Self-propagating brazing high-entropy alloy connecting layer forming method

Abstract

The invention relates to the field of material connection, in particular to a method for forming a self-propagating brazing high-entropy alloy connecting layer, which comprises the following steps of: sputtering a nano multilayer reaction film with specific components on a connecting surface of a material needing to be connected by magnetron sputtering, sputtering a nano multilayer film with specific components on the other connecting surface, and then assembling with a low-melting-point metal foil to form the self-propagating brazing high-entropy alloy connecting layer. And a high-entropy alloy joint is formed after pressurization and heating. In the connecting process, the temperature is increased, so that the nanometer reaction multilayer film is subjected to thermal explosion, the low-melting-point metal foil and the nanometer multilayer film are completely molten to form a liquid phase, the applied pressure ensures that the connecting surface can be tightly combined with the liquid phase, and subsequent heating and heat preservation ensure that the final connecting layer is uniform in component. All joints formed by the connecting layer are solid solution high-entropy alloy structures, and compared with a traditional nickel-based brazing filler metal joint connecting layer, the high-entropy alloy connecting layer has the advantage that the mechanical property of the joints is greatly improved at the same connecting temperature.

Description

Technical Field

[0001] The present invention belongs to the field of material connection, and particularly relates to a connection method for self-propagating brazing to form a high-entropy alloy connection layer at a relatively low temperature. Background Art

[0002] Due to the high-entropy effect in thermodynamics, the sluggish diffusion effect in kinetics, the lattice distortion effect in structure, and the cocktail effect in properties, high-entropy alloys have high strength, excellent high-temperature properties, wear and corrosion resistance, and radiation resistance, etc., and are considered as ideal choices for structural materials at key positions under extreme conditions (such as in advanced nuclear energy systems and the aviation industry, etc.). Similarly, the high-entropy alloy connection layer has also become the optimal choice for the connection layer of materials in scenarios such as high temperature and high irradiation due to the above excellent properties.

[0003] Currently, for the homogeneous connection of materials such as superalloys, high-entropy alloys, and ceramics serving in high-temperature environments, or the heterogeneous connection with structural materials such as stainless steel, copper, and titanium alloys, it is usually achieved by means such as fusion welding, laser welding, brazing, and diffusion bonding. However, grain coarsening and element segregation in the fusion welding and laser welding seams lead to the deterioration of joint properties. And in the brazing process, the occurrence of intermetallic compounds makes the joint brittle and the brazing filler metal undergoes intergranular penetration resulting in stress concentration. Diffusion bonding needs to determine the bonding parameters according to the physical properties of the base material, and the stability of the formed bonding layer at high temperature is not high enough. And due to its high-entropy effect and sluggish diffusion effect, high-entropy alloys have excellent high-temperature resistance in high-temperature environments, and its lattice distortion effect and cocktail effect also guarantee its strength. Therefore, designing a connection means capable of forming a high-entropy alloy connection layer is an effective way to solve the above problems.

[0004] The simplest and most effective method to obtain a high-entropy alloy connection layer is to use high-entropy alloy as the brazing filler metal to braze the joint. However, since high-entropy alloy is a typical high-melting-point (although the melting temperature usually tends to decrease to equiatomic composition) alloy system, the melting point of the high-entropy alloy brazing filler metal is usually higher than the temperature range acceptable for direct brazing. And adding melting-point-lowering elements to high-entropy alloy is a theoretically feasible method, but in fact, reducing the melting point of the high-entropy alloy brazing filler metal usually requires adding a large amount of melting-point-lowering elements, and its liquidus temperature is still much higher than that of most current nickel-based brazing filler metals. Excessively high connection temperature will cause the grains of the base material to grow, damage the mechanical properties of the base material, and pose a serious hidden danger to its service under extreme conditions. At the same time, due to the sluggish diffusion effect, the strength of the joint will not be very high, which will also greatly limit the wide application of the high-entropy alloy connection layer. Therefore, it is urgent to design and develop a method capable of obtaining a high-entropy alloy connection layer at a relatively low temperature. Summary of the Invention

[0005] To solve the above technical problems, the present invention proposes a method for forming a brazed high-entropy alloy joint layer assisted by self-propagating reaction, which provides an instantaneous heat source through the thermal explosion of a nano-reaction multi-layer film, and forms a high-entropy alloy joint layer with uniform composition at a low temperature (≤1100°C) by combining the synergistic effect of a low-melting-point metal foil and the nano multi-layer film.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for forming a self-propagating brazed high-entropy alloy joint layer, comprising the following steps:

[0008] (1) Surface treatment: Grinding, polishing and cleaning the joint surfaces of the workpieces A and B to be joined.

[0009] (2) Deposition of nano-film layer:

[0010] a. Sputtering a nano-reaction multi-layer film on the joint surface of workpiece A.

[0011] b. Sputtering a nano multi-layer film on the joint surface of workpiece B.

[0012] (3) Assembly: Stacking workpiece A, the low-melting-point metal foil and workpiece B in sequence to form a sandwich structure, and the low-melting-point metal foil, the nano-reaction multi-layer film and the nano multi-layer film together constitute the components of the target high-entropy alloy.

[0013] (4) Self-propagating assisted joining: In a vacuum or atmospheric environment, heating the sandwich structure formed in step (3) to the thermal explosion point of the film layer or triggering the thermal explosion by external discharge excitation, then applying a pressure of 10-50 MPa to make the liquid phase fully contact with the interface, and continuing to heat to 800-1100°C and keep it warm for 30-120 min, and then cooling with the furnace.

[0014] The present invention uses magnetron sputtering technology to deposit nano multi-layer reaction films with specific compositions on the two joint surfaces of the materials to be joined. Specifically, a nano multi-layer film (such as FeCo / NiCr film) is sputtered on one joint surface, and a nano-reaction multi-layer film (such as Al / Ni film) is sputtered on the other joint surface. Subsequently, the coated materials are assembled with a low-melting-point metal foil (such as a 20-μm-thick aluminum foil), and a high-entropy alloy joint is formed through a pressure heating process. During the joining process, as the temperature rises, the nano-reaction multi-layer film undergoes a thermal explosion reaction, instantaneously releasing a large amount of heat, promoting the complete melting of the low-melting-point metal foil and the nano multi-layer film to form a liquid phase. At the same time, the applied pressure ensures the close contact between the joint surface and the liquid phase, and the subsequent heating and heat preservation processes ensure the uniformity of the composition of the joint layer. Finally, a joint layer with high-entropy alloy composition is obtained by cooling with the furnace.

[0015] As described above, the compositions and thicknesses of the three thin films need to be selected according to the composition of the high-entropy alloy to be finally formed. The specific selection principle is as follows: select the low-melting-point component as the low-melting-point metal foil, select the elements that can form an energetic thin film to form a nano-reactive multilayer film, and select the remaining elements to form a nano-multilayer film.

[0016] Preferably, the nano-reactive multilayer film refers to a nano-scale alternating-layer thin film that can undergo a self-propagating reaction at a specific temperature. The reactive multilayer nano-film needs to contain a specific sequence of energetic system elements, and the sequence has a specific number of repetitions. Its main function is to provide instant heat as an auxiliary heat source for the joint during the connection process, promoting the melting of the nano-multilayer film and the low-melting-point metal foil to form a liquid phase, and at the same time providing the necessary elemental composition for the final high-entropy alloy connection layer. The nano-reactive multilayer film is composed of at least one energetic material alternating layer of Al / Ni, Al / Ti, Ni / Ti, with a single-layer thickness of 50 - 1000 nm, a repetition number ≥ 5 times, and a total thickness of 1 - 10 μm.

[0017] Preferably, the nano-multilayer film refers to a multi-element alternating thin film that can form a high-entropy alloy with the above nano-reactive multilayer film and the low-melting-point metal foil. Its main function is to provide the elemental composition required for forming a high-entropy alloy for the connection layer during the connection process. The nano-multilayer film is composed of at least one high-entropy alloy element alternating layer of FeCo / NiCr, CoCrCuFeNi / Al, AlTi / AgCu, with a single-layer thickness of 50 - 1000 nm, a repetition number ≥ 5 times, and a total thickness of 1 - 10 μm.

[0018] Preferably, the low-melting-point metal foil refers to a microcrystalline metal thin film with a relatively low melting point and can form a high-entropy alloy with the above two nano-multilayer films. This metal foil needs to be completely melted instantaneously at the thermal explosion of the nano-reactive multilayer film. Its main function is to provide the elemental composition required for forming a high-entropy alloy for the connection layer during the connection process. The low-melting-point metal foil is selected from Al, Sn, Cu, with a thickness of 10 - 50 μm, and the melting point of the low-melting-point metal foil is 150 - 660 °C.

[0019] The heating and pressurization process can be carried out under vacuum or atmospheric conditions. When carried out under atmospheric conditions, a certain pressure needs to be applied to the joint to ensure that the connection surface can be closely combined with the liquid phase; in a vacuum environment, it can be decided whether to apply pressure according to whether the actual strength of the connection layer can meet the actual use requirements.

[0020] Preferably, the temperature is raised to the thermal explosion point of the film layer to trigger thermal explosion by raising the temperature to 500 - 800 °C at a rate of 5 - 20 °C / min; the external discharge excitation triggers thermal explosion.

[0021] The beneficial effects of the present invention:

[0022] 1) Compared with the traditional brazing connection process, the reactive nanomultilayer film not only serves as an auxiliary heat source, but also jointly forms a brazing intermediate layer with the high-entropy alloy component nanomultilayer film and the low-melting-point filler metal. This method can complete isothermal solidification in a shorter time and form a high-entropy alloy connection layer with a complete solid-solution structure at a lower temperature. At the same time, since the materials of the connection layer are all nanostructures and have more grain boundaries, it provides a good diffusion channel for the element diffusion of the joint.

[0023] 2) The existence of the nanomultilayer film can significantly reduce the formation temperature of the high-entropy alloy connection layer, making the connection temperature equivalent to the brazing temperature of the traditional nickel-based filler metal. While basically retaining the mechanical properties of the base material, this method greatly improves the connection strength of the joint.

[0024] 3) The finally formed connection layer is a high-entropy alloy structure with a solid-solution structure, having the basic characteristics of high-entropy alloys, including high strength, good high-temperature resistance, wear and corrosion resistance, and radiation resistance, etc., which are excellent properties conducive to the stable use of the connector under high-temperature and high-radiation conditions. Brief Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0026] Figure 1 Schematic diagram of the process of forming a high-entropy alloy connection layer with an Inconel 625 superalloy plated with a FeCo / NiCr nanomultilayer film, an aluminum foil with a thickness of 20 μm, and an Al0.1CoCrFeNi high-entropy alloy plated with an Al / Ni nanoreactive multilayer film in Example 1.

[0027] Figure 2 Schematic diagram of magnetron sputtering of a [NiCr / FeCo] nanomultilayer film on the connection surface of Inconel 625 alloy in Example 1.

[0028] Figure 3 Schematic diagram of magnetron sputtering of an [Al / Ni] nanoreactive multilayer film on the connection surface of Al0.1CoCrFeNi high-entropy alloy in Example 1. Detailed Description of the Invention

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Example 1:

[0031] This embodiment provides a method for forming a self-propagating brazing high-entropy alloy joint layer between a superalloy and a high-entropy alloy. The superalloy involved is Inconel625; the composition of the high-entropy alloy is Al0.1CoCrFeNi.

[0032] The specific process of this embodiment includes the following steps:

[0033] 1) Treat the joint surface: Use diamond sandpaper with 600 to 7000 meshes and silicon carbide sandpaper to polish the joint surfaces of Inconel625 superalloy and Al0.1CoCrFeNi high-entropy alloy in sequence to remove surface debris and oxide films. Then polish with 0.05μm diamond polishing agent, ultrasonically clean in alcohol for 10 min, and dry.

[0034] 2) Prepare the nano-multilayer film: On the surface of the treated Inconel625 superalloy, use NiCr alloy target (50:50 at%, FHR) and FeCo alloy target (50:50 at%, FHR) to magnetron sputter an equiatomic NiCr layer of 477 nm and an equiatomic FeCo layer of 534 nm, sputtering alternately for 9 times; on the surface of the treated Al0.1CoCrFeNi high-entropy alloy, use pure Al target and pure Ni target to sputter an Al layer of 708 nm and a Ni layer of 468 nm, sputtering alternately for 9 times.

[0035] 3) Assemble the joint: Assemble the joint surface of the above-mentioned Inconel625 superalloy plated with FeCo / NiCr nano-multilayer film, an aluminum foil with a thickness of 20μm, and the joint surface of Al0.1CoCrFeNi high-entropy alloy plated with Al / Ni nano-reaction multilayer film in sequence to form a joint with a "sandwich structure".

[0036] 4) Self-propagating assisted diffusion bonding: Put the above-mentioned "sandwich structure" joint into a self-propagating brazing furnace. Under the atmospheric environment, heat it to 700°C at a heating rate of 10°C / min, keep it warm for 30 min, apply a pressure of 40 MPa, then heat it to 950°C at a heating rate of 10°C / min, keep it warm for 60 min, then unload the pressure and cool it with the furnace to obtain a high-entropy alloy structure joint.

[0037] The shear strength of the joint is 158.4 MPa.

[0038] Example 2

[0039] This example provides a method for forming a self-propagating brazed high-entropy alloy joint layer between a superalloy and a high-entropy alloy. The superalloy involved is Inconel625; the composition of the high-entropy alloy is Al0.1CoCrFeNi.

[0040] The specific process of this example includes the following steps:

[0041] 1) Treat the joint surface: Use diamond sandpaper with 600 to 7000 meshes and silicon carbide sandpaper to polish the joint surfaces of Inconel625 superalloy and Al0.1CoCrFeNi high-entropy alloy in sequence to remove surface debris and oxide films. Then polish with 0.05 μm diamond polishing agent, ultrasonically clean in alcohol for 10 min, and then dry.

[0042] 2) Prepare the nano-multilayer film: On the surface of the treated Inconel625 superalloy, use NiCr alloy target (50:50 at%, FHR) and FeCo alloy target (50:50 at%, FHR) to magnetron sputter an equiatomic NiCr layer of 477 nm and an equiatomic FeCo layer of 534 nm, sputtering alternately for 9 times; on the surface of the treated Al0.1CoCrFeNi high-entropy alloy, use pure Al target and pure Ni target to sputter an Al layer of 708 nm and a Ni layer of 468 nm, sputtering alternately for 9 times.

[0043] 3) Assemble the joint: Assemble the joint surface of the above-mentioned Inconel625 superalloy plated with FeCo / NiCr nano-multilayer film, an aluminum foil with a thickness of 20 μm, and the joint surface of Al0.1CoCrFeNi high-entropy alloy plated with Al / Ni nano-reaction multilayer film in sequence to form a joint with a "sandwich structure".

[0044] 4) Self-propagating assisted diffusion bonding: Put the above "sandwich structure" joint into a self-propagating brazing furnace, in an atmospheric environment, heat it to 700 °C at a heating rate of 10 °C / min, hold for 30 min, apply a pressure of 40 MPa, then heat it to 1050 °C at a heating rate of 10 °C / min, hold for 60 min, then unload the pressure and cool with the furnace to obtain a joint with a high-entropy alloy structure.

[0045] The shear strength of the joint is 231.6 MPa.

[0046] Example 3

[0047] This embodiment provides a method for forming a self-propagating brazing high-entropy alloy joint layer between a superalloy and a high-entropy alloy. The superalloy involved is Inconel625; the composition of the high-entropy alloy is Al0.1CoCrFeNi.

[0048] The specific process of this embodiment includes the following steps:

[0049] 1) Treat the joint surface: Use diamond sandpaper with 600 to 7000 meshes and silicon carbide sandpaper to polish the joint surfaces of Inconel625 superalloy and Al0.1CoCrFeNi high-entropy alloy in sequence to remove surface debris and oxide films. Subsequently, polish with 0.05μm diamond polishing agent, ultrasonically clean in alcohol for 10 min, and then dry.

[0050] 2) Prepare the nano-multilayer film: On the surface of the treated Inconel625 superalloy, use NiCr alloy target (50:50 at%, FHR) and FeCo alloy target (50:50 at%, FHR) to magnetron sputter an equiatomic NiCr layer of 477 nm and an equiatomic FeCo layer of 534 nm, sputtering alternately for 9 times; on the surface of the treated Al0.1CoCrFeNi high-entropy alloy, use pure Al target and pure Ni target to sputter an Al layer of 708 nm and a Ni layer of 468 nm, sputtering alternately for 9 times.

[0051] 3) Assemble the joint: Assemble the joint surfaces of the above-mentioned Inconel625 superalloy plated with FeCo / NiCr nano-multilayer film, an aluminum foil with a thickness of 20μm, and the joint surface of Al0.1CoCrFeNi high-entropy alloy plated with Al / Ni nano-reaction multilayer film in sequence to form a joint with a "sandwich structure".

[0052] 4) Self-propagating assisted diffusion bonding: Put the above "sandwich structure" joint into a self-propagating brazing furnace, in an atmospheric environment, heat it to 700°C at a heating rate of 10°C / min, hold for 30 min, apply a pressure of 40 MPa, then heat it to 1050°C at a heating rate of 10°C / min, hold for 30 min, and then unload the pressure and cool with the furnace to obtain a high-entropy alloy joint.

[0053] The shear strength of the joint is 192.6 MPa.

[0054] Example 4

[0055] This embodiment provides a method for forming a self-propagating brazing high-entropy alloy joint layer between a superalloy and a high-entropy alloy. The superalloy involved is Inconel625; the composition of the high-entropy alloy is Al0.1CoCrFeNi.

[0056] The specific process of this embodiment includes the following steps:

[0057] 1) Process the joint surface: Use diamond sandpaper with 600 to 7000 meshes and silicon carbide sandpaper to polish the joint surfaces of Inconel625 superalloy and Al0.1CoCrFeNi high-entropy alloy in sequence to remove surface debris and oxide films. Subsequently, polish with 0.05μm diamond polishing agent, and ultrasonically clean in alcohol for 10 min and then dry.

[0058] 2) Prepare the nano-multilayer film: On the surface of the treated Inconel625 superalloy, use NiCr alloy target (50:50 at%, FHR) and FeCo alloy target (50:50 at%, FHR) to magnetron sputter an equiatomic NiCr layer of 477 nm and an equiatomic FeCo layer of 534 nm, and alternate sputtering for 9 times; on the surface of the treated Al0.1CoCrFeNi high-entropy alloy, use pure Al target and pure Ni target to sputter an Al layer of 708 nm and a Ni layer of 468 nm, and alternate sputtering for 9 times.

[0059] 3) Assemble the connection joint: Assemble the joint surface of the above-mentioned Inconel625 superalloy plated with FeCo / NiCr nano-multilayer film, the aluminum foil with a thickness of 20μm, and the joint surface of the Al0.1CoCrFeNi high-entropy alloy plated with Al / Ni nano-reaction multilayer film in sequence to form a connection joint with a "sandwich structure".

[0060] 4) Self-propagating assisted diffusion bonding: Put the above "sandwich structure" joint into a self-propagating brazing furnace, in an atmospheric environment, heat it to 700°C at a heating rate of 10°C / min, hold for 30 min, apply a pressure of 40 MPa, and then heat it to 1050°C at a heating rate of 10°C / min, hold for 120 min, and then unload the pressure and cool with the furnace to obtain a high-entropy alloy tissue joint.

[0061] The shear strength of the joint is 283.9 MPa.

[0062] Example 5

[0063] This embodiment provides a method for forming a self-propagating brazing high-entropy alloy connection layer between a superalloy and a high-entropy alloy. The superalloy involved is Inconel625; the composition of the high-entropy alloy is Al0.1CoCrFeNi.

[0064] The specific process of this embodiment includes the following steps:

[0065] 1) Treatment of the joint surface: The joint surfaces of Inconel 625 superalloy and Al0.1CoCrFeNi high-entropy alloy were polished successively with diamond sandpaper and silicon carbide sandpaper with a mesh size of 600 to 7000 to remove surface debris and oxide films. Subsequently, it was polished with 0.05 μm diamond polishing agent, ultrasonically cleaned in alcohol for 10 min, and then dried.

[0066] 2) Preparation of the nanomultilayer film: On the surface of the treated Inconel 625 superalloy, a 477 nm equiatomic NiCr layer and a 534 nm equiatomic FeCo layer were magnetron sputtered alternately 9 times using a NiCr alloy target (50:50 at%, FHR) and a FeCo alloy target (50:50 at%, FHR); on the surface of the treated Al0.1CoCrFeNi high-entropy alloy, a 708 nm Al layer and a 468 nm Ni layer were sputtered alternately 9 times using a pure Al target and a pure Ni target.

[0067] 3) Assembly of the joint: The joint surface of the Inconel 625 superalloy coated with the FeCo / NiCr nanomultilayer film, an aluminum foil with a thickness of 20 μm, and the joint surface of the Al0.1CoCrFeNi high-entropy alloy coated with the Al / Ni nanoreactive multilayer film were assembled in sequence to form a joint with a "sandwich structure".

[0068] 4) Self-propagating assisted diffusion bonding: The above "sandwich structure" joint was placed in a self-propagating brazing furnace. In an atmospheric environment, it was heated to 700 °C at a heating rate of 10 °C / min, held for 30 min, and a pressure of 40 MPa was applied. Subsequently, it was heated to 1000 °C at a heating rate of 10 °C / min, held for 60 min, and then the pressure was unloaded and cooled with the furnace to obtain a joint with a high-entropy alloy structure.

[0069] The shear strength of the joint was 186.7 MPa.

[0070] Example 6

[0071] This example provides a method for forming a self-propagating brazed high-entropy alloy joint layer between a superalloy and a high-entropy alloy. The superalloy involved is Inconel 625; the composition of the high-entropy alloy is Al0.1CoCrFeNi.

[0072] The specific process of this example includes the following steps:

[0073] 1) Treatment of the joint surface: The joint surfaces of Inconel 625 superalloy and Al0.1CoCrFeNi high-entropy alloy were polished successively with diamond sandpaper and silicon carbide sandpaper with 600 to 7000 meshes to remove surface debris and oxide films. Subsequently, it was polished with 0.05 μm diamond polishing agent, ultrasonically cleaned in alcohol for 10 min and then dried.

[0074] 2) Preparation of the nano-multilayer film: On the surface of the treated Inconel 625 superalloy, a 477 nm equiatomic NiCr layer and a 534 nm equiatomic FeCo layer were magnetron sputtered alternately 9 times using NiCr alloy target (50:50 at%, FHR) and FeCo alloy target (50:50 at%, FHR); on the surface of the treated Al0.1CoCrFeNi high-entropy alloy, a 708 nm Al layer and a 468 nm Ni layer were sputtered alternately 9 times using pure Al target and pure Ni target.

[0075] 3) Assembly of the joint: The joint surface of the Inconel 625 superalloy plated with FeCo / NiCr nano-multilayer film, the 20 μm thick aluminum foil and the joint surface of the Al0.1CoCrFeNi high-entropy alloy plated with Al / Ni nano-reaction multilayer film were assembled successively to form a joint with a "sandwich structure".

[0076] 4) Self-propagating assisted diffusion bonding: The above "sandwich structure" joint was put into a self-propagating brazing furnace. In the atmospheric environment, it was heated to 700 °C at a heating rate of 10 °C / min, held for 30 min, a pressure of 40 MPa was applied, and then it was heated to 1080 °C at a heating rate of 10 °C / min, held for 60 min, and then the pressure was unloaded and cooled with the furnace to obtain a joint with a high-entropy alloy structure.

[0077] The shear strength of the joint is 308.5 MPa.

[0078] Example 7

[0079] This example provides a method for forming a self-propagating brazing high-entropy alloy joint layer of a high-entropy alloy. The high-entropy alloy involved has a composition of Al0.1CoCrFeNi.

[0080] The specific process of this example includes the following steps:

[0081] 1) Treatment of the joint surface: The joint surface of the Al0.1CoCrFeNi high-entropy alloy was polished successively with diamond sandpaper and silicon carbide sandpaper with 600 to 7000 meshes to remove surface debris and oxide films. Subsequently, it was polished with 0.05 μm diamond polishing agent, ultrasonically cleaned in alcohol for 10 min and then dried.

[0082] 2) Preparation of nano - multilayer films: On the surface of the treated Al0.1CoCrFeNi high - entropy alloy, using a NiCr alloy target (50:50 at%, FHR) and a FeCo alloy target (50:50 at%, FHR), magnetron sputter a 462 - nm equiatomic NiCr layer and a 508 - nm equiatomic FeCo layer, and alternate sputtering 9 times; on the surface of another treated Al0.1CoCrFeNi high - entropy alloy, using a pure Al target and a pure Ni target, sputter a 708 - nm Al layer and a 468 - nm Ni layer, and alternate sputtering 9 times.

[0083] 3) Assembly of connection joints: Assemble the connection surfaces of the Al0.1CoCrFeNi high - entropy alloy coated with FeCo / NiCr nano - multilayer films, an aluminum foil with a thickness of 20 μm, and the connection surfaces of the Al0.1CoCrFeNi high - entropy alloy coated with Al / Ni nano - reactive multilayer films in sequence to form a connection joint with a "sandwich structure".

[0084] 4) Self - propagating high - temperature synthesis assisted diffusion bonding: Place the above "sandwich - structure" joint into a self - propagating brazing furnace. Under an atmospheric environment, heat it at a heating rate of 10 °C / min to 700 °C, hold for 30 min, apply a pressure of 40 MPa, and then heat it at a heating rate of 10 °C / min to 1050 °C, hold for 60 min, and then unload the pressure and cool it with the furnace to obtain a high - entropy alloy tissue joint.

[0085] The shear strength of the joint is 234.4 MPa.

[0086] Example 8

[0087] This example provides a method for forming a self - propagating brazing high - entropy alloy connection layer of a high - entropy alloy. The high - entropy alloy involved has a composition of Al0.1CoCrFeNi.

[0088] The specific process of this example includes the following steps:

[0089] 1) Treatment of connection surfaces: Use diamond sandpapers with 600 - mesh to 7000 - mesh and silicon carbide sandpapers to polish the connection surfaces of the Al0.1CoCrFeNi high - entropy alloy in sequence to remove surface debris and oxide films. Then polish it with 0.05 - μm diamond polishing agent, and ultrasonically clean it in alcohol for 10 min and then dry it.

[0090] 2) Preparation of nano-multilayer films: On the surface of the treated Al0.1CoCrFeNi high-entropy alloy, using a NiCr alloy target (50:50 at%, FHR) and an FeCo alloy target (50:50 at%, FHR), magnetron sputter a 462-nm equiatomic NiCr layer and a 508-nm equiatomic FeCo layer, alternating sputtering 9 times; on the surface of another treated Al0.1CoCrFeNi high-entropy alloy, using a pure Al target and a pure Ni target, sputter a 708-nm Al layer and a 468-nm Ni layer, alternating sputtering 9 times.

[0091] 3) Assembly of the connection joint: Assemble in sequence the connection surface of the Al0.1CoCrFeNi high-entropy alloy coated with the FeCo / NiCr nano-multilayer film, the aluminum foil with a thickness of 20 μm, and the connection surface of the Al0.1CoCrFeNi high-entropy alloy coated with the Al / Ni nano-reactive multilayer film to form a connection joint with a "sandwich structure".

[0092] 4) Self-propagating assisted diffusion bonding: Place the above "sandwich structure" joint into a self-propagating brazing furnace in an atmospheric environment, heat it to 700 °C at a heating rate of 10 °C / min, hold for 30 min, apply a pressure of 40 MPa, then heat it to 1050 °C at a heating rate of 10 °C / min, hold for 120 min, and then unload the pressure and cool it with the furnace to obtain a high-entropy alloy tissue joint.

[0093] The shear strength of the joint is 296.6 MPa.

[0094] Example 9

[0095] This example provides a method for forming a self-propagating brazing high-entropy alloy connection layer between stainless steel and high-entropy alloy. The stainless steel involved is 304; the composition of the high-entropy alloy is Al0.1CoCrFeNi.

[0096] The specific process of this example includes the following steps:

[0097] 1) Treatment of the connection surface: Use diamond sandpaper and silicon carbide sandpaper with 600 to 7000 meshes to polish the connection surfaces of 304 stainless steel and Al0.1CoCrFeNi high-entropy alloy in sequence to remove surface debris and oxide films. Subsequently, polish with 0.05-μm diamond polishing agent, and ultrasonically clean in alcohol for 10 min and then dry.

[0098] 2) Preparation of nano - multilayer films: On the surface of the treated 304 stainless steel, using a NiCr alloy target (50:50 at%, FHR) and a FeCo alloy target (50:50 at%, FHR), magnetron sputter a 386 - nm equiatomic NiCr layer and a 435 - nm equiatomic FeCo layer, alternating sputtering 9 times; on the surface of the treated Al0.1CoCrFeNi high - entropy alloy, using a pure Al target and a pure Ni target, sputter a 708 - nm Al layer and a 468 - nm Ni layer, alternating sputtering 9 times.

[0099] 3) Assembly of the connecting joint: Assemble the connecting surface of the 304 stainless steel coated with the FeCo / NiCr nano - multilayer film, an aluminum foil with a thickness of 20 μm, and the connecting surface of the Al0.1CoCrFeNi high - entropy alloy coated with the Al / Ni nano - reactive multilayer film in sequence to form a connecting joint with a "sandwich structure".

[0100] 4) Self - propagating high - temperature synthesis (SHS) assisted diffusion bonding: Place the above "sandwich structure" joint into a self - propagating brazing furnace. Under an atmospheric environment, heat it at a heating rate of 10 °C / min to 700 °C, hold for 30 min, apply a pressure of 20 MPa, then heat it at a heating rate of 10 °C / min to 1050 °C, hold for 60 min, and then unload the pressure and cool it with the furnace to obtain a joint with a high - entropy alloy structure.

[0101] The shear strength of the joint is 45.5 MPa.

[0102] Example 10

[0103] This example provides a method for forming a self - propagating brazing high - entropy alloy connection layer between stainless steel and high - entropy alloy. The stainless steel involved is 304; the composition of the high - entropy alloy involved is Al0.1CoCrFeNi.

[0104] The specific process of this example includes the following steps:

[0105] 1) Treatment of the connecting surface: Use diamond sandpaper with 600 - 7000 meshes and silicon carbide sandpaper to polish the connecting surfaces of 304 stainless steel and Al0.1CoCrFeNi high - entropy alloy in sequence to remove surface debris and oxide films. Then polish it with 0.05 - μm diamond polishing agent, and ultrasonically clean it in alcohol for 10 min and then dry it.

[0106] 2) Preparation of nano-multilayer films: On the surface of the treated 304 stainless steel, using NiCr alloy target (50:50 at%, FHR) and FeCo alloy target (50:50 at%, FHR), magnetron sputter an equiatomic NiCr layer of 386 nm and an equiatomic FeCo layer of 435 nm, sputtering alternately for 9 times; on the surface of the treated Al0.1CoCrFeNi high-entropy alloy, using pure Al target and pure Ni target, sputter an Al layer of 708 nm and an Ni layer of 468 nm, sputtering alternately for 9 times.

[0107] 3) Assemble the connecting joint: Assemble the connecting surface of the 304 stainless steel coated with FeCo / NiCr nano-multilayer film, the aluminum foil with a thickness of 20 μm, and the connecting surface of the Al0.1CoCrFeNi high-entropy alloy coated with Al / Ni nano-reaction multilayer film in sequence to form a connecting joint with a "sandwich structure".

[0108] 4) Self-propagating assisted diffusion bonding: Put the above "sandwich structure" joint into a self-propagating brazing furnace. Under the atmospheric environment, heat it to 700 °C at a heating rate of 10 °C / min, hold for 30 min, apply a pressure of 30 MPa, and then heat it to 1050 °C at a heating rate of 10 °C / min, hold for 60 min, and then unload the pressure and cool with the furnace to obtain a joint with a high-entropy alloy structure.

[0109] The shear strength of the joint is 85.4 MPa.

[0110] Example 11

[0111] This example provides a method for forming a self-propagating brazing high-entropy alloy joint layer between stainless steel and high-entropy alloy. The stainless steel involved is 304; the high-entropy alloy composition is Al0.1CoCrFeNi.

[0112] The specific process of this example includes the following steps:

[0113] 1) Treat the connecting surface: Use diamond sandpaper and silicon carbide sandpaper with 600 to 7000 meshes to polish the connecting surfaces of 304 stainless steel and Al0.1CoCrFeNi high-entropy alloy in sequence to remove surface debris and oxide films. Then polish it with 0.05 μm diamond polishing agent, ultrasonically clean it in alcohol for 10 min, and then dry it.

[0114] 2) Preparation of nano-multilayer films: On the surface of the treated 304 stainless steel, using NiCr alloy targets (50:50 at%, FHR) and FeCo alloy targets (50:50 at%, FHR), magnetron sputter an equiatomic NiCr layer of 386 nm and an equiatomic FeCo layer of 435 nm, sputtering alternately 9 times; on the surface of the treated Al0.1CoCrFeNi high-entropy alloy, using pure Al targets and pure Ni targets, sputter an Al layer of 708 nm and an Ni layer of 468 nm, sputtering alternately 9 times.

[0115] 3) Assembly of the connecting joint: Assemble in sequence the connecting surface of the 304 stainless steel coated with FeCo / NiCr nano-multilayer film, the aluminum foil with a thickness of 20 μm, and the connecting surface of the Al0.1CoCrFeNi high-entropy alloy coated with Al / Ni nano-reaction multilayer film to form a connecting joint with a "sandwich structure".

[0116] 4) Self-propagating assisted diffusion bonding: Place the above "sandwich structure" joint into a self-propagating brazing furnace. Under the atmospheric environment, heat it to 700 °C at a heating rate of 10 °C / min, hold for 30 min, apply a pressure of 40 MPa, then heat it to 1050 °C at a heating rate of 10 °C / min, hold for 60 min, and then unload the pressure and cool it with the furnace to obtain a joint with a high-entropy alloy structure.

[0117] The shear strength of the joint is 156.8 MPa.

[0118] Example 12

[0119] This example provides a method for forming a self-propagating brazed high-entropy alloy bonding layer between a metal and a ceramic. The metal involved is Cu; the ceramic involved is SiC.

[0120] The specific process of this example includes the following steps:

[0121] 1) Treatment of the connecting surface: Use diamond sandpapers with 600 to 7000 meshes and silicon carbide sandpapers to polish the connecting surfaces of Cu and SiC ceramics in sequence to remove surface debris and oxide films. Subsequently, polish with 0.05 μm diamond polishing agent, and ultrasonically clean in alcohol for 15 min and then dry.

[0122] 2) Process of magnetron sputtering of nano-multilayer films: On the surface of the treated SiC, using AgCu alloy targets (50:50 at%, FHR) and AlTi alloy targets (50:50 at%, FHR), magnetron sputter an equiatomic AgCu layer of 183 nm and an equiatomic AlTi layer of 204 nm, sputtering alternately 9 times; on the surface of the treated Cu, using pure Al targets and pure Ti targets, sputter an Al layer of 218 nm and a Ti layer of 209 nm, sputtering alternately 10 times.

[0123] 3) Assemble the connection joint: Assemble the SiC connection surface coated with the AlTi / AgCu nano-multilayer film, the Sn foil with a thickness of 20 μm, and the Cu connection surface coated with the Al / Ti nano-reactive multilayer film in sequence to form a connection joint with a "sandwich structure".

[0124] 4) Self-propagating assisted brazing connection: Place the above "sandwich structure" joint into a self-propagating brazing furnace. Under a vacuum environment, heat it to 300 °C at a heating rate of 10 °C / min, hold for 15 min, then heat it to 700 °C at a heating rate of 10 °C / min, hold for 60 min, and then cool it in the furnace to obtain a joint with a high-entropy alloy structure.

[0125] The shear strength of the joint is 38.8 MPa.

[0126] Example 13

[0127] This example provides a method for forming a self-propagating brazing high-entropy alloy connection layer between a metal and a ceramic. The metal involved is Cu; the ceramic involved is SiC.

[0128] The specific process of this example includes the following steps:

[0129] 1) Treat the connection surface: Use diamond sandpaper with 600 to 7000 meshes and silicon carbide sandpaper to polish the connection surfaces of Cu and SiC ceramics in sequence to remove surface debris and oxide films. Then polish it with 0.05 μm diamond polishing agent, and ultrasonically clean it in alcohol for 15 min and then dry it.

[0130] 2) Nano-multilayer film magnetron sputtering process: On the treated SiC surface, use an AgCu alloy target (50:50 at%, FHR) and an AlTi alloy target (50:50 at%, FHR) to magnetron sputter a 183 nm equiatomic AgCu layer and a 204 nm equiatomic AlTi layer, sputtering alternately 9 times; on the treated Cu surface, use a pure Al target and a pure Ti target to sputter a 218 nm Al layer and a 209 nm Ti layer, sputtering alternately 10 times.

[0131] 3) Assemble the connection joint: Assemble the SiC connection surface coated with the AlTi / AgCu nano-multilayer film, the Sn foil with a thickness of 20 μm, and the Cu connection surface coated with the Al / Ti nano-reactive multilayer film in sequence to form a connection joint with a "sandwich structure".

[0132] 4) Self-propagating assisted brazing connection: Place the above "sandwich structure" joint into a self-propagating brazing furnace. Under a vacuum environment, heat it at a heating rate of 10 °C / min to 300 °C, hold for 15 min, then heat it at a heating rate of 10 °C / min to 750 °C, hold for 60 min, and then cool it in the furnace to obtain a joint with a high-entropy alloy structure.

[0133] The shear strength of the joint is 60.9 MPa.

[0134] Example 14

[0135] This example provides a method for forming a self-propagating brazing high-entropy alloy bonding layer between a metal and a ceramic. The metal involved is Cu; the ceramic involved is SiC.

[0136] The specific process of this example includes the following steps:

[0137] 1) Treat the bonding surface: Use diamond sandpaper with 600 to 7000 meshes and silicon carbide sandpaper to polish the bonding surfaces of Cu and SiC ceramics in sequence to remove surface debris and oxide films. Then polish it with 0.05 μm diamond polishing agent, and ultrasonically clean it in alcohol for 15 min and then dry it.

[0138] 2) Magnetron sputtering process of the nano-multilayer film: On the treated SiC surface, use AgCu alloy target (50:50 at%, FHR) and AlTi alloy target (50:50 at%, FHR) to magnetron sputter an equiatomic AgCu layer of 183 nm and an equiatomic AlTi layer of 204 nm, sputtering alternately for 9 times; on the treated Cu surface, use pure Al target and pure Ti target to sputter an Al layer of 218 nm and a Ti layer of 209 nm, sputtering alternately for 10 times.

[0139] 3) Assemble the bonding joint: Assemble the SiC bonding surface coated with AlTi / AgCu nano-multilayer film, a 20-μm-thick Sn foil, and the Cu bonding surface coated with Al / Ti nano-reaction multilayer film in sequence to form a bonding joint with a "sandwich structure".

[0140] 4) Self-propagating assisted brazing connection: Place the above "sandwich structure" joint into a self-propagating brazing furnace. Under a vacuum environment, heat it at a heating rate of 10 °C / min to 300 °C, hold for 15 min, then heat it at a heating rate of 10 °C / min to 700 °C, hold for 30 min, and then cool it in the furnace to obtain a joint with a high-entropy alloy structure.

[0141] The shear strength of the joint is 40.8 MPa.

[0142] Example 15

[0143] This embodiment provides a method for forming a self-propagating brazing high-entropy alloy joint layer between metal and ceramic. The metal involved is Cu; the ceramic involved is SiC.

[0144] The specific process of this embodiment includes the following steps:

[0145] 1) Treat the joint surface: Use diamond sandpaper and silicon carbide sandpaper with 600 to 7000 meshes to polish the joint surfaces of Cu and SiC ceramics in sequence to remove surface debris and oxide films. Subsequently, polish with 0.05μm diamond polishing agent, and ultrasonically clean in alcohol for 15 min and then dry.

[0146] 2) Magnetron sputtering process of nano-multilayer films: On the treated SiC surface, use an AgCu alloy target (50:50 at%, FHR) and an AlTi alloy target (50:50 at%, FHR) to magnetron sputter an equiatomic AgCu layer of 183 nm and an equiatomic AlTi layer of 204 nm, sputtering alternately for 9 times; on the treated Cu surface, use a pure Al target and a pure Ti target to sputter an Al layer of 218 nm and a Ti layer of 209 nm, sputtering alternately for 10 times.

[0147] 3) Assemble the joint: Assemble the SiC joint surface coated with the AlTi / AgCu nano-multilayer film, a 20-μm-thick Sn foil, and the Cu joint surface coated with the Al / Ti nano-reactive multilayer film in sequence to form a joint with a "sandwich structure".

[0148] 4) Self-propagating assisted brazing connection: Place the above "sandwich structure" joint into a self-propagating brazing furnace. Under a vacuum environment, heat it to 300 °C at a heating rate of 10 °C / min, hold for 15 min, then heat it to 700 °C at a heating rate of 10 °C / min, hold for 90 min, and then cool it in the furnace to obtain a high-entropy alloy tissue joint.

[0149] The shear strength of the joint is 48.0 MPa.

[0150] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0151] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for forming a self-propagating brazing high-entropy alloy joint layer, characterized in that, It includes the following steps: (1) Surface treatment: Grind, polish and clean the joint surfaces of the workpieces A and B to be joined; (2) Nanomembrane layer deposition: a. Sputter a nano-reactive multilayer film on the joint surface of workpiece A; b. Sputter a nano-multilayer film on the joint surface of workpiece B; (3) Assembly: Stack workpiece A, low-melting-point metal foil and workpiece B in sequence to form a sandwich structure, and the low-melting-point metal foil, together with the nano-reactive multilayer film and the nano-multilayer film, constitutes the components of the target high-entropy alloy; (4) Self-propagating assisted joining: In a vacuum or atmospheric environment, heat the sandwich structure formed in step (3) to the thermal explosion point of the film layer or trigger thermal explosion by external discharge excitation, then apply a pressure of 0 - 50 MPa to make the liquid phase fully contact with the interface, continue to heat to 700 - 1100 °C and hold for 30 - 120 min, and then cool with the furnace.

2. The method according to claim 1, wherein The nano-reactive multilayer film is a multi-system energetic film composed of alternating stacks of energetic material single-system films, any one of Al / Ni, Al / Ti, Al / Au, Al / Ru, Al / Zr, Al / Pt, Ni / Ti, Ti / B, Ti / C. The thickness of a single-layer film is 50 - 1000 nm, the number of repetitions ≥ 5 times, and the total thickness is 1 - 20 μm.

3. The method according to claim 1, characterized in that, The nano-multilayer film is a high-entropy alloy multilayer film composed of alternating different alloy element layers, any one of FeCo / NiCo, Fe / Co / Ni / Cr, CoCrCuFeNi / Al, AlSi / FeCu, AlTi / AgCu, FeCo / NiTi. The single-layer thickness is 50 - 1000 nm, the number of repetitions ≥ 5 times, and the total thickness is 1 - 10 μm.

4. The method according to claim 1, wherein The low-melting-point metal foil is selected from any one of Al, Sn, Ge, Zn, Cu, with a thickness of 10 - 50 μm, and the melting point of the low-melting-point metal foil is 150 - 660 °C.

5. The method according to claim 1, characterized in that, Heating to the thermal explosion point of the film layer to trigger thermal explosion is heating to 500 - 800 °C at a rate of 5 - 20 °C / min; external discharge excitation to trigger thermal explosion is applying a pulsed voltage with a voltage of 0.1 - 10 kV and a pulse width of 10 - 100 μs to the nano-reactive multilayer film.

6. The method according to claim 1, wherein The workpiece A and the workpiece B are independently selected from any one of superalloys, high-entropy alloys, ceramics, stainless steels, copper, and titanium alloys.

7. The method according to claim 1, wherein Step (1) Surface treatment: Use diamond sandpaper and silicon carbide sandpaper with 600 - 7000 meshes to grind the joint surfaces of workpiece A and workpiece B to remove surface debris and oxide films, then polish with 0.05 μm diamond polishing agent, and ultrasonically clean in alcohol for 10 - 15 min and then dry.

8. The method according to claim 1, wherein In step (4) under atmospheric conditions, apply a pressure of 30 - 40 MPa to make the liquid phase fully contact with the interface, continue to heat to 1050 - 1080 °C and hold for 60 - 120 min, and then cool with the furnace.

9. The method according to claim 1, wherein The workpiece A is Al0.1CoCrFeNi, the workpiece B is Inconel625, the low-melting-point metal foil is an aluminum foil with a thickness of 20 μm, the nano-reactive multilayer film is an Al / Ni multilayer film, and the Al / Ni multilayer film is formed by alternately sputtering a 708-nm Al layer and a 468-nm Ti layer 9 times; the nano-multilayer film is a FeCo / NiCr multilayer film, and the FeCo / NiCr multilayer film is formed by alternately sputtering a 477-nm equiatomic NiCr layer and a 534-nm equiatomic FeCo layer 9 times.

10. The method according to claim 1, wherein The workpiece A is Cu, the workpiece B is SiC, the low-melting-point metal foil is a Sn foil with a thickness of 20 μm, the nano-reactive multilayer film is an Al / Ti multilayer film, and the Al / Ti multilayer film is formed by alternately sputtering a 218-nm Al layer and a 209-nm Ti layer 10 times; the nano-multilayer film is an AlTi / AgCu multilayer film, and the AlTi / AgCu multilayer film is formed by alternately sputtering a 183-nm equiatomic AgCu layer and a 204-nm equiatomic AlTi layer 9 times.

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