AlCoCrFeNi High-entropy Alloy Research Articles

Tribological behavior and characteristics of TIG surface cladded AlCoCrFeNi high-entropy alloy on 304L stainless steel

The present study examines the tribological properties of AlCoCrFeNi high-entropy alloy (HEA) surface cladded on 304L stainless steel via a Tungsten Inert Gas (TIG) heat source. Commercially pure powders of aluminum, cobalt, chromium, and nickel were ball-milled, mixed in specific ratios, and applied onto the substrate with polyvinyl alcohol as a binder. Cladding was performed with optimized parameters to create layers of HEA. Microstructural and EDS analysis revealed equiaxial dendrites rich in aluminum and nickel in dendritic (DI) areas, and rich in iron, chromium, and cobalt in interdendritic (ID) areas. Mixing entropy was calculated by consideration of EDS analysis of the cladding and based on the initial definition of a high-entropy alloy, the high-entropy nature of the cladding was confirmed. XRD analysis showed the presence of FCC, A2/B2, and hard σ phases. Surface alloyed material exhibited higher hardness compared to the base material, with an average of 540 HV versus 200 HV. A pin-on-disc wear test machine was used to assess tribological properties under different loads of 10, 20, and 40 N. The wear rates of the high-entropy cladded material were 36 and 50 % less than those of the 304L stainless steel under applied loads of 10 and 40 N, respectively, while their wear rates were almost similar at 20 N. Friction coefficients of HEA pins were notably lower than 304L at 10 and 20 N, with smoother profiles. Wear mechanisms of the HEA material varied with load: oxidative wear at 10 and 20 N due to the formation of an oxide layer, and abrasion and spallation at 40 N, resulting in a threefold increase in wear rate at this load. Overall, the study highlights the effectiveness of HEA cladding in improving tribological properties, especially under high applied load.

Comprehensive investigation of microwave sintered AlCoCrFeNi/Ti-6Al-4V composite: Microstructural insights, mechanical properties, and tribological performance

Ti-6Al-4 V is an extensively used and highly versatile titanium alloy. It is renowned for its lightweight-to-strength ratio, excellent biocompatibility, and corrosion resistance. The pursuit of advanced materials with enhanced mechanical strength, and wear resistance has led to the exploration of high entropy alloys (HEA) as particle reinforcements. This study combines Ti-6Al-4 V with AlCoCrFeNi HEA at different weight compositions (0 %, 2 %, 4 %, 6 %, 8 %) to create novel composites with tailored properties. The composites were subjected to density, microhardness, tensile, and pin-on-disc tests to evaluate mechanical and tribological properties. Microstructural analysis revealed that microwave sintering has enhanced densification and resulted in uniform dispersion of HEA particles within the Ti-6Al-4 V matrix. The XRD and EBSD analysis revealed the presence of BCC structure in the composite. 8 wt%-AlCoCrFeNi/Ti-6Al-4 V sample exhibited an impressive 81.66 % increase in microhardness and 21.23 % in yield strength, compared to the base sample. Furthermore, noteworthy reductions of 45 % in wear rate and 40 % in coefficient of friction (COF) when subjected to tribological analysis. The worn surface revealed the presence of oxide layer formation at elevated sliding velocity and distance which resulted in reduced wear rate.

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

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

Enhancing wear resistance of laser-clad AlCoCrFeNi high-entropy alloy via ultrasonic surface rolling extrusion

The AlCoCrFeNi high-entropy alloy (HEA) coating was synthesized by laser cladding and subsequently processed by ultrasonic surface rolling extrusion (USRE) with varying static loads of 100 N, 200 N, and 300 N. This study aimed to explore the effects of static load on the microstructure, mechanical properties, and tribological characteristics of the coatings. The findings indicate that increased static load results in the precipitation of martensitic phases, grain refinement, enhanced microhardness, and an elevated dislocation density. Specifically, after USRE with 300 N static load, the coating's microhardness reaches 753 HV, 1.4 times greater than the un-USRE coating. This enhancement is attributed to the synergistic effect of martensite phase transformation, grain refinement, and dislocation strengthening. The volume wear rate of the coating decreases to 1.31 × 10−4 mm3·N−1·m−1 following USRE at 300 N, demonstrating superior resistance to abrasive wear due to the high microhardness. Besides, the high-density dislocations facilitate rapid migration and diffusion of oxygen elements, thereby enhancing the oxide layer's protective properties and improving the coating's resistance to oxidation wear.

Combined experimental and CALPHAD investigation of equimolar AlCoCrFeNiX (X=Mo,Ta,W) High-Entropy Alloys

Aiming to evaluate the effect of refractory metal additions to a quinary AlCoCrFeNi High-Entropy Alloy (HEA), three novel equimolar AlCoCrFeNi-X (X = Mo, Ta, W) HEAs were designed, arc-melted, annealed, and characterized by SEM-EDS, XRD and microhardness measurements. CALPHAD thermodynamic calculations were exploited to design compositions and thermal treatments of the selected HEAs as well as to predict constitution and interpret microstructure of the samples. On the other hand, the experimental results contributed to the validation of the in-house built GHEA thermodynamic database (including the Al, Co, Cr, Fe, Ni, Mo, Ta, W elements) used for the calculations. No TCP intermetallic was found to form in the quinary AlCoCrFeNi alloy. However, the formation of σ, Laves-C14 and μ phases was observed in the samples containing Mo, Ta, and W, respectively, in agreement with the most accepted VEC-based phases stabilization criteria. The addition of the refractory metals led to a microhardness increase for all the investigated alloys. Overall, good agreement was observed between experiments and calculations, especially for compositional trends and phase amounts, allowing the database validation and supporting its applicability to phase equilibria simulation in the six-component HEAs belonging to the Al–Co–Cr–Fe–Ni-X (X = Mo, Ta, W) systems.

Role of TiB2 inoculation particles during welding of a AlCoCrFeNi high entropy alloy

High entropy alloys (HEAs) are a novel class of materials that represent an evolution of common engineering alloys to a wider array of compositional and properties possibilities. As such, the exploration of methodologies to achieve improved microstructure and mechanical characteristics of these materials for potential applications in industry is a requirement that is experiencing extended research efforts. One example of a processing method able to expand the potential applications of these alloys is Gas Tungsten Arc Welding (GTAW), which allows to evaluate the metallurgical evolution and corresponding mechanical performance, associated to the impact of a localized heat input on the material. However, GTAW and related fusion-based welding processes are known to generate large grain sized-structures in the fusion zone, which often is detrimental to the joint performance. Thus, the integration of high temperature inoculant particles on the fusion zone during welding is a potential way to improve this region’s microstructure and, therefore, its mechanical performance. In this work, we discuss the effect that the addition of TiB2 micron-sized particles have on the microstructure of a GTAW AlCoCrFeNi-based HEA. For this, the microstructure of the welds was evaluated by means of optical and electron microscopy, synchrotron X-ray diffraction and CalPhaD-based simulations. Mechanical testing was performed using microhardness mapping and tensile testing coupled with digital image correlation. The results evidenced that successful inoculation with TiB2 proved capable of altering the microstructure of the fusion zone (FZ), refining it. Nevertheless, preferential deformation in the relatively softer heat affected zone during tensile testing resulted on premature failure of the inoculated joints, due to the concomitant higher hardness of the FZ.

Effect of heat treatment on the microstructure and nanoindentation behavior of AlCoCrFeNi high entropy alloy

In the present work, the effect of annealing temperature on the phase evolution, morphology, and nanoindentation behavior of the equiatomic AlCoCrFeNi high entropy alloy (HEA) were investigated, and the correlation between the microstructure and nanoindentation behavior in the dendrite core (DC) and inter-dendrite (ID) regions was revealed. The DC and ID regions in the as-cast alloy are composed of disordered A2 particles and ordered B2 matrix. As the annealing temperature increases, the volume fraction of the face centered cubic (FCC) phase first increases and then decreases, leading to complete dissolution of FCC phase at 1200 °C. In addition, annealing at 700 and 800 °C results in the precipitation of the σ phase in the ID region. DSC and thermodynamic calculations were used to analyze the phase evolution of the alloy with temperature. Changes in morphology and phase constituent inevitably affect the mechanical properties of the alloy, which were characterized by nanoindentation for both ID and DC regions. The results show that the ID region displays higher nano-hardness than the DC region in the as-cast and 600–800 °C samples, but there is no difference in the 900–1200 °C temperature range.

Microstructure and wear behaviour of AlCoCrFeNi-coated SS316L by atmospheric plasma spray process

ABSTRACT The capacity to endure harsh wear in demanding conditions in stainless steel drops under extreme nature and applications. Protecting the surface by providing a coating layer supports the usage in harsh conditions. In this work, SS316L is coated with AlCoCrFeNi high-entropy alloy (HEA) by atmospheric plasma spray process and annealed at 600°C for 2 hours. The AlCoCrFeNi HEA exhibited spherical particles with bcc phase and 20 µm particle size. The coating morphology revealed a uniform coating with a homogeneous distribution of HEA particles over a thickness of 150 µm. The coating post-annealing offered improved microhardness by 12% than the coated sample before annealing. The wear test was executed by varying load, sliding distance, and sliding velocity at normal temperature, 400°C and 600°C and the corresponding worn surface was analysed. The coated samples after annealing showed 57.6%, 87.5%, and 65.4% improved wear resistance at normal temperature than the coated sample before annealing at minimum levels of load, sliding velocity and distance. The wear rate of coated and annealed samples revealed 5.2%, 4.5%, and 4.4% better wear resistance at 400°C than the coated samples before annealing. The worn surface morphology showcased wear mechanisms to be delamination, abrasive wear, and oxide layer formation under all conditions.

Braking Performance of Copper-Based Friction Materials Reinforced by AlCoCrFeNi High-Entropy Alloy

It is essential to improve the braking performance of friction materials for high-speed trains. Copper-based friction materials reinforced with AlCoCrFeNi high-entropy alloy (HEA) contents of 0–40 wt% were prepared by powder metallurgy, and the braking performance of these materials at braking speeds of 40, 80, 120, and 160 km/h was investigated. The composition of AlCoCrFeNi HEA particles changes due to the elemental diffusion and alloying between AlCoCrFeNi HEA particles and the copper matrix during sintering. With the AlCoCrFeNi content increasing, the amount of interfaces between AlCoCrFeNi particles and Cu matrix increases and the bending strength of the materials decreases, owing to the formation of oxides. The friction coefficient, braking time, and absorbing power of copper-based friction materials can be significantly improved by adding AlCoCrFeNi particles. However, the improvement in their wear resistance is not significant. The spalling pits and oxides are detected on the worn surfaces. The dominant wear mechanisms of copper-based friction materials are spalling and oxidation.

Electrochemical and hot corrosion behaviour of annealed AlCoCrFeNi HEA coating over steel

The ability to endure extreme corrosion in challenging environments is reduced in stainless steel. This can be addressed by appropriate surface modification techniques to redefine the surface with the required properties. The characteristics of the atmospheric plasma sprayed AlCoCrFeNi High Entropy Alloy (HEA) on SS316l are presented in this study. The coating characterisation revealed uniform coating with homogeneous deposition of gas-atomized AlCoCrFeNi HEA spanning for 150 µm. The coated substrates were further annealed for 2 h at 400 °C, 550 °C, 700 °C and 850 °C and the annealing at 550 °C offered enhanced microstructure. Annealing the coated sample at 550 °C offered a 46% improvement in microhardness against the uncoated sample post-annealing. The electrochemical corrosion tests showcased improved corrosion resistance after annealing through the formation of a protective oxide layer and the influence of HEA. Hot corrosion tests at 900 °C resulted in 10.1%, 8.49%, and 10.36% improved corrosion resistance for the coated sample annealed at 550 °C than the coated sample pre annealing and 44.09%, 44.25%, and 42.09% than the uncoated sample pre annealing under three salt mixtures respectively. The microstructural analysis examines various corrosion modes and verifies the presence and formation of protective oxide layers.

The influence of ultrasonic assistance on microstructure and properties of AlCoCrFeNi high-entropy alloy prepared by laser cladding

The study investigates the influence of ultrasound on the microstructure and properties of AlCoCrFeNi fabricated by laser cladding. The results indicate that the grain size of AlCoCrFeNi prepared by ultrasonic assistance is smaller than that prepared without ultrasound. Moreover, employing ultrasound in the fabrication process of AlCoCrFeNi results in an improvement in its electrochemical corrosion resistance. This enhancement can be attributed to the homogenization of the microstructure and the reduction of microgalvanic couples. The wear resistance of AlCoCrFeNi is enhanced with the increase in ultrasound amplitude. The sample prepared using a 15 μm ultrasonic amplitude demonstrates the lowest friction coefficient of 0.3876 and the minimal wear loss of 40.8 mg. The tensile strength and elongation of AlCoCrFeNi are improved as the ultrasonic amplitude increases. The sample prepared using a 15 μm ultrasonic amplitude demonstrates the highest tensile strength and elongation, measuring 1039 MPa and 16.2%, respectively. The enhancement of mechanical properties can be attributed primarily to the grain refinement and the reduction of as-cast defects.

Effect of Mn addition on microstructure and corrosion behavior of AlCoCrFeNi high-entropy alloy

In this study, the effects of Mn content on the microstructure and corrosion resistance of AlCoCrFeNiMnx (x = 0, 0.25, 0.5, 0.75, and 1) high-entropy alloys were investigated. The results indicate that with increasing Mn content, the HEAs consistently comprise nanophase BCC geometry with different shapes embedded in the ordered B2-phase matrix, and the morphology of the microstructure changes from a coarse dendritic structure to a fine dendritic structure, then to a completely columnar dendrite structure. The microhardness of the HEAs increases gradually to 620 HV0.2 when x = 1, owing to the solid-solution and fine-grain strengthening. The corrosion resistance of the HEAs in 3.5 wt% NaCl solution first increases and then decreases, reaching a maximum with the lowest self-corrosion current density of 2.869 × 10−8 A∙cm−2 when x = 0.5. Improvement in corrosion resistance is related to a reduction in degree of composition segregation in the microstructure of HEAs, which leads to the formation of a dense and complete passivation film on the surface of the alloys. However, when the Mn content is in the range of 0–0.5, the pitting potential of the HEAs gradually decreases, although the passivation current density also gradually decreases. Higher Mn content (x > 0.5) leads to a transition of the HEAs from passivation to active dissolution. This indicates that the stability of the passivation film on the HEAs decreases with higher Mn content. XPS analysis revealed a gradual decline in the relative content of Cr2O3 and a gradual increase in the presence of unstable oxides such as MnO and Mn2O3 in the passivation film, leading to this phenomenon. The present work reveals that the addition of Mn in the AlCoCrFeNi HEA affects not only the microstructure and composition segregation but also the composition and stability of the passivation film, leading to a non-monotonic variation in the corrosion performance of the present HEAs with respect to the Mn content.

Effect of non-metallic silicon content on the microstructure and corrosion behaviour of AlCoCrFeNi high-entropy alloys

AlCoCrFeNi high-entropy alloys (HEAs) have shown excellent mechanical properties and high-temperature oxidation resistance but poor corrosion resistance owing to the high contents of the aluminium passivation film. In this study, Si was added to these alloys with the aim of improving the composition and stability of the passivation films. The microstructure and corrosion behaviour of AlCoCrFeNiSix (molar ratio x = 0, 0.1, 0.2, 0.3, and 0.4) HEAs were investigated. Dendritic and spinodal decomposition regions were observed in all five alloys. In the dendritic region, the dendritic structures transitioned from a petal shape to a dendritic shape with increasing Si content. Phase separation occurred in the spinodal decomposition region, which predominantly consisted of ordered body-centred cubic (B2) and disordered body-centred cubic (A2) phases. The size of the A2 phase decreased, and the amount of the A2 phase increased with increasing Si content. An optimised Si content could enhance the stability of Al and Cr passivation films, whereas excessive Si imposed an adverse effect by forming a Cr passivation film. The corrosion resistance of AlCoCrFeNiSi0.2 HEAs was optimum with a passive current density of 3.2 μA/cm2, which was 0.2 times that of the obtained AlCoCrFeNi HEAs without Si. The type of corrosion changed from local corrosion of AlCoCrFeNiSix (x ≤ 0.3) HEAs to general corrosion of AlCoCrFeNiSi0.4 HEAs. The corrosion mechanisms of the AlCoCrFeNi HEAs with various Si contents were elucidated.

Effect of non-metallic carbon content on the microstructure and corrosion behavior of AlCoCrFeNi high-entropy alloys

The addition of carbon has been reported to improve the corrosion resistance of various alloys. However, few studies have investigated the effect of non-metallic elements on the corrosion behaviour of AlCoCrFeNi high-entropy alloys (HEAs), which are among the most extensively developed alloys and potential alternatives to structural materials. Therefore, herein the microstructure and corrosion behaviour of AlCoCrFeNiCx (x = 0, 0.1, 0.2, 0.3, and 0.4 in molar ratio) HEAs were studied in a 3.5 wt% NaCl solution. The results show that adding carbon increased the carbide (Cr23C6) content and reduced the mean grain size. Further, increasing the carbon content improved the stability of the passive film and corrosion resistance of the AlCoCrFeNiCx HEAs. The corrosion resistance of AlCoCrFeNiC0.4 HEAs is optimal, and the passive current density is 2.57 μA/cm2, which is 0.16 times that of AlCoCrFeNi HEAs without carbon. The corrosion mechanisms of the AlCoCrFeNi HEAs with various carbon contents were also elucidated. The results of this study provide excellent theoretical guidance and experimental basis for the development and application of corrosion-resistant metallic materials.

Unraveling the oxidation mechanism of Y-doped AlCoCrFeNi high-entropy alloy at 1100 °C

Equimolar AlCoCrFeNi high entropy alloy (HEA) with a coherent dual-phase structure commonly exhibits good strength at high temperatures. Regretfully, the poor oxidation resistance greatly limits its practical application space. In this work, the effect of the reactive element (RE) Y on the oxidation resistance of AlCoCrFeNi HEA is explored. (AlCoCrFeNi)100−xYx (x = 0, 0.1, 0.5 and 1, at.%) were designed and their oxidation mechanisms were unravelled at 1100 °C. Besides the two original B2 phase and A2 phase, the Y-doped HEAs contain (Y, Ni)-rich phase. An appropriate amount of Y blocks the outward Al diffusion and meanwhile inhibits the laterally grown oxides within the existing scale, thereby suppressing the formation of interface pores and rumplings and contributing to superior resistance to oxide scale spallation. However, excessive Y doping causes the formation of (Y, Al)-rich oxide intrusions, which result in the nucleation of cracks near them and thus degrade the interface adherence. The generation and failure mechanisms of oxide scales formed on Y-doped HEAs during 100 h oxidation have been revealed. The presented information proposes new insights to improve the high-temperature oxidation resistance of AlCoCrFeNi HEA and may be useful for assessing the possibility of the practical application of HEAs in aerospace engine components.

Retracted: Processing and Properties of AlCoCrFeNi High Entropy Alloys: A Review

Retracted: Processing and Properties of AlCoCrFeNi High Entropy Alloys: A Review

Effect of the high temperature phase transition on the tribological behavior of atmospheric plasma sprayed AlCoCrFeNi-Bi2O3 coating

Owing to the brittleness of the body-centered cubic (BCC) structure and lack of self-lubrication, plasma-sprayed AlCoCrFeNi high-entropy alloy (HEA) coatings undergo severe abrasive wear, resulting in high friction and wear. In this study, the substrate surface temperature was increased (800 °C) to promote the phase transition from BCC to ductile FCC during spraying. As a result, the prepared AlCoCrFeNi HEA coating contained BCC and FCC phases, exhibiting a higher adhesive strength, lower friction coefficient and wear rate at room temperature (RT)–800 °C. In addition, the elevated substrate surface temperature enabled the transition of the low-temperature stable phase α-Bi2O3 to the high-temperature stable phase δ-Bi2O3. δ-Bi2O3 promoted the formation of low shear strength planes owing to its low interaction parameter and defect-fluorite structure with 25 % anionic vacancies similar to that of the Magnéli phase, which facilitated friction reduction in a wide temperature range. This study confirms that δ-Bi2O3 can effectively improve the anti-wear performance of the AlCoCrFeNi-Bi2O3 coating at RT, 200, 600 and 800 °C. However, at 400 °C, the low melting point and soft nature of the Bi2O3 weakened the mechanical strength of the coating and inhibited the construction of a solid and tough tribo-layer, resulting in a relatively high wear rate for AlCoCrFeNi-Bi2O3 coating. At 800 °C specifically, under the thermal coupling effect, δ-Bi2O3 migrated and aggregated on the worn surface with the oxidation product Al2O3 of the AlCoCrFeNi HEA matrix, and jointly promoted the formation of a compact and smooth tribo-layer with lubricating capability, which not only effectively reduced friction but also inhibited wear.

Preparation, mechanical properties and wear resistance of dual-sized TiC particles reinforced high-entropy alloy cermet coating

The replacement of WC-Co cermet coating partially or entirely has evolved as one of the most promising research hotspots in terms of coating properties as well as economic reasons. In this study, the TiC reinforced AlCoCrFeNi high entropy alloy (HEA) composite coating based on new sintering method was explored. Firstly, the combination of spray drying and plasma spheroidization is proposed to fabricate TiC/HEA composite powder for thermal spraying application. After that, the corresponding composite coating was deposited by high velocity air-fuel (HVAF) process. The results show that the developed TiC/HEA powder has a more compact structure and higher sphericity, which helps to improve powder fluidity, meanwhile, with 50 wt% TiC incorporation, the porosity、hardness、bonding strength and fracture toughness of TiC/HEA composite coating are 0.8 % 765.2 HV0.3, 68.1 Mpa and 2.7 MPa m−1/2, respectively, showing simultaneous hardening, densifying and toughening effects after introducing dual-sized TiC particles. Besides, the good wear performances of TiC/HEA composite coating including low wear rate (4.2 × 10−5 mm3 N−1 m−1) and coefficient of friction (0.34) are obtained，indicating a valuable application prospect. In addition, the wear mechanisms of TiC/HEA composite coating are determined by abrasive and oxidation wears and that of grinding ball is abrasive wear and adhesive wears.

Investigation of the corrosion behavior of AlCoCrFeNi high-entropy alloy in 0.5 M sulfuric acid solution using hard and soft X-ray photoelectron spectroscopy

Recently, high-entropy alloys (HEAs) have demonstrated excellent properties, such as high yield strength, better ductility, and great corrosion resistance, which breaks the conventional alloy design strategy. We investigate the corrosion behavior of AlCoCrFeNi HEAs in 0.5 M H2SO4 solution under ambient conditions using soft and hard X-ray photoelectron spectroscopy (XPS) for surface/bulk (∼5 nm and > 10 nm) analysis. The composition information of the surface and bulk can be achieved and compared via a switchable target system, where the Al (Kα, 1486.6 eV) and Cr (Kα, 5414.8 eV) targets produced X-rays for regular XPS and hard X-ray photoelectron spectroscopy (HAXPES) as the detection source, respectively. The HAXPES provides a precise composition study in the bulk region without the interference of Auger electron signals caused by neighboring transition metals. The dissolution of metallic ions in H2SO4 solution were collected by inductively coupled plasma–mass spectrometry (ICP–MS) and compared with the XPS-HAXPES analysis. The Al and Cr compounds redeposited to the HEA surface, while Fe, Co, and Ni kept dissolving into the acidic solution. It is speculated that the dissolution of Fe, Ni, and especially Co could slow the rate of dissolution of Cr. The passivation layer formed by Cr hydroxide/oxide could thus protect the HEA from further corrosion. Al easily leached before the formation of the Cr passivation layer, however, Al compounds still became the main species on the surface of the HEA. Moreover, our findings examined by the novel analysis technique may provide a new paradigm for the quantification study of HEAs.

Effect of Cavitation Water Jet Peening on Properties of AlCoCrFeNi High-Entropy Alloy Coating

High-entropy alloys have been widely used in engineering manufacturing due to their hardness, good wear resistance, excellent corrosion resistance, and high-temperature oxidation resistance. However, it is inevitable that metallurgical defects, such as micro cracks and micro pores, are produced when preparing the coating, which affects the overall performance of the alloy to a certain extent. In view of this situation, cavitation water jet peening (CWJP) was used to strengthen the AlCoCrFeNi high-entropy alloy coating. The effect of CWJP impact time on the microstructure and mechanical properties of CWJP were investigated. The results show that CWJP can form an effective hardening layer on the surface layer of the AlCoCrFeNi high-entropy alloy. When the CWJP impact time was 4 h, the microhardness of the surface layer of the specimen was harder than that of 2 h and 6 h, and the CWJP impact time had little effect on the thickness of the hardening layer. Observing the surface of the untreated and CWJP-treated specimens using the EBSD test, it was evident that the microstructure was significantly homogenized, the grains were refined, and the proportion of small-angle grain boundaries increased. The system reveals the grain refinement mechanism of the AlCoCrFeNi high-entropy alloy coating during plastic deformation. This study aims to provide a new surface strengthening method for obtaining high-performance AlCoCrFeNi high-entropy alloy coatings.