coatings in the mineral industry in any form to date. Utilizing high-entropy nano-alloys in this industry would introduce innovative alternatives for customers, thereby increasing competitive advantages and providing international markets and customers = with the most efficient choices of operational materials.

scholarly journals Wear Behavior and Tribological Evolution of High Entropy Alloys

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.

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.

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.

Wear behavior of HVOF-sprayed Al0.6TiCrFeCoNi high entropy alloy coatings at different temperatures

2019 ◽  
Vol 358 ◽  
pp. 215-222 ◽  
Author(s):  
Lijia Chen ◽  
Kirsten Bobzin ◽  
Zheng Zhou ◽  
Lidong Zhao ◽  
Mehmet Öte ◽  
...  
Keyword(s):  
Wear Behavior ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Different Temperatures

scholarly journals Influence of Aluminum and Molybdenum on the Microstructure and Corrosion Behavior of Thermally Sprayed High-Entropy Alloy Coatings

2021 ◽  
Author(s):  
Martin Löbel ◽  
Thomas Lindner ◽  
Maximilian Grimm ◽  
Lisa-Marie Rymer ◽  
Thomas Lampke
Keyword(s):  
Corrosion Resistance ◽  
Protective Coatings ◽  
Base Alloy ◽  
Alloy System ◽  
High Entropy Alloy ◽  
Oxide Content ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Structural And Functional Properties ◽  
Wide Range

AbstractHigh-entropy alloys (HEAs) have shown a wide range of promising structural and functional properties. By the application of coating technology, an economical exploitation can be achieved. The high wear and corrosion resistance of HEAs make them particularly interesting for the application as protective coatings. Especially for alloys with a high chromium content, a high corrosion resistance has been revealed. For the current investigations, the equimolar HEA CrFeCoNi with a single-phase face centered cubic structure is considered as a base alloy system. To increase the corrosion resistance as well as the hardness and strength, the influence of the alloying elements aluminum and molybdenum is analyzed. For the current investigations, the high kinetic process high-velocity oxygen fuel thermal spraying (HVOF) has been considered to produce coatings with a low porosity and oxide content. Feedstock is produced by inert gas atomization. The influence of the alloy composition on the microstructure, phase formation and resulting property profile is studied in detail. A detailed analysis of the corrosion resistance and underlying mechanisms is conducted. The pitting and passivation behavior are investigated by potentiodynamic polarization measurements in NaCl and H2SO4 electrolyte. A distinct improvement of the corrosion resistance can be achieved for the alloy Al0.3CrFeCoNiMo0.2.

Compression stress strengthening modelling of a ultrafine-grained equiatomic SPS CoCrFeNiNb high-entropy alloy

2020 ◽  
pp. 095440622094324
Author(s):  
Marcello Cabibbo ◽  
Filip Průša ◽  
Alexandra Šenková ◽  
Andrea Školáková ◽  
Vojtěch Kučera ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Oxide Phase ◽  
High Entropy Alloy ◽  
Induction Melting ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma

High-entropy alloys are known to show exceptionally high mechanical properties, both compression and tensile strength, and unique physical properties, such as their phase stability. These quite unusual properties are primarily due to the microstructure generated by mechanical alloying processes, such as conventional induction arc melting, powder metallurgy, or mechanical alloying. In the present study, an equiatomic CoCrFeNiNb high-entropy alloy was prepared by a sequence of conventional induction melting, powder metallurgy, and compaction via spark plasma sintering. The high-entropy alloys showed uniform sub-micrometer grain microstructure consisted by a mixture of an fcc solid solution strengthened by a hcp Laves phase and a third intergranular oxide phase. The as-cast high-entropy alloys showed an ultimate compression strength (UCS) of ∼1400 MPa, which after sintering and compaction at 1273 K increased up to ∼2400 MPa. Extensive transmission electron microscopy quantitative analyses were carried out to model the UCS. A quite good agreement between the microstructure-strengthening model and the experimental UCS was found.

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