Corrosion-wear-resistant IN625-based composite high-entropy alloy and preparation method thereof
By introducing high-entropy alloying elements of CoCrFeNiMo into Inconel 625 alloy and forming a continuous network σ phase using linear arc additive manufacturing, the problem of easy wear and tear of traditional Inconel 625 alloy under corrosion and wear was solved, and the high hardness and corrosion resistance of the material were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHWEST JIAOTONG UNIV
- Filing Date
- 2026-03-04
- Publication Date
- 2026-05-08
AI Technical Summary
Traditional Inconel 625 alloy is easily worn down under the coupled effects of corrosion and wear, has low hardness and limited wear resistance, and high-entropy alloys are difficult to balance the self-healing rate of the passivation film and the toughness of the matrix under extreme environments, leading to material failure under complex working conditions.
By introducing high-entropy alloy components of CoCrFeNiMo into the Inconel 625 matrix through linear arc additive manufacturing, a continuous network σ phase is formed, which enhances the solid solution strengthening effect, promotes the formation of a stable passivation film, and rapidly rebuilds the protective layer during the friction process, thus inhibiting the interaction between corrosion and wear.
It significantly improves the material's hardness and resistance to plastic deformation, enhances its electrochemical stability and protective performance, reduces the material's total loss in complex environments, and achieves highly efficient corrosion and wear resistance.
Smart Images
Figure CN121992238A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wear-resistant and corrosion-resistant high-entropy alloy technology, and in particular relates to an IN625-based composite high-entropy alloy resistant to corrosion and wear and its preparation method. Background Technology
[0002] Inconel 625 (IN625) is an austenitic nickel-based superalloy with nickel as the matrix and solid solution strengthening by adding elements such as chromium, molybdenum, and niobium. Due to its excellent corrosion resistance in both oxidizing and reducing environments, as well as good weldability and high-temperature strength, it is widely used in extremely harsh environments such as aerospace, marine engineering, chemical equipment, and the nuclear industry.
[0003] High-entropy alloys (HEAs) are a new type of metallic material that breaks through the traditional single-principal-element design concept. They are made by arranging five or more elements in a near-equal atomic ratio, using the high-entropy effect to stabilize the solid solution structure. With their unique hysteretic diffusion, severe lattice distortion and cocktail effect, they exhibit excellent thermal stability and toughness, while showing significant potential in corrosion resistance and wear resistance in extremely harsh environments. At present, this field is at a critical stage of transitioning from basic theoretical exploration to high-performance metal matrix modification and engineering applications, providing a brand-new design paradigm for breaking through the performance bottlenecks of traditional alloys.
[0004] The cocktail effect refers to the comprehensive synergistic enhancement effect of an alloy that surpasses that of a single component, achieved through the scientific ratio and synergistic effect of multiple principal components. This provides theoretical support for materials to achieve high hardness, high toughness, and excellent corrosion and wear resistance.
[0005] For IN625 alloy, with the development of industrial technology, the relevant working environment is becoming increasingly complex. Components often simultaneously endure the combined effects of strong corrosive media erosion and mechanical friction, i.e., corrosion wear. Although traditional IN625 alloy has good corrosion resistance, its hardness is relatively low, and its wear resistance is limited. Under the coupled effect of corrosion and wear, the passivation film on the material surface is easily damaged by repeated mechanical forces, leading to a significant increase in the corrosion rate, which in turn causes serious material loss and equipment failure.
[0006] Despite the excellent physicochemical properties of CoCrFeNiMo high-entropy alloys, their application in current technologies still faces bottlenecks such as high raw material costs, microstructural embrittlement caused by the precipitation of σ-hard and brittle phases, and difficulties in processing and forming large-sized complex components. Furthermore, pure high-entropy alloy systems often struggle to balance the self-healing rate of the passivation film with the toughness of the matrix when dealing with extreme corrosion and wear conditions. For example, the OCP of a single CoCrFeNiMo high-entropy alloy continuously decreases throughout the corrosion and wear environment (e.g., Figure 6 As shown in the figure, the OCP of the CoCrFeNiMo high-entropy alloy continuously decreases throughout the corrosion and wear environment. This indicates that the high-entropy alloy system alone often fails to balance the self-repair rate of the passivation film and the toughness of the matrix when dealing with extreme corrosion and wear conditions. Furthermore, there is currently a lack of research on its deep integration with traditional nickel-based superalloys as a functional component, resulting in a technological gap in achieving synergistic optimization of "strength, toughness, corrosion resistance, and economy". Summary of the Invention
[0007] To address the aforementioned problems, this invention provides a corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy and its preparation method. This invention introduces specific proportions of CoCrFeNiMo high-entropy alloy components (such as Al and A2 series) into the IN625 matrix. Utilizing the unique distribution patterns of elements like Mo and Cr in the high-entropy alloy under multi-principal element environments, this not only enhances the solid solution strengthening effect of the matrix but, more importantly, forms a more protective composite passivation film on the material surface. This design effectively suppresses stress corrosion and abrasive wear induced by friction in corrosive environments, significantly improving the material's service life under harsh conditions and possessing extremely high industrial application value.
[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing an IN625-based composite high-entropy alloy resistant to corrosion and wear. The method involves introducing CoCrFeNiMo high-entropy alloy components into an Inconel 625 matrix using a linear arc additive manufacturing process to prepare the aforementioned IN625-based composite high-entropy alloy resistant to corrosion and wear.
[0009] Furthermore, the preparation method of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy specifically includes the following steps: installing Inconel 625 welding wire and CoCrFeNiMo high-entropy alloy components in a wire-arc additive manufacturing system, setting welding parameters, and introducing shielding gas; introducing the CoCrFeNiMo high-entropy alloy components into the molten pool, and forming a composite material component through a layer-by-layer welding process; and after cooling the composite material component, performing post-processing and machining to obtain the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy.
[0010] Furthermore, the total number of atoms in the CoCrFeNiMo high-entropy alloy component accounts for 25%-66.67% of the total number of atoms in the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy.
[0011] Furthermore, the atomic percentages of each element in the Inconel 625 welding wire are: Cr: 25.23at%, Fe: 2.85at%, Ni: 64.1at%, Mo: 5.84at%, Nb: 1.98at%.
[0012] Furthermore, the atomic percentages of each element in the CoCrFeNiMo high-entropy alloy components are as follows: Co: 19.82 at%, Cr: 19.79 at%, Fe: 21.58 at%, Ni: 18.52 at%, Mo: 20.29 at%.
[0013] Furthermore, the welding parameters are: welding current of 100-250A, voltage of 15-30V, and welding speed of 3-8mm / s.
[0014] Furthermore, the protective gas is argon, and the flow rate of the argon is 10-20 L / min.
[0015] Furthermore, the CoCrFeNiMo high-entropy alloy component is introduced into the molten pool by either synchronous wire feeding or by pre-placing alloy powder.
[0016] Furthermore, the layer-by-layer welding process includes the following steps: S1. After the protective gas is pre-pressed, the Inconel 625 welding wire and CoCrFeNiMo high-entropy alloy components are simultaneously fed in to start the first layer deposition; S2. After the first deposition is completed, allow it to cool naturally in a protective gas atmosphere. Once the interlayer temperature drops to 100-250℃, begin depositing the next layer. Repeat steps S1 and S2 until all the welding is completed. After the deposition is finished, cool to below 80°C under a protective gas atmosphere.
[0017] The technical principle behind the improved corrosion and wear resistance of the IN625-based composite high-entropy alloy provided by this invention is as follows: First, solid solution strengthening and phase transformation mechanism: The introduction of the CoCrFeNiMo high-entropy alloy component increases the lattice distortion energy, significantly improving the material hardness. Simultaneously, with increasing addition amount, the original point-like Laves phase in the microstructure is induced to transform into a more stable network-like σ phase.
[0018] Second, static corrosion resistance mechanism: Under low doping levels, the homogenization of elements such as Mo and Cr in the multi-principal element environment reduces the compositional differences between dendrites, reduces the driving force of micro-galvanic corrosion, and thus promotes the formation of a stable passivation film.
[0019] Third, the synergistic mechanism of corrosion resistance and wear resistance: With the high doping content of the CoCrFeNiMo high-entropy alloy components, the continuous network σ phase acts as a hard "skeleton," supporting the matrix during friction and inhibiting the rate of mechanical damage to the surface. At the same time, this structure accelerates the repassivation process in the wear area, forming a highly efficient protective "third body layer" that blocks the mutually reinforcing cycle of corrosion and wear.
[0020] Secondly, the present invention provides an IN625-based composite high-entropy alloy with corrosion and wear resistance prepared by the preparation method described above, wherein the IN625-based composite high-entropy alloy with corrosion and wear resistance includes a continuous network σ phase induced by the CoCrFeNiMo high-entropy alloy components.
[0021] Compared with the prior art, the present invention has the following advantages and technical effects: This invention relates to a high-entropy alloy-modified Inconel 625-based composite material composition design, which enhances the alloy's hardness and breaks through the traditional single-principal-element modification approach for nickel-based alloys. By introducing a CoCrFeNiMo high-entropy alloy component, it cleverly utilizes the "cocktail effect" of multi-principal-element alloys. While retaining the excellent properties of nickel-based alloys, this design significantly improves the microhardness of the composite material, enhances its resistance to plastic deformation under heavy loads, and effectively solves the technical bottleneck of traditional Inconel 625 alloys being prone to mechanical damage due to their low hardness.
[0022] This invention achieves enhanced static corrosion resistance by controlling the distribution of multiple principal components. By regulating the addition amount of the CoCrFeNiMo high-entropy alloying elements, the electrochemical homogeneity of the alloy surface is optimized, promoting the formation of a more stable and dense passivation film. By reducing compositional fluctuations between the matrix and the precipitated phases, this design significantly suppresses the driving force of interphase microgalvanic corrosion, enabling the material to exhibit superior thermodynamic stability and chemical protection performance in chlorine-containing corrosive media.
[0023] The corrosion and wear resistance of materials is enhanced by utilizing a network-like σ-phase skeleton support mechanism. This structure acts as a mechanical "skeleton" to support the soft matrix. This organizational evolution not only improves the surface repassivation rate, enabling rapid reconstruction of the protective layer during friction, but also fundamentally suppresses the interactive superposition effect of "corrosion-induced wear," significantly reducing the total mass loss of the material under complex dynamic environments. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 Vickers hardness diagrams of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy and Inconel 625 alloy prepared in Examples 1-2; Figure 2 The left image shows the Nyquist plot of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy and Inconel 625 alloy prepared in Examples 1-2, and the right image shows the Bode plot of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy and Inconel 625 alloy prepared in Examples 1-2. Figure 3 (1) is a metallographic micrograph of Inconel 625 alloy, (2) is a metallographic micrograph of A1, (3) is a metallographic micrograph of A2, and (4) is a metallographic micrograph of IN625-based composite high-entropy alloy prepared in Comparative Example 1. Figure 4 (1) is the SEM scan image of Inconel 625 alloy, (2) is the SEM scan image of A1, (3) is the SEM scan image of A2, and (4) is the SEM scan image of IN625-based composite high-entropy alloy prepared in Comparative Example 1. Figure 5 In the middle (1) and (2), respectively, the 2D profile diagram and wear rate diagram of the corrosion-resistant IN625-based composite high-entropy alloy prepared in Examples 1-2, the IN625-based composite high-entropy alloy prepared in Comparative Example 1, and the Inconel 625 alloy after corrosion and wear tests; Figure 6 This is an OCP evolution diagram for a single CoCrFeNiMo high-entropy alloy. Detailed Implementation
[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0027] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0028] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0029] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0030] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0031] The room temperature in this invention refers to 25±2℃.
[0032] This invention provides a method for preparing an IN625-based composite high-entropy alloy resistant to corrosion and wear. The method involves introducing CoCrFeNiMo high-entropy alloy components into an Inconel 625 matrix using a linear arc additive manufacturing process to prepare the aforementioned IN625-based composite high-entropy alloy resistant to corrosion and wear.
[0033] The preparation method of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy specifically includes the following steps: installing Inconel 625 welding wire and CoCrFeNiMo high-entropy alloy components in a wire-arc additive manufacturing system, setting welding parameters, and introducing shielding gas; introducing the CoCrFeNiMo high-entropy alloy components into the molten pool, and forming a composite material component through a layer-by-layer welding process; and after cooling the composite material component, performing post-processing and machining to obtain the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy.
[0034] In some preferred embodiments, the total number of atoms in the CoCrFeNiMo high-entropy alloy component accounts for 25%-66.67% of the total number of atoms in the corrosion-resistant IN625-based composite high-entropy alloy. For example, the total number of atoms in the CoCrFeNiMo high-entropy alloy component accounts for 25% and 66.67% of the total number of atoms in the corrosion-resistant IN625-based composite high-entropy alloy.
[0035] In some preferred embodiments, the atomic percentages of each element in the Inconel 625 welding wire are: Cr: 25.23at%, Fe: 2.85at%, Ni: 64.1at%, Mo: 5.84at%, Nb: 1.98at.
[0036] In some preferred embodiments, the atomic percentages of each element in the CoCrFeNiMo high-entropy alloy component are: Co: 19.82at%, Cr: 19.79at%, Fe: 21.58at%, Ni: 18.52at%, Mo: 20.29at.
[0037] In some preferred embodiments, the welding parameters are: welding current of 100-250A, voltage of 15-30V, and welding speed of 3-8mm / s. For example, the welding current is 150A; the voltage is 22V; and the welding speed is 5mm / s.
[0038] In some preferred embodiments, the protective gas is argon, and the flow rate of the argon is 10-20 L / min.
[0039] In some preferred embodiments, the CoCrFeNiMo high-entropy alloy component is introduced into the molten pool by means of synchronous wire feeding or by pre-placing alloy powder.
[0040] In some preferred embodiments, the layer-by-layer welding process includes the following steps: S1. Start the protective gas, pre-purge with argon for more than 30 seconds to ensure the atmosphere is pure, start the arc and begin the first layer deposition, and simultaneously feed in Inconel 625 welding wire and CoCrFeNiMo high-entropy alloy components; S2. After completing the first layer deposition, stop feeding wire and powder, maintain a protective atmosphere, and wait for the deposited layer to cool naturally in the argon environment. Use an infrared thermometer to monitor the surface temperature of the deposited layer in real time. When the interlayer temperature drops to the range of 100-250℃, the next layer deposition can be carried out. Repeat steps S1 and S2 until all the welding is completed. After the deposition is finished, keep the protective gas flowing until the workpiece cools to below 80°C.
[0041] This invention also provides a corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy prepared by the aforementioned method, wherein the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy comprises a continuous network σ phase induced by the CoCrFeNiMo high-entropy alloy components.
[0042] In the embodiments of this invention, both the Inconel 625 welding wire and the CoCrFeNiMo high-entropy alloy component were purchased commercially.
[0043] The CoCrFeNiMo high-entropy alloy component used in this embodiment of the invention is CoCrFeNiMo high-entropy alloy powder.
[0044] The stress annealing process and machining used in the embodiments of the present invention are carried out using conventional technical means, and the specific process will not be described in detail.
[0045] Example 1: A method for preparing an IN625-based composite high-entropy alloy resistant to corrosion and wear. S1. Raw material preparation and pretreatment: Commercial Inconel 625 welding wire was selected as the base material, and CoCrFeNiMo high-entropy alloy components were used as the modifying materials. The substrate surface of the linear arc additive manufacturing system was polished and degreased to ensure the bonding strength of the deposition interface. S2. Equipment parameter settings: Install commercial Inconel 625 welding wire and CoCrFeNiMo high-entropy alloy components into the linear arc additive manufacturing system, set the welding current range to 150 A, the voltage to 22 V, the welding speed to 5 mm / s, and use high-purity argon as the shielding gas with a flow rate of 7 L / min. S3. Composite Material Layer-by-Layer Deposition: Using a synchronous wire feeding method, the CoCrFeNiMo high-entropy alloy component is introduced into the molten pool according to the total number of atoms in the CoCrFeNiMo high-entropy alloy component being 25 at.% of the total number of atoms in the corrosion-resistant IN625-based composite high-entropy alloy (i.e., calculated based on the total number of atoms: CoCrFeNiMo high-entropy alloy component: IN625-based composite high-entropy alloy = 1:3). A layer-by-layer welding process is adopted, controlling the interpass temperature at 100-250℃, until a composite material component (3mm×10mm×10mm) of the target plate shape is obtained. S4. Post-processing and machining: The composite material component prepared in step S3 is naturally cooled at room temperature, and then stress-relief annealing is performed by placing the component in a vacuum furnace. The component is then machined by CNC milling to obtain a finished surface that meets the accuracy requirements, thus preparing a corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy, denoted as A1.
[0046] The chemical composition of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy prepared in this embodiment is shown in Table 1.
[0047] Example 2: A method for preparing an IN625-based composite high-entropy alloy resistant to corrosion and wear. S1. Raw material preparation and pretreatment: Commercial Inconel 625 welding wire was selected as the base material, and CoCrFeNiMo high-entropy alloy components were used as the modifying materials. The substrate surface of the linear arc additive manufacturing system was polished and degreased to ensure the bonding strength of the deposition interface. S2. Equipment parameter settings: Install commercial Inconel 625 welding wire and CoCrFeNiMo high-entropy alloy components into the linear arc additive manufacturing system, set the welding current range to 150 A, the voltage to 22 V, the welding speed to 5 mm / s, and use high-purity argon as the shielding gas with a flow rate of 7 L / min. S3. Composite material layer-by-layer deposition: By pre-placing alloy powder, the total number of atoms in the CoCrFeNiMo high-entropy alloy component accounts for 66.67 at.% of the total number of atoms in the corrosion-resistant IN625-based composite high-entropy alloy (i.e., calculated based on the total number of atoms: CoCrFeNiMo high-entropy alloy component: IN625-based composite high-entropy alloy = 2:1). The CoCrFeNiMo high-entropy alloy component is introduced into the molten pool, and a layer-by-layer welding process is adopted, controlling the interlayer temperature at 100-250℃, until a composite material component with the target plate shape is obtained. S4. Post-processing and machining: The composite material component prepared in step S3 is naturally cooled at room temperature, and then stress-relief annealing is performed by placing the component in a vacuum furnace. The component is then machined by CNC milling to obtain a finished surface that meets the precision requirements, thus preparing a corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy, denoted as A2.
[0048] The chemical composition of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy prepared in this embodiment is shown in Table 1.
[0049] Comparative Example 1 Same as Example 1, except that in S3, the CoCrFeNiMo high-entropy alloy component is introduced into the molten pool according to the total number of atoms in the CoCrFeNiMo high-entropy alloy component accounting for 80% of the total number of atoms in the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy.
[0050] The chemical composition of the IN625-based composite high-entropy alloy prepared in this comparative example is shown in Table 1.
[0051] Table 1 Chemical composition (at.%) of the tested alloys Performance testing 1. Hardness testing The hardness of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy and Inconel 625 alloy prepared in Examples 1-2 was measured using a microhardness tester. Figure 1 The Vickers hardness diagrams of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy and Inconel 625 alloy prepared in Examples 1-2 are shown below. Figure 1 As can be seen, the hardness value of the composite high-entropy alloy gradually increases with the increase of the content of the CoCrFeNiMo high-entropy alloy components.
[0052] 2. Electrochemical corrosion test The corrosion-resistant IN625-based composite high-entropy alloy and Inconel 625 alloy prepared in Examples 1-2 were tested using an electrochemical workstation equipped with a standard three-electrode system. The test conditions were as follows: electrochemical testing and evaluation were carried out in a 3.5 wt.% NaCl solution at room temperature. The corrosion-resistant IN625-based composite high-entropy alloy and Inconel 625 alloy prepared in Examples 1-2 were used as working electrodes, Ag / AgCl electrode was used as reference electrode, and platinum electrode was used as counter electrode. Figure 2 The left image shows the Nyquist plots of the IN625-based composite high-entropy alloy and the Inconel 625 alloy prepared in Examples 1-2; the right image shows the Bode plots of the IN625-based composite high-entropy alloy and the Inconel 625 alloy prepared in Examples 1-2. Figure 2 The Nyquist curves show that, under pure corrosive conditions, the corrosion resistance is: A1 > Inconel 625 > A2 (the impedance arc of the sample is an incomplete semicircle; the larger the radius of the arc, the better the corrosion resistance of the sample). Figure 2 The Bode curve shows that at 10 5 -10 3 Within the Hz range, the impedance spectrum slope and negative phase angle of all alloys are close to 0, indicating that each test system has approximately the same electrolyte resistance, ensuring the consistency of the experimental environment. The impedance modulus at 0.01 Hz typically corresponds to the polarization resistance of the material and is a key indicator for evaluating the corrosion resistance of the alloy. The Bode curves show that Al exhibits the largest impedance modulus and the largest phase angle at low frequencies, directly demonstrating that a more stable and dense passivation film has formed on its surface, exhibiting the best chemical stability among all tested samples.
[0053] 3. Determination of key electrochemical parameters Key electrochemical parameters of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloys prepared in Examples 1-2, the IN625-based composite high-entropy alloys prepared in Comparative Example 1, and the Inconel 625 alloy were determined, and the results are shown in Table 2.
[0054] Table 2 Rs (solution resistance) reflects the conductivity of the test medium. Y0 (Constant Phase Angle Element CPE): Due to the non-uniformity or roughness of the passivation film surface, CPE (dispersion index) is usually used to describe the behavior of non-ideal capacitance. Where n sl The closer the value is to 1, the closer the interface is to an ideal capacitor, and the denser and smoother the passivation film. Rct (charge transfer resistance): reflects the resistance of an electrochemical reaction across the electric double layer, and is the most crucial indicator for judging corrosion resistance. The larger the Rct value, the higher the polarization resistance of the material and the slower the corrosion rate.
[0055] As shown in Table 2, the charge transfer resistance Rct is ranked as follows: A1 > Inconel 625 > A2 > Comparative Example 1. This indicates that appropriate component modification enhances the polarization resistance of the alloy surface, effectively suppresses the charge transfer process, and significantly improves the static corrosion resistance. Meanwhile, A1 has the lowest Y0 value. In electrochemical theory, a lower admittance amplitude usually corresponds to a thicker or denser passivation film. These data directly demonstrate that the corrosion resistance of the composite alloy can be significantly improved by controlling the doping composition.
[0056] 4. Metallurgical microscope testing The corrosion- and wear-resistant IN625-based composite high-entropy alloys prepared in Examples 1-2, the IN625-based composite high-entropy alloy prepared in Comparative Example 1, and the Inconel 625 alloy were tested using a metallographic microscope. Figure 3 (1) is a metallographic micrograph of Inconel 625 alloy, (2) is a metallographic micrograph of A1, (3) is a metallographic micrograph of A2, and (4) is a metallographic micrograph of the IN625-based composite high-entropy alloy prepared in Comparative Example 1. Figure 3 As can be seen, the Inconel 625 alloy has large dendrites and some eutectic structures. Combined with the metallographic micrograph of A2, it can be indirectly confirmed that with the addition of CoCrFeNiMo high-entropy alloying elements, the composite alloy gradually tends to form a eutectic structure, and there are more continuous σ phases between the dendrites. In contrast, the metallographic micrograph of the IN625-based composite high-entropy alloy prepared in Comparative Example 1 shows that more σ phases precipitate from between the dendrites, and the degree of eutectic is intensified.
[0057] 5. Microstructure testing of the alloy The microstructures of the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloys prepared in Examples 1-2, the IN625-based composite high-entropy alloys prepared in Comparative Example 1, and Inconel 625 were observed using scanning electron microscopy. Figure 4 (1) is the SEM scan image of Inconel 625 alloy, (2) is the SEM scan image of A1, (3) is the SEM scan image of A2, and (4) is the SEM scan image of IN625-based composite high-entropy alloy prepared in Comparative Example 1; Figure 4 From (1) and (2), it can be seen that both Inconel 625 alloy and Al contain dot-like and strip-like Laves phases. With the addition of CoCrFeNiMo high-entropy alloying elements, induced transformation of lamellar and network σ phases (such as...) will gradually occur. Figure 4 In (2), the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy prepared by this invention gradually tends to form a eutectic structure, and more continuous σ phases exist between dendrites. (Comparison) Figure 4 As can be seen from (2) to (4), the eutectic structure of the Inconel 625-based composite high-entropy alloy becomes denser with the increase of the CoCrFeNiMo content.
[0058] 6. Corrosion and wear test Corrosion and wear tests were conducted on the corrosion-resistant IN625-based composite high-entropy alloys prepared in Examples 1-2, the IN625-based composite high-entropy alloy prepared in Comparative Example 1, and the Inconel 625 alloy using a reciprocating tribological testing machine equipped with an electrochemical workstation and a tribological corrosion kit. The test conditions were: 3.5 wt.% NaCl solution, load of 3 N, speed of 18 mm / s, room temperature, and test duration of 40 min. Figure 5 In Figures (1) and (2), the 2D profile and wear rate diagrams of the corrosion-resistant IN625-based composite high-entropy alloy prepared in Examples 1-2, the IN625-based composite high-entropy alloy prepared in Comparative Example 1, and the Inconel 625 alloy after corrosion and wear tests are shown. Figure 5 From (1), it can be seen that the wear depth and wear volume show the order Inconel 625 > A1 > A2, indicating that by controlling the doping composition, the corrosion and wear resistance of Inconel 625 alloy can be improved; from Figure 5As can be seen from (2), the Inconel 625 alloy suffered the most severe wear, while A2 suffered the least wear. This also demonstrates that controlling the doped components can improve the corrosion and wear resistance of the Inconel 625 alloy. In Comparative Example 1, the Inconel 625-based composite high-entropy alloy was prepared. Due to the excessive introduction of the CoCrFeNiMo high-entropy alloy components, the σ phase increased, the phase interface area increased, and the galvanic corrosion intensity increased, resulting in a decrease in corrosion performance. Therefore, in corrosion and wear, the synergistic effect of mechanical removal and galvanic corrosion exacerbated the material loss.
[0059] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing a corrosion- and wear-resistant IN625-based composite high-entropy alloy, characterized in that, The corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy was prepared by introducing CoCrFeNiMo high-entropy alloy components into the Inconel 625 matrix using a linear arc additive manufacturing process.
2. The method for preparing the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy according to claim 1, characterized in that, Specifically, the following steps are included: Inconel 625 welding wire and CoCrFeNiMo high-entropy alloy components are installed in a linear arc additive manufacturing system, welding parameters are set, and shielding gas is introduced; the CoCrFeNiMo high-entropy alloy components are introduced into the molten pool, and a composite material component is formed through a layer-by-layer welding process; after the composite material component is cooled, it is post-processed and machined to prepare the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy.
3. The method for preparing the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy according to claim 2, characterized in that, The total number of atoms in the CoCrFeNiMo high-entropy alloy components accounts for 25%-66.67% of the total number of atoms in the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy.
4. The method for preparing the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy according to claim 2, characterized in that, The atomic percentages of each element in the Inconel 625 welding wire are as follows: Cr: 25.23 at%, Fe: 2.85 at%, Ni: 64.1 at%, Mo: 5.84 at%, Nb: 1.98 at%.
5. The method for preparing the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy according to claim 2, characterized in that, The atomic percentages of each element in the CoCrFeNiMo high-entropy alloy are as follows: Co: 19.82 at%, Cr: 19.79 at%, Fe: 21.58 at%, Ni: 18.52 at%, Mo: 20.29 at%.
6. The method for preparing the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy according to claim 2, characterized in that, The welding parameters are: welding current of 100-250A, voltage of 15-30V, and welding speed of 3-8mm / s.
7. The method for preparing the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy according to claim 2, characterized in that, The protective gas is argon, and the flow rate of the argon is 10-20 L / min.
8. The method for preparing the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy according to claim 2, characterized in that, The CoCrFeNiMo high-entropy alloy component is introduced into the molten pool by either synchronous wire feeding or pre-placed alloy powder.
9. The method for preparing the corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy according to claim 2, characterized in that, The layer-by-layer welding process includes the following steps: S1. After the protective gas is pre-pressed, the Inconel 625 welding wire and CoCrFeNiMo high-entropy alloy components are simultaneously fed in to start the first layer deposition; S2. After the first deposition is completed, allow it to cool naturally in a protective gas atmosphere. Once the interlayer temperature drops to 100-250℃, begin depositing the next layer. Repeat steps S1 and S2 until all the welding is completed. After the deposition is finished, cool to below 80°C under a protective gas atmosphere.
10. A corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy prepared by the preparation method according to any one of claims 1-9, characterized in that, The corrosion-resistant and wear-resistant IN625-based composite high-entropy alloy comprises a continuous network σ phase induced by the CoCrFeNiMo high-entropy alloy components.