Method for realizing low-temperature diffusion bonding of metal material through surface proton irradiation assistance

Abstract

The invention discloses a method for realizing low-temperature diffusion bonding of a metal material through surface proton irradiation assistance, and relates to the technical field of welding. According to the method, an irradiation layer containing a large number of lattice defects and dislocations is prepared on the surface of a metal base material through a proton irradiation method, element diffusion channels are remarkably increased, diffusion connection of Zr-4 alloy under the low-temperature condition of 600-800 DEG C is achieved, and the strength of a welded joint reaches 290-420 MPa and can optimally exceed 90% of the strength of the base material. The method for realizing low-temperature diffusion bonding of the metal material through surface proton irradiation assistance can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a method for achieving low-temperature diffusion connection of metal materials through surface proton irradiation assistance. Background Art

[0002] Diffusion bonding technology is widely used in the connection of homogeneous and heterogeneous metal materials, especially the precision connection of complex components, due to its high welding quality and deformation control. However, the realization of diffusion bonding often requires higher temperature, longer insulation time and higher welding pressure. In composite or coated structures, excessively high connection temperature will cause phase change failure of some composite or coated materials, seriously affecting the performance of the component. In addition, the use of higher welding pressure can slightly reduce the welding temperature, but it will cause increased deformation of the weldment, and ultimately affect the dimensional accuracy of the component.

[0003] At present, the methods of low-temperature diffusion connection of metal materials mainly include adding an intermediate layer, hydrogenation treatment and surface nano-sizing. Among them, the use of materials that can dissolve with the metal to be welded and have a low phase change temperature as the intermediate layer can effectively reduce the connection temperature, but the heterogeneous connection interface will form a multi-element alloy system and form a galvanic cell structure, and the corrosion resistance of the joint cannot meet practical needs. Although hydrogenation treatment of the metal base material can reduce the diffusion connection temperature, the residual hydrogen in the base material leads to increased brittleness and affects the mechanical properties of the joint. At the same time, the risk factor of the hydrogenation process is high and it is difficult to promote and apply in industry. Nano-sizing the surface of the metal base material by mechanical grinding or impact can promote low-temperature diffusion connection, but this method cannot be applied to complex precision weld structures. Summary of the invention

[0004] The purpose of the present invention is to solve the above technical problems and to provide a method for achieving low-temperature diffusion connection of metal materials by surface proton irradiation assistance.

[0005] A method for achieving low-temperature diffusion bonding of metal materials by surface proton irradiation assistance is carried out in the following steps:

[0006] Step S1: pretreatment of the metal to be welded;

[0007] Grinding, polishing and cleaning the surfaces of the metal materials to be welded to obtain pretreated metal materials to be welded;

[0008] Step S2: proton irradiation of the metal to be welded;

[0009] The pretreated metal material to be welded obtained in step S1 is dried in the air, and then the metal material to be welded is placed in an irradiation chamber with the welded surface facing upward, and evacuated, and then subjected to proton irradiation treatment to obtain a metal to be welded having a proton irradiation layer;

[0010] Step S3: low temperature diffusion connection of the metal to be welded;

[0011] The two pieces of metal to be welded with the proton irradiation layer obtained in step S2 are assembled in a manner of stacking the surfaces to be welded, and then placed in a vacuum diffusion furnace, first heated to 300-500°C, and then continued to heat to 600-800°C, and kept warm for 30-120 minutes under the conditions of temperature, vacuum and connection pressure of 600-800°C, and then cooled to room temperature after the insulation is completed, completing the low-temperature diffusion connection of the metal material through surface proton irradiation auxiliary.

[0012] Principle of the present invention:

[0013] The proton irradiation treatment method for the surface of a metal material of the present invention does not introduce other elements and is not affected by a precision welding structure. A proton source is used to generate protons, which are accelerated by an accelerator and collide with atomic nuclei of a metal base material. The atoms after the collision and the deviated protons will continue to collide with other atoms until the kinetic energy after the collision cannot reach the delocalization threshold, thereby forming an irradiation layer on the metal surface. A large number of point defects and dislocations in the irradiation layer form additional atomic diffusion channels, which are beneficial to promoting low-temperature diffusion connection of metal materials. In addition, the thickness of the surface irradiation layer is thin and has no effect on the mechanical properties of the base material itself, so a high-performance joint can be finally obtained.

[0014] Beneficial effects of the present invention:

[0015] (1) The present invention prepares an irradiated layer containing a large number of lattice defects and dislocations on the surface of a metal base material by a proton irradiation method, which significantly increases the element diffusion channels and realizes the diffusion connection of the Zr-4 alloy at a low temperature of 600°C to 800°C. The strength of the welded joint reaches 290 to 420 MPa, and can optimally exceed 90% of the base material strength.

[0016] (2) The present invention adopts the proton irradiation method without introducing additional impurity atoms, thereby ensuring the stability of the joint components in the diffusion bonding of metal materials, especially homogeneous diffusion bonding, and preventing the precipitation of second phases and brittle compounds, thereby avoiding affecting the joint strength and corrosion resistance of the joint.

[0017] (3) The present invention adopts the proton irradiation method to form an extremely thin irradiation layer on the surface of the metal base material, which has no adverse effect on the mechanical properties of the metal base material itself and the joint after welding, and is conducive to obtaining a diffusion-bonded joint with high bonding strength.

[0018] (4) The present invention uses a proton irradiation method with no special requirements on the geometric shape and size of the surface of the metal base material to be welded, and is suitable for diffusion connection of components with complex shapes, small welding sizes and high precision requirements.

[0019] (5) The proton irradiation method adopted in the present invention is widely applicable to metal base materials, the surface pretreatment process of the metal base material is simple, the irradiation process parameters can stably control the irradiation layer, and the repeatability is good.

[0020] The invention can obtain a method for realizing low-temperature diffusion connection of metal materials by assisting surface proton irradiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram showing the process of low-temperature diffusion connection of metal materials assisted by surface proton irradiation of the present invention;

[0022] Figure 2 The microscopic morphology of the Zr-4 alloy diffusion bonded joint after surface irradiation in Example 1 is shown;

[0023] Figure 3 The microscopic morphology of the Zr-4 alloy diffusion bonded joint which has not been irradiated in Comparative Example 1 is shown;

[0024] Figure 4 The microscopic morphology of the Zr-4 alloy diffusion bonded joint after surface irradiation in Example 2 is shown;

[0025] Figure 5 The microscopic morphology of the Zr-4 alloy diffusion bonded joint that has not been irradiated in Comparative Example 2 is shown;

[0026] Figure 6 Indicates 10 18 cm -2 Comparison of shear strength of Zr-4 alloy diffusion bonded joints treated with proton irradiation dose and without proton irradiation treatment at room temperature. DETAILED DESCRIPTION

[0027] Specific implementation method 1: This implementation method is a method for achieving low-temperature diffusion bonding of metal materials by surface proton irradiation (such as Figure 1 As shown), follow these steps:

[0028] Step S1: pretreatment of the metal to be welded;

[0029] Grinding, polishing and cleaning the surfaces of the metal materials to be welded to obtain pretreated metal materials to be welded;

[0030] Step S2: proton irradiation of the metal to be welded;

[0031] The pretreated metal material to be welded obtained in step S1 is dried in the air, and then the metal material to be welded is placed in an irradiation chamber with the welded surface facing upward, and evacuated, and then subjected to proton irradiation treatment to obtain a metal to be welded having a proton irradiation layer;

[0032] Step S3: low temperature diffusion connection of the metal to be welded;

[0033] The two pieces of metal to be welded with the proton irradiation layer obtained in step S2 are assembled in a manner of stacking the surfaces to be welded, and then placed in a vacuum diffusion furnace, first heated to 300-500°C, and then continued to heat to 600-800°C, and kept warm for 30-120 minutes under the conditions of temperature, vacuum and connection pressure of 600-800°C, and then cooled to room temperature after the insulation is completed, completing the low-temperature diffusion connection of the metal material through surface proton irradiation auxiliary.

[0034] Beneficial effects of this embodiment:

[0035] (1) In this embodiment, an irradiation layer containing a large number of lattice defects and dislocations is prepared on the surface of a metal base material by a proton irradiation method, which significantly increases the element diffusion channels and realizes the diffusion connection of the Zr-4 alloy at low temperatures of 600°C to 800°C. The strength of the welded joint reaches 290 to 420 MPa, and can optimally exceed 90% of the base material strength.

[0036] (2) This embodiment uses a proton irradiation method without introducing additional impurity atoms, thereby ensuring the stability of the joint components in the diffusion bonding of metal materials, especially homogeneous diffusion bonding, and preventing the precipitation of second phases and brittle compounds, thereby avoiding affecting the joint strength and corrosion resistance of the joint.

[0037] (3) In this embodiment, the irradiation layer formed on the surface of the metal base material by the proton irradiation method is extremely thin, which has no adverse effect on the mechanical properties of the metal base material itself and the joint after welding, and is conducive to obtaining a diffusion-bonded joint with high bonding strength.

[0038] (4) This embodiment uses the proton irradiation method with no special requirements on the geometric shape and size of the surface of the metal base material to be welded, and is suitable for diffusion welding of components with complex shapes, small welding sizes and high precision requirements.

[0039] (5) The proton irradiation method used in this embodiment is widely applicable to metal base materials, the surface pretreatment process of the metal base material is simple, the irradiation process parameters can stably control the irradiation layer, and the repeatability is good.

[0040] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the metal materials to be welded described in step S1 include but are not limited to Zr and Zr alloys, Ni and Ni alloys, Ti and Ti alloys, and Nb and Nb alloys.

[0041] The other steps are the same as those in the first specific implementation.

[0042] Specific implementation method three: The difference between this implementation method and specific implementation method one or two is that the metal material to be welded is Zr-4 alloy.

[0043] The other steps are the same as those in the first or second embodiment.

[0044] Specific implementation method 4: The difference between this implementation method and specific implementation methods 1 to 3 is that in step S1, 200#, 400#, 1000# and 2000# sandpaper are used for grinding in sequence.

[0045] The other steps are the same as those in Specific Embodiments 1 to 3.

[0046] Specific implementation method 5: The difference between this implementation method and specific implementation methods 1 to 4 is that in step S1, a polishing agent with a particle size of 0.5 μm is used for polishing for 5 to 20 minutes.

[0047] The other steps are the same as those in Specific Embodiments 1 to 4.

[0048] Specific implementation method 6: The difference between this implementation method and specific implementation methods 1 to 5 is that ultrasonic cleaning is used in step S1, the ultrasonic cleaning time is 10 to 30 minutes, and the washing liquid used is anhydrous ethanol or acetone solution.

[0049] The other steps are the same as those in Specific Embodiments 1 to 5.

[0050] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the vacuum degree in the irradiation chamber in step S2 is 4×10 -3 Pa~6×10 -3 Pa, the temperature in the irradiation chamber is 10~30℃.

[0051] The other steps are the same as those in Specific Embodiments 1 to 6.

[0052] Specific embodiment 8: The difference between this embodiment and specific embodiments 1 to 7 is that the parameters of proton irradiation in step S2 are: the proton irradiation energy is 100-300 keV, the proton irradiation flux is 10 6 ~10 20 cm -2 ·s -1 The proton irradiation dose is 10 8 ~10 22 cm -2 The thickness of the proton irradiation layer is 0.2 to 1 μm.

[0053] The other steps are the same as those in Specific Embodiments 1 to 7.

[0054] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the vacuum degree in step S3 is 4×10 -3 Pa~6×10 -3 Pa, the connection pressure is 5~20MPa.

[0055] The other steps are the same as those in Specific Embodiments 1 to 8.

[0056] Specific embodiment ten: The difference between this embodiment and specific embodiments one to nine is that in step S3, the first heating rate is 5-30°C / min, the second heating rate is 1-20°C / min, and the cooling rate is 1-20°C / min.

[0057] The other steps are the same as those in Specific Embodiments 1 to 9.

[0058] The following examples are used to verify the beneficial effects of the present invention:

[0059] Embodiment 1: A method for achieving low-temperature diffusion bonding of metal materials by surface proton irradiation, which is carried out according to the following steps:

[0060] Step S1: pretreatment of the metal to be welded;

[0061] The surfaces of the Zr-4 alloy to be connected were polished with 200#, 400#, 1000# and 2000# sandpaper in turn to remove dirt and oxide film, and then polished with a polishing agent with a particle size of 0.5μm for 10 minutes, and then ultrasonically cleaned for 10 minutes to obtain the pretreated Zr-4 alloy, and the washing liquid used was anhydrous ethanol;

[0062] Step S2: proton irradiation of the metal to be welded;

[0063] The pretreated Zr-4 alloy obtained in step S1 was dried, and then the Zr-4 alloy was placed in an irradiation chamber with the surface to be welded facing upward, and evacuated to a vacuum degree of 5×10 -3 Pa, and then subjected to proton irradiation treatment to obtain a Zr-4 alloy having a proton irradiation layer, wherein the thickness of the proton irradiation layer is 0.44 μm;

[0064] Proton irradiation parameters: proton irradiation energy is 170keV, proton irradiation flux is 10 8 cm -2 ·s -1 The proton irradiation dose is 10 18 cm -2 ; The temperature in the irradiation chamber is 25°C;

[0065] Step S3: low temperature diffusion connection of the metal to be welded;

[0066] The two Zr-4 alloys with proton irradiation layers obtained in step S2 were assembled in a way that the surfaces to be welded were stacked, and then placed in a vacuum diffusion furnace, and heated to 450°C at a rate of 15°C / min, and then heated to 650°C at a rate of 10°C / min. -3 The mixture was kept warm for 30 min under the conditions of a vacuum degree of 100 Pa and a connection pressure of 10 MPa. After the heat preservation, the mixture was cooled to room temperature at a rate of 10 °C / min to complete the low-temperature diffusion connection of Zr-4 alloy assisted by surface proton irradiation.

[0067] Comparative Example 1: The method for direct diffusion bonding of metal materials in this comparative example is carried out according to the following steps:

[0068] Step S1: pretreatment of the metal to be welded;

[0069] The surfaces of the Zr-4 alloy to be connected were polished with 200#, 400#, 1000# and 2000# sandpaper in turn to remove dirt and oxide film, and then polished with a polishing agent with a particle size of 0.5μm for 10 minutes, and then ultrasonically cleaned for 10 minutes to obtain the pretreated Zr-4 alloy, and the washing liquid used was anhydrous ethanol;

[0070] Step S2: low temperature diffusion connection of the metal to be welded;

[0071] The two pretreated Zr-4 alloys obtained in step S1 were assembled in a stacked manner, and then placed in a vacuum diffusion furnace, and heated to 450°C at a rate of 15°C / min, and then heated to 650°C at a rate of 10°C / min. -3 The mixture was kept warm for 30 min under the conditions of a vacuum degree of 100 Pa and a connection pressure of 10 MPa. After the heat preservation, the mixture was cooled to room temperature at a rate of 10 °C / min to complete the low-temperature diffusion connection of Zr-4 alloy assisted by surface proton irradiation.

[0072] Figure 2 The microscopic morphology of the Zr-4 alloy diffusion bonded joint after surface irradiation in Example 1 is shown. Figure 3 The microscopic morphology of the Zr-4 alloy diffusion bonded joint without irradiation treatment in Comparative Example 1 is shown; Figure 2-3 As shown, the proton irradiation method in Example 1 can achieve good bonding of the diffusion bonded joint, the joint weld basically disappears, and the contact interface is basically bridged, and finally the joint shear strength at room temperature reaches 305MPa; while in the non-irradiated comparative example 1, effective welding is not achieved, further proving the importance and significant effect of proton irradiation in promoting diffusion.

[0073] Embodiment 2: A method for achieving low-temperature diffusion bonding of metal materials by surface proton irradiation, which is carried out according to the following steps:

[0074] Step S1: pretreatment of the metal to be welded;

[0075] The surfaces of the Zr-4 alloy to be connected were polished with 200#, 400#, 1000# and 2000# sandpaper in turn to remove dirt and oxide film, and then polished with a polishing agent with a particle size of 0.5μm for 10 minutes, and then ultrasonically cleaned for 10 minutes to obtain the pretreated Zr-4 alloy, and the washing liquid used was anhydrous ethanol;

[0076] Step S2: proton irradiation of the metal to be welded;

[0077] The pretreated Zr-4 alloy obtained in step S1 was dried, and then the Zr-4 alloy was placed in an irradiation chamber with the surface to be welded facing upward, and evacuated to a vacuum degree of 5×10 -3 Pa, and then subjected to proton irradiation treatment to obtain a Zr-4 alloy having a proton irradiation layer, wherein the thickness of the proton irradiation layer is 0.5 μm;

[0078] Proton irradiation parameters: proton irradiation energy is 170keV, proton irradiation flux is 10 8 cm -2 ·s -1 The proton irradiation dose is 10 18 cm -2 ; The temperature in the irradiation chamber is 25°C;

[0079] Step S3: low temperature diffusion connection of the metal to be welded;

[0080] The two Zr-4 alloys with proton irradiation layers obtained in step S2 were assembled in a stacked manner, and then placed in a vacuum diffusion furnace, and heated to 450°C at a rate of 15°C / min, and then heated to 750°C at a rate of 10°C / min. -3 The mixture was kept warm for 30 min under the conditions of a vacuum degree of 100 Pa and a connection pressure of 10 MPa. After the heat preservation, the mixture was cooled to room temperature at a rate of 10 °C / min to complete the low-temperature diffusion connection of Zr-4 alloy assisted by surface proton irradiation.

[0081] Comparative Example 2: The method for direct diffusion bonding of metal materials in this comparative example is carried out according to the following steps:

[0082] Step S1: pretreatment of the metal to be welded;

[0083] The surfaces of the Zr-4 alloy to be connected were polished with 200#, 400#, 1000# and 2000# sandpaper in turn to remove dirt and oxide film, and then polished with a polishing agent with a particle size of 0.5μm for 10 minutes, and then ultrasonically cleaned for 10 minutes to obtain the pretreated Zr-4 alloy, and the washing liquid used was anhydrous ethanol;

[0084] Step S2: low temperature diffusion connection of the metal to be welded;

[0085] The two pretreated Zr-4 alloys obtained in step S1 were assembled in a stacked manner, and then placed in a vacuum diffusion furnace, and heated to 450°C at a rate of 15°C / min, and then heated to 750°C at a rate of 10°C / min. -3 The mixture was kept warm for 30 min under the conditions of a vacuum degree of 100 Pa and a connection pressure of 10 MPa. After the heat preservation, the mixture was cooled to room temperature at a rate of 10 °C / min to complete the low-temperature diffusion connection of Zr-4 alloy assisted by surface proton irradiation.

[0086] Figure 4 The microscopic morphology of the Zr-4 alloy diffusion bonded joint after surface irradiation in Example 2 is shown. Figure 5 The microscopic morphology of the Zr-4 alloy diffusion bonded joint that has not been irradiated in Comparative Example 2 is shown; Figure 4-5 As shown, the proton irradiation method in Example 2 can enable the diffusion bonding joint to achieve good bonding, the joint weld basically disappears, and the contact interface is basically bridged, and the final joint shear strength at room temperature reaches 411MPa; while in the unirradiated comparative example 2, the joint weld is obvious, effective welding is not achieved, and the joint strength is only 291MPa.

[0087] Figure 6 Indicates 10 18 cm -2 Comparison of the shear strength of Zr-4 alloy diffusion bonded joints treated with proton irradiation and without proton irradiation at room temperature. Figure 6 As shown in the figure, under the same welding parameters, the shear strength of the joint can be increased by 41% by using proton irradiation on the alloy surface, and the improvement in joint strength is more obvious under low temperature welding, which further proves the importance and significant effect of proton irradiation in promoting diffusion.

Claims

1. A method for achieving low temperature diffusion bonding of metal materials by surface proton irradiation, characterized in that The method proceeds as follows: Step S1: pretreatment of the metal to be welded; Grinding, polishing and cleaning the surfaces of the metal materials to be welded to obtain pretreated metal materials to be welded; Step S2: proton irradiation of the metal to be welded; The pretreated metal material to be welded obtained in step S1 is dried in the air, and then the metal material to be welded is placed in an irradiation chamber with the welded surface facing upward, and evacuated, and then subjected to proton irradiation treatment to obtain a metal to be welded having a proton irradiation layer; Step S3: low temperature diffusion connection of the metal to be welded; The two pieces of metal to be welded with the proton irradiation layer obtained in step S2 are assembled in a manner of stacking the surfaces to be welded, and then placed in a vacuum diffusion furnace, first heated to 300-500°C, and then continued to heat to 600-800°C, and kept warm for 30-120 minutes under the conditions of temperature, vacuum and connection pressure of 600-800°C, and then cooled to room temperature after the insulation is completed, completing the low-temperature diffusion connection of the metal material through surface proton irradiation auxiliary.

2. The method of claim 1, wherein the method comprises: The metal materials to be welded in step S1 include, but are not limited to, Zr and Zr alloys, Ni and Ni alloys, Ti and Ti alloys, and Nb and Nb alloys.

3. A method for achieving low temperature diffusion bonding of metal materials by surface proton irradiation according to claim 1 or 2, characterized in that The metal material to be welded is Zr-4 alloy.

4. The method of claim 1, wherein the method comprises: In step S1, 200#, 400#, 1000# and 2000# sandpapers are used for grinding in sequence.

5. The method of claim 1, wherein the method comprises: In step S1, a polishing agent with a particle size of 0.5 μm is used for polishing for 5 to 20 minutes.

6. The method of claim 1, wherein the method comprises: In step S1, ultrasonic cleaning is adopted, the ultrasonic cleaning time is 10 to 30 minutes, and the washing liquid used is anhydrous ethanol or acetone solution.

7. The method of claim 1 for achieving low temperature diffusion bonding of metal materials by surface proton irradiation, characterized in that The vacuum degree in the irradiation chamber in step S2 is 4×10 -3 Pa~6×10 -3 Pa, the temperature in the irradiation chamber is 10~30℃.

8. The method of claim 1, wherein the method comprises: The parameters of proton irradiation in step S2 are: proton irradiation energy is 100-300 keV, proton irradiation flux is 10 6 ~10 20 cm -2 ·s -1 The proton irradiation dose is 10 8 ~10 22 cm -2 The thickness of the proton irradiation layer is 0.2 to 1 μm.

9. The method of claim 1, wherein the method comprises: The vacuum degree in step S3 is 4×10 -3 Pa~6×10 -3 Pa, the connection pressure is 5~20MPa.

10. The method of claim 1 for achieving low temperature diffusion bonding of metal materials by surface proton irradiation assistance, characterized in that In step S3, the first heating rate is 5-30°C / min, the second heating rate is 1-20°C / min, and the cooling rate is 1-20°C / min.

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