Single-phase Solid Solution Research Articles

Effect of Dilution on Microstructure and Phase Transformation of AlCrFeMnNi High-Entropy Alloy by Resonant Ultrasonic Vibration-Assisted Laser Cladding

The present study effectively produced a high-entropy alloy (HEA) coating of AlCrFeMnNi on AISI 304L steel using resonant ultrasonic vibration-assisted laser cladding (R-UVALC). An investigation was conducted to examine the impact of dilution rate on the phase composition, microstructure, and mechanical and tribological properties of AlCrFeMnNi coatings. The coating, which was created utilizing the appropriate dilution rate, was thoroughly characterized using EDS mapping and TEM investigation. The results suggest that a higher dilution rate causes a change in the AlCrFeMnNi coating, transforming it from a single solid solution phase (BCC) into a two-phase solid solution containing both FCC and BCC phases. The analysis conducted using transmission electron microscopy (TEM) reveals that the AlCrFeMnNi coating, when diluted at an optimal rate of around 37%, is predominantly composed of a disordered body-centered cubic (BCC) phase and an ordered BCC (B2) phase featuring a spinodal decomposition structure. The AlCrFeMnNi coating has an average microhardness of approximately 540 HV, which is over 2.5 times higher than the microhardness of the substrate. Additionally, it was also established that the dilution rate has an impact on the occurrence of phases, which subsequently affects the mechanical and antifrictional properties of the coating. The integration of ultrasonic vibration in laser cladding enhances quality and improves mechanical and tribological properties, thereby reducing material costs and promoting an environmentally friendly process when compared to conventional cladding.

Thick and dense nitrogen-doped hafnium carbide ultra-high temperature thermal protection coating for outstanding ablation resistance up to 2600 ℃

Transition metal carbon-nitrides, typically represented by HfCN, have become the latest progress among the ultra-high temperature ceramics. In this study, single-phase solid solution HfCN coating was successfully synthesized from spray granulated HfC-HfN composite powder followed by employing the dual solid solution effects of radio frequency inductively coupled plasma spheroidization and supersonic atmospheric plasma spraying processes. The coating was nearly dense (only 2.3% in porosity) with a high thickness of ~ 270 μm. Compared with HfC coating, the HfCN coating exhibited higher hardness and elastic modulus. After plasma ablation at a high heat flux of 8.2MW/m2 for 200s, the HfCN coating exhibited a surface temperature of up to 2600 ℃ and can firmly protect the refractory tungsten substrate from oxidation failure. This outstanding performance illustrates that doping N element in HfC crystal can effectively improve the energy barrier for oxidation reaction and oxygen adsorption compared with typical HfC coating.

High-Entropy Thermistor Ceramics (La1/3Nd1/3M1/3)2(Zr1/2Sn1/2)2O7 (M = Sm, Eu, Gd, or Dy) with High Sensitivity for High-Temperature Measurements.

A series of high-entropy pyrochlore ceramics, specifically (La1/3Nd1/3M1/3)2(Zn1/2Sn1/2)2O7 (M = Sm, Eu, Gd, or Dy), have been synthesized using the solid-state reaction method. Their potential as high-temperature thermistors was investigated by analyzing electrical and aging properties at elevated temperatures. Characterization using X-ray diffraction, scanning electron microscopy, and Raman spectroscopy confirms that these ceramics are dense, single-phase solid solutions with a pyrochlore structure. Electrical analysis demonstrate that these ceramics maintain high resistivity and resistance stability, exhibiting typical negative temperature coefficient features and high B values across a wide temperature range. These characteristics make (La1/3Nd1/3M1/3)2(Zn1/2Sn1/2)2O7 promising candidates for the development of high-sensitivity, long-life high-temperature thermistors suitable for applications within the temperature range of 400-1200 °C.

The thermodynamics of multicomponent high-entropy materials

AbstractHuman development has been based for millennia on manufacturing materials using a conventional alloying strategy of selecting a principal component for the primary property requirement of the material and then adding one or two minor alloying components at relatively low concentrations, either to enhance the primary property or to provide additional secondary properties. We have discovered relatively recently that, with sufficiently large numbers of alloying elements added in sufficiently large concentrations, the configurational entropy of mixing can often become large enough to suppress the formation of brittle compound phases, leading instead to the formation of multicomponent high-entropy solid solutions. In fact, there are literally billions of multicomponent high-entropy single-phase solid-solution materials, with a wide range of exciting new properties, in most cases relatively straightforward to manufacture by conventional processing methods. There seems, however, to be an upper limit to these effects, so that, beyond about ten or twelve alloying components, the inevitable increase in chemical diversity prevents the configurational entropy of mixing from suppressing the increasingly strong chemical reactions between them. This paper discusses in more detail the thermodynamic balance between: (1) increasing configurational entropy and promoting high-entropy solid solutions; and (2) increasing chemical diversity and promoting the formation of brittle compound phases. This is discussed on the basis of regular solution thermodynamics, without the need for more complex, semi-empirical Calphad calculations that can sometimes obscure the underlying key physical and chemical principles. The results show: (1) why large single-phase solid-solution regions are relatively common in multicomponent phase space; (2) why single-phase solid solutions are often favoured over stoichiometric compounds for large numbers of chemically similar components, in concentrated rather than dilute proportions, at high temperatures, and after quenching to room temperature; and (3) the difficulty of detailed thermodynamic analysis in multicomponent materials because of the large numbers of thermodynamic parameters that need to be known and the corresponding lack of underlying thermodynamic measurements.

Enhancing room and cryogenic temperatures mechanical properties of FeCoCrNiMn high entropy alloys with high content of inexpensive element P

FeCoCrNiMn high-entropy alloys (HEAs) exhibit excellent ductility, particularly at cryogenic temperatures. However, their yield strength is relatively low. In this study, an inexpensive element, phosphorus (P), was added to HEAs at a high concentration (0.4 %). The results indicate that adding P not only enhances both strength and ductility, but also avoids embrittlement. The P-added HEAs were single-phase random solid solutions, with P distributed inside the grains and partially segregated at the grain boundaries. Within the grains, regions rich in P and poor in P were observed, along with significant tensile and compressive strain fields in the P-rich regions. These strain fields may lead to large local internal stresses. The presence of P prevents brittleness due to its specific atomic distribution, whether in coarse or fine grains. The yield strength increased from 185.27 MPa in P-free homogenized HEAs to 296.1 MPa in P-added HEAs, representing an increase of approximately 60 % at 298 K. At 77 K, the strengths further increased, irrespective of grain size. Further, P added reduced the stacking fault energy. At room temperature (298 K), P-free HEAs formed dislocation cells and high-density dislocation wall structures, while P-added HEAs formed additional microbands, deformation twins, and stacking faults due to increased lattice frictional stress. P-added HEAs demonstrated excellent mechanical properties at cryogenic temperatures, with good strength-ductility synergy and strain-hardening capacity. These enhancements can be attributed to the synergistic effects of nano deformation twins, hierarchical nano-spaced stacking fault networks, and Lomer-Cottrell locks, as well as their extensive interactions.

Effects of Ta5+ substitution on mechanical and microwave dielectric properties of R(Nb1-xTax)2O6 ceramics

Microwave dielectric ceramics (MWDCs) are prone to mechanical failure, and improving the mechanical properties of MWDCs is of significance for their application under extreme conditions. Novel high-entropy R(Nb1-xTax)2O6 (R = Mg0.2Mn0.2Co0.2Ni0.2Zn0.2) ceramics were prepared by the solid-phase reaction method. The single-phase and composite solid solutions of the R(Nb1-xTax)2O6 series were successfully prepared, as evidenced by XRD, Raman spectra, and combined with EDS energy spectrum analysis. The average grain size was found to increase with the Ta5+ content, while the grain dispersion exhibited a trend of increasing and then decreasing, resulting in a trend of increasing and then decreasing Q×f. The replacement of Nb5+ by Ta5+ has been demonstrated to improve τf and enhance the mechanical properties. An increase in Ta5+ content from 0.5 to 0.75 results in a significant enhancement in εr and mechanical properties, which is primarily attributed to the generation of the RTa2O6 phase. When x = 1, the R(Nb1-xTax)2O6 ceramics exhibit excellent microwave dielectric properties (εr = 31.28, Q×f = 20,722, τf = 48.36) and the most favorable mechanical properties (Hv = 7.99 GPa, σ = 882 MPa, TRS = 237.7 MPa). This study provides a new idea to improve the mechanical properties of MWDCs.

Fabrication and luminescent properties of highly transparent novel high-entropy (Lu0.2Y0.2Gd0.2Yb0.2Er0.2)2O3 ceramic

The highly transparent novel high-entropy (Lu0.2Y0.2Gd0.2Yb0.2Er0.2)2O3 ceramic was successfully fabricated by the addition of 3 at.% ZrO2 and 10 at.% La2O3 introduced as sintering additives via vacuum sintering. A single-phase solid solution cubic structure of the ceramic was obtained with a relative density of 99.95 % and an average grain size of 6.91±3.28 µm. The grain boundary of the (Lu0.2Y0.2Gd0.2Yb0.2Er0.2)2O3 ceramic was clean with a thickness of only 1.3 nm. Further observations revealed uniform distribution of all elements in the grains, and the presence of La and Zr segregation (1.5 nm thick) at few grain boundaries, but causing very little light scattering. The in-line transmittance of high-entropy (Lu0.2Y0.2Gd0.2Yb0.2Er0.2)2O3 ceramic reached 80 % at 1100 nm, which was 98.7 % of the theoretical value of Er2O3 single crystal. Also, there were fluorescence emissions observed in the ultraviolet (311 nm), visible (563, 622 nm), and near-infrared (1032, 1535 nm) regions. In addition, the intense red emission and weak green emission were detected, and the broad emission with a peak at 1.5 μm was attributed to Stark splitting of Er3+ ions, so the corresponding mechanism was discussed. Results obtained suggest that the highly transparent novel high-entropy (Lu0.2Y0.2Gd0.2Yb0.2Er0.2)2O3 ceramic fabricated in this study could have broad application prospects in optical applications such as scintillators, up-conversion luminescent materials, and infrared lasers.

Design, preparation and properties of biomedical Ti-Nb quaternary alloys with high strength and low modulus: insights from first-principles calculations

In this paper, we designed and developed biomedical β-type Ti-Nb quaternary alloy materials with high strength and low modulus. Building upon the d-electron alloy design method and the valence electron concentration e/a method, we use a Python program and thermodynamic theoretical parameters to determine a Ti-Nb quaternary alloy with the characteristics of a single-phase solid solution. Subsequently, we engage in theoretical and experimental investigations on the low modulus alloys identified through first-principles calculations. The results show that both Ti7Nb6Zr1Al2 and Ti11Nb2Ta2Al1 maintain a single β phase before and after cold rolling, which is related to the strong electronic density of states of s and p orbitals at low energy levels in the crystal structure of the two alloys. Ti11Nb2Ta2Al1 has a strong charge distribution on the (001) crystal plane, which causes a large amount of internal stress under large deformation conditions to promote grain crushing and weaken the intensity of the (001)[1-10] texture in the ODF diagram of 2 = 45°. The cold-rolled Ti11Nb2Ta2Al1 exhibits better corrosion resistance and biocompatibility than the cold-rolled Ti7Nb6Zr1Al2, and the good biocompatibility is related to the strong covalent bond between Al and Ta that inhibits the diffusion of Al ions. 90% cold-rolled Ti11Nb2Ta2Al1 stands out as an exceptionally promising orthopedic implant material due to its high elastic allowable strain (ReH/E), good corrosion resistance and biocompatibility.

Natural arsenic bronze from the Varten Kamak copper occurrence, SW Bulgaria

In contrast to the traditionally offered methods for metallurgical production of the first bronze for mankind – arsenic bronze, the present study examines another possible natural source of this alloy. Geologically, the only deposit of native copper has been localized near the Varten Kamak hamlet in the area of the town of Boboshevo, SW Bulgaria. Samples of copper nugget were investigated by the methods of powder X-ray diffraction (XRD) and scanning electron microscopy with a microprobe for elemental composition (SEM-EDS). The results show that the analyzed substance is a single-phase solid solution of Cu and As, with As content up to 3.77%, which, according to the accepted nomenclature of archaeometallurgists, is called arsenic bronze. The present study offers a new perspective on the possible sources of arsenic bronze, which may enrich the archaeological sciences.

Highly dispersed anti-Stokes phosphors based on KGd2F7:Yb,Er single-phase solid solutions

Highly dispersed anti-Stokes phosphors based on KGd2F7:Yb,Er single-phase solid solutions

Rhombohedral phase high-entropy alloy of AlMnCuZnBi as a photo-Fenton catalyst for methyl orange degradation

The formation of solid solutions with five or more elements having nearly equiatomic contributions termed as high entropy alloys (HEA), is recent strategy for the development of new materials. Such alloys have displayed superior properties than the conventional ones. The prepared alloys are generally face- or body-centered cubic structures with a few exceptions for orthorhombic and hexagonal close packed structure. In this, we report the synthesis of HEA of AlMnCuZnBi having rhombohedral crystal structure. The material was prepared by vacuum arc melting route. Both the diffractions (X-ray and electron) confirm its structure. The calculated thermodynamic empirical parameters e.g. ΔSmix, ΔHmix, δ, VEC and Ω even validate the feasibility of this single phase solid solution. The HEA had shown feeble ferromagnetic behaviour. The rhombohedral structured HEA may open up new possibilities for various emerging applications. The proposed HEA acted as a catalyst for photo-Fenton like reaction and could degraded methyl orange dye completely in 170 minutes.

Structural phase transition from rhombohedral to monoclinic phase and physical properties of (1-x) Bi0.85La0.15FeO3 – (x) Ca0.5Sr0.5TiO3 ceramics prepared by the solid-state route

In the present work, a series of solid solutions were synthesized using the solid-state reaction method for x = 0.0, 0.05, 0.10, and 0.15 in system (1-x)Bi0.85La0.15FeO₃-(x)Ca0.5Sr0.5TiO3 or ((1-x)BLFO-(x)CSTO) ceramics. Structural, optical, dielectric, and ferroelectric properties were studied in detail to investigate the impact of CSTO doping in BFO. Rietveld analysis of X-ray diffraction data of all samples revealed the formation of a single-phase solid solution with a distorted rhombohedral perovskite structure for x = 0.00 and 0.05, characterized by R3c symmetry, a mix of rhombohedral (R3c) and monoclinic (Cc) phases for x = 0.10 (R3c 31 % and Cc 69 %), whereas for x = 0.15 a single-phase solid solution with Cc symmetry was found. UV–visible analysis demonstrated that the optical band gap was increased from 2.11 eV for x = 0.0 to 2.21 eV for x = 0.15 in the visible range, and can be used in photovoltaics applications. The room temperature dielectric properties were measured, and a crucial role of CSTO was revealed in modifying the dielectric properties of BLFO ceramics; the dielectric constant and dielectric loss at 10 kHz change from εr = 82 and tanδ = 0.88 for x = 0.0 to εr = 116 and tanδ = 1.08 for x = 0.15. The leakage current density decreases while increasing the CSTO % from x = 0.0 to 0.15 due to the suppression of oxygen and Bi vacancies, a fact that is further reflected in the ferroelectric properties of CSTO-doped BFO ceramics. Room temperature ferroelectric properties improved with CSTO doping, and Pr was found to be 0.24 μC/cm2, 0.28 μC/cm2, and 0.84 μC/cm2 for x = 0.05, 0.10, and 0.15, respectively.

Microsphere LiMn0.6Fe0.4PO4/C cathode with unique rod-like secondary architecture for high energy lithium ion batteries

LiMnxFe1-xPO4/C is considered a promising next-generation cathode material with significant commercial potential, inheriting the safety of LiFePO4 while offering higher energy densities. However, the extremely low conductivity and the Jahn-Teller effect induced by Mn3+ limit its practical capacity and rate performance. Effective modifications can be achieved through particle nanonization and uniform carbon coating. Here, we synthesized microspherical LiMn0.6Fe0.4PO4/C cathode materials using a hydrothermal method combined with spray drying carbon coating. The cathode material exhibits a microsphere structure composed of aggregated nanorods with a uniform 3 nm carbon coating, showing good dispersibility, small specific surface area and high tap density. In-situ diffraction analysis showed that expanding the single-phase solid solution region during (de)lithiation can reduce the energy barrier for electron transport, improve the kinetics of the (dis)charge process, and enhance both cycling and rate performance. The initial capacity at 0.1C can reach 155 mAh/g, and the capacity remains at 133.5 mAh/g with a retention rate of 97.1 % after 300 cycles. The synergistic effect of particle nanonization and uniform carbon coating endows the LiMnxFe1-xPO4/C material with excellent electrochemical performance.

Effect of Cr content on the high temperature oxidation behavior of FeCoNiMnCrx porous high-entropy alloys

FeCoNiMnCr porous high-entropy alloys were prepared using the activation reaction sintering method with Fe, Co, Ni, Mn, and Cr as raw materials. The oxidation behaviors of FeCoNiMnCrx porous high-entropy alloys with different Cr contents, such as pore structure, the surface oxide film phase composition, structure, and morphology, were characterized by X-ray diffraction (XRD), electron probe micro analysis (EPMA), energy dispersive X-ray spectroscopy (EDS), and pore tester after high-temperature oxidation at 800–1000 °C. The results indicate that the initial porous high-entropy alloy comprises a single FCC solid solution phase. With the increase in Cr content, the average pore diameter, average porosity, and air permeability of the porous high-entropy alloy also increase. The oxidation kinetics of the porous high-entropy alloy after exposure to temperatures between 800 °C and 1000 °C follows a single-stage parabolic evolution law. At the same oxidation temperature, With the increase of Cr content, the oxidation gains gradually increased, at the same Cr content at different temperatures, the antioxidant performance of 1000 °C was the weakest, followed by 800 °C, and 900 °C showed excellent antioxidant performance. The oxidation products are mainly Mn2O3, Mn3O4, (Mn, Cr)3O4, Cr2O3and Fe2O3.

Phase Composition of AlTiNbMoV, AlTiNbTaZr and AlTiNbMoCr Refractory Complex Concentrated Alloys: A Correlation of Predictions and Experiment

Designing complex concentrated alloys (CCA), also known as high entropy alloys (HEA), requires reliable and accessible thermodynamic predictions due to vast space of possible compositions. Numerous semiempirical parameters have been developed for phase predictions over the years. However, in this paper we show that none of these parameters is a robust indicator of phase content in various refractory CCA. CALPHAD proved to be a more powerful tool for phase predictions, however, the predictions face several limitations. AlTiNbMoV, AlTiNbTaZr and AlTiNbMoCr alloys were prepared using blended elemental powder metallurgy. Their phase and chemical composition were investigated by the means of scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Apart from the minor contamination phases (Al2O3 and Ti(C,N,O)), AlTiNbMoV and AlTiNbMoCr exhibited single-phase solid solution microstructure at the homogenization temperature of 1400 °C, while Al3Zr5 based intermetallics were present in the AlTiNbTaZr alloy. None of the simple semiempirical parameter was able to predict phase content correctly in all three alloys. Predictions by CALPHAD (TCHEA4 database) were able to predict the phases with limited accuracy only. Critical limitation of the TCHEA4 database is that only binary and ternary phase diagrams are assessed and some more complex phases cannot be predicted.

Improved oxidation behavior of Hf0.11Al0.20B0.69 in comparison to Hf0.28B0.72 magnetron sputtered thin films

The oxidation resistance of Hf0.28B0.72 and Hf0.11Al0.20B0.69 thin films was investigated comparatively at 700 °C for up to 8 h. Single-phase solid solution thin films were co-sputtered from HfB2 and AlB2 compound targets. After oxidation at 700 °C for 8 h an oxide scale thickness of 31 ±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm$$\\end{document} 2 nm was formed on Hf0.11Al0.20B0.69 which corresponds to 14% of the scale thickness measured on Hf0.28B0.72. The improved oxidation resistance can be rationalized based on the chemical composition and the morphology of the formed oxide scales. On Hf0.28B0.72 the formation of a porous, O, Hf, and B-containing scale and the formation of crystalline HfO2 is observed. Whereas on Hf0.11Al0.20B0.69 a dense, primarily amorphous scale containing O, Al, B as well as approximately 3 at% of Hf forms, which reduces the oxidation kinetics significantly by passivation. Benchmarking Hf0.11Al0.20B0.69 with Ti–Al-based boride and nitride thin films with similar Al concentrations reveals superior oxidation behavior of the Hf-Al-based thin film. The incorporation of few at% of Hf in the oxide scale decelerates oxidation kinetics at 700 °C and leads to a reduction in oxide scale thickness of 21% and 47% compared to Ti0.12Al0.21B0.67 and Ti0.27Al0.21N0.52, respectively. Contrary to Ti–Al-based diborides, Hf0.11Al0.20B0.69 shows excellent oxidation behavior despite B-richness.

Design of air-stabilized Mg-Sc alloy with enhanced hydrogen storage properties via in-situ formation of Sc-hydride in Sc dissolved phase

Severe surface oxidation and slow kinetic rates are the main obstacles which limit the industrial application of Mg-based hydrogen storage alloys. In this work, an attempt is carried out to design and develop the highly active and air-stabilized Mg-Scx (x = 1, 2 and 3 at.%) alloys via an inexpensive and efficient method. The Sc atoms are completely dissolved in the Mg matrix to form single-phase solid solution alloy. At 325 °C and 2.0 MPa hydrogen pressure, Mg-Sc2 alloy exhibits the rapidest absorption rate with the hydrogen capacity of 6.25 wt%. The synergism of lattice distortion induced by Sc-doping and the in-situ formed ScH2 nanoparticles enhance the de/hydrogenation kinetics. After exposed to air for 800 h, almost no MgO can be detected and the hydrogen storage capacity is only reduced by 0.11 wt%, maintaining the initial total capacity more than 98 %. Sc can protect Mg-based alloys from O2 and H2O pollution, which is ascribed to the formation of an oxygen atoms exclusion zone around the solute atoms caused by valence electrons transfer.

Controlled synthesis of tantalum-based solid solution and exploration of electrochemical properties as soluble anode for molten salt electrolysis

Metal oxycarbide solid solution possesses an extensive potential applications due to its remarkable physical features. In this paper, TaCxO1-x solid solution is successively and controllably synthesized by carbothermal reduction of Ta2O5. Based on the thermodynamic calculation, the possible reactions under different conditions in the carbothermal reduction process were analyzed, which provides theoretical guidance for controllable regulation and optimization of carbon thermal reduction process. The effects of carbon content, sintering temperature, and holding time on the synthesis of TaCxO1-x solid solution were investigated and the ideal process parameters for the synthesis of single-phase solid solution were identified. A single-phase solid solution with a carbon‑oxygen ratio close to 1:1 can be created as a soluble anode if the synthesis temperature is 1500 °C, the holding period is 6 h, and the molar ratio of C/Ta is 3.42. Moreover, the process feasibility of preparing metal tantalum by electrolysis of tantalum-based soluble anode is discussed, which provides a new method for metal tantalum preparation.

The Micron-Droplet-Confined Continuous-Flow Synthesis of Freestanding High-Entropy-Alloy Nanoparticles by Flame Spray Pyrolysis.

Alloying multiple immiscible elements into a nanoparticle with single-phase solid solution structure (high-entropy-alloy nanoparticles, HEA-NPs) merits great potential. To date, various kinds of synthesis techniques of HEA-NPs are developed; however, a continuous-flow synthesis of freestanding HEA-NPs remains a challenge. Here a micron-droplet-confined strategy by flame spray pyrolysis (FSP) to achieve the continuous-flow synthesis of freestanding HEA-NPs, is proposed. The continuous precursor solution undergoes gas shearing and micro-explosion to form nano droplets which act as the micron-droplet-confined reactors. The ultrafast evolution (<5ms) from droplets to <10nm nanoparticles of binary to septenary alloys is achieved through thermodynamic and kinetic control (high temperature and ultrafast colling). Among them, the AuPtPdRuIr HEA-NPs exhibit excellent electrocatalytic performance for alkaline hydrogen evolution reaction with 23mV overpotential to achieve 10mA cm-2, which is twofold better than that of the commercial Pt/C. It is anticipated that the continuous-flow synthesis by FSP can introduce a new way for the continuous synthesis of freestanding HEA-NP with a high productivity rate.

Manufacturing of Ni-Co-Fe-Cr-Al-Ti High-Entropy Alloy Using Directed Energy Deposition and Evaluation of Its Microstructure, Tensile Strength, and Microhardness.

High-entropy alloys (HEAs) have drawn significant attention due to their unique design and superior mechanical properties. Comprising 5-35 at% of five or more elements with similar atomic radii, HEAs exhibit high configurational entropy, resulting in single-phase solid solutions rather than intermetallic compounds. Additive manufacturing (AM), particularly direct energy deposition (DED), is effective for producing HEAs due to its rapid cooling rates, which ensure uniform microstructures and minimize defects. These alloys typically form face-centered cubic (FCC) or body-centered cubic (BCC) structures, contributing to their exceptional strength, hardness, and mechanical performance across various temperatures. However, FCC-structured HEAs often have low yield strengths, posing a challenge for structural applications. In this study, a Ni-Co-Fe-Cr-Al-Ti HEA was manufactured using the DED method. This study proposes that the addition of aluminum and titanium creates a γ + γ' phase structure within a multicomponent FCC-HEA matrix, enhancing the thermal stability and coarsening the resistance and strength. The γ' phase with an ordered FCC structure significantly improves the mechanical properties. Analysis confirmed the presence of the γ + γ' structure and demonstrated the alloy's high tensile strength and microhardness. This approach underscores the potential of AM techniques in advancing HEA production for high-performance applications.