scholarly journals High-Temperature Wear Behaviour of Spark Plasma Sintered AlCoCrFeNiTi0.5 High-Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 582 ◽  
Author(s):  
Martin Löbel ◽  
Thomas Lindner ◽  
Robert Pippig ◽  
Thomas Lampke
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Bulk Material ◽  
Wear Behaviour ◽  
High Entropy Alloy ◽  
Protective Oxide ◽  
Spherical Powder ◽  
High Entropy ◽  
Spark Plasma

In this study, the wear behaviour of a powder metallurgically produced AlCoCrFeNiTi0.5 high-entropy alloy (HEAs) is investigated at elevated temperatures. Spark plasma sintering (SPS) of inert gas atomised feedstock enables the production of dense bulk material. The microstructure evolution and phase formation are analysed. The high cooling rate in the atomisation process results in spherical powder with a microstructure comprising two finely distributed body-centred cubic phases. An additional phase with a complex crystal structure precipitates during SPS processing, while no coarsening of microstructural features occurs. The wear resistance under reciprocating wear conditions increases at elevated temperatures due to the formation of a protective oxide layer under atmospherical conditions. Additionally, the coefficient of friction (COF) slightly decreases with increasing temperature. SPS processing is suitable for the production of HEA bulk material. An increase in the wear resistance at elevated temperature enables high temperature applications of the HEA system AlCoCrFeNiTi0.5.

scholarly journals Enhanced Wear Behaviour of Spark Plasma Sintered AlCoCrFeNiTi High-Entropy Alloy Composites

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2225 ◽  
Author(s):  
Martin Löbel ◽  
Thomas Lindner ◽  
Thomas Lampke
Keyword(s):  
Wear Resistance ◽  
High Hardness ◽  
Solid Lubricants ◽  
Wear Behaviour ◽  
High Entropy Alloy ◽  
Surface Protection ◽  
High Entropy ◽  
Production Route ◽  
The Coefficient Of Friction ◽  
Spark Plasma

High hardness and good wear resistance have been revealed for the high-entropy alloy (HEA) system AlCoCrFeNiTi, confirming the potential for surface protection applications. Detailed studies to investigate the microstructure and phase formation have been carried out using different production routes. Powder metallurgical technologies allow for much higher flexibility in the customisation of materials compared to casting processes. Particularly, spark plasma sintering (SPS) enables the fast processing of the feedstock, the suppression of grain coarsening and the production of samples with a low porosity. Furthermore, solid lubricants can be incorporated for the improvement of wear resistance and the reduction of the coefficient of friction (COF). This study focuses on the production of AlCoCrFeNiTi composites comprising solid lubricants. Bulk materials with a MoS2 content of up to 15 wt % were produced. The wear resistance and COF were investigated in detail under sliding wear conditions in ball-on-disk tests at room temperature and elevated temperature. At least 10 wt % of MoS2 was required to improve the wear behaviour in both test conditions. Furthermore, the effects of the production route and the content of solid lubricant on microstructure formation and phase composition were investigated. Two major body-centred cubic (bcc) phases were detected in accordance with the feedstock. The formation of additional phases indicated the decomposition of MoS2.

Wear resistance of FeCoCrNiMnAlx high-entropy alloy coatings at high temperature

2020 ◽  
Vol 512 ◽  
pp. 145736 ◽  
Author(s):  
Yan Cui ◽  
Junqi Shen ◽  
Sunusi Marwana Manladan ◽  
Keping Geng ◽  
Shengsun Hu
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
High Entropy Alloy ◽  
High Entropy

Non-equiatomic W10Mo27Cr21Ti22Al20 high-entropy alloy produced by mechanical alloying and spark plasma sintering: Phase evolution and mechanical properties

2022 ◽  
pp. 146442072110510
Author(s):  
Hamed Naser-Zoshki ◽  
Ali-Reza Kiani-Rashid ◽  
Jalil Vahdati-Khaki
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Elevated Temperatures ◽  
High Entropy Alloy ◽  
Solid Solution Phase ◽  
High Entropy ◽  
Plasma Sintering ◽  
Spark Plasma

In this work, non-equiatomic W10Mo27Cr21Ti22Al20 refractory high-entropy alloy (RHEA) was produced using mechanical alloying followed by spark plasma sintering. The phase formation, microstructure, and compressive mechanical properties of the alloy were studied. During mechanical alloying, a Body-centered cubic (BCC) solid solution phase with a particle size of less than 1 µm was obtained after 18 h ball milling. The microstructure of the sintered sample exhibits three distinct phases consisting of two solid solution phases BCC1 and BCC2 as well as fine TiCxOy precipitates distributed in them. The volume fractions of each phase were about 79%, 8%, and 13%, respectively. The sintered W10Mo27Cr21Ti22Al20 showed yield strengths of 2465, 1506, 405, and 290 MPa at room temperature 600, 1000, and 1200°C, respectively, which are about twice that of the same refractory high-entropy alloy produced by vacuum arc melting. At 1000 and 1200°C, the strength after yielding gradually increased to 970 and 718 MPa at a compressive strain of 60%. The studied refractory high-entropy alloy can have good potential in high-temperature applications due to its high specific strength at elevated temperatures compared to conventional Ni-based superalloys and most as-reported refractory high-entropy alloys.

scholarly journals High-throughput design of high-performance lightweight high-entropy alloys

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rui Feng ◽  
Chuan Zhang ◽  
Michael C. Gao ◽  
Zongrui Pei ◽  
Fan Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
High Throughput ◽  
High Throughput Screening ◽  
Elevated Temperatures ◽  
Alloy System ◽  
Computational Method ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Theoretical Understanding ◽  
High Entropy

AbstractDeveloping affordable and light high-temperature materials alternative to Ni-base superalloys has significantly increased the efforts in designing advanced ferritic superalloys. However, currently developed ferritic superalloys still exhibit low high-temperature strengths, which limits their usage. Here we use a CALPHAD-based high-throughput computational method to design light, strong, and low-cost high-entropy alloys for elevated-temperature applications. Through the high-throughput screening, precipitation-strengthened lightweight high-entropy alloys are discovered from thousands of initial compositions, which exhibit enhanced strengths compared to other counterparts at room and elevated temperatures. The experimental and theoretical understanding of both successful and failed cases in their strengthening mechanisms and order-disorder transitions further improves the accuracy of the thermodynamic database of the discovered alloy system. This study shows that integrating high-throughput screening, multiscale modeling, and experimental validation proves to be efficient and useful in accelerating the discovery of advanced precipitation-strengthened structural materials tuned by the high-entropy alloy concept.

scholarly journals New HfNbTaTiZr High-Entropy Alloy Coatings Produced by Electrospark Deposition with High Corrosion Resistance

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4333
Author(s):  
Ciprian Alexandru Manea ◽  
Mirela Sohaciu ◽  
Radu Stefănoiu ◽  
Mircea Ionuț Petrescu ◽  
Magdalena Valentina Lungu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Saline Solution ◽  
Bulk Material ◽  
High Entropy Alloy ◽  
High Corrosion Resistance ◽  
Electrospark Deposition ◽  
High Entropy ◽  
High Corrosion ◽  
Plasma Sintering ◽  
Spark Plasma

The aim of the present paper is to investigate an innovative high corrosion resistance coating realized by electrospark deposition. The coating material was fabricated from HfNbTaTiZr high-entropy alloy. HEA was produced by the mechanical alloying of Hf, Nb, Ta, Ti, and Zr high-purity powders in a planetary ball mill, achieving a good homogenization and a high alloying degree, followed by spark plasma sintering consolidation. The electrodes for electrospark deposition were cut and machined from the bulk material. Stainless steel specimens were coated and electrochemically tested for corrosion resistance in a 3.5% NaCl saline solution.

Welding Parameters and their Influence on the Abrasion Resistance of Structural Steels at Elevated Temperatures

2016 ◽  
Vol 721 ◽  
pp. 461-466 ◽  
Author(s):  
Harald Rojacz ◽  
Hannes Pahr ◽  
Susanne Baumgartner ◽  
Karl Adam ◽  
Markus Varga
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Abrasion Resistance ◽  
Elevated Temperatures ◽  
Hardness Test ◽  
Industrial Applications ◽  
Structural Steels ◽  
Wear Behaviour ◽  
Welding Parameters ◽  
Hot Hardness

In several industrial applications wear resistance of structural steels is required. Also enhanced temperature can occur when handling hot materials, e.g. in steel industry. Within this study a low alloyed structural steel (carbon steel S355) and a high temperature (HT) 9 % Cr steel ASTM A332 P92 were chosen for investigation. Repair welds with flux cored wires which are often required in applications were investigated, aiming on the role of interpass temperatures, the resulting effect of cooling conditions on the microstructure and their HT abrasion resistance. The influence of different microstructural parameters such as phase content, processing and the resulting temperature-hardness coherence on the wear resistance are evaluated within a high temperature abrasion test and a hot hardness test rig. Results indicate a strong influence of interpass temperature and heat input on the hot hardness and wear behaviour of welded structural steels.

scholarly journals Effects of W Alloying on the Lattice Distortion and Wear Behavior of Laser Cladding AlCoCrFeNiWx High-Entropy Alloy Coatings

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5450
Author(s):  
Tao Wu ◽  
Yunxiang Chen ◽  
Shuqin Shi ◽  
Mengting Wu ◽  
Wanyuan Gui ◽  
...  
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Hot Working ◽  
High Entropy Alloy ◽  
Die Steel ◽  
High Entropy ◽  
High Temperature Wear ◽  
Hot Working Die Steel

Friction and wear properties of hot working die steel at above 800 °C are of particular interest for high temperature applications. Here, novel AlCoCrFeNiWx high-entropy alloy (HEA) coatings have been fabricated on the surface of hot working die steel by laser cladding. The effects of the as-prepared AlCoCrFeNiWx HEA coatings on the microstructure and high temperature friction and wear behavior of hot working die steel are investigated through scanning electron microscopy (SEM), electron probe microanalysis (EPMA), X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS). Having benefited from the formation of W-rich intermetallic compounds after the addition of W elements, the high temperature wear resistance of the coatings is obviously improved, and friction coefficient shows a large fluctuation. The microstructural characteristics of the AlCoCrFeNiWx HEA coatings after the high temperature wear resistance test shows a highly favorable impact on microstructure stability and wear resistance, due to its the strong lattice distortion effect of W element on BCC solid solutions and the second phase strengthening of the W-rich intermetallic compounds. These findings may provide a method to design the high temperature wear resistant coatings.

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