High-entropy Alloys Research Articles

High-throughput and data-driven machine learning techniques for discovering high-entropy alloys

High-throughput and data-driven machine learning techniques for discovering high-entropy alloys

Advancements in machine learning for predicting phases in high-entropy alloys: a comprehensive review

High entropy alloys (HEAs) are distinguished by their enhanced physicochemical properties, attributed to the formation of various phases such as solid solution (SS), intermetallic (IM), or a combination (SS + IM). These phases contribute distinctively to the microstructure of the alloys. A critical aspect of alloy design revolves around accurately predicting these phases, which has led to the integration of sophisticated data vetting methods and Machine Learning (ML) algorithms in recent research. This review paper aims to provide a comprehensive analysis of the advancements in phase prediction accuracy within HEAs, an essential component in the development of these alloys. HEAs are known for their intricate compositions, offering a wide spectrum of material properties, making them particularly relevant for applications aimed at future sustainability. Phase engineering in HEAs unlocks the potential for creating materials tailored to eco-friendly technologies and energy-efficient solutions. The challenge in predicting phase selection in HEAs is accentuated by the limited data available on these complex materials. This review delves into how advanced data vetting techniques and ML algorithms are being employed to overcome these challenges, thus contributing significantly to sustainable material design. The paper examines various algorithms used in HEA phase prediction, including KNN (K-Nearest Neighbors), SVM (Support Vector Machines), ANN (Artificial Neural Networks), GNB (Gaussian Naive Bayes), and RF (Random Forest). It discusses the testing accuracy of these algorithms in classifying HEA phases, revealing variations in their effectiveness. The review highlights the superior accuracy of ANNs, followed closely by KNN and SVM, while noting the comparatively lower accuracy of GNB. This comprehensive review synthesizes current research efforts in utilizing computational methods to design HEAs, underlining their broader implications in expediting the discovery and development of diverse metal alloys. These efforts are pivotal in meeting the evolving demands of modern engineering applications, thereby contributing to the advancement of materials science.

Effect of short-range order on lattice distortion, stacking fault energy, and mechanical performance of Co-Fe-Ni-Ti high-entropy alloy at finite temperature

Effect of short-range order on lattice distortion, stacking fault energy, and mechanical performance of Co-Fe-Ni-Ti high-entropy alloy at finite temperature

Research on Mechanical Properties and Corrosion Behavior of (Co34Fe8Cr29Ni8Si7)100−xBx High Entropy Alloy Coating

Research on Mechanical Properties and Corrosion Behavior of (Co34Fe8Cr29Ni8Si7)100−xBx High Entropy Alloy Coating

Design and Development of Ti‐Zr‐Nb‐Ta‐Ag High Entropy Alloy for Bioimplant Applications

Design and Development of Ti‐Zr‐Nb‐Ta‐Ag High Entropy Alloy for Bioimplant Applications

Wear resistance optimized by heat treatment of an in-situ TiC strengthened AlCoCrFeNi laser cladding coating

Abstract An AlCoCrFeNi high-entropy alloy coating containing 20 % mass fraction of TiC was prepared using the laser cladding method. The effect of heat treatment on the coating’s microstructure was analyzed through X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM). It was observed that following high-temperature heat treatment, the phase transition of AlCoCrFeNi–20%TiC shifted from BCC to FCC at 750 °C. Through microhardness and wear resistance tests, the increased diffusion of carbon post-heat treatment led to a higher precipitation of TiC-reinforced phases, resulting in exceptional wear resistance with a notable 128.3 % enhancement.

Fatigue Behavior of Medium Entropy Alloys AlCrFe<sub>2</sub>Ni<sub>2</sub> and AlCrFe<sub>2</sub>Ni<sub>2</sub>Mo<sub>0.1 </sub>- A Comparison with Super Duplex Steel 1.4517

Fatigue Behavior of Medium Entropy Alloys AlCrFe<sub>2</sub>Ni<sub>2</sub> and AlCrFe<sub>2</sub>Ni<sub>2</sub>Mo<sub>0.1 </sub>- A Comparison with Super Duplex Steel 1.4517

Influence of Solution Alkalinity and Alternating Current Density on Anti-corrosion Property of CoCrFeMnNi High-Entropy Alloy in Simulated Concrete Pore Solution

Influence of Solution Alkalinity and Alternating Current Density on Anti-corrosion Property of CoCrFeMnNi High-Entropy Alloy in Simulated Concrete Pore Solution

The effect of replacing molybdenum with vanadium on the tendency to amorphisation, structure and thermal properties of high-entropy alloys of the Fe–Co–Ni–Cr–(Mo,V)–B system

The effect of replacing molybdenum with vanadium on the tendency to amorphisation, structure and thermal properties of high-entropy alloys of the Fe–Co–Ni–Cr–(Mo,V)–B system

Microstructure and Properties of CoCrFeNiMnTix High-Entropy Alloy Coated by Laser Cladding

Microstructure and Properties of CoCrFeNiMnTix High-Entropy Alloy Coated by Laser Cladding

Unveiling the potential of (CoFeNiMnCr)3O4 high-entropy oxide synthesized from CoFeNiMnCr high-entropy alloy for efficient oxygen-evolution reaction

AbstractElectrochemical water-splitting is a promising green technology for the production of hydrogen. One of the bottlenecks, however, is the oxygen evolution half-reaction (OER), which could be overcome with the development of a suitable electrocatalyst. Recently, non-noble metal, high-entropy oxides (HEO) have been investigated as potential OER electrocatalysts, but complex synthesis approaches that usually produce the material in powder form limit their wider utilization. Here, an innovative synthesis strategy of formulating a nanostructured (CoFeNiMnCr)3O4 HEO thin film on a CoFeNiMnCr high entropy alloy (HEA) using facile electrochemical and thermal treatment methods is presented. The CoFeNiMnCr HEA serves as exceptional support to be electrochemically treated in an ethylene glycol electrolyte with ammonium fluoride to form a rough and microporous structure with nanopits. The electrochemically treated CoFeNiMnCr HEA surface is more prone to oxidation during a low-temperature thermal treatment, leading to the growth of a spinel (CoFeNiMnCr)3O4 HEO thin film. The (CoFeNiMnCr)3O4 HEO exhibits a superior overpotential of 341 mV at 10 mA cm−2 and a Tafel slope of 50 mV dec−1 along with remarkable long-term stability in alkaline media. The excellent catalytic activity and stability for the OER can serve as a promising platform for the practical utilization of (CoFeNiMnCr)3O4 HEO. Graphical abstract

Improving tensile and impact properties of Fe50Mn30Co10Cr10 high entropy alloy via microstructural engineering

This study investigates the Fe50Mn30Co10Cr10 high entropy alloy (HEA), featuring a dual-phase structure with face-centered cubic (FCC) and hexagonal close-packed (HCP) phases, in both cast and forged states. The cast samples exhibited an average tensile strength of 675.9 MPa and an elongation at break of 34 %, while the forged samples showed superior properties with a strength of 821.0 MPa and 50 % elongation. Impact tests at room temperature, 200 K, and 77 K revealed that forged samples consistently had higher impact energy (144 J, 119 J, and 109 J, respectively) compared to cast samples (99 J, 80 J, and 66 J). This research underscores the significant influence of the dual-phase structure and fabrication process on the mechanical and impact properties of the Fe50Mn30Co10Cr10 system HEAs.

Flame Spray Pyrolysis Synthesis of Ultra-Small High-Entropy Alloy-Supported Oxide Nanoparticles for CO2 Hydrogenation Catalysts.

The synthesis of high-entropy alloys (HEAs) with ultra-small particle sizes has long been a challenging task. The complex and time-consuming synthesis process hinders their practical application and widespread adoption. This study presents the novel synthesis of TiO2 nanoparticles loaded with a quinary high-entropy alloy through flame spray pyrolysis (FSP) for the first time. The extremely fast heating rate of flame combustion makes the precursor fast pyrolysis gasification, high temperature in the flame field promotes the metal vapor mixing uniformly, and the fast quenching process can reduce the particle aggregation sintering, the ultra-small particle size of HEA firmly attached to the TiO2 surface. The catalysts prepared via this gas-to-particle pathway exhibit excellent performance in CO2 hydrogenation, achieving a conversion rate of 62% at 450°C, and maintaining their activity for over 220h without significant particle agglomeration. This finding provides valuable insights for the future design of catalytically active materials with enhanced activity and long-term stability.

Effects of Selective Laser Melting Process Parameters on Structural, Mechanical, Tribological and Corrosion Properties of CoCrFeMnNi High Entropy Alloy

AbstractThe structural, tribological, mechanical, corrosion, and other properties of materials produced by laser-based powder bed fusion additive manufacturing methods are significantly affected by production parameters and strategies. Therefore, understanding and controlling the effects of the parameters used in the manufacturing process on the material properties is extremely important for determining optimum production conditions and for saving time and materials. This study aimed to determine the optimal laser parameter values for CoCrFeMnNi high-entropy alloy powders using the selective laser melting (SLM) method. The layer thickness was kept constant during experimentation. 5 different laser powers and 10 varying laser scanning speeds were tested, with hatch spacing from 30 to 90%. After determining the optimal laser parameters for SLM, prismatic samples were fabricated in different build orientations (0°, 45°, and 90°), and subsequently, their structural, mechanical, tribological, and corrosion properties were compared. Melt pool morphology could not be obtained at 20—40 and 60W laser powers and at all laser scanning speeds used at these laser powers. At 100 W laser power, 600 mm/s laser scanning speed, and 70% hatch spacing parameters, an ultimate tensile stress of 550 MPa and elongation of 48% were obtained. Among the samples produced in different build orientations, the sample produced with a 0° build orientation exhibited the highest relative density (99.94%), the highest microhardness (201.2 HV0.1), the lowest friction coefficient (0.7025), and the lowest wear and corrosion rates (0.7875 mpy). Additionally, SLM parameters were evaluated to have a significant impact on the performance of all properties of the samples. Graphical Abstract

Production of sub-micron-sized high-entropy alloy particles and nanoparticles via pulsed laser ablation of CrMnFeCoNi targets in water

Production of sub-micron-sized high-entropy alloy particles and nanoparticles via pulsed laser ablation of CrMnFeCoNi targets in water

Fabrication of high-entropy alloy superconducting wires by powder-in-tube method

High-entropy alloys (HEAs) are novel functional materials that exhibit excellent mechanical and chemical properties. Recent discovery of self-healing superconductivity of HEAs under ion irradiation suggests their great potential applications under extreme conditions such as in nuclear fusion reactors or space environments. Here, we report a fabrication of the HEA superconducting (SC) wires using the ex-situ powder-in-tube (PIT) technique for the first time, a crucial stepping stone to achieve various industrial and technological applications. The Ta1/6Nb2/6Hf1/6Zr1/6Ti1/6 HEA SC powder prepared by planetary ball milling was filled into Fe tubes, drawn into wires, and then sintered in evacuated quartz tubes at various temperatures. The HEA SC wire sintered at 700 °C for 1 h exhibits the highest critical current density (Jc) among the HEA SC wires sintered in the temperature range of 600 – 1000 °C. At 4.2 K, the Jc of this wire exceeds the common benchmark value of Jc = 100 kA cm−2, indicating the suitability of the HEA wire for large-scale applications, such as in high-field SC magnets. The SC transition temperature (Tc) of the HEA wire significantly increases from 5.10 K for the as-cast wire to 7.58 K with the sintering time (ts) of 30 min at 700 °C. The scaling of the flux pinning force as a function of the magnetic field indicates that normal point pinning plays a major role in achieving a high in-field Jc in HEA SC wires. These results underscore the significant potential of HEA superconductors for practical applications in high-field SC magnets, SC electric machines, and next-generation nuclear fusion reactors.

The Behavior of Al0.5CoCrFeNiCuPt0.3 High-Entropy Alloy During High-Temperature Oxidation

The Behavior of Al0.5CoCrFeNiCuPt0.3 High-Entropy Alloy During High-Temperature Oxidation

Quantifying Actinide HEA Superconducting Secrets: A Compositional Odyssey

The superconductivity in the actinide-based high entropy alloy superconductor (AHEASC) (TaNb)x(TiUHf)[Formula: see text] is studied in the framework of Bardeen–Cooper–Schrieffer (BCS) theory, and McMillan’s formalism has been studied for the investigation of superconducting state (SC) parameters, viz., Coulomb pseudopotential [Formula: see text], electron–phonon coupling strength [Formula: see text], SC transition temperature [Formula: see text], interaction strength [Formula: see text], band gap [Formula: see text], energy or mass renormalization parameter [Formula: see text], and isotope effect exponent [Formula: see text]. BCS theory in conjunction with McMillan’s formalism has been used for the investigation. The study indicates a strong correlation between the electron–phonon interaction, and the superconducting properties of the high entropy alloy (TaNb)x(TiUHf)[Formula: see text] are highly dependent on its composition. An abrupt change in the isotope effect exponent suggests the presence of additional mechanisms such as magnetic interactions, spin fluctuations, or strong electron correlations.

Microstructure Evolution and Strengthening Mechanism of AlCrFe2NiCuMox High Entropy Alloys

Microstructure Evolution and Strengthening Mechanism of AlCrFe2NiCuMox High Entropy Alloys

Effect of Alloying Elements on the High-Temperature Yielding Behavior of Multicomponent γ′-L12 Alloys

The exceptional mechanical properties of Ni-based high entropy alloys are due to the presence of ordered L12 (γ′) precipitates embedded within a disordered matrix phase. While the strengthening contribution of the γ′ phase is generally accepted, there is no consensus on the precise contribution of the individual strengthening mechanisms to the overall strength. In addition, changes in alloy composition influence several different mechanisms, making the assessment of alloying conditions complex. Multicomponent L12-ordered single-phase alloys were systematically developed with the aid of CALPHAD thermodynamic calculations. The alloying elements Co, Cr, Ti, and Nb were chosen to complexify the Ni3Al structure. The existence of the γ′ single phase was validated by microstructure characterization and phase identification. A high-temperature compression test from 500 °C to 1000 °C revealed a positive temperature dependence of strength before reaching the peak strength in the studied alloys NiCoCrAl, NiCoCrAlTi, and NiCoCrAlNb. Ti and Nb alloying addition significantly enhanced the high-temperature yield strengths before the peak temperature. The yield strength was modeled by summing the individual effects of solid solution strengthening, grain boundary strengthening, order strengthening, and cross-slip-induced strengthening. Cross-slip-induced strengthening was shown to be the key contributor to the high-temperature strength enhancement.