A method for low temperature diffusion bonding of metallic materials by surface proton irradiation

Abstract

The application relates to a method for realizing low-temperature diffusion connection of metal materials through surface proton irradiation, and relates to the welding technical field.The application realizes the diffusion connection of Zr-4 alloy under the condition of low temperature of 600 DEG C to 800 DEG C by preparing an irradiation layer containing a large number of lattice defects and dislocations on the surface of a metal base material through a proton irradiation method, so that the element diffusion channel is obviously increased, the welding joint strength reaches 290 to 420 MPa, and the best can exceed 90% of the base material strength.The application can obtain a method for realizing low-temperature diffusion connection of metal materials through surface proton irradiation.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and more specifically to a method for achieving low-temperature diffusion bonding of metallic materials through surface proton irradiation. Background Technology

[0002] Diffusion bonding technology is widely used for joining homogeneous and dissimilar metals, especially for precision joining of complex components, due to its high weld quality and deformation control. However, achieving diffusion bonding often requires high temperatures, long holding times, and high welding pressures. In composite or clad structures, excessively high bonding temperatures can lead to phase transformation failure of the composite or clad materials, severely affecting the performance of the component. Furthermore, while using higher welding pressure can slightly reduce the welding temperature, it increases the deformation of the weldment, ultimately affecting the dimensional accuracy of the component.

[0003] Currently, methods for low-temperature diffusion bonding of metallic materials mainly include adding an intermediate layer, hydrogen treatment, and surface nano-sizing. Among these, using a material capable of solid solution bonding with the metal to be welded and having a low phase transformation temperature as an intermediate layer can effectively reduce the bonding temperature. However, this can lead to the formation of a multi-element alloy system at the heterogeneous bonding interface, creating a galvanic cell structure, and the joint's corrosion resistance may not meet practical requirements. While hydrogen treatment of the base metal can lower the diffusion bonding temperature, the residual hydrogen in the base metal increases brittleness, affecting the joint's mechanical properties. Furthermore, the hydrogen treatment process has a high risk factor, making it difficult to promote its widespread industrial application. Nano-sizing of the base metal surface using mechanical grinding or impact can promote low-temperature diffusion bonding, but this method cannot be applied to complex precision weld structures. Summary of the Invention

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

[0005] A method for achieving low-temperature diffusion bonding of metallic materials using surface proton irradiation assistance comprises the following steps:

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

[0007] The surfaces of the metal materials to be welded are ground, polished, and cleaned to obtain pre-treated 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, and then the metal material to be welded is placed in the irradiation chamber with the welding side facing up and the vacuum is drawn. Then, proton irradiation treatment is performed to obtain the metal material to be welded with a proton irradiation layer.

[0010] Step S3: Low-temperature diffusion bonding of the metals to be soldered;

[0011] Two pieces of metal to be welded, with proton irradiation layers obtained in step S2, are stacked together with their surfaces to be welded. They are then placed in a vacuum diffusion furnace, heated to 300–500°C, and then further heated to 600–800°C. The furnace is then held at 600–800°C under vacuum and connection pressure for 30–120 minutes. After the holding period, the temperature is lowered to room temperature, thus completing the low-temperature diffusion connection of the metal material assisted by surface proton irradiation.

[0012] The principle of this invention:

[0013] This invention provides a proton irradiation treatment method for metal material surfaces that does not introduce other elements and is unaffected by precision welding structures. It uses a proton source to generate protons, which are then accelerated by an accelerator and collide with the atomic nuclei of the metal substrate. The atoms and the deviated protons continue to collide with other atoms until the kinetic energy after the collisions can no longer reach the dislocation threshold, forming an irradiation layer on the metal surface. The numerous point defects and dislocations within this irradiation layer create additional atomic diffusion channels, which facilitates low-temperature diffusion bonding of the metal material. Furthermore, the thin irradiation layer has no impact on the mechanical properties of the substrate itself, thus ultimately resulting in a high-performance joint.

[0014] The beneficial effects of this invention are:

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

[0016] (2) The present invention uses a proton irradiation method that does not introduce additional impurity atoms. Therefore, it ensures the stability of the joint composition in the diffusion bonding of metal materials, especially in the homogeneous diffusion bonding, and does not produce precipitated second phases and brittle compounds, thus avoiding affecting the joint strength and corrosion resistance of the joint.

[0017] (3) The irradiation layer formed on the surface of the metal substrate by the proton irradiation method of the present invention is extremely thin, which has no adverse effect on the mechanical properties of the metal substrate itself and the welded joint, and is conducive to obtaining a diffusion connection joint with high bonding strength.

[0018] (4) The present invention uses a proton irradiation method that does not have special requirements for the geometry and size of the surface to be welded of the metal base material, and is suitable for diffusion connection of components with complex shapes, small welding dimensions and high precision requirements.

[0019] (5) The proton irradiation method of the present invention has wide applicability in metal substrates, the surface pretreatment process of the metal substrate is simple, the irradiation process parameters have stable control over the irradiated layer, and the repeatability is good.

[0020] This invention provides a method for achieving low-temperature diffusion bonding of metallic materials through surface proton irradiation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the low-temperature diffusion bonding process of the proton irradiation-assisted metal material in this invention.

[0022] Figure 2 This image shows the microstructure of the Zr-4 alloy diffusion joint after surface irradiation in Example 1.

[0023] Figure 3 The image shows the microstructure of the un-irradiated Zr-4 alloy diffusion joint in Comparative Example 1.

[0024] Figure 4 This image shows the microstructure of the Zr-4 alloy diffusion joint after surface irradiation in Example 2.

[0025] Figure 5 The image shows the microstructure of the un-irradiated Zr-4 alloy diffusion joint in Comparative Example 2.

[0026] Figure 6 Indicates 10 18 cm -2 A comparison of the shear strength of Zr-4 alloy diffusion joints at room temperature between proton-irradiated and unirradiated conditions. Detailed Implementation

[0027] Specific Implementation Method 1: This implementation method describes a method for achieving low-temperature diffusion bonding of metallic materials through surface proton irradiation (e.g., ...). Figure 1 (As shown), proceed with the following steps:

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

[0029] The surfaces of the metal materials to be welded are ground, polished, and cleaned to obtain pre-treated 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, and then the metal material to be welded is placed in the irradiation chamber with the welding side facing up and the vacuum is drawn. Then, proton irradiation treatment is performed to obtain the metal material to be welded with a proton irradiation layer.

[0032] Step S3: Low-temperature diffusion bonding of the metals to be soldered;

[0033] Two pieces of metal to be welded, with proton irradiation layers obtained in step S2, are stacked together with their surfaces to be welded. They are then placed in a vacuum diffusion furnace, heated to 300–500°C, and then further heated to 600–800°C. The furnace is then held at 600–800°C under vacuum and connection pressure for 30–120 minutes. After the holding period, the temperature is lowered to room temperature, thus completing the low-temperature diffusion connection of the metal material assisted by surface proton irradiation.

[0034] The beneficial effects of this implementation method are:

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

[0036] (2) This embodiment uses a proton irradiation method that does not introduce additional impurity atoms. Therefore, it ensures the stability of the joint composition in the diffusion bonding of metal materials, especially in homogeneous diffusion bonding, and does not produce precipitated second phases and brittle compounds, thus avoiding affecting the joint strength and corrosion resistance.

[0037] (3) The irradiation layer formed on the surface of the metal substrate by the proton irradiation method in this embodiment is extremely thin, which has no adverse effect on the mechanical properties of the metal substrate itself and the welded joint, and is conducive to obtaining a diffusion connection joint with high bonding strength.

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

[0039] (5) The proton irradiation method used in this embodiment has wide applicability in metal substrates, the surface pretreatment process of the metal substrate is simple, the irradiation process parameters have stable control over the irradiated layer, and the repeatability is good.

[0040] Specific Implementation Method Two: The difference between this implementation method and Specific Implementation Method One is that the metal materials to be welded mentioned 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 in Specific Implementation Method 1.

[0042] Specific Implementation Method 3: The difference between this implementation method and Specific Implementation Method 1 or 2 is that the metal material to be welded is Zr-4 alloy.

[0043] The other steps are the same as in Specific Implementation Method 1 or 2.

[0044] Specific Implementation Method Four: The difference between this implementation method and Specific Implementation Methods One to Three is that in step S1, sandpaper of 200#, 400#, 1000# and 2000# is used for polishing in sequence.

[0045] The other steps are the same as those in Specific Implementation Methods One to Three.

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

[0047] The other steps are the same as those in Specific Implementation Methods One through Four.

[0048] Specific Implementation Method Six: The difference between this implementation method and Specific Implementation Methods One to Five is that ultrasonic cleaning is used in step S1, the ultrasonic cleaning time is 10 to 30 minutes, and the cleaning solution used is anhydrous ethanol or acetone solution.

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

[0050] Specific Implementation Method Seven: The difference between this implementation method and Specific Implementation Methods One through Six is ​​that the vacuum degree in the irradiation chamber in step S2 is 4 × 10⁻⁶. -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 Implementation Methods 1 to 6.

[0052] Specific Implementation Method Eight: The difference between this implementation method and Specific Implementation Methods One to Seven is that the parameters of proton irradiation in step S2 are: proton irradiation energy of 100-300 keV and proton irradiation flux of 10 6 ~10 20 cm -2 ·s -1 The proton irradiation dose was 10 8 ~10 22 cm -2 The thickness of the proton irradiation layer is 0.2–1 μm.

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

[0054] Specific Implementation Method Nine: The difference between this implementation method and Specific Implementation Methods One through Eight is that the vacuum degree in step S3 is 4 × 10⁻⁶. -3 Pa~6×10 -3 Pa, with a connection pressure of 5–20 MPa.

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

[0056] Specific Implementation Method 10: The difference between this implementation method and Specific Implementation Methods 1 to 9 is that the first heating rate in step S3 is 5 to 30°C / min, the second heating rate is 1 to 20°C / min, and the cooling rate is 1 to 20°C / min.

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

[0058] The beneficial effects of the present invention are verified using the following embodiments:

[0059] Example 1: A method for achieving low-temperature diffusion bonding of metallic materials using surface proton irradiation, comprising the following steps:

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

[0061] The surfaces of the Zr-4 alloy to be joined were polished sequentially with 200#, 400#, 1000# and 2000# sandpaper to remove dirt and oxide film. Then, they were polished with a polishing agent with a particle size of 0.5μm for 10 minutes, followed by ultrasonic cleaning for 10 minutes to obtain the pretreated Zr-4 alloy. The cleaning solution 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 is dried, and then placed with the weldable side of the Zr-4 alloy facing upwards in the irradiation chamber, and a vacuum is drawn to a vacuum degree of 5 × 10⁻⁶. -3 Pa is then subjected to proton irradiation treatment to obtain a Zr-4 alloy with a proton irradiation layer, the thickness of which is 0.44 μm;

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

[0065] Step S3: Low-temperature diffusion bonding of the metals to be soldered;

[0066] Two Zr-4 alloy pieces with proton irradiation layers obtained in step S2 were assembled by stacking them with their surfaces to be welded. They were then placed in a vacuum diffusion furnace and heated to 450°C at a rate of 15°C / min, and then to 650°C at a rate of 10°C / min. The furnace was then heated at 650°C with a temperature of 5 × 10⁻⁶ ppm. -3 The alloy was held at a vacuum of 10 MPa and a connection pressure of 10 MPa for 30 minutes. After the holding period, the temperature was lowered to room temperature at a rate of 10 °C / min, thus completing the low-temperature diffusion connection of Zr-4 alloy assisted by surface proton irradiation.

[0067] Comparative Example 1: The direct diffusion bonding method for metallic 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 joined were polished sequentially with 200#, 400#, 1000# and 2000# sandpaper to remove dirt and oxide film. Then, they were polished with a polishing agent with a particle size of 0.5μm for 10 minutes, followed by ultrasonic cleaning for 10 minutes to obtain the pretreated Zr-4 alloy. The cleaning solution used was anhydrous ethanol.

[0070] Step S2: Low-temperature diffusion bonding of the metals to be soldered;

[0071] Two pretreated Zr-4 alloy pieces obtained in step S1 were stacked together with their surfaces to be welded. They were then placed in a vacuum diffusion furnace, where the temperature was first increased to 450°C at a rate of 15°C / min, and then increased to 650°C at a rate of 10°C / min. The furnace was then heated at 650°C with a temperature of 5 × 10⁻⁶ ppm. -3 The alloy was held at a vacuum of 10 MPa and a connection pressure of 10 MPa for 30 minutes. After the holding period, the temperature was lowered to room temperature at a rate of 10 °C / min, thus completing the low-temperature diffusion connection of Zr-4 alloy assisted by surface proton irradiation.

[0072] Figure 2 This image shows the microstructure of the Zr-4 alloy diffusion joint after surface irradiation in Example 1. Figure 3 This shows the microstructure of the un-irradiated Zr-4 alloy diffusion joint in Comparative Example 1; as shown. Figure 2-3 As shown, in Example 1, the proton irradiation method can achieve good bonding of the diffusion joint, the joint weld is basically eliminated, and the contact interface is basically healed. Finally, the shear strength of the joint at room temperature reaches 305 MPa. In contrast, in Comparative Example 1 without irradiation, no effective bonding was achieved, further demonstrating the importance and significant effect of proton irradiation in promoting diffusion.

[0073] Example 2: A method for achieving low-temperature diffusion bonding of metallic materials using surface proton irradiation, comprising the following steps:

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

[0075] The surfaces of the Zr-4 alloy to be joined were polished sequentially with 200#, 400#, 1000# and 2000# sandpaper to remove dirt and oxide film. Then, they were polished with a polishing agent with a particle size of 0.5μm for 10 minutes, followed by ultrasonic cleaning for 10 minutes to obtain the pretreated Zr-4 alloy. The cleaning solution 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 is dried, and then placed with the weldable side of the Zr-4 alloy facing upwards in the irradiation chamber, and a vacuum is drawn to a vacuum degree of 5 × 10⁻⁶. -3 Pa is then subjected to proton irradiation treatment to obtain a Zr-4 alloy with a proton irradiation layer, the thickness of which is 0.5 μm;

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

[0079] Step S3: Low-temperature diffusion bonding of the metals to be soldered;

[0080] Two Zr-4 alloy pieces with proton irradiation layers obtained in step S2 were assembled by stacking them with the surfaces to be welded on top of each other. They were then placed in a vacuum diffusion furnace, where the temperature was first increased to 450°C at a rate of 15°C / min, and then increased to 750°C at a rate of 10°C / min. The furnace was then heated at 750°C with a temperature of 5 × 10⁻⁶ ppm. -3 The alloy was held at a vacuum of 10 MPa and a connection pressure of 10 MPa for 30 minutes. After the holding period, the temperature was lowered to room temperature at a rate of 10 °C / min, thus completing the low-temperature diffusion connection of Zr-4 alloy assisted by surface proton irradiation.

[0081] Comparative Example 2: The direct diffusion bonding method for metallic 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 joined were polished sequentially with 200#, 400#, 1000# and 2000# sandpaper to remove dirt and oxide film. Then, they were polished with a polishing agent with a particle size of 0.5μm for 10 minutes, followed by ultrasonic cleaning for 10 minutes to obtain the pretreated Zr-4 alloy. The cleaning solution used was anhydrous ethanol.

[0084] Step S2: Low-temperature diffusion bonding of the metals to be soldered;

[0085] Two pretreated Zr-4 alloy pieces obtained in step S1 were stacked together with their surfaces to be welded. They were then placed in a vacuum diffusion furnace and heated to 450°C at a rate of 15°C / min, followed by a further heating to 750°C at a rate of 10°C / min. The furnace was then heated at 750°C with a temperature of 5 × 10⁻⁶ ppm. -3 The alloy was held at a vacuum of 10 MPa and a connection pressure of 10 MPa for 30 minutes. After the holding period, the temperature was lowered to room temperature at a rate of 10 °C / min, thus completing the low-temperature diffusion connection of Zr-4 alloy assisted by surface proton irradiation.

[0086] Figure 4 This image shows the microstructure of the Zr-4 alloy diffusion joint after surface irradiation in Example 2. Figure 5 This shows the microstructure of the un-irradiated Zr-4 alloy diffusion joint in Comparative Example 2; as shown. Figure 4-5 As shown, in Example 2, the proton irradiation method can achieve good bonding of the diffusion joint, the joint weld is basically eliminated, and the contact interface is basically healed. Finally, the joint shear strength at room temperature reaches 411 MPa; while in Comparative Example 2 without irradiation, the joint has obvious weld and does not achieve effective bonding, with a joint strength of only 291 MPa.

[0087] Figure 6 Indicates 10 18 cm -2 A comparison of the shear strength of Zr-4 alloy diffusion joints at room temperature between proton-irradiated and unirradiated surfaces. Figure 6 As shown, under the same welding parameters, the shear strength of the joint was increased by 41% by using proton irradiation on the alloy surface, and the increase in joint strength was more obvious under low temperature welding, further demonstrating the importance and significant effect of proton irradiation in promoting diffusion.

Claims

1. A method for achieving low-temperature diffusion bonding of metallic materials using surface proton irradiation-assisted bonding, characterized in that... This method is performed in the following steps: Step S1: Pretreatment of the metal to be welded; The surfaces of the metal materials to be welded are ground, polished, and cleaned to obtain pretreated metal materials to be welded; the metal materials to be welded are Zr-4 alloys. Step S2: Proton irradiation of the metal to be welded; The pretreated metal material to be welded obtained in step S1 is dried, and then the metal material to be welded is placed in the irradiation chamber with the welding side facing up and the vacuum is drawn. Then, proton irradiation treatment is performed to obtain the metal material to be welded with a proton irradiation layer. The parameters for proton irradiation in step S2 are: proton irradiation energy of 100–300 keV and proton irradiation flux of 10 keV. 6 ~10 20 cm -2 ·s -1 The proton irradiation dose was 10 8 ~10 22 cm -2 The thickness of the proton irradiation layer is 0.2–1 μm; Step S3: Low-temperature diffusion bonding of the metals to be soldered; Two pieces of metal to be welded, with proton irradiation layers obtained in step S2, are stacked together with their surfaces to be welded. They are then placed in a vacuum diffusion furnace, heated to 300–500°C, and then further heated to 600–800°C. The furnace is then held at 600–800°C under vacuum and connection pressure for 30–120 minutes. After the holding period, the temperature is lowered to room temperature, thus completing the low-temperature diffusion connection of the metal material assisted by surface proton irradiation.

2. The method for achieving low-temperature diffusion bonding of metallic materials by surface proton irradiation as described in claim 1, characterized in that... In step S1, sanding is performed using 200#, 400#, 1000# and 2000# sandpaper in sequence.

3. The method for achieving low-temperature diffusion bonding of metallic materials by surface proton irradiation as described in claim 1, characterized in that... In step S1, polishing is performed for 5–20 minutes using a polishing agent with a particle size of 0.5 μm.

4. The method for achieving low-temperature diffusion bonding of metallic materials by surface proton irradiation as described in claim 1, characterized in that... In step S1, ultrasonic cleaning is used for 10 to 30 minutes, and the cleaning solution used is anhydrous ethanol or acetone solution.

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

6. The method for achieving low-temperature diffusion bonding of metallic materials by surface proton irradiation as described in claim 1, characterized in that... The vacuum degree in step S3 is 4×10 -3 Pa~6×10 -3 Pa, with a connection pressure of 5–20 MPa.

7. The method for achieving low-temperature diffusion bonding of metallic materials by surface proton irradiation as described in claim 1, 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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