A copper alloy powder and a method for grafting 3D printing on a diamond copper composite material using the same

Abstract

The application discloses a copper alloy powder and a method for grafting 3D printing on a diamond copper composite material by using the copper alloy powder. The application forms stable carbides (such as TiC and Cr3C2) by adding high-activity elements such as Cr and Ti in copper, forms chemical bonding at the interface between the copper alloy and the diamond, significantly reduces the interface energy, and thus improves the wettability. The addition of the element B can not only improve the product performance, but also compensate for the decrease in thermal conductivity caused by the addition of impurity elements other than copper, and reduce the loss of thermal conductivity caused by the addition of impurities in the grafting part. The copper alloy powder is particularly suitable for grafting 3D printing on a diamond copper composite material with a diamond-copper mixed surface layer to obtain a product with excellent heat transfer performance, such as a 3D printing liquid cooling heat dissipation device.

Description

Technical Field

[0001] This invention relates to the field of grafting 3D printing technology. The invention mentions a copper alloy powder and a method for grafting 3D printing on diamond-copper composite materials using the copper alloy powder. Background Technology

[0002] In today's era of rapid technological development, liquid cooling devices have gradually become a core solution for addressing the heat dissipation problems of high-power chips due to their superior heat dissipation performance. Liquid cooling devices consist of a substrate that contacts the heat source and a fine heat dissipation structure connected to the substrate for contact with the cooling medium. The fine heat dissipation structure rapidly transfers the heat from the substrate to the cooling medium through contact with the cooling medium, thereby quickly cooling the heat-generating components (such as chips).

[0003] The high complexity of the intricate heat dissipation structure in liquid-cooled heat dissipation devices can significantly improve heat dissipation efficiency, but such highly complex structures are difficult to manufacture using traditional industrial methods. In contrast, additive manufacturing technologies such as laser powder melting can overcome the limitations of traditional manufacturing, maximize design freedom, and make it possible to manufacture heat dissipation components with complex internal flow channels and intricate surface structures.

[0004] 3D-printed liquid cooling devices typically utilize 3D printing technology to create a single, integrated heat dissipation unit. However, pure copper has a low thermal conductivity, significantly reducing the heat transfer efficiency of the copper substrate in contact with the heat source. Diamond, on the other hand, possesses extremely high thermal conductivity, reaching up to 2500 W / (m·K), and its coefficient of thermal expansion (CTE) is adjustable, ranging from 4–9 ppm / K. Therefore, a composite material combining diamond and copper can effectively improve heat dissipation efficiency when used as a substrate for liquid cooling devices.

[0005] In existing technologies, traditional diamond-coated copper composite materials used for grafting printing generally consist of a diamond core and a copper sheath covering it. The diamond core has an uneven surface to improve the bonding and stability between the diamond core and the copper sheath. The heat transfer path of traditional diamond-coated copper composite materials includes heat source → copper sheath → diamond core → copper sheath → fine heat dissipation structure for grafting printing → cooling medium. To further improve the heat transfer efficiency of diamond-coated copper composite materials, the coated diamond-coated composite material can be replaced with a diamond-coated copper composite material with a mixed diamond and copper surface layer. For example, the grafting printing surface of the original coated diamond-coated composite material can be polished to expose the diamond protrusions after polishing the copper sheath. This allows heat to be transferred directly from the diamond to the fine heat dissipation structure for grafting printing, thus improving heat transfer efficiency. However, the significant chemical inertness of diamond surfaces results in poor wettability with metallic materials. Wettability refers to the ability of a liquid metal droplet to spread or adhere to a solid surface, and its core lies in the affinity of the liquid for the solid surface, usually quantified by the contact angle. Pure diamond surfaces are primarily composed of nonpolar C-C bonds, exhibiting almost no chemical affinity for metals (such as copper). Copper does not spontaneously form carbides on diamond surfaces and cannot form stable chemical bonds (such as covalent or metal-carbon bonds), leading to extremely weak interfacial bonding. Therefore, copper grafting printing on diamond-copper composite materials with a diamond-copper mixed-state surface presents the problem of reduced adhesion between the substrate and the grafted print. Furthermore, poor interfacial adhesion not only easily leads to cracks but also cuts off the pathway for heat transfer from the substrate to the fine heat dissipation structure. Summary of the Invention

[0006] In view of this, the present invention proposes a copper alloy powder that is suitable as a printing copper powder for grafting printing on diamond-copper composite materials with a diamond-copper mixed state surface. It can improve the wettability between diamond and metal materials and improve the structural stability of grafted printed parts.

[0007] Furthermore, this invention also proposes a method for grafting 3D printing of the aforementioned copper alloy powder onto a diamond-copper composite material having a diamond-copper mixed-state surface.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A copper alloy powder comprising the following components in weight percentage:

[0010] Ti 1.0%~2.5%, Cr 0.5%~1.5%, B 0.1%~0.3%, and the balance Cu.

[0011] In this invention, the purpose of adding Ti is to improve the wettability between diamond and printing copper powder by forming a titanium carbide (TiC) interface layer with diamond. Titanium adsorption and dissolution: Titanium adsorbs on the diamond surface, melts, and spreads (contact angle decreases from >90° to <30°); TiC nucleation and growth (900~1100℃): Titanium atoms react with carbon on the diamond surface to form a TiC nanolayer (approximately tens of nanometers thick). TiC can form good bonds with both diamond and titanium, reducing the interfacial energy. Contact angle change: In a vacuum at 1000℃, the contact angle θ of molten titanium on the diamond surface can decrease from >120° (unreacted) to <20° (after TiC formation). The shear strength of the TiC interface can reach 100~200 MPa, far exceeding that of the unreacted mechanical bond (<50 MPa). In this invention, the addition of non-copper metal elements needs to take into account the thermal conductivity of copper alloys, and excessive addition of Ti will lead to interface brittleness. Therefore, the amount of Ti added is 1.0% to 2.5%, preferably 2.0%.

[0012] Cr is an auxiliary wetting element. Cr significantly reduces interfacial energy and improves wettability by forming Cr3C2 with diamond. Furthermore, Cr can inhibit carbon diffusion at the copper / diamond interface, preventing diamond graphitization. Graphitized diamond exhibits significantly reduced thermal conductivity, making the addition of Cr crucial for ensuring the thermal conductivity of diamond at the grafting interface. However, the amount of Cr used needs strict control. Considering the impact of non-copper metal elements on the thermal conductivity of copper alloys and the mechanical properties of grafted printed products, the Cr content should be controlled between 0.5% and 1.5%, preferably 1.0%.

[0013] In this invention, the carbide layer produced by diamond and Ti and Cr serves as a transition phase, which can also alleviate the thermal expansion coefficient of copper and diamond, reduce residual stress, and enhance the interfacial bonding strength. In 3D printing, the molten copper liquid changes the solid / liquid interfacial tension due to the carbide, making it easier for the molten copper to spread on the diamond surface.

[0014] The addition of boron (B) can form borides (such as TiB2) with Ti / Cr, refining the grains and reducing molten pool boundary cracks, significantly improving the strength and hardness of copper alloys, and also enhancing their corrosion resistance. B can react with impurities such as O and S (forming BO2, B2S3, etc.), reducing impurity segregation at grain boundaries. Furthermore, B can fill interstitial spaces in copper alloys through solid solutions, inhibiting crystal growth and lattice rearrangement, thereby enhancing amorphous formation. This structural change can compensate for the loss of thermal conductivity caused by the addition of impurities in copper. However, excessive B addition is detrimental, as it can lead to excessive boride formation and negatively impact thermal conductivity. Therefore, a suitable amount of B not only improves the hardness and strength of copper alloys but also compensates for the reduction in thermal conductivity caused by the addition of non-copper elements. The optimal B addition amount is 0.1% to 0.3%, preferably 0.2%.

[0015] The method for preparing the above-mentioned copper alloy powder includes the following steps:

[0016] S1. Prepare raw materials

[0017] ;

[0018] S2, Vacuum Induction Melting (VIM) Pre-alloying

[0019] Equipment: Vacuum induction melting furnace (ultimate vacuum ≤10) -3 (Pa, Ar gas protection);

[0020] The charging sequence is as follows: first add Cu and Cr (high melting point), then evacuate and fill with Ar (99.999%).

[0021] Heat to 1300~1400℃ (300℃ above the melting point of Cu), melt for 20~30 minutes to completely melt Cr, add Ti and B (or Cu-B alloy), cool to 1200℃±10℃ and hold for 5~15 minutes (to reduce Ti volatilization), stir electromagnetically (frequency 5~10Hz) to ensure uniform composition, take a sample for spectral analysis (O / N content ≤100 ppm), Ti volatilization loss: compensated by excessive addition (105%~110% of the design value);

[0022] Uniformity of B: B is added by using Cu-B master alloy to avoid B segregation and ensure uniform distribution of B in copper alloy;

[0023] S3, Liquid Metal Processing

[0024] Slag removal: After smelting, let stand for 5 minutes to remove surface oxide slag;

[0025] Overheat control: Adjust the temperature of the molten metal to 1150~1200℃ (the optimal viscosity range for gas atomization).

[0026] S4, gas atomization powder production

[0027] Atomization process: Molten metal flows into the atomization tower through a ceramic guide tube (Al2O3 or BN coated), where high-pressure gas breaks the metal flow into tiny droplets through an annular nozzle; the droplets rapidly cool and solidify within the atomization tower (cooling rate 10). 5 ~10 6 K / s), forming spherical powder.

[0028] Atomization parameters:

[0029] ;

[0030] S5. Powder collection and sieving

[0031] Grading system: cyclone separator + vibrating screen, target particle size range: 15-53 μm.

[0032] Anti-oxidation: The collection tank is filled with Ar for protection, and the powder is directly transferred to vacuum packaging.

[0033] Screen size: 15 μm (lower limit), 53 μm (upper limit) to remove oversized particles (>75 μm) and fine powder (<10 μm).

[0034] The aforementioned copper alloy powder is a printing powder suitable for thermally conductive products, particularly for printing on diamond-copper composite materials with a diamond-copper mixed-state surface. The addition of Ti and Cr improves bonding wettability, and optimization of laser power further enhances the bonding between diamond and copper. This results in a tighter bond between the diamond-copper composite material and the grafting area, reducing the likelihood of cracks and ensuring better continuity and thermal conductivity at the grafting interface. It also prevents delamination at the grafting interface from affecting heat dissipation performance. Specifically, it can be used in the fabrication of liquid-cooled heat dissipation devices, printing intricate heat dissipation structures on diamond-copper composite materials with a diamond-copper mixed-state surface.

[0035] Based on the aforementioned copper alloy powder, this invention also proposes a method for grafting 3D printing onto a diamond-copper composite material with a diamond-copper mixed-state surface, comprising the following steps:

[0036] S1. Prepare a diamond-copper composite plate. The upper surface of the diamond-copper composite plate for grafting is a diamond-copper mixed state surface layer. The flatness requirement of the upper surface is 0.02μm. The diamond area ratio in the plane where the diamond-copper mixed state surface layer is located is 45%~55%, preferably 50%.

[0037] S2. Import the model of the part to be grafted and printed into the software, set the process parameters, and generate the corresponding slice file;

[0038] S3. Place the diamond copper composite plate into the fixed frame of the printing platform and complete the leveling and air washing preparations.

[0039] S4. Start printing. The operation scans the D0 layer slice. If there are no abnormalities, start printing from the D0 layer. The entities and contours of the D0 layer are scanned twice. The entities and contours of the D1 layer and subsequent printing layers are scanned once, until printing is finished.

[0040] The grafting printing process parameters are as follows:

[0041] ;

[0042] Selective Laser Melting (SLM) uses a high-power laser to completely melt metal powder, stacking it layer by layer to form a robust metal part. Contour scanning involves the laser melting along the outer contour (boundary) of the part's cross-section, forming the part's edge contour. Properly setting contour scanning parameters can improve surface quality, reduce the staircase effect for a smoother surface, ensure dimensional accuracy, precisely melt the boundaries, and reduce subsequent machining allowances; it also reduces thermal stress, as contour-priority scanning can alleviate heat accumulation deformation caused by internal solid scanning. Solid scanning refers to the laser filling the area inside the contour, melting the powder through a regular path (such as stripes, checkerboard patterns, spirals, etc.) to form a dense solid structure. Properly setting solid scanning parameters can ensure part density, reduce porosity, improve mechanical properties, and optimize the scanning path (such as rotating interlayer strategies) to improve anisotropy; it also increases efficiency, allowing for high-speed scanning of internal areas and shortening printing time.

[0043] In the above printing method, the solid part and the outline part of the D0 layer are scanned twice to complete the remelting. The two scans can preheat the substrate, reduce the uneven thermal stress between the grafted printing part and the substrate, eliminate the influence of uneven thermal stress on the bonding force between the two parts, and prevent the current printed layer from warping, thus providing a good foundation for the construction of subsequent printed layers. The laser power and scanning speed need to be closely matched to ensure that the Cr / Ti reacts fully but is not excessively burned.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] This invention addresses the problem of poor wettability between diamond and copper affecting bonding performance and thermal conductivity when grafting copper structures onto diamond-copper composite materials with a diamond-copper mixed surface in 3D printing. By adding highly reactive elements such as Cr and Ti to the copper, stable carbides (e.g., TiC, Cr3C2) are generated, forming chemical bonds at the copper alloy-diamond interface, significantly reducing interfacial energy and improving wettability. Furthermore, the addition of boron not only enhances product performance (e.g., strength, hardness, and corrosion resistance) but also compensates for the reduction in thermal conductivity caused by the addition of non-copper metal impurities, minimizing the thermal conductivity loss in the grafted section due to impurities. Products obtained using the copper alloy powder of this invention and appropriate printing parameters exhibit excellent thermal and mechanical properties: thermal conductivity > 500 W / mK, shear strength at the grafted interface > 150 MPa, and graphitization rate of the diamond surface < 5%. Attached Figure Description

[0046] Figure 1 This is a side view of the diamond-copper composite material of the present invention.

[0047] Figure 2 This is a schematic diagram of the grafting surface of the diamond-copper composite material of the present invention (the regular hexagon in the figure represents diamond). Detailed Implementation

[0048] To enable those skilled in the art to understand the present invention more clearly and intuitively, the present invention will be further described below with reference to the accompanying drawings.

[0049] Example 1

[0050] This embodiment utilizes a grafting printing method to produce a liquid-cooled heat dissipation device with a copper substrate and a fine copper heat dissipation structure. To improve the thermal conductivity of the liquid-cooled heat dissipation device, the upper surface of the copper substrate used for grafting printing is designed as a diamond-copper composite material with a diamond-copper mixed-state surface layer (e.g., diamond-copper composite material). Figure 1 and 2 As shown in the figure), a fine heat dissipation structure is then grafted and 3D printed. To improve the wettability of the copper-diamond interface, the composition and mass percentage of the copper alloy powder used in this embodiment are as follows:

[0051] Ti 2.0%, Cr 1.0%, B 0.2%, and the balance Cu.

[0052] The method for preparing the copper alloy powder in this embodiment is as follows:

[0053] Prepare raw materials according to the requirements of copper alloys. Among them, Ti element has volatilization loss, which can be compensated by adding an excess (105% of the design value).

[0054] Pre-alloying is performed using a vacuum induction melting furnace (ultimate vacuum ≤10). -3 Under Pa and Ar gas protection, the charging sequence is as follows: first add Cu and Cr (high melting point), then evacuate and fill with Ar (99.999%); heat to 1300℃ (300℃ above the melting point of Cu), melt for 30 minutes to completely melt Cr, add Ti and Cu-B alloy, cool to 1200℃ and hold for 10 minutes (to reduce Ti volatilization), and use electromagnetic stirring (frequency 5Hz) to ensure uniform composition. Take a sample for spectral analysis (O / N content ≤100 ppm).

[0055] After melting, let stand for 5 minutes to remove surface oxide residue, and then adjust the temperature of the molten metal to 1150℃ before gas atomization powdering.

[0056] Atomization process: Molten metal flows into the atomization tower through a ceramic guide tube (Al2O3 or BN coated), where high-pressure gas breaks the metal flow into tiny droplets through an annular nozzle; the droplets rapidly cool and solidify within the atomization tower (cooling rate 10). 5 ~10 6 K / s), forming spherical powder; atomization parameters:

[0057] ;

[0058] Finally, the powder was collected and sieved to obtain copper alloy powder with a target particle size range of 15-53 μm.

[0059] The specific printing method for liquid-cooled heat dissipation devices is as follows:

[0060] Diamond-copper composite material (with diamond area accounting for 50% of the upper surface) is used as the grafting substrate, and the flatness requirement of the upper surface is 0.02μm;

[0061] Import the model of the fine heat dissipation structure that needs to be printed into the software, set the process parameters, and generate the corresponding slice file;

[0062] Place the substrate into the fixed frame of the printing platform and complete the leveling and air washing preparations.

[0063] Start printing. The operation scans the D0 layer slice. If there are no abnormalities, start printing from the D0 layer. The entities and outlines of the D0 layer are scanned twice. The entities and outlines of the D1 layer and subsequent printing layers are scanned once, until printing is finished.

[0064] The grafting printing process parameters are as follows:

[0065] ;

[0066] The printed liquid-cooled heat dissipation device was subjected to performance tests, including the thermal conductivity of the liquid-cooled heat dissipation device, the shear strength of the grafting interface, and the graphitization rate of the diamond surface.

[0067] Example 2

[0068] The only difference between this embodiment and Embodiment 1 is that the composition and mass percentage content of the copper alloy powder are as follows:

[0069] Ti 1.0%, Cr 1.5%, B 0.1%, and the balance Cu.

[0070] Example 3

[0071] The only difference between this embodiment and Embodiment 1 is that the composition and mass percentage content of the copper alloy powder are as follows:

[0072] Ti 2.5%, Cr 0.5%, B 0.3%, and the balance Cu.

[0073] Example 4

[0074] The only difference between this embodiment and Embodiment 1 is that the surface diamond area ratio of the copper-based diamond composite material is 45%.

[0075] Example 5

[0076] The only difference between this embodiment and Embodiment 1 is that the surface diamond area ratio of the copper-based diamond composite material is 55%.

[0077] Example 6

[0078] The only difference between this embodiment and Embodiment 1 is that the grafting printing process parameters are as follows:

[0079] ;

[0080] Example 7

[0081] The only difference between this embodiment and Embodiment 1 is that the grafting printing process parameters are as follows:

[0082] ;

[0083] To investigate the effect of the amount of non-copper elements added to copper alloy powder on the performance of grafted printed products, the amounts of each component were adjusted to the following comparative example:

[0084] Comparative Example 1

[0085] The only difference between this comparative example and Example 1 is that Ti, Cr, and B elements are not added to the copper; that is, pure copper powder is used for grafting printing. Pure copper does not wet the diamond at the grafting surface, resulting in poor interfacial bonding and a break in thermal conduction. Furthermore, the energy density suitable for copper alloys is lower than that of pure copper, leading to poor forming quality. Pure copper has good thermal conductivity, resulting in faster heat conduction in the molten pool, which indirectly promotes the graphitization of diamond at the interface.

[0086] Comparative Example 2

[0087] The difference between this comparative example and Example 1 is that no Cr element is added to the copper. The composition and mass percentage content of the copper alloy powder are as follows:

[0088] Ti 2.0%, B 0.2% and balance Cu.

[0089] Comparative Example 3

[0090] The difference between this comparative example and Example 1 is that Ti is not added to the copper. The composition and mass percentage content of the copper alloy powder are as follows:

[0091] Cr 1.0%, B 0.2%, and the balance Cu.

[0092] Comparative Example 4

[0093] The difference between this comparative example and Example 1 is that element B is not added to the copper. The composition and mass percentage content of the copper alloy powder are as follows:

[0094] Cr 1.0%, Ti 2.0%, and the balance Cu.

[0095] Comparative Example 5

[0096] The only difference between this comparative example and Example 1 is that the mass percentage content of Ti is reduced to 0.5%. Specifically, the composition and mass percentage content of the copper alloy powder are as follows:

[0097] Ti 0.5%, Cr 1.0%, B 0.2%, and the balance Cu.

[0098] Comparative Example 6

[0099] The only difference between this comparative example and Example 1 is that the mass percentage content of Ti element is increased to 2.8%. Specifically, the composition and mass percentage content of the copper alloy powder are as follows:

[0100] Ti 2.8%, Cr 1.0%, B 0.2%, and the balance Cu.

[0101] Comparative Example 7

[0102] The only difference between this comparative example and Example 1 is that the mass percentage content of Cr element is reduced to 0.4%. Specifically, the composition and mass percentage content of the copper alloy powder are as follows:

[0103] Ti 2.0%, Cr 0.4%, B 0.2%, and the balance Cu.

[0104] Comparative Example 8

[0105] The only difference between this comparative example and Example 1 is that the mass percentage content of Cr element is increased to 1.6%. Specifically, the composition and mass percentage content of the copper alloy powder are as follows:

[0106] Ti 2.0%, Cr 1.6%, B 0.2%, and the balance Cu.

[0107] Comparative Example 9

[0108] The only difference between this comparative example and Example 1 is that the mass percentage content of element B is reduced to 0.05%. Specifically, the composition and mass percentage content of the copper alloy powder are as follows:

[0109] Ti 2.0%, Cr 1.0%, B 0.05%, and the balance Cu.

[0110] Comparative Example 10

[0111] The only difference between this comparative example and Example 1 is that the mass percentage content of element B is increased to 0.4%. Specifically, the composition and mass percentage content of the copper alloy powder are as follows:

[0112] Ti 2.0%, Cr 1.0%, B 0.4%, and the balance Cu.

[0113] Furthermore, to examine the impact of the surface diamond area ratio of the copper-based diamond composite material on the performance of the grafted printed product, the following comparative example was set up:

[0114] Comparative Example 11

[0115] The only difference between this comparative example and Example 1 is that the surface diamond area of ​​the copper-based diamond composite material accounts for 40%. The results show that the surface diamond area is too low, resulting in a larger pure copper area. Although the bonding strength is improved, less heat is transferred through the diamond at the contact interface, leading to lower heat exchange efficiency.

[0116] Comparative Example 12

[0117] The only difference between this comparative example and Example 1 is that the surface diamond area of ​​the copper-based diamond composite material accounts for 60%. The results show that the excessively high surface diamond ratio and insufficient pure copper area, while significantly improving thermal conductivity, result in a marked decrease in interfacial bonding strength, failing to meet application requirements.

[0118] Comparative Example 13

[0119] The only difference between this comparative example and Example 1 is that the copper-based diamond composite material is replaced with a pure copper substrate. The results show that although the bonding strength is much better, the lack of the rapid heat transfer path provided by diamond results in a significant decrease in the product's thermal conductivity.

[0120] Furthermore, to investigate the impact of repeated scanning of solids and contours in layer D0 on the performance of grafted printed products, the following comparative example was set:

[0121] Comparative Example 14

[0122] The only difference between this comparative example and Example 1 is that the D0 layer solid and contour are not scanned repeatedly. The results show that scanning the D0 layer solid and contour only once can slightly avoid the thermal impact of remelting on the diamond on the grafting surface, but the resulting bonding strength is weaker, and the product performance is somewhat reduced.

[0123] Comparative Example 15

[0124] The only difference between this comparative example and Example 1 is that the solid and contour of the D0 layer were scanned three times each. The results show that excessive scanning of the solid and contour of the D0 layer significantly impacts the thermal conductivity of the diamond on the grafting surface, increasing the diamond carbonization rate, affecting thermal conductivity, and causing overheating of the interface, thus affecting the bonding quality.

[0125] In addition, the present invention includes Comparative Example 16, which examines the effect of physical laser power on product performance.

[0126] Comparative Example 16

[0127] The difference between this comparative example and Example 1 is that a solid laser with a power of 250W and a solid scanning speed of 800mm / s was used to print the grafting part. The results show that the solid laser input energy density was too high, resulting in a slight increase in adhesion at the interface. However, the excessive energy caused problems such as molten pool sputtering, leading to poor forming quality and reduced strength in the grafted part. Furthermore, the excessive energy accelerated the graphitization of diamond at the interface, causing a break in heat conduction at the grafting interface.

[0128] Performance test results of liquid-cooled heat dissipation devices obtained by grafting and printing in various embodiments and comparative examples

[0129]

[0130] As can be seen from the results of the various embodiments and Comparative Example 1 in the table above, by replacing the pure copper substrate with copper-based diamond composite material based on grafting 3D printing, the heat dissipation performance of the product is further improved. The main reason is that the grafting interface increases the heat transfer path between the diamond and the copper in the grafted part, which significantly improves the heat transfer effect.

[0131] As can be seen from the results of Example 1 and Comparative Examples 2-4 in the table above, the absence of any one or two elements has a significant impact on performance; in particular, the addition of B can not only significantly improve product performance, but more importantly, it can also compensate for the loss of thermal conductivity caused by the addition of non-copper elements, bringing a significant effect on improving the thermal conductivity of the product.

[0132] The results of Comparative Examples 5-10 show that using Cu-Ti-Cr-B quaternary alloy powder with specific component amounts can provide reaction conditions for Ti, Cr and C elements during the additive manufacturing process by utilizing the molten pool temperature. This enhances the wettability of the interface between diamond and the grafted copper alloy and avoids diamond graphitization, effectively ensuring good bonding of the grafted parts and high thermal conductivity.

[0133] Based on the results of Comparative Examples 11-12 and Example 1 in the table above, a suitable diamond area ratio is beneficial to enhancing interfacial bonding and improving thermal conductivity.

[0134] As can be seen from the results of Comparative Examples 14 and 15 in the table above, the selection of the number of scans for the DO layer needs to consider its thermal effect on diamond and the impact of the preheating effect on the substrate on the bonding strength. Too many or too few scans for the DO layer are not conducive to obtaining products with excellent performance. In addition, as can be seen from the results of Comparative Examples 16 and Examples 6 and 7 in the table above, the selection of laser power has a significant impact on the forming quality of the grafted part and the bonding degree of the grafting interface. Excessive laser power has a very poor effect on the quality and thermal conductivity of the product.

[0135] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. A copper alloy powder, characterized in that, The components include the following components by weight percentage: Ti 1.0%~2.5%, Cr 0.5%~1.5%, B 0.1%~0.3%, and the balance Cu.

2. The copper alloy powder as described in claim 1, characterized in that, The components include the following components by weight percentage: Ti 2.0%, Cr 1.0%, B 0.2%, and the balance Cu.

3. The method for preparing copper alloy powder as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Prepare the raw materials required for copper alloy powder; S2, Vacuum Induction Melting Pre-alloying First, add Cu and Cr raw materials to the vacuum induction melting furnace, evacuate the furnace and then fill it with argon; heat to 1300~1400℃ and melt for 20~30 minutes to completely melt Cr; add Ti and B raw materials, cool to 1200℃±10℃ and hold for 5~15 minutes to reduce Ti volatilization; stir until uniform to obtain molten metal. S3, Liquid Metal Processing Slag removal: Melt and let stand, skim off surface oxide slag; adjust the temperature of the molten metal to 1150~1200℃; S4, gas atomization powder production The molten metal is guided into the atomizing tower through a ceramic guide tube, and high-pressure gas is used to break the metal flow into tiny droplets through an annular nozzle; the droplets are rapidly cooled and solidified in the atomizing tower to form spherical powder; S5. Powder collection and sieving Spherical powders were collected and sieved to obtain copper alloy powders with a target particle size range of 15-53 μm.

4. The application of the copper alloy powder as described in claim 1 or 2 as a printing powder in grafted printing heat transfer devices, wherein the substrate for grafting printing is a diamond-copper composite material with a diamond-copper mixed state surface layer.

5. The application as described in claim 4, characterized in that, The diamond area accounts for 45% to 55% of the diamond-copper mixed surface layer on the grafted printed substrate.

6. The application as described in claim 5, characterized in that, The diamond area accounts for 50% of the diamond-copper mixed surface layer on the grafted printed substrate.

7. The application as described in claim 5, characterized in that, The heat transfer device is a liquid-cooled heat dissipation device, which includes a diamond-copper composite material substrate with a diamond-copper mixed state surface and a grafted printed copper alloy heat dissipation structure.

8. A method for grafting 3D printing based on the copper alloy powder of claim 1 or 2, characterized in that, Includes the following steps: S1. Prepare a diamond-copper composite plate. The upper surface of the diamond-copper composite plate to be grafted is a diamond-copper mixed surface layer. The flatness requirement of the upper surface is 0.02mm±0.01mm. The diamond area ratio in the plane where the diamond-copper mixed surface layer is located is 45%~55%. S2. Import the model of the part to be grafted and printed into the software, set the process parameters, and generate the corresponding slice file; S3. Place the diamond copper composite plate into the fixed frame of the printing platform and complete the preparation work for leveling and air washing. S4. Start printing. The operation scans the D0 layer slice. If there are no abnormalities, start printing from the D0 layer. The entities and contours of the D0 layer are scanned twice. The entities and contours of the D1 layer and subsequent printing layers are scanned once, until printing is finished. The grafting printing process parameters are as follows: 。 9. The grafting 3D printing method as described in claim 8, characterized in that, In the plane containing the diamond-copper mixed surface layer, the diamond area accounts for 50%.

10. A liquid-cooled heat dissipation device, characterized in that, The material is printed using the grafting 3D printing method described in claim 8 or 9, wherein the diamond copper composite material plate is the substrate, and the part grafted and printed using copper alloy powder is a fine heat dissipation structure.

11. The liquid-cooled heat dissipation device as described in claim 10, characterized in that, Thermal conductivity > 500 W / mK, grafting interface shear strength > 150 MPa, and diamond surface graphitization rate < 5%.

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