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 High-Entropy Alloys: Formation and Properties

2018 ◽  
Author(s):  
Michael C. Gao ◽  
Paul D. Jablonski ◽  
Jeffrey A. Hawk ◽  
David E. Alman
Keyword(s):  
Density Functional ◽  
Thermomechanical Processing ◽  
Dynamics Simulation ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
Ongoing Research ◽  
High Entropy ◽  
Face Centered

This paper presents ongoing research at NETL aimed at gaining fundamental understanding of high-entropy alloys (HEAs) formation and their properties, and developing highperformance HEAs for high-temperature fossil energy applications. First-principles density functional theory (DFT), Monte Carlo simulation, and molecular dynamics simulation are carried out to predict enthalpy of formation, the entropy sources (i.e., configurational entropy, vibrational entropy, and electronic entropy), and elastic properties of model single-phase HEAs with the face-centered cubic, body-centered cubic and hexagonal closed-packed structures. Classical elastic theory, which considers the interactions between dislocations and elastic fields of solutes, has also been used to predict solid solution strengthening. Large-size (∼7.5 kg) HEAs ingots are produced using vacuum induction melting and electroslag remelting methods, followed by homogenization treatment resulting in greater than 99% homogeneity. Subsequent thermomechanical processing produces fully-wrought face-centered cubic microstructures. The tensile behavior for these alloys have been determined as a function of temperature, and based on these results screening creep tests have been performed at selected temperatures and stresses.

scholarly journals Microstructure and Mechanical Properties of TaNbVTiAlx Refractory High-Entropy Alloys

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 282 ◽  
Author(s):  
Li Xiang ◽  
Wenmin Guo ◽  
Bin Liu ◽  
Ao Fu ◽  
Jianbo Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
High Entropy Alloys ◽  
Strengthening Effect ◽  
High Entropy ◽  
Solid Solution Strengthening ◽  
Specific Strength ◽  
Compression Properties ◽  
Uniform Microstructure ◽  
Solution Strengthening

A series of TaNbVTiAlx (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) refractory high-entropy alloys (RHEAs) with high specific strength and reasonable plasticity were prepared using powder metallurgy (P/M) technology. This paper studied their microstructure and compression properties. The results show that all the TaNbVTiAlx RHEAs exhibited a single BCC solid solution microstructure with no elemental segregation. The P/M TaNbVTiAlx RHEAs showed excellent room-temperature specific strength (207.11 MPa*cm3/g) and high-temperature specific strength (88.37 MPa*cm3/g at 900 °C and 16.03 MPa*cm3/g at 1200 °C), with reasonable plasticity, suggesting that these RHEAs have potential to be applied at temperatures >1200 °C. The reasons for the excellent mechanical properties of P/M TaNbVTiAl0.2 RHEA were the uniform microstructure and solid solution strengthening effect.

scholarly journals Nanoporous Quasi-High-Entropy Alloy Microspheres

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 345 ◽  
Author(s):  
Lianzan Yang ◽  
Yongyan Li ◽  
Zhifeng Wang ◽  
Weimin Zhao ◽  
Chunling Qin
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Specific Surface Area ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Hierarchical Porous

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.

scholarly journals Effects of Different Contents of Each Component on the Structural Stability and Mechanical Properties of Co-Cr-Fe-Ni High-Entropy Alloys

2021 ◽  
Vol 11 (6) ◽  
pp. 2832
Author(s):  
Haibo Liu ◽  
Cunlin Xin ◽  
Lei Liu ◽  
Chunqiang Zhuang
Keyword(s):  
Mechanical Properties ◽  
Structural Stability ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
Obvious Effect ◽  
High Entropy ◽  
Precise Control ◽  
Component Content ◽  
Face Centered ◽  
And Performance

The structural stability of high-entropy alloys (HEAs) is closely related to their mechanical properties. The precise control of the component content is a key step toward understanding their structural stability and further determining their mechanical properties. In this study, first-principle calculations were performed to investigate the effects of different contents of each component on the structural stability and mechanical properties of Co-Cr-Fe-Ni HEAs based on the supercell model. Co-Cr-Fe-Ni HEAs were constructed based on a single face-centered cubic (FCC) solid solution. Elemental components have a clear effect on their structure and performance; the Cr and Fe elements have an obvious effect on the structural stability and equilibrium lattice constant, respectively. The Ni elements have an obvious effect on stiffness. The Pugh ratios indicate that Cr and Ni addition may increase ductility, whereas Co and Fe addition may decrease it. With increasing Co and Fe contents or decreasing Cr and Ni contents, the structural stability and stiffness of Co-Cr-Fe-Ni HEAs are improved. The structural stability and mechanical properties may be related to the strength of the metallic bonding and covalent bonding inside Co-Cr-Fe-Ni HEAs, which, in turn, is determined by the change in element content. Our results provide the underlying insights needed to guide the optimization of Co-Cr-Fe-Ni HEAs with excellent mechanical properties.

Mechanical properties of high-entropy alloys with emphasis on face-centered cubic alloys

2019 ◽  
Vol 102 ◽  
pp. 296-345 ◽  
Author(s):  
Zezhou Li ◽  
Shiteng Zhao ◽  
Robert O. Ritchie ◽  
Marc A. Meyers
Keyword(s):  
Mechanical Properties ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Face Centered

scholarly journals Compositional Design of Soft Magnetic High Entropy Alloys by Minimizing Magnetostriction Coefficient in (Fe0.3Co0.5Ni0.2)100−x(Al1/3Si2/3)x System

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 382 ◽  
Author(s):  
Yong Zhang ◽  
Min Zhang ◽  
Dongyue Li ◽  
Tingting Zuo ◽  
Kaixuan Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Base Alloy ◽  
Soft Magnetic Materials ◽  
Tensile Yield Strength ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
Soft Magnetic ◽  
High Entropy ◽  
Wide Range ◽  
Magnetostriction Coefficient

Developing cost-effective soft magnetic alloys with excellent mechanical properties is very important to energy-saving industries. This study investigated the magnetic and mechanical properties of a series of (Fe0.3Co0.5Ni0.2)100−x(Al1/3Si2/3)x high-entropy alloys (HEAs) (x = 0, 5, 10, 15, and 25) at room temperature. The Fe0.3Co0.5Ni0.2 base alloy composition was chosen since it has very the smallest saturation magnetostriction coefficient. It was found that the (Fe0.3Co0.5Ni0.2)95(Al1/3Si2/3)5 alloy maintains a simple face-centered cubic (FCC) solid solution structure in the states of as-cast, cold-rolled, and after annealing at 1000 °C. The alloy after annealing exhibits a tensile yield strength of 235 MPa, ultimate tensile strength of 572 MPa, an elongation of 38%, a saturation magnetization (Ms) of 1.49 T, and a coercivity of 96 A/m. The alloy not only demonstrates an optimal combination of soft magnetic and mechanical properties, it also shows advantages of easy fabrication and processing and high thermal stability over silicon steel and amorphous soft magnetic materials. Therefore, the alloy of (Fe0.3Co0.5Ni0.2)95(Al1/3Si2/3)5 holds good potential as next-generation soft magnets for wide-range industrial applications.

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 the W-Ni-Co System Refractory High-Entropy Alloys

2015 ◽  
Vol 816 ◽  
pp. 324-329 ◽  
Author(s):  
Hui Jiang ◽  
Li Jiang ◽  
Yi Ping Lu ◽  
Tong Min Wang ◽  
Zhi Qiang Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Melting Temperatures ◽  
Arc Melting ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Face Centered

The elements Mo, Cr and V were added to the W-Ni-Co system high entropy alloys, the effects of these added elements on microstructure and mechanical properties of these alloys were studied. The alloys were produced by vacuum arc melting. The compositions were W0.5Ni2Co2VMo0.5,W0.5Ni2Co2VCr0.5and W0.5Ni2Co2CrMo0.5(denoted as Alloy 1, Alloy 2 and Alloy 3) respectively. The theoretical melting temperatures were higher than 2000 K. X-ray diffraction, SEM and energy dispersive spectroscopy (EDS) results indicated that the matrix of the alloys is face-centered cubic (FCC) solid-solution, the alloys showed dendrite crystal structure. Ni, Co elements were enriched in the dendrite areas, the W, Mo were enriched in the inter-dendrite regions ,while V, Cr elements were uniform distribution. The Vickers hardness of these alloys was 376.1 HV, 255.88 HV and 306.8 HV, respectively. The yield strength values (σ0.2) of Alloy 1, Alloy 2 and Alloy 3 were approximately 1000MPa, 750MPa, 250MPa, respectively. The alloys show good compression plasticity deformation capacity at RT.

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.

Sign in / Sign up

Export Citation Format

Share Document