High-entropy Alloys Research Articles

The effects of interstitial oxygen on mechanical properties of TiZrNb medium-entropy alloy over a wide temperature range

Interstitial oxygen plays an important role in the microstructure and mechanical properties of recently developed refractory high-entropy or complex concentrated alloys. However, the mechanical properties of the oxygen-doped complex concentrated refractory alloy over a wide temperature range remain unclear. In this work, the effect of interstitial oxygen on the mechanical behavior of TiZrNb medium-entropy alloys (MEAs) has been investigated. At room temperature (RT), the interstitial oxygen improves the yield strength and tensile ductility owing to interstitial solid-solution strengthening and strain-hardening enhancement. However, simultaneous improvement of the RT strength-ductility by adding interstitial oxygen comes at the expense of increasing the ductile-brittle transition temperature (DBTT). Furthermore, the high-temperature yield strength of TiZrNb alloy can be improved up to 800 °C with the addition of 2 at% oxygen. The results above provide valuable insight into the mechanical properties of TiZrNb MEA, which would contribute to optimizing the high-performance refractory complex concentrated alloys in various applications.

Grain-selective growth makes Al0.1CoCrFeNi high entropy alloys strong and ultra-ductile

The trade-off between strength and ductility of structural materials has always been a concern, and the pursuit of higher strength often comes with the inevitable sacrifice of ductility, which poses challenges for the design and manufacture of high-performance engineering materials. In this study, we introduce a novel concept called grain-selective growth (GSG) to address the strength-ductility trade-off by effectively triggering the strain hardening capacity of the single-phase FCC HEAs. Specifically, we prepared an Al0.1CoCrFeNi high-entropy alloy with a heterogeneous grain structure using cyclic rolling and annealing. By employing this approach, our GSG HEA achieves an ultra-ductility with ∼53% uniform elongation and an ultimate tensile strength of 1165 MPa. Rapidly accumulating geometrically necessary dislocations in the domain boundary region, as revealed through electron backscatter diffraction analysis, have led to the development of high-level heterogeneous deformation-induced (HDI) stress. In addition, we also observed synergistic strain hardening effects generated by various deformation mechanisms, such as dislocation pile-ups, stacking faults (SFs), deformation twinning, dislocation walls, and SF networks. This study provides valuable insights for the manufacturing of high-performance heterostructure materials, making it possible to develop advanced alloys with higher strength and ductility, suitable for a wide range of engineering applications.

Combinatorial Alloy Design: Renaissance in the Accelerated Development of High-Entropy Alloys

Combinatorial Alloy Design: Renaissance in the Accelerated Development of High-Entropy Alloys

Microstructure Evolution and Nanomechanical Behavior of Micro-Area in Molten Pool of Selective Laser Melting (CoCrNi)82Al9Ti9 High-Entropy Alloy

Microstructure Evolution and Nanomechanical Behavior of Micro-Area in Molten Pool of Selective Laser Melting (CoCrNi)82Al9Ti9 High-Entropy Alloy

Designing of high entropy alloys with high hardness: a metaheuristic approach

The near-infinite compositional space of high-entropy-alloys (HEAs) is a huge resource-intensive task for developing exceptional materials. In the present study, an algorithmic framework has been developed to optimize the composition of an alloy with chosen set of elements, aiming to maximize the hardness of the former. The influence of phase on hardness prediction of HEAs was thoroughly examined. This study aims to establish generalized prediction models that aren’t confined by any specific set of elements. We trained the HEA identification model to classify HEAs from non-HEAs, the multi-labeled phase classification model to predict phases of HEAs also considering the processing route involved in the synthesis of the alloy, and the hardness prediction model for predicting hardness and optimizing the composition of the given alloy. The purposed algorithmic framework uses twenty-nine alloy descriptors to compute the composition that demonstrates maximum hardness for the given set of elements along with its phase(s) and a label stating whether it is classified as HEA or not.

The recrystallization behavior of cryo- and cold-rolled AlCoCrFeNiTi high entropy alloy

The present work was conducted on the non-equiatomic Al0·2Co1·5CrFeNi1·5Ti0.3 high entropy alloy (HEA), which was separately subjected to 50% cold- and cryo-rolling. Subsequent annealing was performed within the temperature range of 800–1000 °C to investigate their recrystallization behavior. A partial recrystallization was achieved up to 900 °C for the cold-rolled material, while the cryo-rolled one had shown nearly fully recrystallized microstructure after 800 °C. A significant reduction in grain size from the solution-treated state (∼784 μm) to fully recrystallized state (∼71 μm for cold-rolled and ∼6 μm for cryo-rolled) was observed. A combined XRD and TEM analysis confirms that the cryo-rolled sample exhibits higher dislocation density than the cold-rolled sample, which resulted in faster recrystallization kinetics observed in the former than in the latter. Additionally, the Johnson–Mehl–Avrami–Kolmogorov model was employed to understand the recrystallization behavior.

Effect of titanium on the structural, mechanical and surface properties of CoCrFeMnNiTix high entropy alloy fabricated by selective laser melting

In this study, the effect of titanium (Ti) on the microstructure, mechanical properties, wear resistance and corrosion behavior of CoCrFeMnNi high-entropy alloy (HEA) was examined. The selective laser melting (SLM) method was used to produce HEAs without Ti addition (HEA-1) and with Ti additions of 3 and 5 wt% (HEA-2 and HEA-3, respectively). While the HEA-1 sample exhibited a single-phase face-centered cubic (FCC) structure, the HEA-2 and HEA-3 samples exhibited intermetallic phase structures (Sigma and Laves) along with FCC. The addition of Ti and the presence of intermetallic phases in the HEA-2 sample revealed an improvement in mechanical properties without reducing the ductility value of the structure. However, in parallel with the increasing Ti ratio, the formation of more brittle intermetallic phases in the microstructure of the HEA-3 alloy caused a significant increase in strength but a decrease in ductility. Microstructural examinations revealed that all alloys had a cellular/dendritic structure and the relative densities of the samples were above 99%. While the ultimate tensile stress (UTS) of the HEA-1 sample was 548 MPa and the UTS of the HEA-3 alloy was 832.1 MPa, elongation values were obtained as 48% and 2%, respectively. HEA-2 sample exhibited more ideal results with an elongation value of approximately 22% and UTS values of 760.8 MPa. It was observed that the addition of Ti significantly increased the wear resistance in sliding conditions due to the increase in the hardness of the alloy. The highest hardness and lowest wear rate were obtained with HEA-3 coded samples. The HEA-1 sample exhibited the best corrosion rate, with higher corrosion potential (Ecorr) and lower corrosion current density (Icorr) values. The highest corrosion rate was observed in the HEA-3 sample.

Effect of Ti additions on the mechanical properties and thermal expansion properties of Ni9Cr9Co9Fe9Tix (x=1, 2, 3) high entropy alloy

The mechanical properties and thermal expansion properties of high entropy alloys (HEAs) are crucial for practical applications. However, there is a scarcity of research on how to optimize the relationship between the mechanical and thermal expansion properties, which currently restricts the application of HEAs as precision structural materials. To address this critical issue, the present study investigates the mechanical properties and thermal expansion properties of Ni9Cr9Co9Fe9Tix (x=1,2,3) HEAs fabricated via repeated arc melting and casting in a vacuum environment. The results show that Ni9Cr9Co9Fe9Tix HEAs exhibit a typical microstructure characteristic of dendritic and inter-dendritic phase, and a small amount of Ni3Ti phase is formed in the Ni9Cr9Co9Fe9Tix HEAs. The addition of Ti notably increases the tensile strength of Ni9Cr9Co9Fe9Tix HEAs, while the presence of the Ni3Ti phase contributes to a reduction in its thermal expansion coefficient. Notably, HEAs with higher Ti content demonstrate increased yield strength but diminished ductility. The primary mechanisms that strengthen the HEA are solid-solution strengthening, secondary phase hardening and dislocations strengthening of the FCC matrix. This study provides superior mechanical properties for HEAs structural components and reduces the thermal expansion coefficient of the matrix alloy, which also indicated the potential of this material for the design and development of HEAs for precision structural components.

A machine learning interatomic potential for high entropy alloys

High entropy alloys (HEAs) possess a vast compositional space, providing exciting prospects for tailoring material properties yet also presenting challenges in their rational design. Efficiently achieving a well-designed HEA often necessitates the aid of atomistic simulations, which rely on the availability of high-quality interatomic potentials. However, such potentials for most HEA systems are missing due to the complex interatomic interaction. To fundamentally resolve the challenge of the rational design of HEAs, we propose a strategy to build a machine learning (ML) interatomic potential for HEAs and demonstrate this strategy using CrFeCoNiPd as a model material. The fully trained ML model can achieve remarkable prediction precision (>0.92 R2) for atomic forces, comparable to the ab initio molecular dynamics (AIMD) simulations. To further validate the accuracy of the ML model, we implement the ML potential for CrFeCoNiPd in parallel molecular dynamics (MD) code. The MD simulations can predict the lattice constant (1% error) and stacking fault energy (10% error) of CrFeCoNiPd HEAs with high accuracy compared to experimental results. Through systematic MD simulations, for the first time, we reveal the atomic-scale deformation mechanisms associated with the stacking fault formation and dislocation cross-slips in CrFeCoNiPd HEAs under uniaxial compression, which are consistent with experimental observations. This study can help elucidate the underlying deformation mechanisms that govern the exceptional performance of CrFeCoNiPd HEAs. The strategy to establish ML interatomic potentials could accelerate the rational design of new HEAs with desirable properties.

Phase transformation of AB5 to AB2 type phase on substitution of Mn with Zr in TiVCoNi (ZrxMn2-x) (x = 0, 0.3, 0.6, 1.0) high entropy alloys

In this present investigation, we discussed the synthesis, microstructure, and phase transformation from BCC (AB5) to C14 Laves (AB2) phase in TiVCoNi (ZrxMn2-x) (x = 0, 0.3, 0.6, 1.0) high entropy alloys on substituting Mn with Zr. These high entropy alloys were synthesized using a 35 kW radio frequency induction furnace under argon atmosphere. At x = 0 (i.e in quinary HEA), the single BCC phase is observed, whereas at x = 1 (i.e, in hexanery HEA), the single C14 Laves phase was found to be stable. The calculations of the thermodynamic parameters have been done with the help of Miedema's semi-empirical model and other models available in literature. TiVCoNi (ZrxMn33.32-x) high entropy alloys have exhibited mixing enthalpy corresponding to TiVCoNi (ZrxMn2-x) at x = 0, 0.3, 0.6, 1 as −15.6 kJ/mol, −18.1 kJ/mol, −22.8 kJ/mol, −25.3 kJ/mol respectively. The corresponding atomic radius mismatch was found to be 10.03%, 11.85%, 10.18%, and 9.86%. It is established that on replacing Mn with Zr, the mixture of the BCC and Laves phase was observed, which was converted into a single C14 intermetallic Laves phase at equiatomic composition i.e., x = 1. Further, the study of surface morphology and elemental composition of these as-cast high entropy alloys gives us the idea that hardness increases on substitution of Mn in BCC phased-based TiVCoNi (ZrxMn2-x) (x = 0, 0.3, 0.6, 1.0) high entropy alloys due to the evolution of hard C14 Laves phase.

Microstructure characterization and phase evolution of equiatomic AlCoMoFeNi high entropy alloy synthesized by mechanical alloying

The present study deals with the fabrication of a novel AlCoMoFeNi high-entropy (HEA) alloy using mechanical alloying techniques. The developed HEA was characterized by X-ray diffraction, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) equipped with energy dispersive x-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The crystallite size of the high-entropy alloy solid solution was determined to be 20±1 nm, with a lattice strain of 0.467±0.03 % and a lattice parameter of 3.98±0.08 Å. A number of characteristics, including melting point, mixing enthalpy change, mixing entropy change, atomic size difference, electronegativity difference, and valence electron concentration, were computed in order to ascertain the conditions regulating the formation of high-entropy alloys. A HEA with BCC and FCC solid solution was obtained after mechanical alloying, which was confirmed by experimental findings as well as thermodynamic calculations.

New insights on bonding mechanism of FCC and BCC high entropy alloy microparticles upon supersonic impact using micromechanical adhesion test

Coating buildup in cold spraying (CS) relies on particle bonding upon impact, thus making it a significant area of study. High entropy alloys (HEAs) are a class of materials with superior work-hardening ability and resistance to softening, making their particle impact and bonding particularly important to understand for their cold sprayability. In this study, the splat adhesion strength is measured with a scratch test for FCC CoCrFeMnNi and BCC AlCrFeMnNi HEA microparticles deposited on mirror-polished SS304 substrates. Nanoindentation tests were conducted to estimate the tensile and shear strengths of the HEA powders. The results showed that particle deformation and jetting were dominant in the FCC HEA/SS304 system, while substrate deformation was dominant in the BCC HEA/SS304 system. Focused ion beam cross sections of particles confirmed that the FCC HEA had good bonding and underwent significant deformation and grain refinement at the substrate/particle interface, while the BCC HEA had limited bonding only in the sheared zone of the particles.In spite of the very limited deformation of BCC splats, their average adhesion strength was measured to be 451 ± 141 MPa, which is significantly higher than that of FCC splats, with an average value of 308.7 ± 69.3 MPa. Fracture surface analysis revealed that FCC splats consistently exhibit ductile fracture, regardless of whether it occurs at the particle, substrate, or interface. In contrast, for BCC splats, fracture was ductile when occurring at the interface and substrate sides, while it was cleavage when occurring on the particle side. These findings suggest that the toughness and shear strength of the bonding developed at the interface were higher than those of the particle. It was found that the flattening ratio (FR) of the particles decreases for both FCC and BCC HEA splats with an increase in particle size, resulting in a decrease in adhesion strength. Metallurgical bonding has been identified as the primary factor contributing to the adhesion strength of both FCC and BCC HEA splats. Particle penetration, indicative of mechanical interlocking, appears to have little or no effect on adhesion strength. However, it does positively influence the increase in adhesion energy of the splats.

First-principles calculation of phase transitions and mechanical properties of (CoCrNi)100−xAlx (0 ≤ x ≤ 28 at. %) high-entropy alloys

In the two-phase high-entropy alloys (HEAs) (i.e., FCC, BCC), the modulation of the BCC phase is crucial for improving the mechanical properties of FCC-type HEAs. The stability of the phase of (CoCrNi)100−xAlx (0 ≤ x ≤ 28 at. %) HEAs is studied using first-principles calculations. The Al content on the phase transition of CoCrNi HEAs is discussed. The theoretical values of lattice parameter a (x) increase with increasing Al concentration, which is consistent with the earlier experimental findings. The crystal structure transitions from the FCC to BCC crystal structure as the Al content increases. At x < 11.8 at. %, Al alloying lowers the elastic stability of the BCC and FCC phases, whereas excessive Al doping causes the FCC phase to BCC phase transition (x > 21.4 at. %). The crystal structure has an ideal mix phase of BCC and FCC at x = 18.8 at. %, which results in excellent strength-ductility synergy of HEAs. There is a phase transition point at x = 11.8 at. %, where there may be a competition between phase transition and dislocation nucleation, which improves strength. The work in this paper provides new ideas for the design of future high-performance duplex phase HEAs.

Non-precious metal high-entropy electrocatalysts (Al0.5NiCoCr-X0.5) for OER application

The high entropy alloy electrocatalysts demonstrate exceptional efficiency in the production of hydrogen through water electrolysis. Consequently, the development of durable and economically efficient electrocatalysts has become an urgent objective to accomplish. In order to achieve this goal, a bulk non-precious metal high-entropy alloy, Al0.5NiCoCr-X0.5 (Mo, Mn, Cu, V, Fe), was synthesized and characterized in this study through physical phase analysis and electrochemical property test. To explore the reasons for the influence of the five added elements on the catalytic performance of high entropy alloys in this system and to find the OER electrocatalyst with the best catalytic performance. Electrochemical performance tests were performed in 1M KOH electrolyte. At a current density of 10mA·cm-2, the overpotential of the high-entropy alloy catalyst Al0.5NiCoCrMo0.5 was lower than that of the high-entropy alloy with the addition of the other four elements respectively, which was only 327mV, and lower than that of the conventional noble metal catalyst RuO2, which had an overpotential of 342mV. This is attributed to the addition of Mo element, which makes Al0.5NiCoCr produce a large number of HCP phases on top of the original FCC phase and a very small number of BCC phases, which is more conducive to the generation of active sites on the surface of the catalysts, and thus improves the OER activity, and the stability can be maintained for at least 20hours. Therefore, Al0.5NiCoCrMo0.5 high-entropy alloy catalysts can be used in industrial hydrogen production instead of the traditional precious metal catalysts, and it has a rather broad application prospect, and at the same time, it lays a solid foundation for the application of transition metals in catalysts.

Fabrication of (TiZrNbSiMo)1-xNx high entropy alloy coatings using a high power impulse magnetron sputtering technique: Effects of nitrogen addition

Due to the outstanding mechanical and physical properties of high entropy alloy (HEA) coatings, the global academic and industrial communities have made significant research efforts in recent years, aiming to expand their industrial applications. In this study, TiZrNbSiMo and (TiZrNbSiMo)1-xNx HEA nitride coatings with different nitrogen contents were fabricated using a high power impulse magnetron sputtering (HiPIMS) system. By varying the nitrogen flow rates, the nitrogen contents of coatings increased from 0 to 48.8 at. %. The deposition rate decreased with increasing nitrogen content due to the target poisoning effect. Very fine and dense microstructure can be seen for each coating. The amorphous structure was obtained as the nitrogen content was lower than 19.1 at.%, whereas a nanocrystalline FCC structure was formed when the nitrogen content reached 34.9 at. %. Furthermore, the corrosion resistance of TiZrNbSiMo and four TiZrNbSiMoN HEA coatings in 0.5 M H2SO4 aqueous solution were superior to uncoated 304 stainless steel. We can conclude that the nanocrystalline TiZrNbSiMoN HEA coatings with a nitrogen content of 34.9 at. % exhibited a high hardness of 15.6 GPa, an electrical resistivity of 766.5 μΩ·cm, and an excellent corrosion polarization resistance of 9.71 × 105 Ω·cm2, 610.7 times higher than 304SS. This study provides valuable insights for future promising applications of (TiZrNbSiMo)1-xNx HEA nitride coatings in severely corrosive environments, such as the protective coatings on stainless steel bipolar plates in proton exchange membrane fuel cells.

Achieving ultrahigh strength and ductility via high-density nanoprecipitates triggering multiple deformation mechanisms in a dual-aging high-entropy alloy with precold deformation

How to achieve high-entropy alloys (HEAs) with ultrahigh strength and ductility is a challenging issue. Precipitation strengthening is one of the methods to significantly enhance strength, but unfortunately, ductility will be lost. To overcome the strength–ductility trade-off, the strategy of this study is to induce the formation of high-density nanoprecipitates through dual aging (DA), triggering multiple deformation mechanisms, to obtain HEAs with ultrahigh strength and ductility. First, the effect of precold deformation on precipitation behavior was studied using Ni35(CoFe)55V5Nb5 (at.%) HEA as the object. The results reveal that the activation energy of recrystallization is 112.2 kJ/mol. As the precold-deformation amount increases from 15% to 65%, the activation energy of precipitation gradually decreases from 178.8 to 159.7 kJ/mol. The precipitation time shortens, the size of the nanoprecipitate decreases, and the density increases. Subsequently, the thermal treatment parameters were optimized, and the DA process was customized based on the effect of precold deformation on precipitation behavior. High-density L12 nanoprecipitates (∼3.21 × 1025 m−3) were induced in the 65% precold-deformed HEA, which led to the simultaneous formation of twins and stacking fault (SF) networks during deformation. The yield strength (YS), ultimate tensile strength, and ductility of the DA-HEA are ∼2.0 GPa, ∼2.2 GPa, and ∼12.3%, respectively. Compared with the solid solution HEA, the YS of the DA-HEA increased by 1,657 MPa, possessing an astonishing increase of ∼440%. The high YS stems from the precipitation strengthening contributed by the L12 nanoprecipitates and the dislocation strengthening contributed by precold deformation. The synergistically enhanced ductility stems from the high strain-hardening ability under the dual support of twinning-induced plasticity and SF-induced plasticity.

Mechanical-thermal coupling fatigue failure of CoCrFeMnNi high entropy alloy

High entropy alloys exhibit excellent performance under different-temperature conditions. In order to investigate the effect of temperature on the mechanical-thermal coupling fatigue failure of classical CoCrFeMnNi high entropy alloy to accelerate the application of high entropy alloys, the uniaxial tensile and fatigue tests at temperatures ranging from RT to 500 °C were conducted, and statics simulation analysis of fatigue specimens under fatigue loading conditions was conducted. The results of the uniaxial tensile tests illustrated that the yield stress and tensile strength of the alloy decreased with increasing temperature. In contrast, the elongation after the fracture of the alloy increased with temperature. The fatigue test results revealed that the fatigue life decreased as the temperature increased. The fracture morphology of the fatigue specimens and the flank morphology and dislocation distribution near the crack nucleation zone were collected to support the investigation. Accordingly, the reasons for the high-temperature-induced decrease in fatigue crack nucleation and propagation lives were systematically investigated. The main reasons for the higher-temperature-induced decrease in crack nucleation lives were a decrease in the yield stress of the alloy, more easily triggered dislocation motion and stress homogenization. The reasons for the decrease in fatigue crack propagation lives induced by higher temperatures were the more prone occurrence of dislocation motion, a decrease in yield stress, and a decrease in the area of the crack propagation region.

Evolution of interfacial phases between Al alloy and high entropy alloy during annealing

While the interfacial phases between Al and high-entropy alloy (HEA) share the same types as that between Al and steel, it has been found previously that the thermal stability of the Al-HEA interfacial phases is significantly higher than that of the Al-steel interfacial phases. To further elucidate the reason for the exceptional thermal stability of Al-HEA interfacial phases, this study investigated the evolution of the interfacial phases formed between Al alloy and FeCoCrNiMn HEA during annealing. An Al-FeCoCrNiMn thin film diffusion couple was extracted from a friction stir lap welding (FSLW) joint by focused ion beam and then annealed at 400 °C. An amorphous layer is formed initially at the interface due to the high strain rate deformation during FSLW. The amorphous layer remained even after prolonged annealing at 400 °C (~0.72 Tm of Al alloy) for 60 min with very limited thickening (from 50 nm to 55 nm), showing remarkable thermal stability at the relatively high temperature. Al13Fe4-type IMC with the Fe site occupied by Fe, Co, Cr, Ni and Mn first nucleates at the interface between Al alloy and amorphous layer. With the annealing time extended to 180 min, the amorphous layer is partially transformed into Al5Fe2-type IMC. The rate constant for the thickening of the reaction layer at the Al/FeCoCrNiMn interface is 0.03 μm∙min1/2, which is much smaller than (only 0.02 times) that at the Al/steel interface under similar annealing condition. The high thermal stability of Al-HEA interfacial layer is thus attributed to the slow kinetics in crystallization of the initially formed amorphous layer, the barrier effect of amorphous layer for interdiffusion, and the reduced diffusivity inside of IMCs caused by significant fluctuations in lattice potential energy due to high-density doping with HEA elements. This finding provides new insights into the fabrication of thermally stable Al-HEA hybrid structures suitable for service conditions involving high-temperature exposure.

Strengthening Al0.1CoCrFeNi high-entropy alloy via multiaxial cryogenic forging and low temperature annealing

Face-centered cubic (FCC) high-entropy alloys (HEAs) exhibit excellent fracture toughness and fatigue properties at both ambient and cryogenic temperatures. However, the relatively low strength of FCC HEAs at room temperature limits their widespread application. Herein, we present a novel approach to tailoring the microstructure of the Al0.1CoCrFeNi HEA and improving its room temperature tensile strength through multiaxial cryogenic forging (MACF) and low temperature annealing (LTA). After the treatments, the tensile strength increases from 687 MPa for the as-prepared fine-grained HEA to 1487 MPa for the MACF specimens annealed at 673 K for 48 h. Our analysis indicates that the strengthening mechanisms are twofold: the tensile strength increased by about 455 MPa after the MACF treatment, which is due to the synergistic effect of dislocations and nanotwins; after LTA, the tensile strength abnormally increased by about 345 MPa, which can be attributed to stacking faults, hexagonal close-packed, and 9R structures formed by thermal relaxation of nanotwin boundaries.

Machine learning prediction and characterization of sigma-free high-entropy alloys

Precipitation hardening provides a great potential to achieve superior strength-ductility trade-off in high-entropy alloys (HEAs). However, the formation of some precipitates such as brittle sigma phases may significantly deteriorate the ductility. Empirical criteria such as PSFE, VEC, and Md were proposed to predict the formation of undesirable phases during aging, nevertheless, they are insufficient to describe their stability and are not dependable for the noted purpose. Accordingly, for the first time, machine-learning models were conducted for this prediction. A feature selection based on Pearson correlation and mutual information has been used to improve the performance of models. Linear regression, second-order polynomial regression, decision tree, and neural network are conducted by machine learning methods in this paper. Among the implemented methods, the neural network had the best performance which improved the accuracy of the prediction by ~25% compared to the conventional methods. Additionally, a new parameter based on linear regression, which is more reliable and user-friendly than thermodynamic parameters was developed in this investigation. The results showed that some elements such as Cr, Mo, and V may promote sigma precipitation. A HEA with a sigma-free microstructure was developed for validation of the model. We strongly believe that this HEA has great potential for overcoming the strength-ductility trade-off because of not only the lack of sigma precipitate but also the presence of NiAl precipitate. The results are a step forward in designing alloys with the potential of microstructure engineering to achieve superior properties.