Plasma cladding preparation method of AlCu2 (NiCr) 2Ti-(WC) x high-entropy alloy wear-resistant coating

Abstract

The invention discloses a plasma cladding preparation method of an AlCu2 (NiCr) 2Ti-(WC) x high-entropy alloy wear-resistant coating, and relates to a high-entropy alloy cable type welding wire material technology and a welding wire and powder collaborative conveying technology. The high-entropy alloy material provided by the invention comprises the following chemical components in atomic percent: 6%-7% of Al, 14%-22% of Cu, 6%-7% of Ni, 6%-8% of Cr, 40%-55% of Ti, 1%-10% of W and 5%-17% of C. The material provided by the invention is a high-hardness wear-resistant high-entropy alloy material for plasma cladding, which is suitable for strengthening the surfaces of parts produced by taking TC11 titanium alloy as a raw material in the aerospace field. A corresponding composite coating is prepared by using the high-entropy alloy cable type welding wire and WC reinforced powder and adopting a plasma cladding technology, and the hardness and the wear resistance of the composite coating have good effects. According to the method, the most suitable surface treatment method can be selected according to different requirements. In addition, the material has good weldability and is a material suitable for plasma additive manufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance metal wires and powder materials, and in particular to a high-entropy alloy, a preparation method and a plasma cladding method. Background Art

[0002] The concept of high entropy alloy is a new alloy design concept proposed in recent years. Different from the previous single main element or traditional alloy, high entropy alloy is usually composed of multiple elements, and the content of each element is between 5% and 35%. This alloy design method will fully increase the entropy value in the alloy system, so it is called high entropy alloy. High entropy alloy has a series of excellent properties, such as high hardness, wear resistance, corrosion resistance and high temperature stability.

[0003] However, in the process of casting high entropy alloys, problems such as component segregation and uneven crystal structure are prone to occur, and the material processing is also difficult. If the overall material is replaced with special materials in order to improve some of the performance of the parts, the overall casting cost will increase significantly and cause waste of resources of some special materials. Therefore, it is necessary to explore a more effective method for preparing high entropy alloys to solve the above problems. Coating surface modification can be performed by cladding the surface of ordinary inexpensive metal materials, or by directly infiltrating the coating into the designed composite metal material. This method can not only meet the performance requirements of the parts, but also greatly reduce the production cost, making the manufacturing of parts more flexible and economical. This technology allows manufacturers to choose the most suitable surface treatment method according to different needs and uses, greatly improving production efficiency and quality.

[0004] At present, the main preparation methods of high entropy alloy composite coatings include mechanical alloying, magnetron sputtering, thermal spraying, electrochemical deposition, laser cladding, plasma cladding, etc. Among them, plasma cladding technology has advantages that other technologies cannot match, such as high degree of automation in the preparation process, wide range of coating material selection, strong metallurgical bonding between the coating and the substrate, dense and fine structure of the prepared coating, low dilution rate, small size restriction, simple pre-treatment, etc. It is expected to become one of the main preparation methods for high entropy alloys to achieve large-scale promotion and application, and has become one of the hot research directions in the field of high entropy alloys at home and abroad. However, the types and specific components of high entropy alloys suitable for plasma cladding have not yet formed a system, especially the surface modification and strengthening related processes suitable for important aerospace parts still need further exploration. In view of this, the present invention is specially proposed. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects and shortcomings of the above-mentioned prior art and to provide an AlCu2(NiCr)2Ti-(WC) x Plasma cladding preparation method for high entropy alloy wear-resistant coating.

[0006] The present invention is achieved in that: In a first aspect, the present invention provides a high entropy alloy of AlCu2(NiCr)2Ti-(WC)x, wherein the chemical composition and atomic percentage by mass of the high entropy alloy are: Al: 6% to 7%, Cu: 14% to 22%, Ni: 6% to 7%, Cr: 6% to 8%, Ti: 40% to 55%, W: 1% to 10%, and C: 5% to 17%.

[0007] In a second aspect, the present invention provides a method for preparing an AlCu2(NiCr)2Ti high entropy alloy cable welding wire.

[0008] Preferably, a cable-type welding wire twisting machine is used, with Al, Cu, Ni, Cr, and Ti single wires with a diameter of 0.5 mm as raw materials, Al wire as the central wire, and other welding wires as planetary wires. An AlCu2(NiCr)2Ti high-entropy alloy cable-type welding wire is obtained by twisting, compacting, straightening, and loading, which is used for preparing high-entropy alloy composite coatings using plasma additive manufacturing technology.

[0009] In a third aspect, the present invention also provides an application of the above-mentioned high entropy alloy in preparing a high entropy alloy coating or preparing a high entropy alloy composite coating on a TC11 surface.

[0010] Preferably, the WC reinforced powder is used for preparing high entropy alloy by plasma additive manufacturing technology, and more preferably for preparing high entropy alloy composite coating by plasma cladding.

[0011] In a fourth aspect, the present invention also provides a method for preparing a high entropy alloy coating, using a high entropy alloy cable welding wire and a reinforced powder to prepare a high entropy alloy composite coating.

[0012] Preferably, the method for preparing the high entropy alloy composite coating is selected from at least one of magnetron sputtering, electron beam physical vapor deposition, arc ion plating, flame spraying, atmospheric plasma spraying, vacuum plasma spraying, cold / hot spraying, plasma spraying-physical vapor deposition, pulse electroplating, plasma cladding and laser cladding, preferably plasma additive manufacturing, more preferably plasma cladding.

[0013] In a fifth aspect, the present invention also provides a plasma cladding formed coating formed by optimizing plasma cladding process parameters.

[0014] Preferably, when the plasma cladding body is TC11 titanium alloy, the optimal process parameters are powder feeding gas flow rate 5L / min, wire feeding speed 8mm / s, welding speed 3mm / s, current 120A, and the distance between the welding gun nozzle and the substrate is 5mm; under the optimal parameters, the plasma cladding formed coating is metallurgically bonded with the substrate, and the microhardness is as high as 943.97HV 0.2, which is 2.62 times of the substrate, and the average wear rate is 8.6075×10 -6 mm 3 / (N•m).

[0015] In a sixth aspect, the present invention also provides a plasma cladding formed coating formed by optimal plasma cladding process parameters.

[0016] Preferably, the AlCu2(NiCr)2Ti-(WC)x (x=25r / min, 50r / min, 75r / min, 100r / min) high entropy alloy coating prepared by the optimal plasma cladding process parameters has a microhardness of 867.14HV0.2, 892.00HV0.2, 943.97HV0.2 and 879.94HV0.2, respectively; which is 140.9%, 147.8%, 162.2 and 144.4% higher than the average microhardness of the substrate (360HV0.2), respectively.

[0017] The wear rates are 9.8093×10-6mm3 / (N•m), 8.6075×10-6mm3 / (N•m), 9.7506×10-6mm3 / (N•m), and 1.10123×10-7mm3 / (N•m), respectively; which are 21.6%, 31.1%, 22.0%, and 11.2% lower than the wear rate of TC11 substrate (1.24985×10-7mm3 / (N•m)), respectively.

[0018] In a seventh aspect, the present invention also provides an application of the above-mentioned plasma cladding formed coating in high-hardness, wear-resistant and high-temperature materials.

[0019] Preferably, the plasma cladding formed coating is used in high temperature, heavy load, high impact, high hardness and wear resistant materials in the field of important parts in the aerospace field.

[0020] More preferably, the plasma cladding formed coating is used in the modification and strengthening of high hardness and wear resistance surfaces of blades and vanes.

[0021] The present invention has the following beneficial effects: The present invention provides a high entropy alloy, a preparation method and a plasma cladding method. The high entropy alloy is composed of AlCu2(NiCr)2Ti-(WC) x ( x=25r / min, 50r / min, 75r / min, 100r / min), the chemical composition, atomic percentage and mass percentage of the high entropy alloy are: Al: 6%~7%, Cu: 14%~22%, Ni: 6%~7%, Cr: 6%~8%, Ti: 40%~55%, W: 1%~10%, C: 5%~17%. , the addition speed of WC is 25r / min, 50r / min, 75r / min, 100r / min. The alloying elements selected for the high entropy alloy cable welding wire in this experiment are all relatively common metal elements, which can ensure that the prepared high entropy alloy composite coating has high economy, among which Ti, Cr, Ni, and Cu are the fourth period sub-group elements, and Al is the third period main group element. Among them, Ti atoms have a larger atomic radius, and the addition of Ti atoms can increase the lattice distortion and improve the hardness, strength and wear resistance of the alloy. The Cr element can form a solid solution with other elements in the alloy, reduce the hardness, strength and brittleness of the alloy, and improve plasticity and toughness. The Ni element can form a solid solution with other elements in the alloy, making the alloy paramagnetic and improving the plasticity and toughness of the alloy. The ionic radius of the Cu element is small, and it is easy to diffuse and segregate in the intergranular region, and can form a Cu-rich nanophase, which helps to improve the hardness and wear resistance of the alloy. The high entropy alloy material is added with the Al element, and the Ti element in the matrix is ​​diluted into the coating during the plasma cladding process, which reduces the material density while promoting the material's antioxidant properties and hardness, achieving the effect of light weight, high hardness and high strength. WC particles, as an excellent reinforcement phase, further enhance the material's high hardness, high strength, wear resistance and wettability as well as low thermal expansion coefficient. Using the above-mentioned high entropy alloy cable welding wire and reinforced powder, the corresponding high-strength, high-hardness, wear-resistant high entropy alloy coating can be prepared by plasma cladding technology, and its hardness and wear resistance have excellent effects. The high entropy alloy material prepared by the present invention is a special high entropy alloy material with good weldability and suitable for plasma additive manufacturing, which expands the scope of material use in the field of additive manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 Schematic diagram of the composition of the AlCu2(NiCr)2Ti high entropy alloy cable welding wire of Examples 1-4 of the present invention.

[0024] Figure 2AlCu2(NiCr)2Ti-(WC) of Examples 1-4 of the present invention x ( x =25r / min, 50r / min, 75r / min, 100r / min) schematic diagram of the high entropy alloy composite coating preparation platform.

[0025] Figure 3 AlCu2(NiCr)2Ti-(WC) of Examples 1-4 of the present invention x ( x =25r / min, 50r / min, 75r / min, 100r / min) XRD spectrum of high entropy alloy composite coating.

[0026] Figure 4 AlCu2(NiCr)2Ti-(WC) of Examples 1-4 of the present invention x ( x =25r / min, 50r / min, 75r / min, 100r / min) cross-sectional view of high entropy alloy composite coating.

[0027] Figure 5 AlCu2(NiCr)2Ti-(WC) of Examples 1-4 of the present invention x ( x =25r / min, 50r / min, 75r / min, 100r / min) Microscopic SEM images of high entropy alloy composite coating.

[0028] Figure 6 AlCu2(NiCr)2Ti-(WC) of Examples 1-4 of the present invention x ( x =25r / min, 50r / min, 75r / min, 100r / min) friction and wear morphology of high entropy alloy composite coating.

[0029] Description of reference numerals: 1. Robotic arm; 2. Plasma welding machine; 3. Plasma welding gun; 4. Argon gas system; 5. Powder conveying device; 6. Wire feeding gun; 7. Automatic wire feeder; 8. TC11 titanium alloy substrate; 9. Workbench DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0031] The purpose of the present invention is to develop a wear-resistant high-entropy alloy material specially used for plasma additive manufacturing in high-load, heavy-load and large-impact fields such as aircraft engine blades and blades produced with TC11 as the substrate, and to provide a method for rapidly preparing the high-entropy alloy material, so as to achieve the purpose of improving its mechanical properties such as strength, hardness and wear resistance.

[0032] In order to meet the use conditions of important aerospace components and prepare new high-entropy alloy materials with high hardness, good strength, high temperature resistance and excellent wear resistance, the embodiment of the present invention has developed a new cable-type welding wire high-entropy alloy suitable for plasma cladding and a new process for coordinated delivery of WC powder, and provided a corresponding plasma cladding method, which can achieve rapid near-net forming of surface coatings of complex structural parts while improving the strength, hardness, high temperature resistance and wear resistance of the coating, so as to solve the above-mentioned problems.

[0033] In order to achieve the above-mentioned purpose of the present invention, the following technical scheme is specially adopted.

[0034] In a first aspect, an embodiment of the present invention provides a high entropy alloy, wherein the composition of the high entropy alloy is AlCu2(NiCr)2Ti-(WC) x ( x =25r / min, 50r / min, 75r / min, 100r / min), the chemical composition and atomic percentage of high entropy alloy: Al: 6%~7%, Cu: 14%~22%, Ni: 6%~7%, Cr: 6%~8%, Ti: 40%~55%, W: 1%~10%, C: 5%~17%, the adding speed of WC is 25r / min, 50r / min, 75r / min, 100r / min respectively.

[0035] The alloying elements used in the high entropy alloy cable welding wire in this experiment are all relatively common metal elements, which can ensure that the prepared high entropy alloy composite coating has high economic efficiency, as shown in Table 1, where Ti, Cr, Ni, and Cu are the fourth period sub-group elements, and Al is the third period main group element. Among them, the Ti atom has a larger atomic radius. The addition of Ti atoms can increase the lattice distortion and improve the hardness, strength and wear resistance of the alloy. The Cr element can form a solid solution with other elements in the alloy, reduce the hardness, strength and brittleness of the alloy, and improve the plasticity and toughness. The Ni element can form a solid solution with other elements in the alloy, making the alloy paramagnetic and improving the plasticity and toughness of the alloy. The Cu element has a small ion radius and is easy to diffuse and segregate in the intergranular region. It can form a Cu-rich nanophase, which helps to improve the hardness and wear resistance of the alloy. The high entropy alloy material is added with Al element. The Ti element in the matrix is ​​diluted in the coating during the plasma cladding process, which reduces the material density while promoting the material's antioxidant properties and hardness, achieving the effect of light weight, high hardness and high strength. WC particles as an excellent reinforcement phase further enhance the material's high hardness, high strength, wear resistance, wettability and low thermal expansion coefficient.

[0036] In a second aspect, the present invention provides a method for preparing an AlCuNiCrTi high entropy alloy cable welding wire.

[0037] In an optional embodiment, the preparation of the high entropy alloy cable welding wire comprises the following steps: Step 1: Prepare Al, Cu, Ni 80 Cr 20 , Ti metal wire, put it on a reel for later use, including Cu, Ni 80 Cr 20 Two pieces of metal monofilament need to be prepared.

[0038] Step 2: Place the Al wire at the center wire position, and distribute the remaining single wires symmetrically in pairs, and use a wire twisting machine to twist, relieve stress and straighten them.

[0039] Step 3: Reel the twisted high entropy alloy cable welding wire and divide it into reels for later use.

[0040] In an optional embodiment, the purity of various metal wires in step 1 is higher than 99.5 wt.%.

[0041] In an optional embodiment, the diameter of each metal monofilament in step 1 is 5 mm.

[0042] In a third aspect, an embodiment of the present invention further provides an application of the above-mentioned high entropy alloy in the preparation of a high entropy alloy composite coating or a bulk high entropy alloy material.

[0043] Preferably, the high entropy alloy cable welding wire is used for plasma additive manufacturing to prepare the high entropy alloy coating, and more preferably for plasma cladding to prepare the high entropy alloy coating. Table 1 Characteristic parameters of each element in the alloy In a fourth aspect, the present invention also provides a method for preparing a high entropy alloy coating, which uses a high entropy alloy cable welding wire and enhanced powder co-transportation to prepare the high entropy alloy coating.

[0044] Preferably, the method for preparing the high entropy alloy composite coating is selected from at least one of magnetron sputtering, electron beam physical vapor deposition, arc ion plating, flame spraying, atmospheric plasma spraying, vacuum plasma spraying, cold / hot spraying, plasma spraying-physical vapor deposition, pulse electroplating, plasma cladding and laser cladding, preferably plasma additive manufacturing, more preferably plasma cladding.

[0045] In an optional embodiment, the preparation of a high entropy alloy coating by plasma cladding includes the following steps: after planning the cladding trajectory in a plasma cladding forming system, high entropy alloy powder is used to form and prepare a high-performance coating.

[0046] Preferably, the process parameters of plasma cladding are: powder feeding gas flow rate, wire feeding speed, welding speed, current, and distance between welding gun nozzle and substrate.

[0047] Preferably, the particle size of the reinforcement phase particles suitable for plasma cladding is 100-150 meshes.

[0048] In a fifth aspect, an embodiment of the present invention further provides a plasma cladding formed coating formed by using plasma cladding technology.

[0049] Step 4: Use a robotic plasma cladding system to prepare the coating on the surface of the TC11 titanium alloy plate.

[0050] In an optional embodiment, the plasma cladding shielding gas, ion gas and powder feeding gas in step 3 are preferably argon or helium, and the purity of both is 99.99 vol.%.

[0051] Step 5: The prepared coating is used to prepare metallographic specimens, microhardness specimens and wear resistance test specimens using a CNC wire cutting machine and a polishing machine.

[0052] Preferably, when the substrate is TC11 titanium alloy, the plasma cladding formed coating is metallurgically bonded to the substrate, and the microhardness is as high as 943.97HV 0.2 , which is 2.62 times of the substrate, and the average wear rate is 8.6075×10 -6 mm 3 / (N•m).

[0053] In a sixth aspect, an embodiment of the present invention further provides an application of the above-mentioned plasma cladding formed coating in high-hardness and wear-resistant materials.

[0054] Preferably, the plasma cladding formed coating is used in the surface modification and strengthening of aero-engine blades made of TC11 titanium alloy as raw material.

[0055] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0056] Example 1 A high-hardness, high-temperature, and wear-resistant AlCu2(NiCr)2Ti(WC) 25 A high entropy alloy and a preparation method thereof. The chemical composition and atomic percentage of the high entropy alloy are: Al: 6%, Cu: 16%, Ni: 7%, Cr: 6%, Ti: 40%, C: 5%, W: 0.5%. The prepared AlCu2 (NiCr) 2Ti high entropy alloy cable welding wire is placed in an automatic wire feeder; the WC powder is dried in a drying oven at 100° C. for 1 hour.

[0057] The preparation method thereof comprises the following steps: Step 1: The configured AlCu2(NiCr)2Ti high entropy alloy cable welding wire and WC powder are coated by a robotic plasma cladding system; the process parameters are powder feeding gas flow rate 5L / min, wire feeding speed 8mm / s, welding speed 3mm / s, current 120A, and the distance between the welding gun nozzle and the substrate is 5mm.

[0058] Step 2: Use CNC wire cutting machine and polishing machine to prepare metallographic specimens, microhardness specimens and wear resistance test specimens.

[0059] The cross-sectional morphology of the samples was tested by scanning electron microscopy. Figure 4 As shown in a, the prepared high entropy alloy coating and substrate are in a metallurgical bonding state, and the surface and cross-section of the coating sample are complete without cracks; it is suitable for plasma cladding.

[0060] The phase composition of the coating sample is Figure 3 As shown in the figure, the coating is mainly composed of BCC phase and FCC phase. This is because the coating contains alloying Al and Cr elements, which promote the transformation of FCC phase to BCC phase. In addition, Al element forms an ordered phase of intermetallic compound during melting, which causes the original high entropy alloy lattice to transform. After multiple measurements, it is known that the average microhardness of the coating can reach 867.14HV 0.2 .

[0061] The wear morphology of the coating sample is shown in Figure 6As shown in a, the left side of a is a low-magnification wear morphology image; the right side of a is a high-magnification wear morphology image; it can be observed from the figure that the coating wear mechanism is mainly oxidative wear, and from the morphology of the worn surface, there are a small amount of plastic deformation pits and peeling caused by tearing along the wear direction.

[0062] After the friction and wear test, the average wear rate is 9.5916×10 -6 mm 3 / (N•m), the specific test conditions are: load 1500g, rotation speed 318.08 r / min, friction radius 3mm, grinding time 30min, grinding ball Si3N4.

[0063] Example 2 A high-hardness, high-temperature, and wear-resistant AlCu2(NiCr)2Ti(WC) 50 A high entropy alloy and a preparation method thereof, wherein the chemical composition and atomic percentage of the high entropy alloy are: Al: 6%, Cu: 16%, Ni: 8%, Cr: 7%, Ti: 43%, C: 15%, W: 5%, and the prepared AlCu2(NiCr)2Ti high entropy alloy cable welding wire is placed in an automatic wire feeder; the WC powder is dried in a drying oven at 100° C. for 1 h, and the cladding process parameters are substantially consistent with the key parameters provided in Example 1.

[0064] The alloy material was prepared by plasma cladding technology, and the mechanical properties of the obtained coating samples were tested; the cross-sectional morphology of the samples was tested by scanning electron microscopy, such as Figure 6 As shown in b, it can be seen from the figure that the coating and the substrate are in a metallurgical bonding state, and there are no obvious cladding defects such as pores and cracks; The phase composition of the coating sample is Figure 3 As shown in Figure 2, the coating is mainly composed of BCC phase and FCC phase; the wear morphology of the coating sample is shown in Figure 2. Figure 6 As shown in b, the left side of b is a low-magnification morphology of wear; the right side of b is a high-magnification morphology of wear; it can be observed from the figure that the wear mechanism of the coating is mainly oxidative wear, and from the morphology of the worn surface there is a small amount of peeling caused by tearing along the wear direction.

[0065] After multiple measurements, it is known that the average microhardness of the coating can reach 892.00HV 0.2 After the friction and wear test, the average wear rate is 8.5869×10 -6 mm 3 / (N·m), the specific test conditions are: load 1500g, rotation speed 318.08 r / min, friction radius 3mm, grinding time 30min, grinding ball Si3N4.

[0066] Example 3 A high-hardness, high-temperature, and wear-resistant AlCu2(NiCr)2Ti(WC) 75 A high entropy alloy and a preparation method thereof, wherein the chemical composition and atomic percentage of the high entropy alloy are: Al: 6%, Cu: 14%, Ni: 7%, Cr: 5%, Ti: 42%, C: 18%, W: 7%, and the prepared AlCu2 (NiCr) 2Ti high entropy alloy cable welding wire is placed in an automatic wire feeder; the WC powder is dried in a drying oven at 100° C. for 1 hour, and the cladding process parameters are substantially consistent with the key parameters provided in Example 1.

[0067] The alloy material was prepared by plasma cladding technology, and the mechanical properties of the obtained coating samples were tested; the phase composition of the coating samples was as follows Figure 3 As shown in the figure, the coating is mainly composed of BCC phase and carbide phase with higher hardness; the cross-sectional morphology of the sample was tested by scanning electron microscopy, such as Figure 5 As shown in Figure c, the prepared high entropy alloy coating and substrate are in a metallurgical bonding state, and the surface and cross-section of the coating sample are complete without cracks; the wear morphology of the coating sample is shown in Figure Figure 6 As shown in c, the left side of c is a low-magnification wear morphology image; the right side of c is a high-magnification wear morphology image; it can be observed from the figure that the coating wear mechanism is mainly oxidative wear, and from the morphology of the worn surface, there are a small amount of plastic deformation pits and peeling caused by tearing along the wear direction.

[0068] After multiple measurements, it is known that the average microhardness of the coating can reach 944.0HV 0.2 After the friction and wear test, the average wear rate is 9.7537×10 -6 mm 3 / (N·m), the specific test conditions are: load 1500g, rotation speed 318.08r / min, friction radius 3mm, grinding time 30min, grinding ball Si3N4.

[0069] Example 4 A high-hardness, high-temperature, and wear-resistant AlCu2(NiCr)2Ti(WC) 100 A high entropy alloy and a preparation method thereof, wherein the chemical composition and atomic percentage of the high entropy alloy are: Al: 6%, Cu: 14%, Ni: 6%, Cr: 6%, Ti: 40%, C: 17%, W: 10%, and the prepared AlCu2(NiCr)2Ti high entropy alloy cable welding wire is placed in an automatic wire feeder; the WC powder is dried in a drying oven at 100° C. for 1 h, and the cladding process parameters are substantially consistent with the key parameters provided in Example 1.

[0070] The alloy material was prepared by plasma cladding technology, and the mechanical properties of the obtained coating samples were tested; the cross-sectional morphology of the samples was tested by scanning electron microscopy, such as Figure 5d; it can be observed from the figure that the coating and the substrate are in a highly metallurgical bonding state with no obvious defects; the phase composition of the coating sample is as follows Figure 3 As shown in Figure 2, the coating is mainly composed of BCC phase and carbide phase with higher hardness; the wear morphology of the coating sample is shown in Figure 2. Figure 6 As shown in d, the left side of d is a low-magnification morphology of wear; the right side of d is a high-magnification morphology of wear; it can be observed from the figure that the wear mechanism of the coating is mainly oxidative wear, and a small amount of oxide layer peeling off can be seen from the morphology of the worn surface.

[0071] After multiple measurements, it is known that the average microhardness of the coating can reach 879.9HV 0.2 After the friction and wear test, the average wear rate is 1.11816×10 -7 mm 3 / (N·m), the specific test conditions are: load 1500g, rotation speed 318.08r / min, friction radius 3mm, grinding time 30min, grinding ball Si3N4.

[0072] The four embodiments described in the present invention have the same main process, but different high entropy alloy compositions, so the performance test data are different.

[0073] Compared with other high entropy alloy inventions with similar properties, the high entropy alloy provided in the embodiment of the present invention has the properties of simple preparation, low cost, uniform structure and excellent weldability, and is a special additive manufacturing material suitable for plasma cladding. The specific comparison is as follows: A large amount of Al element is added to the high entropy alloy. The atomic radius of Al element is large, which can increase the degree of alloy lattice distortion. At the same time, Al element can also promote the precipitation of BCC phase, improve the strength and wear resistance of the alloy, and the addition of Al element can adjust the phase balance in the high entropy alloy, change its phase ratio and phase stability; its addition can regulate the microstructure and properties of the high entropy alloy; and the dilution effect produced during the cladding process allows a large amount of matrix Ti element to penetrate into the coating, which greatly improves the plasticity of the coating.

[0074] In summary, the embodiments of the present invention provide a high entropy alloy, a preparation method and a plasma cladding method. The chemical composition and atomic percentage of the provided high entropy alloy are: Al: 6% to 7%, Cu: 14% to 22%, Ni: 6% to 7%, Cr: 6% to 8%, Ti: 40% to 55%, W: 1% to 10%, C: 5% to 17%. The high-hardness and wear-resistant high-entropy alloy material of the present invention is a high-entropy alloy material suitable for plasma cladding for surface modification and strengthening of titanium alloys. The present invention also provides a method for preparing a high-hardness and wear-resistant high-entropy alloy material, using a cable welding wire made of the above alloy components and adding a WC reinforcement phase, and using plasma cladding technology to efficiently prepare a corresponding high-strength, high-hardness and wear-resistant high-entropy alloy coating, which has excellent hardness and wear resistance. In addition, the material has good weldability and is a special high-entropy alloy material suitable for plasma additive manufacturing.

[0075] Compared with the prior art, the solution provided by the embodiment of the present invention has the following beneficial effects.

[0076] (1) The alloying elements used in the high-entropy alloy cable welding wire in this experiment are all relatively common metal elements, which can ensure that the prepared high-entropy alloy composite coating has high economy. The high-entropy alloy material is added with WC reinforcing phase with excellent hardness, which can regulate the Al and Ti elements of the coating structure, and can effectively improve the wear resistance and corrosion resistance of the material while ensuring the high-entropy alloy coating has a dense structure.

[0077] (2) The high entropy alloy material provided by the embodiment of the present invention is added with Al element, and the dilution and penetration effect of Ti element in the cladding process reduces the material density while promoting the material's antioxidant performance and hardness, achieving the effect of light weight, high hardness and high strength. The Ni element can form a solid solution with other elements in the alloy, making the alloy paramagnetic and improving the plasticity and toughness of the alloy. The Cu element has a small ion radius, is easy to diffuse and segregate in the intergranular region, and can form a Cu-rich nanophase, which helps to improve the hardness and wear resistance of the alloy.

[0078] (3) The high entropy alloy material provided in the embodiment of the present invention is a special high entropy alloy cable welding wire with good weldability and suitable for plasma additive manufacturing, which expands the scope of material use in the field of additive manufacturing.

[0079] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A AlCu2(NiCr)2Ti-(WC) x A method for preparing a high entropy alloy wear-resistant coating by plasma cladding, characterized in that: Using cable-type welding wire and powder co-transport plasma cladding to prepare the high entropy alloy composite coating; The high entropy alloy is AlCu2(NiCr)2Ti-(WC)x alloy, where x is the powder feeding speed. The cable welding wires are made of metal wires with a diameter of 0.5 mm, wherein Al, Cu, and Ti are made of pure metal wires, (Ni Cr) uses alloy wires with a diameter of 0.5 mm, and the alloy powder uses WC powder with a purity higher than 99%. The particle size of the high entropy alloy powder suitable for plasma cladding is 100-150 meshes. The powder gas flow rate is 2-6L / min, the powder feeding speed is 0-100r / min, the welding speed is 1-10mm / s, the wire feeding speed is 7-10mm / s, the welding current is 80-120A, and the distance between the welding gun nozzle and the substrate is 5-12.5mm; The preparation of the high entropy alloy comprises the following steps: using metal wires with a purity of more than 99% and a diameter of 0.5 mm as raw materials, wherein Al Cu Ti is composed of pure metal wires, (Ni Cr) uses alloy wires with a diameter of the same 0.5 mm, and the reinforcing powder uses WC powder with a purity of more than 99%, and drying them in an XMA-2000 electric heating blast drying oven at 100° C. for 1 h; Composite coating was prepared on the surface of TC11 titanium alloy plate using a DML-V02BD plasma welding machine equipped with a MOTOMAN UP6 6-DOF industrial robot.

2. The preparation method according to claim 1, characterized in that: The MOTOMAN UP6 6-DOF industrial robot arm uses its own programming software.

3. The plasma cladding preparation method of AlCu2(NiCr)2Ti-(WC)x high entropy alloy wear-resistant coating according to claim 1 is characterized in that: The following steps are also included: AlCu2(NiCr)2Ti-(WC)x (x=50r / min) high entropy alloy cable welding wire and reinforced powder were used as parameter optimization raw materials, and a robotic plasma cladding system was used for parameter selection and optimization; five cladding parameters, including powder feeding gas flow rate, powder feeding speed, welding speed, current, and the distance between the welding gun nozzle and the substrate were selected for parameter optimization; the final process parameters were optimized as powder feeding gas flow rate 6L / min, wire feeding speed 8mm / s, welding speed 3mm / s, current 120A, and the distance between the welding gun nozzle and the substrate 5mm.

4. The plasma cladding preparation method of high entropy alloy wear-resistant coating according to claim 1, characterized in that: When the target cladding entity is TC11 titanium alloy, the plasma cladding formed composite coating is metallurgically bonded to the substrate, and the microhardness is as high as 943.97HV 0.2 , which is 2.62 times of the substrate, and the average wear rate is 9.7557×10 -7 mm 3 / (N•m).

5. The plasma cladding preparation method of AlCu2(NiCr)2Ti-(WC)x high entropy alloy wear-resistant coating according to claim 1 is characterized in that: The following steps are also included: The microhardness of AlCu2(NiCr)2Ti-(WC)x (x=25r / min, 50r / min, 75r / min, 100r / min) high entropy alloy composite coatings prepared by optimal plasma cladding process parameters are 867.14HV0.2, 892.00HV0.2, 943.97HV0.2 and 879.94HV0.2 respectively; compared with the average microhardness of the substrate (360HV 0.2 ) increased by 140.9%, 147.8%, 162.2 and 144.4% respectively.

6. The plasma cladding preparation method of AlCu2(NiCr)2Ti-(WC)x high entropy alloy wear-resistant coating according to claim 1 is characterized in that: The following steps are also included: The wear rates of AlCu2(NiCr)2Ti-(WC)x(x=0, 25r / min, 50r / min, 75r / min, 100r / min) high entropy alloy composite coatings prepared by the optimal plasma cladding process parameters are 9.8093×10 -6 mm 3 / (N•m),8.6075×10 - 6 mm 3 / (N•m),9.7506×10 -6 mm 3 / (N•m),1.10123×10 -7 mm 3 / (N•m); respectively, compared with the wear rate of TC11 matrix (1.24985×10 -7 mm 3 / (N•m)) decreased by 21.6%, 31.1%, 22.0% and 11.2%.

7. Application of a plasma cladding high entropy alloy wear-resistant coating prepared according to the preparation method according to any one of claims 4 to 6 in high hardness and wear-resistant materials.

8. The use according to claim 1, characterized in that: The plasma cladding high entropy alloy wear-resistant coating is used in high-load, high-impact, high-hardness and wear-resistant materials in the fields of aerospace and aviation.

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