Physicomechanical and design characteristics of surface high-entropy alloys

2021 ◽  
pp. 146442072199748
Author(s):  
Peter Rusinov ◽  
Zhesfina Blednova
Keyword(s):  
Thermomechanical Treatment ◽  
Structural Phase ◽  
Mechanical Tests ◽  
Theoretical Strength ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Cyclic Durability ◽  
Design Characteristics ◽  
Experimental Values ◽  
Surface Modified

We investigated the phase composition of high-entropy shape memory alloys CoCuTiZrHf, NiCoTiZrHf, NiCuTiZrHf, ZrCuNiCoTi, TiNiZrHfCoCu after HVOF, thermomechanical treatment and thermal cycling. We have also developed criteria for calculating the energy capacity, enthalpy, entropy, theoretical strength of high-entropy alloys, taking into account the chemical composition and structural-phase state according to the results of X-ray phase analysis. We proposed a criterion for assessing the damageability of high-entropy alloys. The article describes calculations of energy consumption, entropy, enthalpy, theoretical strength of high-entropy alloys CoCuTiZrHf, NiCoTiZrHf, NiCuTiZrHf, ZrCuNiCoTi, TiNiZrHfCoCu both after HVOF and after thermomechanical treatment. After full-scale mechanical tests of surface-modified layers of high-entropy materials for bending with rotation, we obtained experimental values of cyclic durability and plotted fatigue curves. The calculated assessment of the cyclic durability was carried out according to the developed mathematical criteria. We calculated the damageability of high-entropy alloys and constructed the graphical curves of the dependence of the damageability on the cyclic life.

Microstructure and Mechanical Tests of AlNiMnZnCu High Entropy Alloys

2014 ◽  
Vol 1036 ◽  
pp. 95-100
Author(s):  
Iulia Florea ◽  
Gheorghe Buluc ◽  
Radu Comaneci ◽  
Oana Baltatescu ◽  
Nicanor Cimpoesu ◽  
...  
Keyword(s):  
Binary Systems ◽  
Induction Furnace ◽  
Testing Machine ◽  
Mechanical Tests ◽  
Great Promise ◽  
High Entropy Alloys ◽  
Nickel Aluminum ◽  
Cobalt Chromium ◽  
High Entropy ◽  
Five Elements

High entropy alloys (HEAs) are a newly developed family of multi-component alloys composed of several major alloying elements, such as copper, nickel, aluminum, cobalt, chromium, iron, silicon, titanium, etc. The fact that HEA alloys is formed participation molar is approximately equal with at least five elements, entropy configuration is double that of binary systems, entitles us to call them "high entropy alloys'. Recent studies suggested that the refractory HEAs exhibited great promise for high temperature structural materials. This alloy can be processed and analyzed as an ordinary material AlNiMnZnCu high-entropy alloys are prepared by an induction furnace. The microstructure and properties of alloy samples were examined by SEM and testing machine for obtained materials. Mechanical tests were made with a INSTRON 3382 machine.

scholarly journals High-entropy alloys: Structure, mechanical properties, deformation mechanisms and application

2021 ◽  
Vol 64 (4) ◽  
pp. 249-258
Author(s):  
K. A. Osintsev ◽  
V. E. Gromov ◽  
S. V. Konovalov ◽  
Yu. F. Ivanov ◽  
I. A. Panchenko
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Yield Strength ◽  
High Strength ◽  
Mechanical Tests ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Temperature Range ◽  
Deformation Curves ◽  
Fcc Lattice

The article considers a brief review of the foreign publications on the study of the structure, phase composition and properties of five-component high-entropy alloys (HEAs) in different structural states in a wide temperature range over the past two decades. HEAs attract the attention of scientists with their unique and unusual properties. The difficulties of comparative analysis and generalization of data are noted due to different methods of obtaining HEAs, modes of mechanical tests for uniaxial compression and tension, sizes and shapes of the samples, types of thermal treatments, and phase composition (bcc and fcc crystal lattices). It is noted that the HEA with a bcc lattice has mainly high strength and low plasticity, and the HEA  with a fcc lattice has low strength and increased plasticity. A significant increase in the properties of the FeMnCoCrNi HEA with a fcc lattice can be achieved by alloying with boron and optimizing the parameters of thermal mechanical treatment at alloying with carbon in the amount of 1 % (at.). The deformation curves analyzed in the temperature range –196 ÷ 800 °C indicate an increase in the yield strength with a decrease in the grain size from 150 to 5 microns. As the temperature decreases, the yield strength and elongation increase. The effect of deformation rate on the mechanical properties is an increase in the ultimate strength and yield strength, which is most noticeable at high rates of 10–2 ÷ 103 s–1. The features of HEAs deformation behavior in the mono- and poly-crystalline states are noted. The complex of high operational properties of HEAs makes it possible to use them in various industries. There are good prospects of using energy treatment to modify the surface layers and further improve HEAs properties.

High-Entropy Alloys as Catalysts for the CO2 and CO Reduction Reactions

2019 ◽  
Author(s):  
Jack Pedersen ◽  
Thomas Batchelor ◽  
Alexander Bagger ◽  
Jan Rossmeisl
Keyword(s):  
Density Functional ◽  
Rational Design ◽  
Hydrogen Adsorption ◽  
Co Adsorption ◽  
Reduction Reaction ◽  
Supervised Machine Learning ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Co Reduction ◽  
Disordered Alloy

Using the high-entropy alloys (HEAs) CoCuGaNiZn and AgAuCuPdPt as starting points we provide a framework for tuning the composition of disordered multi-metallic alloys to control the selectivity and activity of the reduction of carbon dioxide (CO2) to highly reduced compounds. By combining density functional theory (DFT) with supervised machine learning we predicted the CO and hydrogen (H) adsorption energies of all surface sites on the (111) surface of the two HEAs. This allowed an optimization for the HEA compositions with increased likelihood for sites with weak hydrogen adsorption{to suppress the formation of molecular hydrogen (H2) and with strong CO adsorption to favor the reduction of CO. This led to the discovery of several disordered alloy catalyst candidates for which selectivity towards highly reduced carbon compounds is expected, as well as insights into the rational design of disordered alloy catalysts for the CO2 and CO reduction reaction.

Effect of the structure of vacuum condensates of high entropy alloys of Cr–Fe–Co–Ni–Cu system on their mechanical properties

2020 ◽  
Vol 2020 (4) ◽  
pp. 16-22
Author(s):  
A.I. Ustinov ◽  
◽  
V.S. Skorodzievskii ◽  
S.A. Demchenkov ◽  
S.S. Polishchuk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Vacuum Condensates
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