Predictive multiphase evolution in Al-containing high-entropy alloys

The as-cast CoCrFeNi high-entropy alloys show simple FCC structure and outstanding deformation ability at room temperature. Respectively, after 50% of deforming at room temperature and annealing at intermediate temperature range of 600 °C–800 °C for 2 h, CoCrFeNi alloys still show simple-phase FCC structure. It is noteworthy that CoCrFeNi high-entropy alloys can’t be strengthened by means of annealing, while deformation is an effective way to strengthen the alloys. It is investigated that the formation of sigma (σ) phase in high-entropy alloys is closely related to the difference of atomic radius (δ), the concentration of valence electron (VEC) and paired sigma-forming element (PSFE) content, and PSFE plays an crucial role. When PSFE > 40 at.%, 6.75 ≤ VEC ≤ 7.86, 4.0 ≤ δ ≤ 7.2, σ phase is prone to form in high-entropy alloys. In addition, alloying and processing route are two important factors that affect the sigma-formation in CoCrFeNi high-entropy alloys.

A systematic framework for choosing the most determinant combination of predictor features and solving the multiclass phase classification problem associated with high-entropy alloy (HEA) was recently proposed [1]. The data associated with that research paper, titled “Machine learning-based prediction of phases in high-entropy alloys”, is presented in this data article. This dataset is a systematic documentation and comprehensive survey of experimentally reported HEA microstructures. It contains microstructural phase experimental observations and metallurgy-specific features as introduced and reported in peer-reviewed research articles. The dataset is provided with this article as a supplementary file. Since the dataset was collected from experimental peer-reviewed articles, these data can provide insights into the microstructural characteristics of HEAs, can be used to improve the optimization HEA phases, and have an important role in machine learning, material informatics, as well as in other fields.

Effect of the addition of carbon on phase formations in AlxCoCrFeNiCu (x = 0.3, 1.5, 2.8) high-entropy alloys (HEAs) was studied. Free diffusion of carbon from graphite crucible resulted in the partitioning of the entire Cr from the matrix and the formation of the (Cr,Fe)23C6 phase in all HEAs. No other metal-carbide phase was detected. The formation of (Cr,Fe)23C6 enhanced the overall hardness of the HEAs. By increasing the amount of Al, the Cr amount decreased resulting in the reduction of carbon diffusion and volume fraction of the (Cr,Fe)23C6 phase in HEAs. The hardness of matrix phases and the overall hardness of HEAs increased with an increase in the amount of Al.Impact statementThe detailed phase analysis reveals that C addition to AlxCoCrFeNiCu HEAs leads to the formation of the (Cr,Fe)23C6 phase. The overall hardness can be controlled by the amount of C and/or Al.

Competition between solid solution and multi-component Laves phase in a dual-phase refractory high-entropy alloy CrHfNbTaTi

High-entropy alloys (HEAs) containing multiple principle alloying elements exhibit unique properties so they are currently receiving great attention for developing innovative alloy designs. In FeCoNi-based HEAs, magnetic behaviors strongly depend on the addition of alloying elements, usually accompanied by structural changes. In this work, the effect of non-magnetic components on the ferromagnetic transition and magnetic behaviors in equiatomic FeCoNiCrX (X=Al, Ga, Mn and Sn) HEAs was investigated. Alloy ingots of nominal compositions of HEAs were prepared by arc melting and the button ingots were cut into discs for magnetic measurements as functions of magnetic field and temperature. The HEAs of FeCoNiCrMn and FeCoNiCrSn show typical paramagnetic behaviors, composed of solid solution FCC matrix, while the additions of Ga and Al in FeCoNiCr exhibit ferromagnetic behaviors, along with the coexistence of FCC and BCC phases due to spinodal decomposition. The partial phase transition in both HEAs with the additions of Ga and Al would enhance ferromagnetic properties due to the addition of the BCC phase. The saturation magnetization for the base alloy FeCoNiCr is 0.5 emu/g at the applied field of 20 kOe (TC = 104 K). For the HEAs of FeCoNiCrGa and FeCoNiCrAl, the saturation magnetization significantly increased to 38 emu/g (TC = 703 K) and 25 emu/g (TC = 277 K), respectively. To evaluate the possibility of solid solution FCC and BCC phases in FeCoNiCr-type HEAs, we introduced a parameter of valence electron concentration (VEC). The proposed rule for solid solution formation by the VEC was matched with FeCoNiCr-type HEAs.

Synergistic effect of Ti and Al on L12-phase design in CoCrFeNi-based high entropy alloys

Doping strategies for β-Ga2O3 based on high-throughput first-principles calculations

Wear and mechanical properties of novel (CuCrFeTiZn)100-xPbx high entropy alloy composite via mechanical alloying and spark plasma sintering

Abstract. High-entropy alloy is a promising structural material for high-temperature service applications due to the designable superior properties. Superplasticity, normally achieved at relatively high temperature and low strain rate, enables difficult to formation materials to manufacture complex-shaped parts. This paper presents a feasibility experimental study on the deformation and microstructure of CoFeMnNi high-entropy alloy under hot deformation conditions with low strain rate. A series of hot uniaxial tests were conducted at the temperature range between 800-1000℃ with typical strain rates of 10-4 and 10-5/s to determine the stress-strain behaviours. Additionally, to understand the deformation mechanism, microstructure evolution after deformation was characterized. Finally, a mechanism based constitutive model of high-entropy alloy was developed, which facilities the process optimization by finite element simulations.

Learning What Makes Catalysts Good

Purpose. The study aims to develop and characterize a new nanostructured FeCo0,854Nb0,146NiB0,7Si0,3 high-entropy metallic glass with enhanced soft magnetic and mechanical properties. The research seeks to explore the interplay between the alloy’s amorphous structure and its functional properties to advance the understanding of high-entropy metallic glasses. Design / Method / Approach. The amorphous films of the FeCo0,854Nb0,146NiB0,7Si0,3 alloy was synthesized using splat-quenching technique. The cooling rate, estimated based on the film thickness, was ~106 K/s. Structural properties were analyzed via X-ray diffraction (XRD), differential thermal analysis (DTA), and electrical resistivity measurements. Magnetic properties were assessed using a B–H curve tracer and vibrating sample magnetometer, while microhardness was measured with a PMT-3 tester. Findings. The alloy exhibits a fully glassy structure with a crystallite size of ~3 nm, low coercivity (40 A/m), high saturation magnetization (74 A·m2/kg), and microhardness ≥ 8000 MPa, indicating decent soft magnetic and mechanical properties. Theoretical Implications. The research provides significant insights into the role of atomic-size differences, configurational entropy, and thermodynamic parameters in stabilizing the glassy phase in high-entropy alloys. It advances the theoretical framework for designing high-entropy amorphous materials. Practical Implications. The characteristics of the material make it promising for use in electronic devices and mechanical engineering parts. Originality / Value. This study provides a comprehensive analysis of the high-entropy metallic glass FeCo0,854Nb0,146NiB0,7Si0,3, offering new insights of its magnetic and mechanical properties through advanced characterization techniques. Research Limitations / Future Research. Further studies are needed to investigate the long-term stability of the fabricated amorphous alloy. Article Type. Applied Research. PURL: https://purl.org/cims/4.284

Composition of Intermetallic Phases in High-Entropy Alloys: Compositional Inheritance of High-Entropy Sigma Phases from Binary Counterparts

The structural properties, formation heats, cohesive energies, elastic properties and electronic structures of common intermetallics in CrMnFeCoNiZr system high-entropy alloys are analyzed by using density functional theory. The calculation results show that Co1Zr1, Co2Zr1, Fe2Zr1 and Fe[Formula: see text]Zr6 phases may form in the casting process of the alloy, which indicates good agreement with the XRD results of the self-designed alloys. The calculated elastic constants reveal that Co2Zr1, Fe2Zr1 and Fe[Formula: see text]Zr6 are mechanically stable. In addition, the results show that Co2Zr1, Fe2Zr1 and Fe[Formula: see text]Zr6 with high shear modulus and elastic modulus would be excellent strengthening phases in high-entropy alloy and would improve the hardness of the alloys.

Irradiation behaviors of two novel single-phase bcc-structure high-entropy alloys for accident-tolerant fuel cladding

Effects of carbon addition on microstructure and mechanical properties of Fe50Mn30Co10Cr10 high-entropy alloy prepared by powder metallurgy