A topologically coupled gradient porous two-phase cold plate and an additive manufacturing method thereof

Abstract

This invention discloses a topologically coupled gradient porous two-phase cold plate and its additive manufacturing method, belonging to the field of thermal management technology for high-power electronic devices. The cold plate's base thermally conductive layer, multi-stage gradient liquid distribution manifold layer, and variable-aperture graded vapor distribution porous core are integrally formed using multi-material LPBF. The variable-aperture graded vapor distribution porous core has four layers of continuously gradient functional materials along the thickness direction of the heat source. The liquid distribution manifold adopts multi-stage tapered and branched flow channels. The porous core contains dual-scale nested holes with micron-sized vaporization pits on the hole walls. This invention effectively solves industry problems such as flow deviation, localized dryness, flow channel blockage, and high interfacial thermal resistance in traditional heat dissipation devices; the product's critical heat flux density is greater than 500 W·cm³. ‑2 The chip surface temperature difference is controlled at 2-3℃, the structure is lightweight and the vibration resistance is excellent. It can be widely used in high heat-generating equipment such as SiC / GaN power modules, 3D stacked chips, AI computing boards, aerospace and automotive electronic control.

Description

Technical Field

[0001] This invention belongs to the field of thermal management technology for high-power electronic devices, specifically relating to a radial liquid distribution-axial vapor separation topologically coupled gradient porous two-phase cold plate and its additive manufacturing method, which is particularly suitable for SiC / GaN power modules, 3D stacked chips, AI accelerator cards, and other devices with heat flux densities ≥300 W·cm². -2 It provides cooling for precision components and can operate stably for a long time under alternating vibration conditions in aerospace, new energy vehicle electronic control, supercomputing centers, and other applications. Background Technology

[0002] With the development of third-generation semiconductors and advanced chip packaging technologies, electronic devices are rapidly evolving towards high integration, miniaturization, and high power. The heat flux density of SiC power modules and 3D stacked chips has exceeded 300 W·cm². -2 Under extreme conditions, it can reach 500 W·cm -2 In summary, localized hotspot accumulation, two-phase flow vapor blockage, and interfacial thermal resistance mismatch have become key bottlenecks restricting device performance and lifespan. Existing mainstream heat dissipation components each have significant shortcomings: conventional straight-through multi-hole heat exchangers rely solely on a single axial through-hole for heat exchange, lacking a radial liquid distribution structure. Insufficient coolant replenishment in the central high-temperature region easily leads to localized drying failure. Furthermore, the use of homogeneous metal results in a large difference in thermal expansion between the metal and the semiconductor silicon substrate, leading to persistently high interfacial thermal resistance. Traditional branched flow-equalizing cold plates offer excellent radial heat uniformity, but insufficient axial heat exchange volume, making them prone to heat accumulation and saturation under high heat load conditions.

[0003] Currently, most composite heat dissipation products on the market are assembled using separate mechanical parts. The gaps at the joints between the branched flow channels and the porous heat exchange core are large, resulting in poor medium connectivity, disordered gas-liquid flow, and unbalanced branch flow distribution. At the same time, traditional casting and drilling processes cannot achieve simultaneous molding of multi-component gradient substrates and complex irregular structures. The overall rigidity of the assembly is low, and it is prone to seal cracking and medium leakage under vehicle and aviation vibration conditions.

[0004] Therefore, developing a novel two-phase cold plate with integrated molding, topological coupling of liquid distribution and vapor distribution, continuous material gradient, and directional gas-liquid separation is the key to solving the heat dissipation problem of ultra-high heat flux density devices. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a radial liquid distribution-axial steam distribution topologically coupled gradient porous two-phase cold plate. It integrates three unique structural features: multi-stage tapered bifurcation manifold liquid distribution, dual-scale nested porous core axial steam distribution, and four-layer continuous gradient substrate thermal matching. Combined with a low-GWP environmentally friendly working fluid, it forms a closed-loop two-phase cycle. Through multi-material laser powder bed melting technology, it achieves integrated molding, realizing the synergistic unity of peripheral radial uniform liquid distribution, central axial directional steam exhaust, and low thermal resistance matching of multi-layer substrates. This fundamentally solves problems such as dry burning, steam blockage, poor temperature uniformity, and low assembly reliability in traditional heat dissipation structures.

[0006] The technical solution of this invention is as follows: A radial liquid distribution-axial vapor separation topological coupling type gradient porous two-phase cold plate, characterized in that it includes a base heat-conducting layer, a multi-stage gradient liquid distribution manifold layer, a variable aperture graded vapor separation porous core, and a top cover assembly. The base heat-conducting layer, the multi-stage gradient liquid distribution manifold layer, and the variable aperture graded vapor separation porous core are integrally formed by a multi-material laser powder bed melting process. An annular connecting groove is formed on the upper surface of the base heat-conducting layer, and several liquid phase supply ports are provided on the base heat-conducting layer, each liquid phase supply port being connected to the annular connecting groove.

[0007] The multi-stage gradient liquid distribution manifold layer is disposed on the upper surface of the base heat-conducting layer and located in the annular connecting groove. The multi-stage gradient liquid distribution manifold layer is provided with multi-stage progressively branching and tapering flow channels. The cross-section of the outermost flow channel gradually narrows from the outside to the center, and the outermost flow channel is connected to the annular connecting groove.

[0008] The variable-aperture, graded vapor distribution porous core is located at the center of the multi-stage gradient liquid distribution manifold layer. The variable-aperture, graded vapor distribution porous core is made of gradient functional materials, which include, from bottom to top, a chip bonding interface layer, an intermediate transition gradient layer, a main thermally conductive layer, and a condensation strengthening layer. The variable-aperture, graded vapor distribution porous core includes a central dual-scale nested porous region. This porous region includes large-aperture exhaust holes and small-aperture capillary vaporization micropores arranged alternately in the axial direction. The walls of the large-aperture exhaust holes and small-aperture capillary vaporization micropores are provided with micron-sized pit vaporization structures. The bottoms of the large-aperture exhaust holes and small-aperture capillary vaporization micropores are connected to the flow channels of the multi-stage gradient liquid distribution manifold layer.

[0009] A steam outlet is opened on the top cover assembly corresponding to the central area of ​​the core. The coolant enters the multi-stage gradient distribution manifold layer from the liquid phase supply port, and is evenly distributed from the periphery to the center through the step-by-step branching channels. After the medium enters the variable aperture staged steam distribution porous core, it is heated and undergoes nucleation boiling. The generated steam is discharged vertically upward along the large aperture channel of the core from the outlet, forming a complete closed two-phase heat exchange loop.

[0010] Furthermore, an annular retaining ring is provided on the thermally conductive base layer, and the bottom outer edge of the top cover assembly is connected to the upper surface of the multi-stage gradient liquid distribution manifold layer. An annular connecting groove is located between the annular retaining ring and the outer edge of the top cover assembly. A fluororubber sealing ring is embedded between the annular connecting groove and the outer edge of the top cover assembly.

[0011] Furthermore, the aforementioned thermally conductive base layer is a square flat plate structure, using Cu-Mo alloy substrate with a thickness of 2-5 mm. The lower surface is the heat source bonding surface with a surface roughness Ra≤0.8 μm, and mounting and fixing holes with a diameter of 3~5 mm are opened at the four corners.

[0012] Furthermore, the aforementioned multi-stage gradient liquid distribution manifold layer is integrated onto the upper surface of the substrate heat-conducting layer, and the overall structure is a 3-4 stage progressively branching and tapering flow channel configuration, divided into a primary main channel, a secondary branch channel, and a tertiary capillary channel; the primary main channel extends from the edge liquid inlet to the center, with a flow cross-section of 8-10 mm. 2 Gradually shrink to 2~3 mm 2 Secondary branch channels branch laterally from the primary channel, with branch angles ranging from 20° to 60° and cross-sections ranging from 2 to 3 mm. 2 Gradually shrink to 0.5~1 mm 2 The tertiary capillary channels are densely distributed in the gaps between the secondary channels, and the bottom cross-section of the pores connecting the ends of the tertiary capillary channels to the porous region is 0.2~0.5 mm. 2 The depth of all flow channels is 0.5~1 mm, and the width of the flow channels decreases linearly from the outer periphery to the center at a ratio of 1.2:1, so as to achieve a coolant distribution deviation of ≤8% in each branch.

[0013] Furthermore, the aforementioned variable-aperture, graded steam-distribution porous core is integrally formed above the manifold layer, including a central dual-scale nested porous region. The central porous region consists of alternating large-aperture exhaust channels and small-aperture capillary vaporization micropores. The large-aperture channels serve as the main steam exhaust channels, with a pore size of 200~500 μm and a porosity of 40%~60%. The small-aperture micropores serve as liquid phase storage and boiling channels, with a pore size of 50~150 μm and a porosity of 30%~40%. The spatial connectivity between the two types of channels is ≥95%. Micron-sized pit vaporization structures are provided on the inner walls of the channels and the walls of the connecting grooves to increase the boiling vaporization core.

[0014] Furthermore, the aforementioned central dual-scale nested porous region is made of a graded functional material, which is divided into four continuously gradient components along the thickness direction from the heat source surface: the chip bonding interface layer (thickness 0~0.5 mm) is a Cu-Mo alloy with a Mo content of 60-65 vol% and CTE = 6.2~6.5 × 10⁻⁶. -6 K -1 Thermal conductivity 180 W·m -1 ·K -1The intermediate transition layer (thickness 0.5~2 mm) is a Cu-Mo-Cr graded alloy, with the CTE gradually transitioning to 10.8~11×10⁻⁶. -6 K -1 Thermal conductivity 180~320 W·m -1 ·K -1 The main heat-conducting layer (2-5 mm thick) is made of pure Cu or Cu-Cr, with a CTE ≈ 17 × 10⁻⁶. -6 K -1 Thermal conductivity 380 W·m -1 ·K -1 The condensation reinforcement layer is made of Cu-Ni-P superhydrophobic modified material with a contact angle >150°.

[0015] Furthermore, the aforementioned top cover assembly has a thickness of 1-3mm and is arranged in 3-5 units. φ =5~8mm steam outlet, total opening area ≥ total area of ​​all liquid replenishment ports.

[0016] Furthermore, the internal circulating coolant of the cold plate is a low-GWP environmentally friendly coolant with a boiling point of 50-100℃, such as deionized water, ethylene glycol aqueous solution, R1234ze(E), etc.

[0017] This invention employs a topologically coupled flow path with radial liquid replenishment at the periphery and axial vapor exhaust at the center. It achieves uniform distribution of coolant across the entire surface using a graded manifold, and separates the gas and liquid spaces through dual-scale channels. Combined with a gradient substrate matching the chip's thermal expansion coefficient and a low-GWP environmentally friendly closed-loop two-phase circulation system, it effectively solves industry problems such as flow deviation, localized dryness, vapor blockage in the flow channels, and high interfacial thermal resistance in traditional heat dissipation devices. The product's critical heat flux density is greater than 500 W·cm³. -2 The chip surface temperature difference is controlled at 2-3℃, the structure is lightweight and the vibration resistance is excellent. It can be widely used in high heat-generating equipment such as SiC / GaN power modules, 3D stacked chips, AI computing boards, aerospace and automotive electronic control.

[0018] In addition, this invention also proposes a method for preparing the above-mentioned radial liquid distribution-axial vapor separation topological coupling type gradient porous two-phase cold plate, which is characterized by including the following steps: (1) Structural parameter design: Based on the target heat flux density, determine the number of manifold stages, the flow channel diameter reduction ratio, the bifurcation angle, the dual-scale pore size and pore parameters of the multi-porous core, the distribution ratio of each group of the gradient layer, and select the corresponding circulating working fluid. (2) Three-dimensional modeling: Based on the parameters, build an overall three-dimensional model, and model the gradient functional material, multi-level gradient liquid distribution manifold layer, and variable pore size graded vapor separation porous core to ensure that the flow channels are interconnected and there are no dead cavities. (3) Integrated additive manufacturing: Using multi-material LPBF equipment, Cu-Mo, Cu-Mo-Cr, pure Cu, and Cu-Ni-P powders are replaced sequentially, and the process is controlled in zones: laser power 280-350 W, scanning speed 500-800 mm·s -1 The printing layer thickness is 30-50μm, and the forming accuracy is ±50 μm. (4) Micro-dimple processing on the hole wall: A femtosecond laser is used to process vaporization pits on all the inner walls of the multi-hole core. The laser pulse width is ≤500 fs, the power is 1~2 W, and the travel speed is 80~120 mm·s. -1 ; (5) Magnetism-thermal synergistic post-treatment: First, pulse magnetization: 0.5T, 10Hz, heat preservation for 15~20min, to promote the preferential arrangement of the {100} crystal planes of the copper substrate and improve thermal conductivity; then laser shock strengthening: laser shock single pulse energy 5J, spot 1mm, shock 2~3 times, to introduce -300~-500 MPa residual compressive stress into the surface layer, and refine the grain to 100~200 nm; (6) Sealing assembly: The heat source contact surface is polished to Ra≤0.8 μm, and the top cover and the upper edge of the porous core are sealed under vacuum ≥1×10 -5 Brazing at 400~450℃ for 60~90 min achieves metallurgical sealing. A fluororubber sealing ring is installed between the annular connecting groove and the outer edge of the top cover assembly.

[0019] Advantages of this invention: 1) This invention features a unique peripheral radial liquid distribution-central axial vapor distribution topological coupling structure. A 3-4 stage gradient manifold enables precise coolant replenishment from the periphery to the center, reducing the chip's overall temperature difference from 8-10℃ to 2-3℃, improving temperature uniformity by over 60%. Large-sized macroscopic exhaust pores and small-sized capillary vaporization micropores form a dual-scale nested porous structure with scale differences. The large-diameter channels macroscopically guide and discharge steam, while the small-diameter micropores rely on capillary force to adsorb and store the liquid working fluid, achieving spatial gas-liquid separation through large-pore exhaust and micropore liquid vaporization. Combined with densely packed pits on the wall surface, the critical heat flux exceeds 500 W·cm⁻¹. -2 The heat exchange efficiency is 3 to 5 times higher than that of traditional single porous water cooling, completely eliminating the problems of dryness and steam blockage failure in the central high-temperature zone; 2) The graded functional material substrate is integrally formed by additive manufacturing, with the coefficient of thermal expansion smoothly transitioning from the chip surface to the heat dissipation surface, reducing the thermal resistance at the substrate-silicon chip interface to 0.03 cm. 2 ·K·W -1 Within; the entire structure has no gaps between the parts, and the weight of the whole machine is reduced by 40% to 50% compared with the products assembled separately. The structural rigidity and vibration resistance are suitable for complex vibration conditions in vehicles and aviation. 3) The LPBF integrated molding allows for flexible adjustment of flow channels, apertures, and gradient ratios as needed, adapting to various specifications of high heat flux chips; it is equipped with low GWP environmentally friendly working fluid, making it green and safe, with good assembly compatibility and convenient industrialization. Attached Figure Description

[0020] Figure 1. Schematic diagram of the overall three-dimensional structure of the radial liquid distribution-axial vapor distribution topology coupling cold plate of the present invention; Figure 2 Cross-sectional view of the radial liquid distribution-axial vapor distribution topology coupling cold plate of this invention; Figure 3 Explosive assembly diagram of the radial liquid distribution-axial steam distribution topological coupling cold plate of the present invention; Figure 4 Schematic diagram of the multi-stage gradient liquid distribution manifold layer of the present invention; Figure 5 A schematic diagram of the cross-sectional structure of the variable aperture graded steam separation porous core of this invention.

[0021] In the figure: 1-substrate thermal conductive layer, 11-liquid phase supply port, 12-fixing hole; 2-Multi-stage gradient liquid distribution manifold layer, 21-Primary main flow channel, 22-Secondary branch flow channel, 23-Tertiary capillary flow channel; 3-Variable pore size graded steam separation porous core, 31-Large pore size exhaust steam through hole, 32-Small pore size capillary vaporization micropore, 33-Annular connecting groove, 34-Micron-sized pit vaporization structure; 4-Top cover assembly, 41-Steam outlet; 5-Gradient functional material, 51-Chip bonding interface layer, 52-Intermediate transition gradient layer, 53-Main thermal conductive layer, 54-Condensation reinforcement layer. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention provides a radial liquid distribution-axial vapor separation topologically coupled gradient porous two-phase cold plate and its preparation method. Through multiple innovations such as topological coupling configuration, continuous gradient substrate, built-in self-regulating throttling, and integrated additive manufacturing, it solves the pain points of high heat flux devices such as local dryness, gas blockage, and high interface thermal resistance.

[0024] See Figures 1-5A radial liquid distribution-axial vapor separation topologically coupled gradient porous two-phase cold plate includes a base heat-conducting layer 1, a multi-stage gradient liquid distribution manifold layer 2, a variable pore size graded vapor separation porous core 3, and a top cover assembly 4. The base heat-conducting layer 1, the multi-stage gradient liquid distribution manifold layer 2, and the variable pore size graded vapor separation porous core 3 are integrally formed by a multi-material laser powder bed melting process. The lower surface of the base heat-conducting layer 1 is the heat source bonding surface, and the upper surface has an annular connecting groove 33. Four liquid phase supply ports 11 are symmetrically arranged on the base heat-conducting layer 1, and each liquid phase supply port 11 is connected to the annular connecting groove 33.

[0025] See Figure 3 The multi-stage gradient liquid distribution manifold layer 2 is disposed on the upper surface of the base heat-conducting layer 1 and located in the annular connecting groove 33. The multi-stage gradient liquid distribution manifold layer 2 is provided with multi-stage progressively branching and tapering flow channels. The cross-section of the three-stage capillary flow channel 23 gradually narrows from the outside to the center. The outermost flow channel is connected to the annular connecting groove 33.

[0026] See Figure 3 and Figure 5 The variable pore size graded vapor distribution porous core 3 is located at the center of the multi-stage gradient liquid distribution manifold layer 2. The variable pore size graded vapor distribution porous core 3 is made of gradient functional material 5, which includes a chip bonding interface layer 51, an intermediate transition gradient layer 52, a main thermal conductive layer 53, and a condensation strengthening layer 54 arranged from bottom to top. The variable pore size graded vapor distribution porous core 3 includes a central dual-scale nested porous region. The porous region includes large-diameter exhaust steam through holes 31 and small-diameter capillary vaporization micropores 32 arranged alternately in the axial direction. The walls of the large-diameter exhaust steam through holes 31 and small-diameter capillary vaporization micropores 32 are provided with micron-sized pit vaporization structures 34. The bottom of the large-diameter exhaust steam through holes 31 and small-diameter capillary vaporization micropores 32 are connected to the flow channel of the multi-stage gradient liquid distribution manifold layer 2.

[0027] A steam outlet 41 is opened on the top cover assembly 4 corresponding to the central area of ​​the core; the coolant enters the multi-stage gradual liquid distribution manifold layer 2 from the liquid phase supply port 11, and is uniformly guided and distributed from the periphery to the center through the step-by-step branching flow channels. After the medium enters the variable aperture staged steam distribution porous core 3, it is heated and undergoes nucleation boiling. The generated steam is discharged vertically upward along the large aperture channel of the core from the outlet, forming a complete closed two-phase heat exchange circuit.

[0028] As a preferred embodiment of the present invention, see [link to previous document]. Figures 1-3 The thermally conductive base layer 1 is also provided with an annular baffle ring. The bottom edge of the top cover assembly 4 is connected to the upper surface of the multi-stage gradient liquid distribution manifold layer 2. The annular connecting groove 33 is located between the annular baffle ring and the outer edge of the top cover assembly 4. A fluororubber sealing ring is embedded between the annular connecting groove 33 and the outer edge of the top cover assembly 4. Four liquid phase supply ports 11 are provided on the side wall of the annular baffle ring and are evenly and symmetrically arranged along the circumference of the base. Each liquid phase supply port is directly connected to the annular connecting groove 33.

[0029] As a preferred embodiment of the present invention, the above-mentioned base heat-conducting layer 1 is a square plate structure, using Cu-Mo alloy substrate, with a thickness of 2-5 mm, the lower surface is the heat source bonding surface, the surface roughness Ra≤0.8 μm, and mounting and fixing holes 12 with a diameter of 3~5 mm are opened at the four corners.

[0030] As a preferred embodiment of the present invention, see [link to previous document]. Figure 4 The aforementioned multi-stage gradient liquid distribution manifold layer 2 is integrated on the upper surface of the substrate heat-conducting layer 1, and the overall structure is a 3-4 stage progressively branching and tapering flow channel configuration, divided into a primary main channel 21, a secondary branch channel 22, and a tertiary capillary channel 23; the primary main channel 21 extends from the edge liquid inlet to the center, and the flow cross-section is 8-10 mm. 2 Gradually shrink to 2~3 mm 2 Secondary branch channels 22 branch laterally from the primary channel, with branch angles ranging from 20° to 60° and cross-sections ranging from 2 to 3 mm. 2 Gradually shrink to 0.5~1 mm 2 The tertiary capillary channels 23 are densely distributed in the gaps between the secondary channels, and the bottom cross-section of the porous area at the end of the tertiary capillary channels 23 is 0.2~0.5 mm. 2 The depth of all flow channels is 0.5~1 mm, and the width of the flow channels decreases linearly from the outer periphery to the center at a ratio of 1.2:1, so as to achieve a coolant distribution deviation of ≤8% in each branch.

[0031] As a preferred embodiment of the present invention, see [link to previous document]. Figure 5 The aforementioned variable-aperture, graded vapor separation porous core 3 is integrally formed above the manifold layer. The aforementioned central dual-scale nested porous region is made of gradient functional material 5, which is divided into four continuously gradient components along the thickness direction from the heat source surface: the chip bonding interface layer 51 (thickness of 0~0.5 mm) is a Cu-Mo alloy with a Mo content of 60-65 vol%, CTE = 6.2~6.5 × 10⁻⁶. -6 K -1 Thermal conductivity 180 W·m -1 ·K -1 The intermediate transition layer 52 (thickness 0.5~2 mm) is a Cu-Mo-Cr gradient alloy, with the CTE gradually transitioning to 10.8~11×10⁻⁶. -6 K -1 Thermal conductivity 180~320 W·m -1 ·K -1 The main thermally conductive layer 53 (2-5 mm thick) is made of pure Cu or Cu-Cr, with a CTE ≈ 17 × 10⁻⁶. -6 K -1 Thermal conductivity 380 W·m -1 ·K -1The condensation reinforcement layer 54 is made of Cu-Ni-P superhydrophobic modified material with a contact angle >150°. The gradient functional material substrate is integrally formed by additive manufacturing, and the coefficient of thermal expansion smoothly transitions from the chip surface to the heat dissipation surface, reducing the thermal resistance at the substrate-silicon chip interface to 0.03 cm. 2 ·K·W -1 Within.

[0032] The variable-pore-size graded vapor separation porous core 3 has a central dual-scale nested porous region. The central porous region is composed of large-diameter exhaust steam passages 31 and small-diameter capillary vaporization micropores 32 arranged alternately. The large-diameter channel serves as the main steam exhaust channel, with a pore size of 200~500 μm and a porosity of 40%~60%. The small-diameter micropores serve as liquid phase storage and boiling channels, with a pore size of 50~150 μm and a porosity of 30%~40%. The spatial connectivity between the two types of channels is ≥95%. The inner wall of the channels and the wall of the connecting groove are provided with micron-sized pit vaporization structures 34 to increase the boiling vaporization core.

[0033] As a preferred embodiment of the present invention, see [link to previous document]. Figure 1 The aforementioned top cover assembly 4 has a thickness of 1-3mm and is arranged in 3-5 units. φ =5~8mm Steam outlet 41, total opening area ≥ total area of ​​all liquid replenishment ports.

[0034] As a preferred embodiment of the present invention, the internal circulating coolant of the cold plate is any one of deionized water, ethylene glycol aqueous solution, or R1234ze(E), with a boiling point of 50-100°C.

[0035] The specific steps of the above-mentioned radial liquid distribution-axial vapor separation topological coupling type gradient porous two-phase cold plate are as follows: Step S1, Structural parameter design: Targeting 500 W·cm -2 SiC power module customized parameters: The liquid distribution manifold adopts a 4-stage bifurcation configuration, with the first-stage main channel having a cross-section of 9 mm. 2 Shrinking towards the center to 2.5 mm 2 The secondary branch bifurcation angle is 45° and the cross-section is 2.5 mm. 2 Shrink to 0.8 mm 2 The cross-section of the three-stage guide channel is 0.3 mm. 2 The flow channel depth is 0.8 mm, and the width reduction factor is 1.2:1; the porous core has macropores of 300 μm (50% porosity) and micropores of 100 μm (40% porosity), with a pit diameter of 10 μm and a surface density of 5×10⁻⁶. 7 pcs / cm 2 The interface layer has a molybdenum content of 60 vol%, and the intermediate transition layer has a thermal expansion of 6.5 × 10⁻⁶. -6 K -1 Gradient to 11×10 -6 K-1 Deionized water is used as the circulating medium.

[0036] Step S2, 3D model building: Construct a 50 mm × 50 mm × 8 mm 3D model of the whole machine. The manifold guide channel and the core connecting channel are precisely connected. The overall channel connectivity rate is 96%, with no fluid dead zones.

[0037] Step S3: Integrated additively formed substrate thermally conductive layer 1, multi-stage gradient liquid distribution manifold layer 2, variable pore size graded vapor distribution porous core 3: LPBF. Equipment parameters: laser 300 W, scanning 600 mm·s. -1 With a layer thickness of 40 μm, Cu-Mo, Cu-Mo-Cr, pure Cu, and Cu-Ni-P powders were successively replaced and printed layer by layer, resulting in a density of 99.7% after molding.

[0038] Step S4: Machining of wall micro-pits for large-diameter exhaust holes 31 and small-diameter capillary vaporization micro-holes 32: Femtosecond laser 400 fs, power 1.5 W, travel speed 100 mm·s -1 The preparation of the micron-depression vaporization structure 34 was completed.

[0039] Step S5, Magnetothermal Post-treatment: Magnetize at 0.5 T / 10 Hz for 15 min; 5 J laser shock 3 times, residual compressive stress on the surface layer -400 MPa, grain refinement to 150 nm.

[0040] Step S6, Sealing Assembly: First, install a fluororubber sealing ring between the outer edge of the annular connecting groove (33) and the top cover assembly (4); polish the substrate heat source contact surface, and the roughness Ra after polishing is 0.6 μm; then heat at 420℃ for 2×10 -5 Brazing and heat preservation under vacuum for 70 min completes the metallurgical airtight seal between the top cover assembly (4) and the upper edge of the variable aperture graded steam distribution porous core (3).

[0041] Actual product test results: Maximum temperature difference of the chip ≤ 2.5℃, overall thermal resistance 0.07 cm. 2 ·K·W -1 Critical heat flux density: 1200 W·cm -2 With a pump consumption of 0.025 W, it can operate for a long time without drying out or clogging, and its vibration resistance meets the standards for use in vehicle-mounted electronic control systems.

[0042] The core innovation of this invention lies in its unique topological coupling of radial liquid distribution and axial vapor distribution, multi-layer continuous gradient thermal matching, and integrated additive post-processing. This approach overcomes various inherent defects in existing heat dissipation methods through synergistic optimization of flow field and materials. The fabrication process focuses on controlling four key parameters: multi-material powder feeding ratio, laser processing, femtosecond pit morphology, and vacuum brazing temperature range. During assembly, nano-silver solder paste can be used on the heat source surface to further reduce the thermal resistance of the assembly contact.

[0043] In summary, this invention, relying on a unique topological coupling structure and gradient material design, balances uniform flow, uniform temperature, efficient two-phase boiling, and adaptive flow conversion, achieving a flow rate of 500 W·cm⁻¹. -2 The above-mentioned third-generation semiconductor devices provide lightweight and highly reliable heat dissipation solutions, with broad prospects for engineering applications.

[0044] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related system fields, are similarly included within the scope of protection of the present invention.

Claims

1. A radial liquid distribution-axial vapor separation topologically coupled gradient porous two-phase cold plate, characterized in that: From bottom to top, it includes a base heat-conducting layer (1), a multi-level gradient liquid distribution manifold layer (2), a variable pore size graded vapor distribution porous core (3), and a top cover assembly (4). The lower surface of the thermally conductive base layer (1) is the heat source bonding surface, and the upper surface is provided with an annular connecting groove (33). The thermally conductive base layer (1) is provided with a number of liquid phase supply ports (11), and each liquid phase supply port (11) is connected to the annular connecting groove (33). The multi-stage gradient liquid distribution manifold layer (2) is disposed on the upper surface of the base heat-conducting layer (1) and located in the annular connecting groove (33). The multi-stage gradient liquid distribution manifold layer (2) is provided with multi-stage progressively branching and tapering flow channels. The cross-section of the outermost flow channel gradually narrows from the outside to the center. The outermost flow channel is connected to the annular connecting groove (33). The variable aperture graded vapor distribution porous core (3) is located at the center of the multi-stage gradient liquid distribution manifold layer (2). The variable aperture graded vapor distribution porous core (3) is made of gradient functional material (5). The gradient functional material (5) includes a chip bonding interface layer (51), an intermediate transition gradient layer (52), a main heat-conducting layer (53), and a condensation strengthening layer (54) arranged from bottom to top. The gradient functional material (5) has a porous region, which includes large-diameter exhaust steam through holes (31) and small-diameter capillary vaporization micropores (32) arranged alternately in the axial direction. The walls of the large-diameter exhaust steam through holes (31) and small-diameter capillary vaporization micropores (32) are provided with micron-sized pit vaporization structures (34). The bottom of the large-diameter exhaust steam through holes (31) and small-diameter capillary vaporization micropores (32) are connected to the flow channel of the multi-stage gradient liquid distribution manifold layer (2). The top cover assembly (4) is sealed and covered on the variable aperture graded steam distribution porous core (3), and a steam outlet (41) is opened on the upper part of the top cover assembly (4). The base heat-conducting layer, the multi-stage gradient liquid distribution manifold layer and the variable aperture graded steam distribution porous core are integrally formed. The coolant is distributed radially from the liquid phase supply port (11) through the multi-stage gradient liquid distribution manifold layer (2) to the center. After boiling and generating steam in the variable aperture graded steam distribution porous core (3), it is discharged axially from the steam outlet (41).

2. The cold-rolled plate according to claim 1, characterized in that: The base heat-conducting layer (1) is also provided with an annular retaining ring. The bottom edge of the top cover assembly (4) is connected to the upper surface of the multi-stage gradient liquid distribution manifold layer (2). The annular connecting groove (33) is located between the annular retaining ring and the outer edge of the top cover assembly (4). A sealing ring is provided between the annular connecting groove (33) and the outer edge of the top cover assembly (4).

3. The cold-rolled plate according to claim 1, characterized in that: The multi-stage flow channels of the multi-stage gradient liquid distribution manifold layer (2) include a primary main flow channel (21), a secondary branch flow channel (22) and a tertiary capillary flow channel (23), with a bifurcation angle of 20-60°; The cross-section of the primary main channel (21) is 8-10 mm. 2 Gradually shrink to 2-3 mm 2 The cross-section of the secondary branch channel (22) is 2-3 mm. 2 Gradually shrink to 0.5-1 mm 2 The three-stage capillary channel (23) has a cross-section of 0.2-0.5 mm. 2 The total flow channel depth is 0.5-1 mm, and the branch flow distribution deviation is ≤8%.

4. The cold-rolled plate according to claim 1, characterized in that: The large-aperture exhaust pores (31) have a diameter of 200-500 μm and a porosity of 40%-60%; the small-aperture capillary vaporization micropores (32) have a diameter of 50-150 μm and a porosity of 30%-40%; the micron-sized pit vaporization structures (34) have a diameter of 5-20 μm, a depth of 3-8 μm, and an areal density of 10. 6 -10 8 pcs / cm 2 .

5. The cold-rolled plate according to claim 1, characterized in that: The chip bonding interface layer (51) is a 0-0.5 mm Cu-Mo alloy with a Mo content of 60-65 vol% and a CTE of 6.2-6.5 × 10⁻⁶. -6 K -1 The intermediate transition layer (52) is a Cu-Mo-Cr gradient alloy of 0.5-2 mm, with a smooth CTE transition to 10.8-11×10⁻⁶. -6 K -1 The main heat-conducting layer (53) is 2-5 mm of pure Cu or Cu-Cr alloy, with a CTE of approximately 17 × 10⁻⁶. -6 K -1 The condensation reinforcement layer (54) is made of Cu-Ni-P superhydrophobic material with a contact angle of >150°.

6. The cold-rolled plate according to claim 1, characterized in that: The number of steam outlets (41) is 3 to 5, the diameter of a single hole is 5 to 8 mm, and the total flow area is ≥ the total area of ​​all liquid phase supply ports; the annular connecting groove (33) has a width of 1 to 2 mm and a depth of 0.5 to 1 mm.

7. The cold-rolled plate according to claim 1, characterized in that: The coolant used is a low-GWP environmentally friendly coolant.

8. A method for additive manufacturing of a cold plate as described in any one of claims 1 to 7, characterized in that: S1. Parameter design: Determine the material specifications of the multi-stage gradient liquid distribution manifold layer (2), the variable pore size graded vapor separation porous core (3), and the gradient functional material (5) and select the coolant; S2. 3D Modeling: Partitioned modeling ensures full connectivity of the flow channels with no dead zones; S3, Integrated additive manufacturing: The multi-material LPBF equipment is used to integrally form the base heat-conducting layer (1), the multi-level gradient liquid distribution manifold layer (2), and the variable pore size graded vapor distribution porous core (3). Process parameters are set in zones, and each structure is formed layer by layer. S4. Micro-pit fabrication of the hole wall: Micro-pit vaporization structure is fabricated on the inner wall of the porous area using femtosecond laser processing equipment (34). S5. Magnet-thermal synergistic post-processing: Pulse magnetization and laser shock strengthening are performed sequentially. S6. Interface treatment and sealing assembly: Polish the heat source bonding surface and seal the top cover assembly (4) with the upper edge of the variable aperture graded steam distribution porous core (3) by vacuum brazing.

9. The preparation method according to claim 8, characterized in that: In step S3, The process parameters for the multi-material LPBF equipment are: laser power of 280-350W, scanning speed of 500-800mm / s, layer thickness of 30-50μm, printing accuracy of ±50μm, and relative density of the structure after molding ≥99.5%.

10. The preparation method according to claim 8, characterized in that: In step S5, the pulse magnetization treatment time is 15-20 min; the number of laser shocks is 2-3; in step S5, the vacuum brazing temperature is 400-450℃, and the vacuum degree is ≥1×10 -5 Pa, heat preservation time 60-90min, roughness Ra≤0.8μm after polishing of the heat source bonding surface.

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