The Magnetic, Electronic, and Thermodynamic Properties of High Entropy Alloy CrMnFeCoNi: A First‐Principles Study

Abstract

A theoretical investigation into the electronic and thermodynamic properties of the high entropy alloy CrMnFeCoNi in nonmagnetic (NM) and ferrimagnetic (FIM) states based on first-principles calculations has been implemented. Compared with the NM state, there is an obvious localized distribution of charges between Cr and Mn atoms with the lower valence electronic concentration (VEC) in the FIM state, showing covalent characters. Different spin-polarized behaviors in compositional atoms have been proposed in the FIM state, suggesting the primary contribution to the total magnetic moment arises from the spin polarization of Fe d and Mn d states. Temperature-dependent Debye temperature θ D , heat capacity C V , and thermal expansion coefficient α as well as the total Helmholtz free energy F for both states have been investigated. Analysis of the contributions of configurational, electronic, magnetic, and vibrational free energy allows to infer the magnetic properties of the constituent atoms play an important role in the thermodynamics of CoCrFeMnNi high entropy alloy (HEA).

Machine Learning for Novel Thermal-Materials Discovery: Early Successes, Opportunities, and Challenges

“…Several methods have been employed to describe HEAs on the electronic scale 66 , including the virtual crystal approximation (VCA) 12 , coherent potential approximation (CPA) 67 , special quasi-random structures (SQS) 14,[68][69][70][71][72] , and molecular dynamics (MD) based methods [73][74][75] . Only a few studies have assessed the thermal conductivity of HEAs, using semi-empirical MD 76,77 .…”

High energy density liquid state asymmetric supercapacitor devices using Co–Cr–Ni–Fe–Mn high entropy alloy

“…22,23 TMHEAs are formed by mixing various metallic elements and have specific physicochemical characteristics, such as outstanding magnetic and electrical properties, and high thermomechanical stability when the size is decreased to nanometer range. 24,25 Also, TMHEAs exhibit more redox active sites, and their three-dimensional diffusion channels aid towards the easy flow of the electrolyte, 16 almost ending the limitations of poor cycling stability and material degradation during electrochemical tests. In this regard, various TMHEAs and their oxides have been studied with different morphologies, such as nanoporous, 26 quasi spherical, 27 and nano agglomerations, 28 along with some HEA composites, such as rHEA-CNT, 29 MnO 2 -FeCrCoMnNiAl 0.75 , 30 and HEAnitrides, 31 for supercapacitor applications.…”

Temperature-Dependent Configurational Entropy Calculations for Refractory High-Entropy Alloys

“…However, the small system sizes accessible in DFT calculations can drastically affect the many-body correlations and the entropy of mixing. [2] On the other hand, in the case of stainless steel (consisting of Cr, Fe, Mn, Mo, and Ni), Wang et al [14] reported that vibrational entropy contributions are higher than TDS ideal at temperatures above 600 K. At temperatures less than 600 K, even though the configurational entropy calculated is higher than the other contributions, it is not clear if this is valid for the actual configurational entropy contribution, which is supposed to be lower than DS ideal . Thus, a systematic analysis of the temperature dependence of the short range order and the configurational entropy is also important because many solid solution HEA design guidelines that use DS ideal have been proposed in the literature.…”