CoCrFeNi High-entropy Alloy Research Articles

Microstructure characterization and mechanical properties of electron beam welded joints of WRe alloy and CoCrFeNi high entropy alloys

In this study, vacuum electron beam welding was performed on WRe/CoCrFeNi alloy, resulting in joint interfaces resembling brazing. The research primarily focused on microstructure, phase composition, grain orientation and texture, interface bonding characteristics, mechanical properties, and fracture mechanisms of the welded joints. The weld zone consisted of columnar, cellular, and equiaxed regions, influenced by solidification rate. Employing the PHACOMP method, it is predicted that the introduction of W element in the weld zone tends to precipitate the FCC phase into the μ-phase. Grain competition during weld growth led to differences in grain orientation. A strong cubic texture {001} <100> was observed in the weld, enhancing its ductility. The impact of Kirkendall voids and IMCs on the bonding at the WRe/WZ interface was discussed. Microhardness of the weld increased due to grain refinement and precipitation strengthening. The joint exhibited a tensile strength of 189 MPa and an elongation of 10 %, with a fracture mechanism characterized by interface brittle fracture and fusion zone ductile fracture. The interface fracture was attributed to Kirkendall voids, IMCs, and significant residual stresses induced by material CTE mismatch. Furthermore, deep dimples and slip bands on cleavage planes at the fracture surface bottom, along with low-angle grain boundaries promoting localized slip, indicated good plasticity in the fusion zone.

Microstructure and corrosion property of TC4 coating with Al0.5CoCrFeNi high-entropy alloy interlayer by laser cladding

In this work, TC4 coating was prepared on 45 steel surface successfully by laser cladding and Al0.5CoCrFeNi high-entropy alloys (HEA) coating was designed as an intermediate layer. Microstructure, microhardness and electrochemical corrosion characteristics of TC4/HEA composite coating were evaluated in detail. The interfaces without cracks of HEA layer/substrate and TC4 layer/HEA layer are clear and straight, and a metallurgical bonding is obtained when the line energy density is 315 J/mm2 and 180 J/mm2. A reactive layer consisted of TiAl and TiFe intermetallic compounds (IMC) is formed at TC4/HEA interface. The HEA transition layers are composed of uniformly distributed equiaxed matrix (FCC) and intercrystalline phase (BCC), while a transition from Widmanstätten structure to coarse acicular crystal was found in TC4 layer. The microhardness of HEA coating is slightly higher than the substrate and lower than the TC4 coating, and the microhardness value of TC4 layer is up to 745.8 HV0.2. Potential dynamic polarization curves test results show that a comparatively small corrosion zone is concluded for TC4/HEA composite coating sample and the corrosion resistance of the composite coating is significantly improved with an increased value of 55.9 % in Ecorr (−0.325 V) and a decreased value of 99.3 % in Icorr (0.1 μA/cm2) compared to the substrate.

Effect of Heat Treatment on the Microstructure and Mechanical Properties of the Al0.6CoCrFeNi High-Entropy Alloy.

The effect of heat treatment on the microstructure and tensile properties of an as-cast Al0.6CoCrFeNi high-entropy alloy (HEA) was investigated in this paper. The results show that the as-cast Al0.6CoCrFeNi HEA presents a typical FCC dendrite morphology with the interdendritic region consisting of BCC/B2 structure and heat treatment can strongly affect the microstructure and mechanical properties of HEA. Microstructure analysis revealed the precipitation of a nano-sized L12 phase in the FCC dendrite and the formation of the FCC and σ phases in the interdendritic region after annealing at 700 °C. The coarse B2 phase was directly precipitated from the FCC dendrite in the 900 °C-annealed sample, with the coexistence of the B2, FCC, and σ phases in the interdendritic region. Then, the interdendritic region converted to a B2 and FCC dual-phase structure caused by the re-decomposition of the σ phase after annealing at 1100 °C. The tensile test results show that the 700 °C-annealed HEA presents the most significant strengthening effect, with increments of corresponding yield strength being about 107%, which can be attributed to the numerous nano-sized L12 precipitates in the FCC dendrite. The mechanical properties of 1100 °C-annealed alloy revert to a level close to that of the as-cast alloy, which can be attributed to the coarsening mechanism of B2 precipitates and the formation of a soft FCC phase in the interdendritic region. The observed variation in mechanical properties during heat treatment follows the traditional trade-off relationship between strength and plasticity.

Transport Properties of Equiatomic CoCrFeNi High-Entropy Alloy with a Single-Phase Face-Centered Cubic Structure

The key thermophysical properties necessary for the successful design and use of CoCrFeNi alloy in thermophysical applications have been measured experimentally, and the results have been compared with literature values and results previously obtained for commercial Ni-Cr alloys and equiatomic CoCrFeNi alloy. In particular, the thermal diffusivity, coefficient of thermal expansion (CTE), and specific heat capacity were measured for the as-cast and homogenized equiatomic CoCrFeNi alloy over a temperature range allowing the thermal conductivity to be calculated up to 1173 K. The thermal conductivity and thermal diffusivity of the equiatomic CoCrFeNi alloy were found to deviate from monotonic behavior in the temperature range from 773 to 1100 K. Such a deviation was previously observed in the behavior of the temperature dependence of CTE and specific heat capacity of the equiatomic CoCrFeNi alloy. The non-linear behavior is primarily the result of order/disorder phenomena for the as-cast and homogenized sample, as well as non-equilibrium solidification under arc melting conditions for the as-cast sample. The measured data of thermophysical properties are provided for thermally differently treated samples, and it is shown that there is a difference in the behavior of the temperature dependences of CTE, thermal diffusivity, and heat capacity.

Preparation and effect of vanadium addition on the mechanical properties of CoCrFeNiVx high-entropy alloy

High-entropy alloys (HEAs) have attracted considerable attention due to their unique phase structures and excellent properties. However, the existing preparation processes for HEAs involve high temperatures, lengthy procedures, and high costs, which limit their practical applications and confine them to the realm of fundamental research. Here, a novel method combining low-temperature solid-phase molten salt electrolysis and hot-press sintering was proposed to prepare CoCrFeNi HEA. Moreover, the study explored the addition of metal V, to modulate the composition of the HEA and improve its mechanical properties. The results showed that the molten salt electrolysis process could achieve the direct deoxidation of metal oxide mixtures, enabling one-step preparation of HEAs. During the early stages of deoxidation, the metals Ni and Co were obtained first and, under the influence of the mixed entropy, formed a non-stoichiometric NiCoCr alloy. As deoxidation progressed, Cr and Fe were successively reduced and further alloyed with the NiCoCr to form the non-stoichiometric CoCrFeNi HEA. Eventually, the aggregated dendritic metal Fe diffused and solid-solved into the non-stoichiometric CoCrFeNi HEA, resulting in the formation of a stoichiometric CoCrFeNi HEA. The CoCrFeNiVx (x = 0, 0.5, 1, 1.5) alloy maintained a single-phase FCC structure, where V effectively improved the hardness of the CoCrFeNi HEA, with minimal impact on its phase structure. V played a role in solid-solution strengthening, grain refinement, and reducing Cr segregation in the alloy. Additionally, the appropriate addition of V simultaneously increased the tensile strength, hardness, and ductility of the CoCrFeNi HEA.

Influences of Ti and Mo alloying on the microstructure and properties of laser cladding for CoCrFeNi high-entropy alloys

The CoCrFeNiTi_(1-x) Mo_x high-entropy-alloy coating was prepared using a powder presetting method. The work investigated the influences of Ti and Mo addition on the microstructure and properties of CoCrFeNi high-entropy alloys. The first-principles calculation showed that CoCrFeNiTi_(1-x) Mo_x was mainly composed of the FCC phase, BCC phase, and IMCs. The coating exhibited high hardness, and the mechanical stability of the high-entropy alloys of FCC and BCC phases was maintained when x = 0.5. The coating primarily consisted of FCC, BCC, σand CoTi2 phases when x ≤ 0.75. The coating primarily consisted of FCC, BCC, σand Co2Mo3 phases when x = 1. It exhibited high microhardness, elastic modulus, elastic stiffness, and wear resistance when x = 0.5. Its average microhardness, local elastic modulus, and elastic stiffness were 873.28 HV0.5, 265.5606 GPa, and 102.8008 GPa, respectively. Besides, COF and the wear mass loss were 0.7026 mm3 and 0.0410 mm3, respectively. The coating exhibited exceptional corrosion resistance with a self-corrosion voltage of −0.700 V and a self-corrosion current of 5.387e-007 A when x = 1. The results offer practical guidance for preparing high-entropy-alloy coatings with various advantages as well as a theoretical foundation for preparing such alloys by laser cladding.

Microstructure and bending behavior of Ti/Al laminated composites reinforced with high-entropy alloy particles

Ti/Al laminated composites embedded with Al0.5CoCrFeNi high entropy alloy particles were prepared by vacuum hot press sintering process at temperatures of 660 °C and 730 °C. The microstructure of the material was initially examined using XRD, SEM, EDS, EBSD, and TEM techniques. The results of microstructural characterisation show that Al3Ti is the only newly generated phase in the materials prepared at two temperatures. The Al3Ti generated at the temperature of 660 °C is concentrated at the Ti/Al interface position. The Al3Ti generated at a temperature of 730 °C is dispersed in the Al matrix, leading to the formation of numerous Al3Ti/Al interfaces. The residual HEA particles were observed at the sites of oxide aggregation, potentially enhancing the connectivity of the weak interfaces. Following that, the flexural strength and fracture toughness of the composites were evaluated. The results indicate that the materials prepared at a temperature of 730 °C exhibit superior properties. The flexural strength perpendicular to the layer direction reaches 515.89 MPa, while the flexural strength parallel to the layer direction reaches 487.1 MPa. These findings demonstrate clear anisotropy in the flexural performance. Additionally, the material exhibits excellent resistance to crack extension, with a fracture toughness of 32.67 MPa√m.

Effects of Mo and Nb on the microstructure and high temperature oxidation behaviors of CoCrFeNi-based high entropy alloys

A series of CoCrFeNi(Mo, Nb) high entropy alloys (HEAs) were prepared using vacuum arc-melting. The effect of Nb and Mo on the microstructure and high temperature anti-oxidation properties of HEAs was investigated. The addition of only Mo was found to not cause formation of new phase, but did increase the lattice distortion. After the addition of Nb, as-prepared CoCrFeNiMo0.2Nb0.1 and CoCrFeNiMo0.2Nb0.2 alloys are characteristic of duplex-phase structures of FCC and Laves, in which the Laves phase is semi-coherent with FCC matrix. Our studies also revealed that the oxidation kinetics of the alloys followed parabolic rate law and the corresponding oxidation rate constants were calculated. Due to the synergistic effects of Mo and Nb, the anti-oxidation properties of HEAs improved significantly. It was also discovered that the new Laves phase containing Mo and Nb at the inner oxidation layer hindered the outward diffusion of active metal cations, ergo improving the oxidation resistance of HEAs. With increase of Nb content, it was further recognized that the layered structure of Laves phase was thinner and denser. Therefore, the oxygen ion diffusion process in the CoCrFeNiMo0.2Nb0.2 alloy can be inhibited effectively by the new formation of duplex-phase structures with undulated Laves phase and FCC matrix.

Effects of Ni/MoS2, Ag and Cr2O3 on the Microstructure and Mechanical Performance of a CoCrFeNi High-Entropy Alloy over a Wide Temperature Range

In the field of aerospace, core components require excellent wear resistance, lubrication and mechanical properties over a wide temperature range. In this study, three groups of CoCrFeNi high-entropy alloy (HEA)-based self-lubricating composites were designed with the addition of Ag, Ni/MoS2 and Cr2O3 using discharge-plasma-sintering technology. Their microstructure, phase composition, mechanical properties, friction and wear properties were analyzed. The results showed that, with the addition of Ag, the hardness and yield stress of HEA-Ni/MoS2-Ag were reduced by 36 HV and 24 MPa, respectively, while the plastic strain was increased by 2%. With the addition of Cr2O3, the hardness (382 HV) and yield stress (430 MPa) of HEA-Ni/MoS2-Ag-Cr2O3 reached their highest values, but the plastic strain reached its lowest value. HEA-Ni/MoS2-Ag-Cr2O3 had the smallest friction coefficient in which the friction coefficient at 800 °C was only 0.42. Additionally, it had a small wear rate of 3.2 × 10−6 mm3/Nm over a wide temperature range. At lower temperatures, Ni/MoS2 and Ag were conducive to lubrication, and the wear resistance was improved by the presence of Cr2O3. At high temperatures, a nickel oxide phase and a variety of silver molybdate phases were formed via a tribochemical reaction, which was vital to the high-temperature tribological properties.

Temperature gradient enhances the solidification process and properties of a CoCrFeNi high-entropy alloy: Atomic insights from molecular dynamics simulations

Material properties are substantially affected by the process during fabrication. To what extent for high-entropy alloys (HEAs), however, is still an open question. Herein, we investigated the effect of a temperature gradient on the solidification of a CoCrFeNi HEA using molecular dynamic simulations. The nucleation and crystal growth under gradient temperatures significantly differ from those under homogeneous temperatures. The HEA solidified by a temperature gradient forms a single and uniform face-centered cubic (FCC) crystalline phase, and the residual stresses in the solidified tissue are optimized. During the homogeneous solidification process, in addition to the FCC phase, the hexagonal close-packed (HCP) phase and a small amount of body-centered cubic (BCC) phase were also formed. When the temperature gradient is 100 K, the stress distribution in the solidification microstructure is relatively low. Increasing the temperature gradient can enhance the crystallinity of the solidification microstructure. While, an increase in cooling rate will lead to a reduction in the crystallinity of the solidification microstructure and an increase in internal stresses within the solidification microstructure. A slight short-range order (SRO) phenomenon present in both solidified structures. Our atomistic insights might be helpful in the fundamental understanding and material design of HEAs.

Coalescence of Al0.3CoCrFeNi polycrystalline high-entropy alloy in hot-pressed sintering: a molecular dynamics and phase-field study

Existing hot sintering models based on molecular dynamics focus on single-crystal alloys. This work proposes a new multiparticle model based on molecular dynamics to investigate coalescence kinetics during the hot-pressed sintering of a polycrystalline Al0.3CoCrFeNi high-entropy alloy. The accuracy and effectiveness of the multiparticle model are verified by a phase-field model. Using this model, it is found that when the particle contact zones undergo pressure-induced evolution into exponential power creep zones, the occurrences of phenomena, such as necking, pore formation/filling, dislocation accumulation/decomposition, and particle rotation/rearrangement are accelerated. Based on tensile test results, Young’s modulus of the as-sintered Al0.3CoCrFeNi high-entropy alloy is calculated to be 214.11 ± 1.03 GPa, which deviates only 0.82% from the experimental value, thus further validating the feasibility and accuracy of the multiparticle model.

Microstructure analysis of a CoCrFeNi high-entropy alloy after compressive deformation

A sharp increase in the dislocation density and in the fraction of low-angle grain boundaries (LAGBs) has often been observed during the early-stage deformation of high-entropy alloys. To study the underlying reasons for this behavior, the microstructure of plastic deformation applying at a low compressive strain of 3.3% was analyzed in the CoCrFeNi high-entropy alloy. This deformation results in a relatively higher dislocation density in the CoCrFeNi alloy in comparison to that in pure Nickel. A significantly increased dislocation density was observed near grain boundaries that is collaborated by a low value of the anisotropy factor (Az ∼ 2.37) in CoCrFeNi alloys offering favorable conditions for dislocation generation. Moreover, the low anisotropy factor in CoCrFeNi alloys appears to be caused by their strong chemical heterogeneity. The relatively easy dislocation generation provides an important feature of dislocation interactions in the CoCrFeNi alloy. Local high hardness and high Young's modulus values were observed at newly-formed LAGBs. The evolution of LAGBs strongly depends on the grain orientation and the internal strain, and LAGBs are gradually formed by the accumulation and self-organization into LAGBs at a surprisingly low strain of about 2.61%. The formation of these boundaries is intrinsically promoted by the low stacking fault energy of the CoCrFeNi alloy. An easy dislocation generation and a low strain of LAGB formation result in a high density of retained dislocations, giving rise to the observed mechanical performance of the material.

Effect of Pt Addition on the Oxidation and Corrosion Resistance of Al0.25CoCrFeNi High-Entropy Alloy

The effect of minor platinum alloying on the microstructure, phase composition, oxidation and corrosion resistance of Al0.25CoCrFeNi high-entropy alloy (HEA) has been studied. It was observed that Pt does not segregate as a separate phase, but it is incorporated into the fcc solid solution. High-temperature oxidation of the as-cast Al0.25CoCrFeNi and Al0.25CoCrFeNiPt0.1 high-entropy alloys was carried out in a muffle furnace under isothermal conditions at 900 °C for 0–50 h (weighing was carried out every 10 h) in air atmosphere. The specific weight gain decreased from 0.58 mg/cm2 for Al0.25CoCrFeNi to 0.31 mg/cm2 for the platinum-doped Al0.25CoCrFeNiPt0.1 sample. It was determined that Pt triggers the formation of an interlayer Al-rich oxide phase between the outer Cr-rich oxide layer and the interior of the alloy, significantly reducing the oxidation rate of Al0.25CoCrFeNiPt0.1 HEA. Electrochemical tests in 0.5 M H2SO4 solution demonstrated passive behavior with anodic control of the process.

An atomistic study on grain-size and temperature effects on mechanical properties of polycrystal CoCrFeNi high-entropy alloys

The origin of the outstanding mechanical properties of high-entropy alloys (HEAs) is still elusive. In this paper, we have investigated the influence of grain size and temperature on the mechanical properties of polycrystalline CoCrFeNi HEAs via molecular dynamics simulations. The critical grain size for the inverse Hall-Petch effect in CoCrFeNi HEAs is approximately 11.65 nm. During the stage of the positive Hall-Petch effect (where smaller grain sizes lead to higher tensile strength), there is a positive correlation between the tensile strength and dislocation density in CoCrFeNi HEAs. The higher tensile strength at low temperatures in CoCrFeNi HEAs is also attributed to an increase in dislocation density. At low temperatures, the reduced thermal vibrations of atoms slow down the motion of dislocations, leading to an increased storage time of dislocations within the crystal. In the stage of the inverse Hall-Petch effect, due to a significant reduction in grain size, the storage capacity of dislocations within grains decreases. This leads to the accumulation of more dislocations at grain boundaries, forming defects, and consequently causing a decrease in the tensile strength of CoCrFeNi HEAs as the grain size decreases. Our results might be helpful in material design of polycrystal HEAs.

Interstitial-oxygen induced and magnetically driven HCP-to-FCC transformation in CoCrFeNiOx high-entropy alloy: a first-principles study

ABSTRACT We report the influences of oxygen interstitials and magnetisms on phase stability and structural transformation of CoCrFeNi high-entropy alloy (HEA) from first-principles calculations. It is found the formation of oxygen interstitials is energetically favourable to occur in face-centred cubic (FCC) CoCrFeNiOx HEA as compared with that in hexagonal close-packed (HCP) one, and at those octahedral sites neighbouring with more Cr or less Ni. Meanwhile, it is determined the HEA prefers FCC over HCP phases when the oxygen concentration exceeds 4.2 and 5.1 at.% with and without considering its magnetisms, respectively. The HCP-to-FCC structural transformation in CoCrFeNiOx HEA could be magnetically driven, accompanied by the significant changes in the atomic magnetic moments in the HEA, particularly with an oxygen interstitial concentration larger than 2.7 at.%. Furthermore, the HCP-to-FCC transformation under hydrostatic pressure in CoCrFeNi and CoCrFeNiOx HEAs is investigated from generalised stacking fault energies, and it is revealed that the synergy effects of oxygen interstitials and magnetisms could facilitate the transformation in CoCrFeNiOx HEA. The coupled interstitials-induced and magnetically driven structural transformation paves a new avenue for the application of HEAs.

Fabrication of large-depth and multiscale gradient microstructure in dual-phase high entropy alloy via shock loading

Large-depth and multiscale gradient microstructure in dual-phase Al0.6CoCrFeNi high entropy alloy (HEA) were fabricated by explosion hardening (EH) technique. The gradient microstructure evolution was investigated in detail. The microhardness distribution and tensile properties near EH affected surface were also determined. The formation and strengthening mechanisms of gradient microstructure after EH treatment were subsequently analyzed. Experimental results showed that the multiscale gradient microstructure in terms of grain size, phase morphology, dislocation structure, texture was induced in dual-phase (BCC + FCC) HEA by EH technique. The closer to EH affected surface, the finer grain size, higher dislocation density and stronger texture intensity. The deformation and break of spinodal decomposition and formation of new grain boundaries by dislocation structure contributed to grain refinement and transition of equiaxed grains to dendritic grains from lower area to EH affected surface. After EH treatment, the microhardness generally increased with a maximum increase of ∼67% within 5 mm from EH affected surface, the tensile yield stress increased from 320 MPa to maximum of 700 MPa. The strengthening mechanism is different at various depth positions: near EH affected surface, the main strengthening mechanism is high-density dislocations, stacking faults and grain refinement; in areas relatively far from EH affected surface, only dislocation structure contributed to the strengthening of mechanical properties.

Effect of microstructure evolution on wear resistance of equal molar CoCrFeNi high-entropy alloy

Effect of microstructure evolution on wear resistance of equal molar CoCrFeNi high-entropy alloy

Effect of Doping with Different Nb Contents on the Properties of CoCrFeNi High-Entropy Alloys.

A series of five-element CoCrFeNi-Nbx (x = 0, 1, 3, 5, 7, and 9 wt%) high-entropy alloys were prepared using high-energy ball milling and discharge plasma sintering methods. Then, the effects of doping with Nb elements on the organization and properties of the CoCrFeNi HEAs were systematically investigated by tensile testing, hardness testing, and examining their micro-morphologies. The results show that with the addition of the Nb element, the lattice distortion of the alloy due to the large size of the Nb atoms causes the microstructure of CoCrFeNi HEAs to change from a single-phase FCC structure to a dual-phase structure of FCC and Laves. With the increase in the Nb content, the increase in the volume fraction of the hard and brittle Laves phase leads to the enhancement of the HEA's tensile strength, yield strength, and hardness, and a decrease in plasticity. The Nb5 alloy showed the most excellent comprehensive performance, with a tensile strength, yield strength, and plasticity of 879.1 MPa, 491.8 MPa, and 39.8%, respectively, and all the properties were improved compared with those of the HEAs obtained by the arc melting method. The increase in the hardness of the HEAs was nearly proportional to the increase in the volume fraction of the Laves phase, which was the direct cause of the increase in the hardness of the HEA. Therefore, since the Laves phase is the direct cause of the increase in HEA hardness, the doping of CoCrFeNi HEAs with Nb can significantly improve the properties of HEAs.

Temperature-dependent liquid metal embrittlement of Al0.7CoCrFeNi high-entropy alloys induced by equiatomic GaInSnZn melts

The equiatomic GaInSnZn (GISZ) high-entropy alloys (HEAs) are considered to have the potential as coolants to engage the thermal management owing to their high thermal conductivity. However, the incompatibility between them and other structural materials hinders these practical applications. On the way to seeking suitable structural metals with liquid metal embrittlement (LME) resistance in GISZ environment, the Al0.7CoCrFeNi alloys are selected and their temperature-dependent LME sensitivity is investigated through high temperature and slow strain-rate tensile tests at 100, 300 and 500 ℃. The sharp decrease in tensile ductility and serious LME phenomenon are explicitly inspected at all temperatures. The transformation of the LME mechanism, which shifts from adsorption-induced reduction in cohesion of the interior or boundaries of grain colonies to grain/phase boundary wetting with temperature increasing, is corroborated by the fractographic analysis and crack propagation path. This study not only provides guidance for the LME of this new system, but also encourages a promising landscape for searching for protective measures of Al0.7CoCrFeNi alloys and new materials adapted to GISZ, thereby laying a solid foundation for promoting liquid metal cooling applied to the actual industry.

A Study of the Microstructure and Mechanical and Electrochemical Properties of CoCrFeNi High-Entropy Alloys Additive-Manufactured Using Laser Metal Deposition

This work demonstrates the successful additive manufacturing of an in situ-alloyed CoCrFeNi HEA with a single phase (FCC) structure via the laser metal deposition (LMD) technique. In this work, bulk specimens of the CoCrFeNi high entropy alloy (HEA) of size 15 mm × 15 mm × 45 mm were additive-manufactured (AMed). An H320-type additive-subtractive manufacturing all-in-one system with a 2 kW fiber laser with a coaxial nozzle head integrated in a five-axis CNC machine was used. The effect of varying laser powers (1000 W, 1300 W, and 1600 W) on the microstructure and mechanical and electrochemical properties of the AMed HEA specimens was investigated. The AMed specimens were analyzed for their microstructure, elemental distributions, microhardness, and mechanical and electrochemical properties. An increase in the laser power led to a non-uniform cooling rate and non-steady solidification rates of the molten area during the AM process. As a result, the crystal constant decreased, and the microhardness fluctuated within a narrow range across the specimen. Among the three laser powers, the AMed CoCrFeNi HEA at 1300 W had the optimal mechanical properties and the best electrochemical behavior in 3.5 wt.% NaCl solution.