Copper alloy vapor chamber based on interface nano texturing and low-temperature diffusion welding method

Abstract

The invention discloses a copper alloy vapor chamber based on interface nano texturing and a low-temperature diffusion welding method.The vapor chamber comprises an upper cover plate and a lower cover plate which are connected through low-temperature diffusion welding, and a vacuum cavity containing a capillary structure and working fluid is defined by the upper cover plate and the lower cover plate; the welding interface is provided with a nanometer interlocking transition area formed by embedding, diffusing and recrystallizing a nanometer velvet layer. The method comprises the following steps: S1, interface nano texturing pretreatment; s2, assembling and pressurizing; s3, low-temperature diffusion welding; and S4, cooling and unloading. Metallurgical bonding and nanometer interlocking are achieved, the nanometer velvet layer provides a huge specific surface area and abundant atom diffusion channels, atom interdiffusion can be rapidly achieved at the low temperature, a formed nanometer interlocking transition area combines a metallurgical bonding mechanism and a mechanical interlocking mechanism, and the connector strength, toughness and fatigue resistance are far away from ultralow-temperature brazing.

Description

Technical Field

[0001] This invention relates to the field of advanced connection technology and high-efficiency heat dissipation devices, specifically to a copper alloy heat sink based on interface nanotexturization and a low-temperature diffusion soldering method. Background Technology

[0002] Vacuum vapor chambers are key components for solving the heat dissipation problem of high-power electronic chips. The core manufacturing challenge lies in achieving a permanent, high-strength, airtight, and low-thermal-resistance seal between the upper and lower copper cover plates. Traditional processes mainly face the contradiction between "high temperature" and "strength." High-temperature brazing (>600℃): High connection strength, but huge thermal stress, which can easily lead to deformation of thin cover plates, damage to internal precision capillary structures, and low yield.

[0003] Low-temperature soft soldering (<250℃): low thermal stress, but the use of soft solders such as Sn-Bi and In results in poor creep and fatigue resistance of the joint, making it difficult to guarantee long-term reliability, and it is prone to failure in high-temperature working environments.

[0004] Solid-state diffusion welding is an ideal solution, as it involves applying pressure and holding the weld at a temperature below the melting point of the base material, allowing atoms at the contact interface to diffuse and form a metallurgical bond, resulting in a joint performance close to that of the base material. However, for copper alloys, achieving high-quality diffusion welding typically requires extremely high temperatures (>700°C) and pressures, or extremely long holding times, which can also introduce thermal damage and sacrifice production efficiency.

[0005] Therefore, how to significantly reduce the temperature and pressure thresholds of copper alloy diffusion welding while obtaining joint performance close to that of high-temperature processes has become a long-standing technical bottleneck in this field. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a copper alloy heat spreader based on interface nanotexturization and a low-temperature diffusion welding method.

[0007] The technical solution of this invention is: A copper alloy heat sink based on interface nanotexturization includes an upper cover plate and a lower cover plate connected by low-temperature diffusion welding. The two plates form a vacuum cavity containing capillary structures and working fluid. At the welding interface between the upper cover plate and the lower cover plate, there is a nano-interlocking transition region formed by the intercalation, diffusion and recrystallization of the nanotextured layers on the surfaces of the upper cover plate and the lower cover plate. The thickness of the nano-interlocking transition region is 5~10μm.

[0008] This invention also provides a low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization, comprising the following steps: S1. Interface nanotexturization pretreatment: The welding surfaces of the upper cover plate and the lower cover plate are pretreated by electrochemical deposition to generate a nanotextured layer with a three-dimensional structure composed of nanoscale fibers on the surface of the welding surfaces. The thickness of the nanotextured layer is 20±1μm and the diameter of the nanotextured fibers is 1±0.1μm. S2. Assembly and pressurization: Align and assemble the pre-treated upper cover plate and the lower cover plate with the surfaces to be welded, and apply an initial pressure of 0.5~20MPa above the welding area to make the nanofiber layers come into contact with each other and undergo partial elastic deformation. S3. Low-temperature diffusion welding: In a protective atmosphere or vacuum environment, the assembly is heated to the welding temperature and held at that temperature, which is between 0.35 and 0.5 times the melting point of the copper alloy base material. The pressure is maintained or finely adjusted during the holding period. S4. Cooling and Unloading: After heat preservation, the plate is cooled to below room temperature while maintaining pressure, and then the pressure is unloaded to obtain a diffusion-welded copper alloy heat exchange plate.

[0009] Further, in S1, the specific steps of the pretreatment by the electrochemical deposition method are as follows: the upper cover plate and the lower cover plate are placed in an electrolyte, the surfaces of the bonding surfaces to be welded are anoly oxidized, graphite is used as the cathode, and the voltage, current density and time are controlled to grow the copper nanowire textured layer of the specified size in situ on the surfaces of the bonding surfaces to be welded.

[0010] Note: The preparation of nanotextiles by anodic oxidation is a controllable, in-situ growth technique for nanotextiles.

[0011] Furthermore, the electrolyte is an alkaline or acidic solution with a molar concentration of 0.5-3 mol / L, wherein a complexing agent with a molar concentration of 0.01-0.1 mol / L is added.

[0012] Note: By rationally selecting electrolyte components, we ensure that the generated copper nanowire textured layer has a regular morphology and pure composition.

[0013] Preferably, the alkaline solution is sodium hydroxide or potassium hydroxide, the acidic solution is oxalic acid or phosphoric acid, and the complexing agent is potassium sodium tartrate or disodium ethylenediaminetetraacetate.

[0014] Note: The formation of other oxides or impurities is avoided by optimizing the electrolyte system.

[0015] Furthermore, the pretreatment voltage for electrochemical deposition is 10~20V, and the anolyte current density is 20~50mA / cm². 2 The time is 20~40 minutes and the temperature is 20~40℃.

[0016] Note: By using precise voltage, current, time, and temperature parameters, it is crucial to ensure that the nanotextile layer can be grown to the specified precise size in a repeatable and efficient manner, which is a key guarantee for process stability and consistency.

[0017] Furthermore, in S3, the welding temperature is 350℃~500℃, the holding time is 0.5~2h, and the protective atmosphere is nitrogen or argon.

[0018] Note: By reasonably controlling the welding temperature, the recrystallization coarsening, oxidation and deformation of the base material are suppressed to the greatest extent, while providing sufficient driving force for atomic diffusion.

[0019] Furthermore, in S3, when fine-tuning the pressure, dynamic compensation is performed based on the predicted creep deformation, as shown in the following formula: in, t s This is the start time of entering the heat preservation stage, measured in seconds. P 2 (t) This is the suggested pressure at the current time t, in MPa; Creep Compensation Item △P creep The calculation formula is as follows: Where C is the creep compensation coefficient, in MPa; t c The creep characteristic time is a material constant that describes how quickly creep reaches a steady state. Feedback and fine-tuning items △P feedback The calculation formula is as follows: in, This represents the real-time displacement rate, expressed in μm / min; a negative value indicates gap closure. The target displacement change rate is set to a small negative value close to zero during the middle and later stages of heat preservation, ranging from -0.05 to -0.1 μm / min; K p and K i The proportional gain coefficient is determined through process debugging to ensure the stability of the control system and is dimensionless. The time constant reflects the system's response speed to an increase in pressure and is related to the equipment stiffness; it is taken as 1~5 min.

[0020] Explanation: By introducing intelligent dynamic pressure control based on creep model and real-time displacement feedback, the interface is ensured to continuously bear effective pressure throughout the insulation period, promoting diffusion and significantly improving the stability, consistency, and quality uniformity of the final interlocking transition zone of the welding process.

[0021] Furthermore, in S4, the room temperature is 25~28℃.

[0022] Note: By cooling to near standard room temperature (25~28℃) before depressurization, the interface is kept constrained until the material is completely cooled, solidified, and its strength is restored. This prevents thermal stress caused by cooling and shrinkage from causing microcracks or weakening of the bond at the interface, thus ensuring the integrity of the joint.

[0023] The beneficial effects of this invention are: (1) The copper alloy heat sink based on interface nanotexturization of the present invention achieves metallurgical bonding and nano-interlocking by introducing a nanotextured layer: the nanotextured layer provides a huge specific surface area and abundant atomic diffusion channels, and atomic interdiffusion can be achieved quickly at low temperature. The formed "nano-interlocking transition zone" combines the dual mechanisms of metallurgical bonding and mechanical interlocking, and the joint strength, toughness and fatigue resistance are far superior to low temperature brazing.

[0024] (2) The copper alloy heat spreader based on interface nanotexturing of the present invention has extremely high sealing reliability. The nano-interlocking structure has a self-filling and blocking effect on interface micro-defects (such as micropores). At the same time, the extremely low thermal stress ensures the high stability of the cover plate shape after welding, so that the airtightness of the weld reaches an extremely high level (leakage rate <10%). -10 Pa·m 3 / s), meeting aerospace-grade requirements.

[0025] (3) The low-temperature diffusion welding method of copper alloy heat spreader based on interface nanotexturization of the present invention reduces the temperature of high-quality diffusion welding of copper alloy from the traditional >700℃ to the range of 350-500℃, and the pressure requirement is also significantly reduced, fundamentally eliminating high thermal stress damage; at the same time, the interface thermal resistance is extremely low: since the connection is a complete metallurgical bond, and the transition zone has a dense structure and fine grains, there is no traditional brazing filler layer or oxide inclusions, the thermal conductivity of the weld is close to that of the copper base material itself, which greatly improves the overall heat dissipation efficiency of the heat spreader.

[0026] (4) The low-temperature diffusion welding method of copper alloy heat exchange plate based on interface nanotexturing of the present invention has good process universality and is not sensitive to copper alloy grade. It is particularly suitable for various high-performance but difficult-to-weld precipitation-strengthened copper alloys (such as chromium zirconium copper), opening up new space for the selection of high-end heat exchange plate materials.

[0027] (5) The low-temperature diffusion welding method of copper alloy heat exchange plate based on interface nanotexturization of the present invention introduces intelligent dynamic pressure control based on creep model and real-time displacement feedback to ensure that the interface continuously bears effective pressure during the entire heat preservation period, promotes diffusion, and significantly improves the stability, consistency and quality uniformity of the final interlocking transition zone of the welding process. Attached Figure Description

[0028] Figure 1 This is a scanning electron microscope (SEM) schematic diagram of the nanotexture thickness of the nanotexture layer on the surface of the copper alloy in the experimental example of the present invention; Figure 2 This is a scanning electron microscope (SEM) schematic diagram of the nanofiber diameter of the nanofiber layer on the surface of the copper alloy in the experimental example of the present invention; Figure 3 This is a schematic diagram of the microstructure of the copper alloy nano-interlocking transition region in the experimental example of this invention; Figure 4 This is a metallographic image of the copper alloy weld joint in the experimental example of this invention; Figure 5 This is a Cu element distribution diagram at the copper alloy weld joint in the experimental example of this invention; Figure 6 This is a Cr element distribution diagram at the copper alloy weld in the experimental example of this invention; Figure 7 This is a schematic cross-sectional view of the heat spreader product in the experimental example of this invention. Detailed Implementation

[0029] Example 1 A copper alloy heat sink based on interface nanotexturization includes an upper cover plate and a lower cover plate connected by low-temperature diffusion welding. The two plates form a vacuum cavity containing capillary structures and working fluid. At the welding interface between the upper cover plate and the lower cover plate, there is a nano-interlocking transition zone formed by the intercalation, diffusion and recrystallization of the nanotextured layers on the surfaces of the upper cover plate and the lower cover plate. The thickness of the nano-interlocking transition zone is 8 μm.

[0030] Example 2 The difference between this embodiment and Embodiment 1 is that: The thickness of the nano-interlocking transition region is 5 μm.

[0031] Example 3 The difference between this embodiment and Embodiment 1 is that: The thickness of the nano-interlocking transition region is 7 μm.

[0032] Example 4 The difference between this embodiment and Embodiment 1 is that: The thickness of the nano-interlocking transition region is 10 μm.

[0033] Example 5 This embodiment is a low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization, as described in Embodiment 1, and includes the following steps: S1. Interface nanotexturization pretreatment: The welding surfaces of the upper and lower cover plates are pretreated by electrochemical deposition to generate a nanotextured layer with a three-dimensional structure composed of nanoscale fibers on the surface of the welding surfaces. The thickness of the nanotextured layer is 20 μm and the diameter of the nanotextured fibers is 1 μm. The specific steps for pretreatment using the electrochemical deposition method are as follows: The upper and lower cover plates are placed in an electrolyte solution with a concentration of 1 mol / L. The electrolyte solution is sodium hydroxide, and the complexing agent is potassium sodium tartrate. A complexing agent concentration of 0.06 mol / L is added. Anodizing treatment is then performed on the surfaces to be welded, using graphite as the cathode. The voltage, current density, and time are controlled: the voltage is 17V, and the anolyte current density is 35 mA / cm². 2 The process takes 35 minutes and takes 25°C, during which a copper nanowire textured layer of the required size is grown in situ on the surface of the bonding surface to be welded. S2. Assembly and pressurization: Align and assemble the pre-treated upper and lower cover plates with the surfaces to be welded, and apply an initial pressure of 100MPa above the welding area to make the nanofiber layers come into contact with each other and undergo partial elastic deformation. S3, Low-temperature diffusion welding: In a protective atmosphere, the assembly is heated to the welding temperature and held at that temperature. The welding temperature is between 0.4 times the melting point of the copper alloy base material. Pressure is maintained during the holding period. The welding temperature is 400℃ and the holding time is 1 hour. The protective atmosphere is argon. S4. Cooling and Unloading: After heat preservation, the temperature is cooled to below 25°C under pressure, and then the pressure is unloaded to obtain a diffusion-welded copper alloy heat exchange plate.

[0034] Example 6 The difference between this embodiment and embodiment 5 is that: In S1, the thickness of the nanofiber layer is 21 μm and the diameter of the nanofiber layer is 1.1 μm.

[0035] Example 7 The difference between this embodiment and embodiment 5 is that: In S1, the thickness of the nanofiber layer is 9 μm and the diameter of the nanofiber layer is 0.9 μm.

[0036] Example 8 The difference between this embodiment and embodiment 5 is that: In S1, the thickness of the nanofiber layer is 20.5 μm, and the diameter of the nanofiber layer is 1.05 μm.

[0037] Example 9 The difference between this embodiment and embodiment 5 is that: The specific steps for pretreatment using the electrochemical deposition method are as follows: The upper and lower cover plates are placed in an electrolyte solution with a concentration of 2 mol / L. The electrolyte solution is potassium hydroxide, and the complexing agent is disodium ethylenediaminetetraacetate (EDTA). A complexing agent concentration of 0.04 mol / L is added. Anodizing treatment is then performed on the surfaces to be welded, using graphite as the cathode. Voltage, current density, and time are controlled: the voltage is 18V, and the anolyte current density is 40 mA / cm². 2 The process takes 30 minutes and is carried out at a temperature of 30°C, during which a copper nanowire textured layer of the required size is grown in situ on the surface of the bonding surfaces to be welded.

[0038] Example 10 The difference between this embodiment and embodiment 5 is that: The specific steps for pretreatment using the electrochemical deposition method are as follows: The upper and lower cover plates are placed in an electrolyte solution with a concentration of 0.5 mol / L. The electrolyte solution is oxalic acid, and the complexing agent is potassium sodium tartrate. A complexing agent concentration of 0.01 mol / L is added. Anodizing treatment is then performed on the surfaces to be welded, using graphite as the cathode. The voltage, current density, and time are controlled: the voltage is 10V, and the anolyte current density is 20 mA / cm². 2 The process takes 40 minutes and is carried out at a temperature of 40℃, during which a copper nanowire textured layer of the required size is grown in situ on the surface of the bonding surface to be welded.

[0039] Example 11 The difference between this embodiment and embodiment 5 is that: The specific steps for pretreatment using the electrochemical deposition method are as follows: The upper and lower cover plates are placed in an electrolyte solution with a concentration of 3 mol / L. The electrolyte solution is phosphoric acid, and the complexing agent is disodium ethylenediaminetetraacetate (EDTA). A complexing agent concentration of 0.1 mol / L is added. Anodizing treatment is then performed on the surfaces to be welded, using graphite as the cathode. Voltage, current density, and time are controlled: the voltage is 20V, and the anolyte current density is 50 mA / cm². 2 The process takes 20 minutes and is carried out at a temperature of 20°C, during which a copper nanowire textured layer of the required size is grown in situ on the surface of the bonding surfaces to be welded.

[0040] Example 12 The difference between this embodiment and embodiment 5 is that: S2. Assembly and pressurization: Align and assemble the pre-treated upper and lower cover plates with the surfaces to be welded, and apply an initial pressure of 0.5 MPa above the welding area to make the nanofiber layers come into contact with each other and undergo partial elastic deformation. S3, Low-temperature diffusion welding: In a protective atmosphere, the assembly is heated to the welding temperature and held at that temperature. The welding temperature is 0.35 times the melting point of the copper alloy base material. The pressure is finely adjusted during the holding period. The welding temperature is 350℃ and the holding time is 2 hours. The protective atmosphere is nitrogen. When fine-tuning the pressure, dynamic compensation is performed based on the predicted creep deformation, as shown in the following formula: in, t s This is the start time of entering the heat preservation stage, measured in seconds. P 2 (t) This is the suggested pressure at the current time t, in MPa; Creep Compensation Item △P creep The calculation formula is as follows: Where C is the creep compensation coefficient, in MPa; t c The creep characteristic time is a material constant that describes how quickly creep reaches a steady state. Feedback and fine-tuning items △P feedback The calculation formula is as follows: in, This represents the real-time displacement rate, expressed in μm / min; a negative value indicates gap closure. The target displacement change rate is set to a small negative value close to zero, -0.05 μm / min, during the later stages of heat preservation; K p and K i The proportional gain coefficient is determined through process debugging to ensure the stability of the control system and is dimensionless. The time constant reflects the system's response speed to an increase in pressure and is related to the equipment stiffness; it is taken as 1 minute. Example 13 The difference between this embodiment and embodiment 5 is that: S2. Assembly and pressurization: Align and assemble the pre-treated upper and lower cover plates with the surfaces to be welded, and apply an initial pressure of 20 MPa above the welding area to make the nanofiber layers come into contact with each other and undergo partial elastic deformation. S3, Low-temperature diffusion welding: In a vacuum environment, the assembly is heated to the welding temperature and held at that temperature. The welding temperature is 0.5 times the melting point of the copper alloy base material. The pressure is finely adjusted during the holding period. The welding temperature is 500℃ and the holding time is 0.5h. When fine-tuning the pressure, dynamic compensation is performed based on the predicted creep deformation, as shown in the following formula: in, t s This is the start time of entering the heat preservation stage, measured in seconds. P 2 (t) This is the suggested pressure at the current time t, in MPa; Creep Compensation Item △P creep The calculation formula is as follows: Where C is the creep compensation coefficient, in MPa; t c The creep characteristic time is a material constant that describes how quickly creep reaches a steady state. Feedback and fine-tuning items △P feedback The calculation formula is as follows: in, This represents the real-time displacement rate, expressed in μm / min; a negative value indicates gap closure. The target displacement change rate is set to a small negative value close to zero, -0.1 μm / min, during the later stages of heat preservation; K p and K i The proportional gain coefficient is determined through process debugging to ensure the stability of the control system and is dimensionless. The time constant reflects the system's response speed to an increase in pressure and is related to the equipment stiffness; it is taken as 5 min. Example 14 The difference between this embodiment and embodiment 13 is that: When fine-tuning the pressure, dynamic compensation is performed based on the predicted creep deformation, as shown in the following formula: in, t s This is the start time of entering the heat preservation stage, measured in seconds. P 2 (t) This is the suggested pressure at the current time t, in MPa; Creep Compensation Item △P creep The calculation formula is as follows: Where C is the creep compensation coefficient, in MPa; t c The creep characteristic time is a material constant that describes how quickly creep reaches a steady state. Feedback and fine-tuning items △P feedbackThe calculation formula is as follows: in, This represents the real-time displacement rate, expressed in μm / min; a negative value indicates gap closure. The target displacement change rate is set to a small negative value close to zero, -0.08 μm / min, during the later stages of heat preservation; K p and K i The proportional gain coefficient is determined through process debugging to ensure the stability of the control system and is dimensionless. The time constant reflects the system's response speed to an increase in pressure and is related to the equipment stiffness; it is taken as 3 minutes.

[0041] Example 15 The difference between this embodiment and embodiment 5 is that: S4. Cooling and Unloading: After heat preservation, the plate is cooled to below room temperature (28°C) under pressure. Then the pressure is unloaded to obtain a diffusion-welded copper alloy heat exchange plate.

[0042] Experimental Example Taking the copper alloy heat spreader in Example 1 prepared by the method of Example 13 of the present invention as an example, experimental tests were conducted, such as... Figure 1 As shown in the figure, SEM reveals a three-dimensional nanofiber layer composed of nanoscale fibers on the surfaces of the upper and lower cover plates. A schematic diagram of the diameter is shown below. Figure 2 As shown in the diagram, the microstructure of the "nano-interlocking transition region" formed after low-temperature diffusion welding is illustrated in the figure below. Figure 3 As shown.

[0043] Figure 4 This is a metallographic image of the welded joint area after low-temperature diffusion welding. It can be seen that the transition zone and its thickness are formed by nanofiber interlocking after diffusion welding. Its microstructure consists of fine equiaxed crystals with grain size smaller than that of the base material. Figure 5 and Figure 6 This is an elemental distribution diagram of the welded region after low-temperature diffusion welding of Cu and Cr. It can be seen that the elemental distribution in the transition zone after diffusion welding is tested, and the results prove the phenomenon of atomic interdiffusion during the welding process. Figure 7 This is a cross-sectional structural diagram of the heat spreader product. Its room temperature tensile strength is not less than 80% of the strength of the base material, and its shear strength is not less than 100MPa (up to 128MPa). After undergoing 1000 heat cycles from -40℃ to 90℃, the air tightness retention rate is above 99.9%.

[0044] Meanwhile, the copper alloy heat spreader prepared by the method in Example 5 in Example 3 was tested. Its room temperature tensile strength was not less than 80% of the strength of the base material, and its shear strength was not less than 100 MPa (up to 125 MPa). After undergoing 1000 thermal cycles from -40℃ to 90℃, the airtightness retention rate was above 99.9%.

[0045] It can be seen that the material properties are slightly better after dynamic compensation for creep deformation. In Example 13, the specific calculated values ​​for dynamic compensation of creep deformation are as follows: Dynamic compensation is performed based on the predicted creep deformation, using the following formula: in, t s This is the start time of entering the heat preservation stage, measured in seconds. P 2 (t) The suggested pressure at the current time t is 22 MPa. Creep Compensation Item △P creep The calculation formula is as follows: Where C is the creep compensation coefficient, taken as 2 MPa, which is 10% of the initial pressure, used to compensate for pressure relaxation; t c The creep characteristic time, a material constant, describes how quickly creep reaches steady state, and is taken as 600 s; finally, the creep compensation term... △P creep The negative sign indicates that an additional positive pressure is needed to compensate for the pressure loss caused by creep. Therefore, the compensation amount is +1.386 MPa.

[0046] Feedback and fine-tuning items △P feedback The calculation formula is as follows: in, This represents the real-time displacement rate, expressed in μm / min. A negative value indicates gap closure. ; The target displacement change rate is set to a small negative value close to zero, -0.1 μm / min, during the later stages of heat preservation; K p Take 0.5 MPa·min / μm, and K i Take 0.1 MPa·min 2 / μm is the proportional gain coefficient, which is determined through process debugging to ensure the stability of the control system and is dimensionless; The time constant reflects the system's response speed to an increase in pressure and is related to the equipment stiffness; it is taken as 5 min. The control system will drive the actuator to adjust the actual pressure to approximately 23.476 MPa.

[0047] The table below shows the calculation logic and results of pressure regulation every 300 seconds from the start of heat preservation (t=0) to the end (t=1800s).

[0048] Table 1. Calculation logic and results of pressure adjustment every 300 seconds during the period from the start (t=0) to the end (t=1800s) of heat preservation.

Claims

1. A copper alloy heat spreader based on interface nanotexturization, comprising an upper cover plate and a lower cover plate connected by low-temperature diffusion welding, the two forming a vacuum cavity containing capillary structures and working fluid, characterized in that, At the welding interface between the upper cover plate and the lower cover plate, there is a nano-interlocking transition region formed by the intercalation, diffusion and recrystallization of the nano-textured layers on the surfaces of the upper cover plate and the lower cover plate, and the thickness of the nano-interlocking transition region is 5~10μm.

2. The low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization according to claim 1, characterized in that, Includes the following steps: S1. Interface nanotexturization pretreatment: The welding surfaces of the upper cover plate and the lower cover plate are pretreated by electrochemical deposition to generate a nanotextured layer with a three-dimensional structure composed of nanoscale fibers on the surface of the welding surfaces. The thickness of the nanotextured layer is 20±1μm and the diameter of the nanotextured fibers is 1±0.1μm. S2. Assembly and pressurization: Align and assemble the pre-treated upper cover plate and the lower cover plate with the surfaces to be welded, and apply an initial pressure of 0.5~20MPa above the welding area to make the nanofiber layers come into contact with each other and undergo partial elastic deformation. S3. Low-temperature diffusion welding: In a protective atmosphere or vacuum environment, the assembly is heated to the welding temperature and held at that temperature, which is between 0.35 and 0.5 times the melting point of the copper alloy base material. The pressure is maintained or finely adjusted during the holding period. S4. Cooling and Unloading: After heat preservation, the plate is cooled to below room temperature while maintaining pressure, and then the pressure is unloaded to obtain a diffusion-welded copper alloy heat exchange plate.

3. The low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization according to claim 2, characterized in that, In S1, the specific steps of the pretreatment by the electrochemical deposition method are as follows: the upper cover plate and the lower cover plate are placed in an electrolyte, the surfaces of the bonding surfaces to be welded are anoly oxidized, graphite is used as the cathode, and the voltage, current density and time are controlled to grow the copper nanowire textured layer of the specified size in situ on the surfaces of the bonding surfaces to be welded.

4. The low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization according to claim 3, characterized in that, The electrolyte is an alkaline or acidic solution with a molar concentration of 0.5-3 mol / L, wherein a complexing agent with a molar concentration of 0.01-0.1 mol / L is added.

5. A low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization according to claim 4, characterized in that, The alkaline solution is sodium hydroxide or potassium hydroxide, the acidic solution is oxalic acid or phosphoric acid, and the complexing agent is potassium sodium tartrate or disodium ethylenediaminetetraacetate.

6. The low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization according to claim 3, characterized in that, The pretreatment voltage for electrochemical deposition is 10~20V, and the anolyte current density is 20~50mA / cm². 2 The time is 20~40 minutes and the temperature is 20~40℃.

7. A low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization according to claim 2, characterized in that, In S3, the welding temperature is 350℃~500℃, the holding time is 0.5~2h, and the protective atmosphere is nitrogen or argon.

8. A low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization according to claim 2, characterized in that, In S3, when fine-tuning the pressure, dynamic compensation is performed based on the predicted creep deformation, as shown in the following formula: in, t s This is the start time of entering the heat preservation stage, measured in seconds. P 2 (t) This is the suggested pressure at the current time t, in MPa; Creep Compensation Item △P creep The calculation formula is as follows: Where C is the creep compensation coefficient, in MPa; t c The creep characteristic time is a material constant that describes how quickly creep reaches a steady state. Feedback and fine-tuning items △P feedback The calculation formula is as follows: in, This represents the real-time displacement rate, expressed in μm / min; a negative value indicates gap closure. The target displacement change rate is set to a small negative value close to zero during the middle and later stages of heat preservation, ranging from -0.05 to -0.1 μm / min; K p and K i The proportional gain coefficient is determined through process debugging to ensure the stability of the control system and is dimensionless. The time constant reflects the system's response speed to an increase in pressure and is related to the equipment stiffness; it is taken as 1~5 min.

9. A low-temperature diffusion welding method for a copper alloy heat spreader based on interface nanotexturization according to claim 2, characterized in that, In S4, the room temperature is 25~28℃.

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