scholarly journals Effect of Mo Element on the Mechanical Properties and Tribological Responses of CoCrFeNiMox High-Entropy Alloys

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 486
Author(s):  
Ying Liu ◽  
Yongxin Xie ◽  
Shaogang Cui ◽  
Yanliang Yi ◽  
Xuewei Xing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Volume Fraction ◽  
Molar Ratio ◽  
High Entropy Alloys ◽  
Wear Properties ◽  
High Entropy ◽  
Chemical Content ◽  
Friction And Wear Properties ◽  
Mo Content

Certain amounts of precipitate in CoCrFeNiMox (simplified as Mox) is beneficial to the wear resistance; however, the optimal chemical content of Mo and the anti-wear mechanism behind it remains unclear. The Mox (x = 0, 0.3, 0.5, 1, 1.5 in molar ratio) high entropy alloys (HEAs) were manufactured, the evolution of their microstructure, mechanical, friction, and wear properties with Mo content was studied. The results displayed that the mechanical properties of the FCC solid solution were enhanced from Mo0 to Mo0.3, then kept unchanged till x = 1.5. The volume fraction of the precipitates increased with Mo content. The Mo1 presents the lower average friction coefficient and wear rate, attributed to the desired types, amount, size, distribution of the hard σ and μ phases in the ductile FCC solid solution. The detailed mechanism behind their tribological behaviors were discussed in the manuscript.

Effect of Interstitial Elements on the Cryogenic Mechanical Behavior of FCC High Entropy Alloys

2021 ◽  
Vol 1016 ◽  
pp. 1386-1391
Author(s):  
Anastasia Semenyuk ◽  
Margarita Klimova ◽  
Sergey Zherebtsov ◽  
Nikita Stepanov
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Thermomechanical Processing ◽  
Induction Melting ◽  
High Entropy Alloys ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
High Entropy ◽  
C And N ◽  
Interstitial Elements

High entropy alloys (HEAs) with face-centered cubic (fcc) structure, namely equiatomic CoCrFeMnNi alloy, have attracted considerable attention because of impressive cryogenic mechanical properties – strength, ductility, and fracture toughness. Further increase of the properties can be achieved, for example, by proper alloying. A particularly attractive option is the addition of interstitial elements like carbon or nitrogen. In present work, a series of CoCrFeMnNi-based alloys with different amounts of C and N (0-2 at.%) was prepared by induction melting. The alloys doped with C had lower Cr content to increase the solubility of carbon in the fcc solid solution. It was revealed that the solid solution strengthening effect of both C and N is significantly increased when the testing temperature decreases from 293K to 77K. The effect of thermomechanical processing on the structure and mechanical properties of the alloys is analyzed.

scholarly journals Effect of Mo Addition on The Microstructure and Mechanical Properties of CoCuFeNi High Entropy Alloy

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1017
Author(s):  
Yang Shao ◽  
Huan Ma ◽  
Yibing Wang
Keyword(s):  
Mechanical Properties ◽  
Solution Structure ◽  
Tensile Tests ◽  
Atomic Ratio ◽  
Vacuum Arc ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Microstructure And Mechanical Properties ◽  
Mo Content

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.

Microstructural Characterization and Mechanical Properties of Laser Deposited High Entropy Alloys

2014 ◽  
Vol 783-786 ◽  
pp. 2370-2375
Author(s):  
Harihar Sistla ◽  
Joseph W. Newkirk ◽  
F. Frank Liou
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Microstructural Characterization ◽  
Alloy System ◽  
Lattice Parameter ◽  
Laser Deposition ◽  
Advanced Materials ◽  
Mechanical And Thermal Properties ◽  
High Entropy Alloys ◽  
High Entropy

High entropy alloys have attracted great interest due to their flexibility in composition accompanied with very interesting properties, which make these materials candidates for further research. The formation of single solid solution phases as a preference to complex mixtures of intermetallic phases leads to good mechanical and thermal properties. Additive manufacturing in the form of Laser deposition presents us with a very unique way to manufacture near net shape metallic components with advanced materials. The present study focusses on the characterization of High entropy alloys manufactured through laser deposition. The alloy system considered for this study is (AlFeCoCrNi). The ratio of aluminum to nickel was decreased to observe the transition of the solid solution from a BCC structure to a FCC structure. The lattice parameter increased from .288 nm to .357 nm and the hardness decreased from Hv 670 to Hv 149 respectively. The effect of composition on thermodynamic variables, microstructure and mechanical properties were analyzed.

Microstructure and Mechanical Properties of FeNiCrCuAl High Entropy Alloys

2014 ◽  
Vol 1036 ◽  
pp. 101-105
Author(s):  
Gheorghe Buluc ◽  
Iulia Florea ◽  
Oana Bălţătescu ◽  
Costel Roman ◽  
Ioan Carcea
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
High Hardness ◽  
High Strength ◽  
High Entropy Alloys ◽  
Engineering Applications ◽  
High Entropy ◽  
Good Thermal Stability ◽  
Microstructure And Mechanical Properties ◽  
Wide Range

This paper presents the microstructure and the mechanical properties of FeNiCrCuAl high entropy alloys. The microstructure and mechanical properties of the annealed FeNiCrCuAl high entropy alloys were investigated using scanning electron microscopy, and X-ray diffraction. High entropy alloys have been known as a new type of materials and have been defined as having five or more principal elements, each one having a concentration between 5 and 35 at.%. Previous researches show that HEAs can be processed to form simple solid solution structures instead of intermetallics and other complicated compounds. This phenomenon is commonly attributed to the high configurational entropy in the solid solution state of HEAs. Furthermore, HEAs have also exhibited interesting properties such as high hardness and high strength, good thermal stability outstanding wear and oxidation resistance which offer great potential for engineering applications. The HEA systems explored in the past decade show that metallic elements are the most commonly used, e.g. Al, Cr, Fe, Co, Ni, Cu,Ti, etc. A wide range of HEAs exhibit high hardness, high strength, distinctive electrical and magnetic properties, high-temperature softening resistance, as well as favorable combination of compression strength and ductility. This combination of properties and the particular structures of HEAs are attractive for a number of potential engineering applications.

Tailoring Microstructures and Mechanical Properties of AlCoCrFeNiTi0.3 High-Entropy Alloys by Heat Treatment

2013 ◽  
Vol 745-746 ◽  
pp. 768-774 ◽  
Author(s):  
Jun Wei Qiao ◽  
Y.F. Wang ◽  
R.Q. Wang ◽  
J.Y. Shi ◽  
S.B. Sang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Volume Fraction ◽  
Treatment Temperature ◽  
High Entropy Alloys ◽  
Static Compression ◽  
High Entropy ◽  
Bcc Structure ◽  
Microstructures And Mechanical Properties ◽  
Quasi Static Compression

The microstructures and mechanical properties of AlCoCrFeNi0.3 high-entropy alloys (HEAs) are tailored through heat treatment. During heat treatment, the dendrite phase with a body-centered-cubic (bcc) structure transformed into the interdendrite phase with a bcc structure. Due to the element accumulation with higher hardness in the interdendrites and the increase of volume fraction of interdendrites, the average hardness of AlCoCrFeNi0.3 HEAs increased with the heat-treatment temperature, and the highest hardness was 625 HV. After 500 heat treatment, the optimized mechanical properties under quasi-static compression were achieved, and the yielding strength and fracture plasticity were 2.30 GPa and 9 %, respectively. Upon dynamic loading, the mechanical properties of HEAs were greatly enhanced.

scholarly journals Strengthening Mechanisms in CoCrFeNiX0.4 (Al, Nb, Ta) High Entropy Alloys Fabricated by Powder Plasma Arc Additive Manufacturing

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 721
Author(s):  
Yupeng Zhang ◽  
Qingkai Shen ◽  
Xizhang Chen ◽  
Subramanian Jayalakshmi ◽  
Ramachandra Arvind Singh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Atomic Radius ◽  
Eutectic Structure ◽  
Precipitation Strengthening ◽  
High Entropy Alloys ◽  
Plasma Arc ◽  
High Entropy ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

In high entropy alloys (HEAs), the addition of large-size atoms results in lattice distortion and further leads to solid solution strengthening or precipitation strengthening. However, the relationship between atomic radius, solid solution strengthening and precipitation strengthening has not been discerned yet. In this work, CoCrFeNiX0.4 (X = Al, Nb, Ta, with an equi-atomic radius) HEAs were prepared by powder plasma arc additive manufacturing (PPA-AM) and evaluated for their mechanical properties. Compression and nano-indentation hardness tests showed that the HEA with Ta showed the best properties. The influence of atomic radius and solid solubility on solid solution strengthening was investigated and the main strengthening mechanism that determines the mechanical properties of the developed HEAs was analyzed. The results showed that (i) the CoCrFeNiAl0.4 alloy did not show any solid solution strengthening effect and that a clear relation between solid solution strengthening and atomic size was not observed; (ii) in both CoCrFeNiTa0.4 and CoCrFeNiNb0.4 HEAs, precipitation strengthening and grain boundary strengthening effects are observed, wherein the difference in mechanical properties between both the alloys can be mainly attributed to the formation of fine eutectic structure in CoCrFeNiTa0.4; and (iii) from the microstructural analyses, it was identified that, in the CoCrFeNiTa0.4 HEA, the location containing a fine eutectic structure is accompanied by the formation of low-angle grain boundaries (LAGBs), which is also the region where deformed grains gather, giving rise to improved mechanical strengthening.

Effect of Aging Treatment on Microstructure and Wear Properties of CoCrFeNiTiNbB1.25 High Entropy Alloys Coatings by Laser Cladding

2021 ◽  
Vol 13 (7) ◽  
pp. 1280-1288
Author(s):  
Lin Ding ◽  
Hongxin Wang ◽  
Xiumin Quan
Keyword(s):  
Abrasive Wear ◽  
Mass Loss ◽  
Laser Cladding ◽  
Volume Fraction ◽  
Aging Treatment ◽  
Treatment Temperature ◽  
High Entropy Alloys ◽  
Wear Properties ◽  
H13 Steel ◽  
High Entropy

ABSTRACTLaser cladding CoCrFeNiTiNbB1.25 high entropy alloys (HEAs) coatings on H13 steel was fabricated. The effect of aging treatment temperature on microstructure and wear resistance of the HEAS coatings was investigated. Results showed the phases of the HEAs coatings were not changed as the aging treatment increased, the volume fraction of TiB phase was firstly increased, then reduced. The diffraction peak of fcc phase was firstly shifted to the right, and then shifted to the left. The HEAs coatings consisted of typical dendrite, interdendritic eutectic and dispersed intermetallic compound after aging treatment, and the dendrite obviously was coarsened after aging treatment at 850 °C. Compared with HEAs coatings before aging treatment, the microhardness of the HEAs coatings was firstly increased as the aging treatment temperature increased, then decreased, and the mass loss was opposite. The microhardness and mass loss was decreased by 4.3% and 11.9%, respectively for the aging treatment at 750 °C. The wear mechanism of the HEAs coatings before aging treatment was the abrasive wear, and was the abrasive wear and adhesive wear after aging treatment.

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