Fe Cr Ni Alloys Research Articles

Heterogeneous grain size and enhanced hardness by precipitation of the BCC particles in medium entropy Fe–Ni–Cr alloys

We report the chemical-composition-dependent precipitation of Cr-rich BCC particles and their role in the hardening of Fe–Cr–Ni medium entropy alloys (MEAs). Three alloys with different chemical compositions: 33Fe–32Cr–35Ni MEA (33Fe), 40Fe–30Cr–30Ni MEA (40Fe), and 45Fe–30Cr–25Ni MEA (45Fe) (at%), were investigated. After annealing at 800 and 950 °C, all three alloys had a heterogeneous grain size distribution, except for 40Fe annealed at 950 °C. The samples annealed at 800 °C showed a more heterogeneous grain size distribution, smaller average grain size, and lower degree of recrystallization than the samples annealed at 950 °C. This difference is ascribed mainly to the contents and precipitation kinetics of Cr-rich BCC particles at the two temperatures. The hardness decreased with the increase in annealing temperature for all the samples. The 33Fe sample exhibited higher hardness than 40Fe and 45Fe because of the joint effect of grain boundary strengthening and precipitation strengthening by the Cr-rich BCC particles. Different peak-load-dependent hardness behaviors were observed in 33Fe-A800 with relatively coarse BCC particles and 40Fe-A800 with fine BCC particles. The fine particles led to higher local hardness, whereas coarse particles resulted in higher microhardness owing to the hetero-deformation-induced strengthening effect. These results provide new insights into the strength optimization of medium- and high-entropy alloys through the dispersion of coarse Cr-rich BCC particles.

Toward an efficient recycling system: Evaluating recyclability of end‐of‐life stainless steels by considering elements distribution during a remelting process

AbstractStainless steel is a special category of steel and contains high chromium and nickel. With particular attention to chromium and nickel, the solvent metal phase of recycling of end‐of‐life (EoL) ferritic and austenitic stainless steels by remelting is considered Fe–Cr alloy and Fe–Cr–Ni alloy instead of pure iron, respectively. Understanding the element elimination behavior from the solvent metal phase during the remelting process is important for the improvement of the resource efficiency of the stainless steel recycling. The elimination behavior of 23 alloying elements from Fe–Cr alloy and 22 alloying elements from Fe–Cr–Ni alloy were quantitatively evaluated by the thermodynamic method. The conventional metallurgical process, including slagging (oxidation) and evaporation, can efficiently eliminate lots of alloying elements but has its limitation for the elimination of some alloying elements such as copper, antimony, and tin. Moreover, improvement of the elimination is hard to expect with optimizing remelting conditions. Developing novel metallurgical refining processes, such as chlorination and sulfurization, is efficient for eliminating specific alloying elements. However, besides the effort from metallurgical technologies, developing advanced physical separation technologies of collected EoL products in the short term and optimizing the alloy/products design principle in the long term are much more important for improving the resource efficiency of recycling of EoL stainless steel products. Feedback of the alloying elements' elimination behavior during the remelting process to the upstream of the stainless steel cycle is critical.

Artificial Intelligence Approach to Predict Elevated Temperature Cyclic Oxidation of Fe–Cr and Fe–Cr–Ni Alloys

Artificial Intelligence Approach to Predict Elevated Temperature Cyclic Oxidation of Fe–Cr and Fe–Cr–Ni Alloys

Visualizing the Nanoscale Oxygen and Cation Transport Mechanisms during the Early Stages of Oxidation of Fe–Cr–Ni Alloy Using In Situ Atom Probe Tomography (Adv. Mater. Interfaces 20/2022)

Visualizing the Nanoscale Oxygen and Cation Transport Mechanisms during the Early Stages of Oxidation of Fe–Cr–Ni Alloy Using In Situ Atom Probe Tomography (Adv. Mater. Interfaces 20/2022)

In situ neutron diffraction unravels deformation mechanisms of a strong and ductile FeCrNi medium entropy alloy

• An equiatomic medium entropy FeCrNi alloy with excellent strength-ductility balance at 293 and 15 K was presented. • The single-crystal elastic constants and bulk moduli were calculated by neutron diffraction and density functional theory simulation. • The role of severe lattice distortion and dislocations in strengthening the medium entropy alloy was explored and quantified in 293 and 15 K. • Severe lattice distortion made the greatest contribution to the yield strength of the alloy. We investigated the mechanical and microstructural responses of a high-strength equal-molar medium entropy FeCrNi alloy at 293 and 15 K by in situ neutron diffraction testing. At 293 K, the alloy had a very high yield strength of 651 ± 12 MPa, with a total elongation of 48% ± 5%. At 15 K, the yield strength increased to 1092 ± 22 MPa, but the total elongation dropped to 18% ± 1%. Via analyzing the neutron diffraction data, we determined the lattice strain evolution, single-crystal elastic constants, stacking fault probability, and estimated stacking fault energy of the alloy at both temperatures, which are the critical parameters to feed into and compare against our first-principles calculations and dislocation-based slip system modeling. The density functional theory calculations show that the alloy tends to form short-range order at room temperatures. However, atom probe tomography and atomic-resolution transmission electron microscopy did not clearly identify the short-range order. Additionally, at 293 K, experimental measured single-crystal elastic constants did not agree with those determined by first-principles calculations with short-range order but agreed well with the values from the calculation with the disordered configuration at 2000 K. This suggests that the alloy is at a metastable state resulted from the fabrication methods. In view of the high yield strength of the alloy, we calculated the strengthening contribution to the yield strength from grain boundaries, dislocations, and lattice distortion. The lattice distortion contribution was based on the Varenne-Luque-Curtine strengthening theory for multi-component alloys, which was found to be 316 MPa at 293 K and increased to 629 MPa at 15 K, making a significant contribution to the high yield strength. Regarding plastic deformation, dislocation movement and multiplication were found to be the dominant hardening mechanism at both temperatures, whereas twinning and phase transformation were not prevalent. This is mainly due to the high stacking fault energy of the alloy as estimated to be 63 mJ m −2 at 293 K and 47 mJ m −2 at 15 K. This work highlights the significance of lattice distortion and dislocations played in this alloy, providing insights into the design of new multi-component alloys with superb mechanical performance for cryogenic applications.

Chemical Analysis and Electrochemical Monitoring of Extremely Low-Concentration Corrosive Impurity MgOHCl in Molten MgCl2–KCl–NaCl

MgCl2–KCl–NaCl is a promising thermal energy storage (TES) material and heat transfer fluid (HTF) with high operating temperatures of >700°C for next-generation concentrating solar power (CSP) plants. One major challenge for future implementation of the molten chloride TES/HTF technology arises from the presence of some corrosive impurities, especially MgOHCl, a hydrolysis product of hydrated MgCl2. Even extremely low-concentration MgOHCl (tens of ppm O in weight) can cause unneglectable corrosion of commercial Fe–Cr–Ni alloys, which limits their service time as the structural materials in the molten chloride TES/HTF system. Thus, the chemical analysis and monitoring techniques of MgOHCl at the tens of ppm O level are vital for corrosion control. In this work, a chemical analysis technique based on direct titration and a high-precision automatic titrator was developed for an exact measurement of MgOHCl at the tens of ppm O level. It shows a standard deviation below 5 ppm O and an average error below 7 ppm O when the concentration of MgOHCl is 36 ppm O. Moreover, compared to other methods available in some literature reports, it can exclude the influence of co-existing MgO on the MgOHCl concentration measurement. This chemical analysis technique was used to calibrate the previously developed electrochemical method based on cyclic voltammetry (CV) to achieve reliable in situ monitoring of MgOHCl in the MgCl2–KCl–NaCl molten salt at a concentration as low as the tens of ppm O level. The in situ monitoring technique shows a monitoring limitation of <39 ppm O. The two techniques for MgOHCl measurement developed in this work could be used to develop an in situ corrosion control system to ensure the long service time of the molten chloride TES/HTF system in next-generation CSP plants.

Visualizing the Nanoscale Oxygen and Cation Transport Mechanisms during the Early Stages of Oxidation of Fe–Cr–Ni Alloy Using In Situ Atom Probe Tomography

AbstractUnderstanding the early stages of interactions between oxygen and material surfaces—especially at very high spatial resolutions—is highly beneficial for fields ranging from materials degradation, corrosion, geological sciences, forensics, and catalysis. The ability of in situ atom probe tomography (APT) is demonstrated to track the diffusion of oxygen and metal ions at nanoscale spatial resolution during the early stages of oxidation of a model Fe–Cr–Ni alloy. Using 18O isotope tracers in these in situ APT experiments and complementary ex situ multimodal microscopy, spectroscopy, and computational simulations allows to precisely analyze the kinetics of oxidation and determine that outward cation diffusion to oxide/air interface is the primary mechanism for intragranular oxide growth in this alloy at 300 °C. This unique in situ isotopic tracer APT approach and the insights gained can be highly beneficial for studying early stages of gas–surface reactions in a broad array of materials.

Combined thermal desorption spectroscopy, hydrogen visualization, HRTEM and EBSD investigation of a Ni–Fe–Cr alloy: The role of hydrogen trapping behavior in hydrogen-assisted fracture

The role of hydrogen trapping behavior in hydrogen-assisted cracking in a Ni–Fe–Cr alloy has been investigated using thermal desorption spectroscopy (TDS), hydrogen visualization, and high-resolution microstructural characterization methods. The results indicate that hydrogen resides at interstitial lattice sites, dislocations, and vacancies with the ascending order of the desorption activation energies. This study firstly shows that hydrogen is trapped reversibly at dislocations including misfit dislocations at the austenite/δ phase interface, and deformation-induced dislocations. The hydrogen trapping behavior is proved by TDS and hydrogen visualization technique. The weakly trapped hydrogen at dislocations provides sufficient hydrogen to build up a required critical hydrogen concentration at potential flaws for crack nucleation and to activate hydrogen enhanced decohesion mechanism. Further, it was found that δ phase precipitation exacerbates the hydrogen embrittlement sensitivity. For the first time, evidence for hydrogen transport by dislocations in a Ni-based alloy is observed by the hydrogen visualization technique.

Interstitial concentration effects on incipient plasticity and dislocation behaviors of face-centered cubic FeNiCr multicomponent alloys based on nanoindentation

• The interstitial concentration effects on dislocation behavior and incipient plasticity of a typical equiatomic FeNiCr multicomponent alloy are newly investigated via systematic nano-mechanical experimental study. • The dislocation nucleation of FeNiCr alloy processes in a manner of heterogenous nucleation mode with an activation volume exceeding one single principal atom, by the exchange between primary atoms and vacancies. • Interstitial-atom effects severely suppress the mobility of dislocations in the FeNiCr multicomponent alloys, which hinder the occurrence of pop-ins. • With increasing the concentration of interstitial atoms, both the critical shear stress and activation volume corresponding to the onset of incipient plasticity are enhanced. Interstitial atoms that commonly occupy the octahedral or tetrahedral interstices of face-centered cubic (FCC) lattice, can significantly affect the dislocation behaviors on deformation. Recently, interstitial doping has been applied to tune the mechanical properties of the emerging multicomponent, often termed high-entropy alloys (HEAs) or medium-entropy alloys (MEAs). However, the fundamental mechanisms of the dislocation nucleation and the onset of plasticity of interstitial multicomponent alloys governed by the concentration of interstitial atoms are still unclear. Therefore, in the present work, an instrumented nanoindentation was employed to investigate the interstitial concentration effects of carbon atoms on single FCC-phase equiatomic FeNiCr MEAs during loading. The results show that the pop-in events that denote the onset of incipient plasticity are triggered by the sudden heterogeneous dislocation nucleation via the primary atoms-vacancy exchange with the instant stress field, regardless of the interstitial concentration. Moreover, the measured activation volumes for dislocation nucleation of the FeNiCr MEAs are determined to be increased with the interstitial concentration, which definitely suggests the participation of interstitial atoms in the nucleation process. Besides, it is also found that the average value measured in statistics of the maximum shear stress corresponding to the first pop-in is enhanced with the interstitial concentration. Such scenario can be attributed to the improved local change transfer and lattice cohesion caused by the interstitial atoms with higher concentrations. Furthermore, the significant drag effect of interstitial carbon atoms hinders the mobile dislocations before exhaustion, which severely suppresses the subsequent occurrence of pop-in events in the carbon-doped specimens. The work gives a microscale view of interstitial effects on the mechanical properties of multicomponent alloys, which can further help to develop new interstitial strengthening strategies for structural materials with remarkable performance.

Surface texture characterization for thin-wall NASA HR-1 Fe–Ni–Cr alloy using laser powder directed energy deposition (LP-DED)

Additive Manufacturing (AM) offers new design and manufacturing opportunities of thin-wall microchannel heat exchangers for aerospace and industrial applications. Laser Powder Directed Energy Deposition (LP-DED) is an AM process providing large scale manufacturing of thin-wall microchannel heat exchangers. Successful industrialization of the LP-DED process requires critical quantification and understanding of the metallurgical, geometric, and process limitations. Specifically, understanding the as-built surface texture, inclusive of roughness and waviness, is significant due to its effects on the friction factor and pressure drop within a heat exchanger. This experimental study completed a design of experiments (DOE) to determine the critical build parameters that impact surface texture for enclosed thin-wall samples. This study summarizes the characterization work of the LP-DED process for 1 mm enclosed walls with an Fe–Ni–Cr (NASA HR-1) alloy. The LP-DED parameters including laser power, powder feedrate, travel speed, layer height, and rotary atomized powder feedstock were modified in the experiment. An evaluation of the DOE samples and resulting surface texture is provided along with conclusions from these experiments. Results indicate that 3D areal and 2D profile (directional) surface texture is estimated by 2x the powder diameter that becomes captured or partially melted on the trailing edge of the melt pool. The fine powder showed a higher sensitivity to parameter changes but resulted in a higher density material and 23% reduction in roughness. Surface texture was also shown to vary between closed channel shapes (internal) due to ricochets, recirculation, and higher volume of powder available to bond compared to external (outer) surfaces. The understanding of the LP-DED process as-built surface texture is essential to fluid flow applications such as heat exchanges and can modify performance for enhanced heat transfer or can be a detriment to pressure drop.

Evaluation of Ni-Fe base alloys as inert anode for low-temperature aluminium electrolysis

• Oxidation behaviors of Ni-Fe-Cr alloys with different Cr content were investigated in air at 800 °C and 900 °C °. • A multilayer oxide structure with an inner Cr 2 O 3 , a middle (Ni,Fe,Cr) 3 O 4 , and an outer (Ni,Fe) 3 O 4 /Fe 2 O 3 layers was formed on Ni-Fe-15Cr alloy. • Increasing of oxidation temperature or Cr content for Ni-Fe-Cr alloys not only accelerates to form Cr 2 O 3 inner layer, but also reduces Fe 2 O 3 content. • The (Ni,Fe) 3 O 4 /(Ni,Fe,Cr) 3 O 4 /Cr 2 O 3 layered scale was highly oxidation/corrosion resistant in molten alumina-cryolite at 800 °C. Isothermal oxidation behaviors of Ni–Fe (wt.%) and of the same alloy with additions of 10 and 15%Cr alloys in the air at 800 °C and 900 °C and their anodic behaviors in aluminum electrolysis system at 800 °C were evaluated. The composition morphologies of oxide scales were characterized by XRD, SEM, and EDS. Results show that the scales formed on Ni–Fe alloy at both temperatures consisted of an inner (Ni,Fe) 3 O 4 layer and an outer Fe 2 O 3 layer. For Ni–Fe–10Cr alloy, an external (Ni,Fe) 3 O 4 /Fe 2 O 3 layers and an internal oxidation zone were formed at 800 °C, while a continuous Cr 2 O 3 layer forms at the internal oxidation zone/substrate interface at 900 °C. A multilayer structure oxide of Cr 2 O 3 /(Ni,Fe,Cr) 3 O 4 /(Ni,Fe) 3 O 4 /Fe 2 O 3 was formed on Ni–Fe–15Cr alloy at 800 °C, while at 900 °C the Fe 2 O 3 becomes discontinuous disperses in the (Ni,Fe) 3 O 4 layer close to the surface. Increases in oxidation temperature or Cr content for Ni–Fe–Cr alloys promote the growth of the inner Cr 2 O 3 layer and simultaneously reduce Fe 2 O 3 content. After 4 h of electrolysis at an anode current density of 0.25 A cm −2 , the oxidation resistance of Ni–Fe–15Cr anode is superior to the Ni–Fe anode.

Effect of concurrent grain growth on radiation-induced segregation in nanocrystalline Fe–Cr–Ni alloys

Irradiation of crystalline materials modifies their microchemistry and microstructure. This includes solute segregation toward defect sinks such as grain boundaries (GBs), a phenomenon commonly known as radiation-induced segregation (RIS). Unlike in coarse-grained alloys where GBs are nearly static, RIS is usually accompanied and affected by either thermal or irradiation-induced grain growth in nanocrystalline materials. This work presents a modeling study of concurrent grain growth and RIS in austenitic Fe–Cr–Ni adopting realistic 2D grain structures. RIS can be significantly affected by concurrent grain growth due to (i) increasing grain size, (ii) motion of GBs as defect sinks, and (iii) their combined effect. Consequently, RIS is enhanced by grain growth due to increased grain size and sink motion. More notably, RIS in nanocrystalline materials were found to induce grain-level compositional redistribution in addition to RIS at defect sinks, resulting in grain-size-dependent compositions in individual grains. Without concurrent grain growth, elements depleted at the sinks due to RIS, such as Cr in austenitic steels, will have lower concentrations in smaller grains than in larger grains. The opposite trend becomes true when concurrent grain growth takes place. The compositional difference in individual grains can be significant enough to affect local phase stability. These findings are not discernible with the classical 1D bicrystal model, and they highlight the different effects of RIS in nanocrystalline alloys compared to their coarse-grained counterparts.

On the solid-state dendritic growth of [formula omitted] carbide at interfaces in an austenitic system

Solid-state growth of M7C3 carbide at different interfaces in an austenitic Ni–Cr–Fe alloy (Alloy 600) was studied in-situ by high temperature confocal laser scanning microscopy during continuous cooling from 1140 °C. The carbide develops a dendritic morphology and grows laterally across the free surface via a diffusion-assisted mechanism. Primary dendrite arms can extend beyond 100 μm, with some dendrites also developing secondary arms with spacing approximately 3.0 μm. By using focused ion beam tomography, some of the surface carbides are found to be directly connected to dendritic carbide at grain boundaries in the bulk confirming they originated from the same nucleus. Matrix deformation is induced in the vicinity of a carbide during growth. This work provides significant insight into the important topic of carbide development by a rare combination of both in-situ microscopy and a 3D tomographic technique; the new knowledge discovered is expected to apply to other austenitic systems.

Microstructure and mechanical properties of novel Si-added CrFeNi medium-entropy alloy prepared via vacuum arc-melting

In this paper, a series of novel Co-free CrFeNiSix (x = 0.05, 0.15, 0.25) MEAs was prepared via vacuum arc-melting. The addition of Si induced the formation of (Cr, Si)-rich σ phase in CrFeNiSix MEAs, which effectively hindered the migration of dislocations and grain boundaries, resulting in the grain refinement. Meanwhile, the existence of σ phase inhibited the formation of twinning, leading to the decreasing fractions of low-Σ CSL boundaries with the increasing Si addition. Compared with CrFeNi alloy, both the strength and microhardness of CrFeNiSix MEAs were significantly improved, but the plasticity had deteriorated. Overall, there was a good trade-off between strength and ductility in CrFeNiSi0.15 MEA, including the yield strength of 550 ± 5.5 MPa, ultimate tensile strength of 795 ± 7.1 MPa, and elongation of 20 ± 0.4%. In addition, the experimental results demonstrated that the grain boundary strengthening and precipitation strengthening played a dominant role for the strengthening of CrFeNiSix MEAs. The decreased plasticity was mainly attributed to the formation of σ phase and the reduced twinning. Furthermore, the increasing σ phase also resulted in the transformation of fracture mechanisms from ductile fracture to the mixed fracture. Our work provides significant reference for the further development of high performance Co-free MEAs/HEAs.

Computational study of nanoscale mechanical properties of Fe–Cr–Ni alloy

ABSTRACT Mechanical properties of Fe–Cr–Ni alloy nanowires have been investigated using molecular dynamics simulation with embedded atom method and first principles approach. Various cases of uniaxial tension, compression and shear deformations have been performed and studied in this work. From the first principles calculations, the higher magnitudes of uniaxial and shear deformations resulted in higher probability of martensitic transformations. Before the first yielding, nanowires preserved the elastic stage and then the mechanical deformation proceeded in alternating quasi-elastic and yielding stages. The plastic behaviour was not observed in compression while both tensile and shear deformations showed apparent plastic behaviour. In shear deformation, due to the martensitic phase transformation, the plastic behaviour persisted for total strain of 0.6 which was much larger than that during tensile and compression. This validated the previous experimental observations. In the studied Fe–Cr–Ni nanowires, deformations were controlled by dislocations. Dislocation-mediated twinnings were captured by common neighbour analysis. Twin quantification showed that the twin activity increased with increasing strain rate. Twinnings originated from stacking faults led by 1/6 <112> Shockley partial dislocations. At elevated temperature (beyond 500 K), the materials softening happened, and 316L nanowire became more plastic under a lower stress.

Shock temperatures and melting curve of an Fe–Ni–Cr alloy up to 304 GPa

The melting temperatures of Fe–Ni alloys and their densities in the liquid state at relevant pressure–temperature (P–T) conditions present in the core are of great importance for understanding the composition and thermal structure of the Earth's core. We measured shock temperatures of the Fe–11Ni–18Cr (wt. %) alloy up to ∼304 GPa using a special target configuration, a quasi-spectral pyrometer, and velocimeter diagnostics in a two-stage light-gas gun. The present results show that Fe–11Ni–18Cr starts to melt at the pressure of 210 (8) GPa and 4700 (300) K and completes at the pressure of 280 (10) GPa and 5250 (350) K under shock loading, which is ∼1000 K lower than some previous shock temperature measurements. The melting temperatures of the Fe–11Ni–18Cr alloy are 4100 (250) K and 5500 (450) K at the pressures present at the core-mantle boundary (∼136 GPa) and inner-core boundary (∼330 GPa), respectively, which are slightly lower than that of pure iron. Combined with the previous results of the pressure–density measurements at Hugoniot states, our results indicate that the presence of limited amounts of Ni and Cr into Fe has a minor effect on its melting curve and density in the liquid state, suggesting that sufficient light elements are required in the outer core to satisfy both the core density deficit and the reduced melting temperature.

Experimental Measurements and Numerical Analysis of Al Deoxidation Equilibrium of Molten Fe–Cr–Ni Alloy

Experimental Measurements and Numerical Analysis of Al Deoxidation Equilibrium of Molten Fe–Cr–Ni Alloy

Surface lattice Green’s functions for high-entropy alloys

We study the surface elastic response of pure Ni, the random alloy FeNiCr and an average FeNiCr alloy in terms of the surface lattice Green’s function. We propose a scheme for computing per-site Green’s function and study their per-site variations. The average FeNiCr alloys accurately reproduces the mean Green’s function of the full random alloy. Variation around this mean is largest near the edge of the surface Brillouin-zone and decays as q −2 with wavevector q towards the Γ-point. We also present expressions for the continuum surface Green’s function of anisotropic solids of finite and infinite thickness and show that the atomistic Green’s function approaches continuum near the Γ-point. Our results are a first step towards efficient contact calculations and Peierls–Nabarro type models for dislocations in high-entropy alloys.

Surface energies and relaxation of NiCoCr and NiFeX (X = Cu, Co or Cr) equiatomic multiprincipal element alloys from first principles calculations

First principles calculations of the energies and relaxation of unreconstructed low-index surfaces, i.e. (001), (011) and (111) surfaces, in NiCoCr and NiFeX (X = Cu, Co or Cr) equiatomic multi-principal element alloys (MPEAs) are presented. The calculations were conducted for 12-layer slabs represented by special quasi-random supercells using the projector augmented wave method within the generalized gradient approximation. While experimental predictions are unavailable for comparison, the calculated surface energies agree fairly well with those from thermodynamic modeling and a bond-cutting model. In addition, the calculations unveil an important surface structure, namely, that the topmost surface layer is in contraction except for the (001) surface of NiFeCr alloy, the next layer below is in extension, and the bulk spacing is gradually recovered from the subsequent layers down. Additionally, the surface contraction is the most pronounced on the (011) plane, being about 4%–10% relative to the bulk spacings. The results presented here can provide an understanding of surface-controlled phenomena such as corrosion, catalytic activities and fracture properties in these equiatomic MPEAs.

Interdiffusion behaviors between NiCrFe alloy and low-/medium-/high-entropy alloys

Six groups of fcc solid/solid diffusion couples, including Ni-Cr-Fe/ low-entropy (pure Ni, and NiCo, NiCr, and NiCoCr) alloys, Ni-Cr-Fe/ medium-entropy (CoCrNi) alloys, and Ni-Cr-Fe/ high-entropy (CoCrFeNi) alloys, were prepared, and their composition profiles were experimentally measured. Concentration-dependent interdiffusion and tracer diffusion coefficients in fcc Ni-Co-Cr-Fe system at 1473 K were retrieved with the aid of High-throughput Determination of Interdiffusion Coefficients (HitDIC) software and their reliability was validated. In most cases, D˜CrCrNi>D˜FeFeNi>D˜CoCoNi. The comprehensive comparison between the interdiffusivities/tracer diffusivities in the NiCo, NiCr, NiCoCr low-entropy, CoCrNi medium-entropy, and CoCrFeNi high-entropy alloys and those reported data available in the literatures indicates that the interdiffusivities Co, Cr, and Fe in low-entropy alloys are the largest than those in the other two types of alloys. While the tracer diffusivity in Co-Cr-Fe-Ni HEAs may have no sluggish phenomenon when the absolute temperature is used.