Short-period, low-cost and high-performance copper alloy and preparation method thereof

Abstract

The invention discloses a short-period, low-cost and high-performance copper alloy and a preparation method thereof, and belongs to the technical field of copper alloy materials. The preparation method comprises the following steps: preparing CuCrNb alloy powder by adopting a gas atomization method; the alloy powder is subjected to 3DP glue spraying printing treatment, and a copper alloy framework is obtained; sequentially carrying out vacuum sintering treatment and hot isostatic pressing treatment on the copper alloy framework to obtain an initial product; and after the initial product is subjected to finish machining, the copper alloy which is short in period, low in cost and high in performance is obtained. According to the method, one-time forming of parts with complex internal structures is achieved through the 3DP glue spraying and printing technology, multiple machining steps in the traditional forging and machining process are avoided, and the material utilization rate is greatly increased; compared with an existing additive manufacturing technology, the manufacturing efficiency is further improved, and the manufacturing cost is greatly reduced; and meanwhile, the novel high-temperature-resistant CuCrNb alloy is adopted, so that the problem of poor thermal stability of the traditional copper alloy is effectively solved.

Description

Technical Field

[0001] This application belongs to the field of copper alloy materials technology, specifically relating to a short-cycle, low-cost, high-performance copper alloy and its preparation method. Background Technology

[0002] Copper alloys, with their excellent thermal conductivity, are widely used in the field of liquid rocket engines and are key materials for manufacturing heat-bearing components. In recent years, with the development of additive manufacturing technology, the application scope of copper alloys has been further broadened, enabling the direct molding of components with complex internal structures, providing a new technological path for the manufacturing of complex components in the aerospace field.

[0003] However, with the continuous increase in the carrying capacity requirements of space rockets, more stringent requirements have been placed on the performance, cost, and manufacturing cycle of engines. On the one hand, the high-temperature resistance of heat-bearing components needs to be further improved to adapt to the harsher working environment of the engines. On the other hand, manufacturing costs need to be reduced and the manufacturing cycle shortened while ensuring performance, thereby improving product delivery efficiency. This presents new challenges to high-performance copper alloys and their manufacturing processes.

[0004] In existing technologies, traditional copper alloys (such as CuCrZr and CuCr) have good thermal conductivity, but they are prone to softening and deformation at high temperatures, making it increasingly difficult to meet the high-temperature resistance requirements of heat-bearing components in the aerospace field. Regarding manufacturing processes, for components with complex internal structures, traditional manufacturing processes (such as casting, forging, and machining) suffer from low material utilization, long manufacturing cycles, and high costs. While additive manufacturing significantly improves material utilization and shortens the manufacturing cycle through layer-by-layer accumulation, it still has significant limitations: to ensure the printing quality of complex and precision components, the printing layer thickness and printing speed must be controlled, resulting in a long overall printing time; simultaneously, it places extremely high demands on the stability of the printing equipment, increasing equipment costs; and if cracks appear on the printed surface, subsequent hot isostatic pressing cannot achieve effective densification, leading to extremely high scrap costs.

[0005] In summary, existing copper alloy materials and manufacturing processes cannot simultaneously meet the requirements of "high performance, low cost, and short cycle" for aerospace liquid rocket engines. There is an urgent need to develop a copper alloy manufacturing method that can take into account the above requirements. Summary of the Invention

[0006] The purpose of this application is to provide a short-cycle, low-cost, high-performance copper alloy and its preparation method. Through innovative material design and process optimization, the manufacturing cycle can be significantly shortened and the manufacturing cost reduced while ensuring the high performance of the copper alloy.

[0007] To achieve the above objectives, this application provides a method for preparing a short-cycle, low-cost, high-performance copper alloy, comprising the following steps: CuCrNb alloy powder was prepared by gas atomization. The alloy powder was processed by 3DP spray printing to obtain a copper alloy skeleton; The copper alloy skeleton was subjected to vacuum sintering and hot isostatic pressing in sequence to obtain the initial product. After refining the initial product, a short-cycle, low-cost, high-performance copper alloy is obtained.

[0008] Furthermore, the CuCrNb alloy powder contains 1.6wt%~6.5wt% Cr, 1.5wt%~5.8wt% Nb, and the balance is copper. Preferably, the atomic ratio of Cr to Nb is 2:1.

[0009] Furthermore, the process of preparing CuCrNb alloy powder using the gas atomization method includes: Weigh out high-purity oxygen-free copper and chromium-niobium master alloy as raw materials; The raw material is induction melted at a temperature of 1600℃~1800℃ under an inert atmosphere, and then refined for 20min~40min to obtain the melt. The melt was rapidly cooled by gas atomization and then sieved to obtain CuCrNb alloy powder with a particle size of 10μm to 50μm; the gas used in the gas atomization method was argon, and the pressure was 4MPa to 6MPa.

[0010] Furthermore, the 3DP spray printing process includes the following steps: The alloy powder is layered and spread, and an adhesive is sprayed onto the surface of the alloy powder for bonding. After drying, a single-layer blank is obtained. Repeat the steps of spreading powder, bonding and drying to obtain the green body.

[0011] Furthermore, the thickness of a single layer of powder is 30μm~100μm, and the powder spreading speed is 10mm / s~50mm / s.

[0012] Furthermore, the adhesive is a polymer adhesive or a silicone-based adhesive, and the adhesive is sprayed using a piezoelectric or thermal foaming nozzle. The sprayed droplet size is 10 pL to 80 pL, the spraying frequency is 1 kHz to 20 kHz, and the mass of the adhesive is 0.5% to 5% of the mass of the alloy powder.

[0013] Furthermore, the drying method is infrared drying or hot air drying, and the drying temperature is 50℃~80℃, and the time is 5s~15s.

[0014] Furthermore, the vacuum sintering process is carried out at a sintering temperature of 850℃~950℃, a sintering time of 8h~15h, and a pressure of 10. -2 Pa~10 -3 Pa.

[0015] Furthermore, the heating temperature of the hot isostatic pressing treatment is 850℃~950℃, the pressure is 120MPa~150MPa, and the holding time is 3h~5h.

[0016] On the other hand, this application also discloses a short-cycle, low-cost, high-performance copper alloy prepared by the above method, wherein the short-cycle, low-cost, high-performance copper alloy has a conductivity of 86% IACS to 88% IACS and a hardness of 90 HBW to 100 HBW.

[0017] In summary, this application has the following advantages: 1. The preparation method provided in this application shortens the forming time through 3DP printing. Vacuum sintering and hot isostatic pressing are combined to reduce unnecessary steps. The overall process is more efficient than traditional processes (melting, casting, forging and machining) and existing additive manufacturing (long printing time), and has the advantage of short cycle.

[0018] 2. The preparation method provided in this application improves material utilization by reducing raw material waste, and the 3DP equipment has low cost. Combined with the two-step densification process, it reduces the scrap rate, thereby comprehensively reducing manufacturing costs and has the advantage of low cost.

[0019] 3. The preparation method provided in this application uses CuCrNb alloy powder, which has better high-temperature resistance than traditional copper alloys. Combined with a fully densified microstructure, it can meet the high-performance requirements of aerospace engines for heat-bearing components. Attached Figure Description

[0020] Figure 1 This is a schematic flowchart illustrating the method for preparing short-cycle, low-cost, high-performance copper alloys provided in this application embodiment.

[0021] Figure 2 This is a schematic diagram of the Cr2Nb precipitate phase formed by Cr and Nb in a copper matrix in an embodiment of this application. Detailed Implementation

[0022] The principles and features of this application are described below with reference to embodiments. The examples are for illustrative purposes only and are not intended to limit the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0023] In existing technologies, traditional copper alloys (such as CuCrZr and CuCr) are prone to softening and deformation at high temperatures, making it difficult to meet the high-temperature resistance requirements of aerospace heat-bearing components. 3DP (Three-Dimensional Printing), also known as Binder Jetting, is a 3D printing technology that uses a nozzle to spray an adhesive to bond powder materials layer by layer. Its core principle is to spray an adhesive (such as silicone) onto the surface of a powder layer, causing the powder particles to adhere to each other and accumulate layer by layer to form a solid structure. It mainly uses powder materials such as ceramics, metals, and plastics, and requires an adhesive to achieve cross-sectional shaping. This application is the first to use 3DP printing technology to manufacture CuCrNb material, offering significant advantages such as low cost, high efficiency, short cycle time, and high performance.

[0024] Based on this, firstly, this application provides a method for preparing short-cycle, low-cost, high-performance copper alloys, such as... Figure 1 As shown, it includes the following steps: S1. CuCrNb alloy powder was prepared by gas atomization.

[0025] This application employs a CuCrNb alloy system. Compared to traditional CuCrZr and CuCr alloys, the introduction of Nb significantly improves the alloy's high-temperature stability (Nb forms a stable strengthening phase in the copper matrix, hindering grain growth and dislocation migration at high temperatures). This effectively mitigates the high-temperature softening defects of traditional copper alloys, enhances the material's high-temperature resistance, and meets the high-temperature load-bearing requirements of heat-bearing components in the aerospace field. It solves the problem that traditional copper alloys are prone to softening and deformation at high temperatures, making it difficult to meet the high-temperature performance requirements of aerospace heat-bearing components.

[0026] In a specific embodiment, the CuCrNb alloy powder contains 1.6wt%~6.5wt% Cr and 1.5wt%~5.8wt% Nb, with an atomic ratio of Cr to Nb of 2:1, and the balance being copper. In this application, Cr (chromium) and Nb (niobium) can form a Cr2Nb reinforcing phase in the copper matrix (e.g., Figure 2As shown, the gray phase is Cr2Nb. Under rapid cooling conditions, the CuCrNb alloy can form a fine Cr2Nb phase, which possesses excellent thermodynamic stability and a high elastic modulus, resulting in a significant precipitation strengthening effect. The content ratio of the two elements has been optimized. When the Cr content is too low (<0.8wt%), the amount of strengthening phase is insufficient, making it difficult to improve high-temperature strength; when it is too high (>6.5wt%), it increases manufacturing difficulty and cost, and reduces material plasticity. The Nb content matches the Cr content (atomic ratio 2:1), allowing chromium and niobium to react completely to form the Cr2Nb phase. This avoids hydrogen embrittlement caused by excess niobium in a liquid hydrogen environment, ensuring the alloy maintains a stable strengthening effect above 600℃. Furthermore, within the content range specified in this application, the surface energy and particle morphology of the alloy powder are better suited to the adhesive wetting requirements of 3DP spray printing, avoiding powder agglomeration or uneven bonding due to compositional deviations, and ensuring the forming accuracy of the subsequent printed skeleton.

[0027] In a specific embodiment, the process of preparing CuCrNb alloy powder using gas atomization includes: weighing high-purity oxygen-free copper and chromium-niobium master alloy as raw materials; induction melting the raw materials at a temperature of 1600℃~1800℃ under an inert atmosphere, and refining the melt for 20min~40min to obtain a melt; rapidly cooling the melt using gas atomization, and then sieving to obtain CuCrNb alloy powder with a particle size of 10μm~50μm; the gas used in the gas atomization method is argon, and the pressure is 4MPa~6MPa. In this application, induction melting at 1400℃~1600℃ under an inert atmosphere (such as argon) can effectively avoid the reaction of elements such as copper, Cr, and Nb with oxygen and nitrogen in the air to form oxides or nitrides, ensuring the purity of the melt; at the same time, the electromagnetic stirring effect of induction melting ensures that Cr and Nb elements are evenly distributed in the copper matrix, avoiding component segregation. Secondly, the gas atomization method breaks up the melt through high-speed airflow, achieving rapid solidification, which can suppress the coarse growth of the strengthening phase and form a fine and uniform microstructure. The 10μm~50μm particle size powder obtained by sieving not only meets the requirements of 3DP printing for powder flowability (too small a particle size is prone to agglomeration, while too large a particle size leads to poor interlayer bonding), but also reduces the risk of oxidation during subsequent sintering through a smaller specific surface area, laying the foundation for densification in vacuum sintering.

[0028] In summary, compared with traditional mechanical alloying, the powder prepared by the gas atomization method has higher sphericity (typically >90%), more concentrated particle size distribution, and stronger batch stability, which reduces the quality deviation caused by powder characteristic fluctuations in subsequent 3DP printing.

[0029] S2. The alloy powder is processed by 3DP spray printing to obtain a copper alloy skeleton.

[0030] Traditional processes typically involve multiple steps such as casting, forging, and machining, resulting in low material utilization (significant material waste due to machining) and long manufacturing cycles (time-consuming multi-process transfers). This application utilizes 3DP adhesive spray printing (additive manufacturing technology) to prepare copper alloy skeletons, inheriting the core advantage of additive manufacturing's "layer-by-layer accumulation." This significantly improves material utilization, achieving near-net-shape forming and reducing subsequent machining allowances. Furthermore, it eliminates the need for complex molds, directly forming complex structural parts, thus avoiding the time-consuming multi-process transfers of traditional methods and shortening the overall manufacturing cycle. Existing additive manufacturing methods (such as SLM and EBM) require controlling high and low printing speeds for thin layers to ensure the printing quality of complex and precision components, leading to long overall printing times; they also demand extremely high equipment stability (maintaining high-precision printing parameters), resulting in high equipment costs. This application employs 3DP adhesive spray printing, a type of adhesive jet additive manufacturing, whose process characteristics are more suitable for complex structures. For example, the printing process does not require precise control of high-energy heat sources such as lasers / electron beams. By optimizing adhesive spraying parameters (such as droplet size and spraying frequency), the printing speed can be appropriately increased while ensuring the accuracy of skeleton forming (without strictly limiting excessively thin layers), thus shortening the printing stage time. For example, using 3DP adhesive spraying printing requires less equipment stability than laser / electron beam additive manufacturing, which can reduce equipment procurement and maintenance costs and indirectly shorten the cycle time (e.g., reducing downtime due to equipment failure; for example, there is no need to print dense products, only skeletons that meet the size requirements need to be printed, and density can be achieved through subsequent sintering and hot isostatic pressing).

[0031] In a specific embodiment, the 3DP spray printing process includes the following steps: S201. The alloy powder is layered and spread, an adhesive is sprayed onto the surface of the alloy powder for bonding, and then dried to obtain a single-layer blank.

[0032] Preferably, the single-layer powder layer thickness is 30μm~100μm, and the powder spreading speed is 10mm / s~50mm / s. The 30μm~100μm powder layer thickness of this application is significantly greater than that of laser powder-spread printing (typically 5μm~50μm). Combined with a high powder spreading speed of 10mm / s~50mm / s, it can significantly reduce the total number of printing layers and powder spreading time while ensuring interlayer bonding accuracy, directly improving overall printing efficiency. Simultaneously, this thickness range matches the 10μm~50μm particle size of the alloy powder. Since the powder particle size is smaller than the powder layer thickness, uniform density within the layer can be ensured through particle filling, avoiding excessively large interlayer gaps caused by overly coarse powder. For complex internal structures in the aerospace field (such as irregular flow channels and thin-walled meshes), this powder spreading parameter can both ensure the forming accuracy of fine structures with a thinner thickness (30μm) and accelerate the printing speed of simple areas with a thicker thickness (100μm), achieving on-demand efficiency optimization.

[0033] Preferably, the binder is a polymer binder or a silicone-based binder, and the binder is sprayed using a piezoelectric or thermal foaming nozzle. The sprayed droplet size is 10 pL to 80 pL, the spraying frequency is 1 kHz to 20 kHz, and the mass of the binder is 0.5% to 5% of the mass of the alloy powder. This application uses a polymer binder or a silicone-based binder, whose molecular chains can form good wetting and adsorption with the surface of CuCrNb alloy powder, avoiding green compact cracking due to insufficient adhesion. Compared to traditional inorganic binders, these organic binders can completely decompose and volatilize during subsequent sintering, leaving no residual impurities that affect the alloy purity. The selection of piezoelectric or thermal foaming nozzles, combined with droplet sizes of 10 pL to 80 pL and spray frequencies of 1 kHz to 20 kHz, enables precise microscopic positioning of the binder. This means the droplet size matches the powder particle size, ensuring that a single droplet covers 1 to 3 powder particles, preventing powder agglomeration due to excessively large droplets or weak adhesion due to excessively small droplets. The high-frequency spraying of 1 kHz to 20 kHz ensures uniform bonding in complex structural details. Simultaneously, the binder mass is controlled at 0.5% to 5% of the alloy powder mass, meeting the green compact strength requirements (preventing breakage during handling) while reducing volatilization during subsequent sintering, thus minimizing porosity defects caused by binder residue.

[0034] Preferably, the drying method is infrared drying or hot air drying, and the drying temperature is 50℃~80℃ for 5s~15s. In this application, the temperature range of 50℃~80℃ is lower than the glass transition temperature of the adhesive, which can avoid premature curing of the adhesive or oxidation of powder particles due to high temperature. At the same time, the uniform heating of infrared / hot air ensures rapid evaporation of moisture in the layer, preventing undried adhesive from contaminating the new powder layer during subsequent powder application. The drying time is matched with the time consumed in the powder application and spraying stages, so as not to prolong the single cycle due to slow drying, ensuring the continuity of the overall printing process, thereby further consolidating the short cycle advantage of the 3DP process.

[0035] S202, the steps of repeated powder spreading, bonding, and drying are used to obtain the green body. This application forms the green body through repeated powder spreading, bonding, and drying steps. This cyclical process can be fully automated through program presets, avoiding human error. For aerospace components with complex internal structures, the parameters of each layer (such as powder thickness and binder spraying density) can be dynamically adjusted according to structural characteristics (such as reducing droplet size in thin-walled areas and increasing powder spreading speed in thick-walled areas), maximizing production efficiency while ensuring forming quality, and providing a stable process foundation for the large-scale production of complex and precision components.

[0036] S3. The copper alloy skeleton is subjected to vacuum sintering and hot isostatic pressing in sequence to obtain the initial product.

[0037] Existing additive manufacturing technologies, if cracks appear on the printed surface, will prevent subsequent hot isostatic pressing (HIP) from achieving densification, leading to the direct scrapping of parts and incurring extremely high costs. This application employs a synergistic approach of vacuum sintering and HIP. Vacuum sintering pre-densifies the porous 3DP-printed skeleton (reducing porosity and microcracks through particle diffusion welding), lowering the risk of surface and internal cracking. Subsequent HIP further eliminates residual porosity under high temperature and pressure, achieving complete densification. Even if the printed skeleton has a few minor defects, the pretreatment by vacuum sintering ensures proper densification during HIP, significantly reducing the probability of scrapping due to cracks and minimizing the cost of high-value materials and initial processing.

[0038] In a specific embodiment, the sintering temperature of the vacuum sintering treatment is 850℃~950℃, the sintering time is 8h~15h, and the pressure is 10. -2 Pa~10 -3Pa. The temperature range of 850℃ to 950℃ falls within the recrystallization temperature range of copper and is lower than the solidus temperature of CuCrNb alloys. This allows for initial densification through particle diffusion welding, while avoiding skeletal deformation or abnormal grain growth caused by high temperatures. For 3DP-printed green blanks (containing binder residue), this temperature range promotes the complete decomposition and volatilization of organic binders (polymer / silicone-based binders are essentially decomposed at 400℃ to 600℃), reducing porosity defects caused by binder residue. Furthermore, the sintering time of 8h to 15h provides sufficient impetus for atomic diffusion, especially for skeletal structures with complex internal structures, ensuring consistent densification between thick-walled and thin-walled regions and preventing localized porosity due to insufficient diffusion. In addition, CuCrNb alloys exhibit excellent thermal stability; during sintering and hot isostatic pressing, the Cr2Nb phase is uniformly distributed, and neither the Cr2Nb phase nor the grains undergo significant growth, thus preserving the material properties. The entire sintering process takes place in a vacuum environment, which effectively isolates oxygen and prevents the copper alloy from oxidizing at high temperatures, thus ensuring the purity of the skeleton and further avoiding damage to the final performance caused by oxidation inclusions.

[0039] In a specific embodiment, the heating temperature of the hot isostatic pressing (HIP) process is 850℃~950℃, the pressure is 120MPa~150MPa, and the holding time is 3h~5h. The HIP temperature is kept consistent with the vacuum sintering temperature to avoid thermal stress cracking caused by drastic temperature changes. At this temperature, the copper matrix is ​​in a plastic state. Combined with the high pressure of 120MPa~150MPa, the synergistic effect of high-temperature softening and high-pressure densification eliminates the micropores remaining after vacuum sintering, achieving complete densification. Furthermore, the 3h~5h holding time ensures that the pressure is fully transmitted to the internal corners of complex structures (such as irregular flow channels and thin-walled gaps) while avoiding grain coarsening caused by excessively long holding times, achieving a balance between efficiency and performance. For the high density (≥99.9%) required in the aerospace field, this pressure parameter can effectively close micro-cracks that are difficult to eliminate after vacuum sintering, reducing the risk of scrap.

[0040] In summary, this application allows for direct hot isostatic pressing (HIP) without the need for a casing, while still meeting the material density requirements. Sintering aims to improve material density; the 3DP-printed skeleton has low density, and without a casing, HIP cannot achieve densification (due to the presence of through-holes). Only by first improving density (eliminating most defects) can HIP be performed directly without a casing, significantly simplifying the process and greatly improving process stability. The consistent temperature range of both processes avoids stress accumulation caused by thermal cycling, reducing the risk of part deformation. This is particularly suitable for complex and precision components (such as irregularly shaped heat-bearing parts in aerospace engines), ensuring the dimensional accuracy of the final product and reducing subsequent machining allowances and costs. S4. After refining the initial product, a short-cycle, low-cost, high-performance copper alloy is obtained.

[0041] In a specific embodiment, finishing includes processing the outer surface according to the product dimensions to improve accuracy, and also includes processing the internal structure by sandblasting or abrasive flow.

[0042] Secondly, based on a general inventive concept, this application also discloses a short-cycle, low-cost, high-performance copper alloy prepared by the above method, wherein the short-cycle, low-cost, high-performance copper alloy has a conductivity of 86% IACS to 88% IACS and a hardness of 90 HBW to 100 HBW.

[0043] In summary, the short-cycle, low-cost, high-performance copper alloy and its preparation method provided in this application have at least the following advantages: (1) Break through the bottleneck of high temperature resistance of materials to meet the core requirements of aerospace heat-bearing components. Traditional copper alloys such as CuCrZr and CuCr are prone to softening and deformation at high temperatures, making them unsuitable for the high-temperature resistance requirements of aerospace heat-bearing components. This application innovatively employs a novel Cu-Cr-Nb alloy system. By introducing Nb, a more stable strengthening mechanism is constructed—Nb forms the intermetallic compound Cr2Nb within the copper matrix, which is less prone to coarsening at high temperatures. This effectively hinders grain growth and dislocation migration, significantly improving the alloy's high-temperature strength and resistance to softening. Compared to traditional alloys, the high-temperature resistance of the Cu-Cr-Nb alloy is better suited to the extreme operating conditions of aerospace engine heat-bearing components, fundamentally addressing the performance shortcomings of existing alloys.

[0044] (2) The preparation method was reformed, achieving a synergistic effect of efficient forming of complex structures and high material utilization. This application addresses the problems of low material utilization (severe cutting waste) and long cycle time (multi-process flow) in traditional manufacturing (casting, forging, machining), as well as slow printing speed and high equipment cost in conventional additive manufacturing (such as SLM). This application adopts 3DP spray-on printing technology, achieving a dual breakthrough. First, relying on the additive characteristics of 3DP spray-on printing, which involves layer-by-layer additive bonding, parts with complex internal structures can be directly formed in one step, eliminating the need for multi-stage processing and mold dependence in traditional processes. This significantly improves material utilization, bringing it close to near-net-shape forming levels and thus greatly reducing material waste. Second, 3DP spray-on printing achieves interlayer bonding through adhesive spraying, eliminating the need for point-by-point melting from high-energy heat sources such as lasers / electron beams. By optimizing droplet spraying parameters (such as frequency and coverage density), thicker printing layers and higher printing speeds can be used while maintaining forming accuracy, significantly shortening the forming cycle. Simultaneously, its equipment structure and control logic are simpler than laser-based additive manufacturing equipment, with lower stability requirements, directly reducing equipment procurement and maintenance costs.

[0045] (3) The density of the material is improved by combining vacuum sintering and hot isostatic pressing. In the vacuum sintering stage, this application first pre-densifies the loose skeleton printed by 3DP, eliminating some porosity and microcracks through particle diffusion welding, thereby improving density and meeting the requirements of hot isostatic pressing (HIP). During the HIP stage, residual porosity is further eliminated under high temperature and high pressure, achieving a density exceeding 99.9% and simultaneously realizing microstructure homogenization. This "dual densification" mechanism effectively closes micro-defects that may occur during the printing process, avoiding HIP failure caused by surface cracks in traditional additive manufacturing, minimizing the risk of scrap, and significantly controlling overall costs.

[0046] In summary, the preparation method of this application ensures the high-temperature performance of copper alloys through the innovation of the material system, improves the forming efficiency and material utilization of copper alloys through 3DP spray printing, and improves the density of copper alloys through the combination of vacuum sintering and hot isostatic pressing. The synergistic effect of these three factors not only shortens the entire process cycle from powder to finished product, but also optimizes costs by improving material utilization, reducing equipment costs, and reducing scrap risk. The final copper alloy parts produced can meet the stringent requirements of the aerospace field for heat-bearing components in terms of high-temperature resistance and structural complexity, forming a dual advantage in terms of technology and economy.

[0047] The technical solutions described above in this application will be explained in detail below with reference to specific embodiments.

[0048] Example 1 This embodiment provides a short-cycle, low-cost, high-performance copper alloy, which is prepared by the following method: (1) Weigh high-purity oxygen-free copper and chromium-niobium master alloy (Cr 3.1wt%, Nb 2.6wt%, and Cu in the raw materials) according to the mass percentage, and carry out induction melting in a helium atmosphere at 1600℃. After the raw materials are melted, refine for 40 minutes to obtain the melt.

[0049] (2) The melt was rapidly cooled to room temperature by gas atomization to obtain alloy powder. After sieving, 10 μm alloy powder was taken for later use. The gas used in the gas atomization method was argon, and the pressure was 5 MPa.

[0050] (3) The alloy powder is processed by 3DP spray printing according to the product drawings to obtain the copper alloy skeleton. The 3DP spray printing process includes the following steps: The powder is evenly spread on the forming platform using a scraper or roller, with a typical spreading speed of 10 mm / s and a powder layer thickness of 30 μm.

[0051] Use a piezoelectric or thermal foaming nozzle to spray the binder (such as polymer or silicone-based), with a droplet size of 10 pL; the binder content is approximately 0.5% of the powder weight, and the spraying frequency is 1 kHz.

[0052] After bonding, the material is dried by infrared or hot air (at 50°C for 15 seconds) to prevent interlayer deformation and obtain a single-layer blank.

[0053] Repeat the steps of powder spreading, bonding and drying to obtain a green blank of copper alloy skeleton.

[0054] (4) The green blank of the copper alloy skeleton is subjected to a temperature of 850°C for 10 minutes. -2 Vacuum sintering at a pressure of Pa for 15 hours resulted in a product density exceeding 95%.

[0055] (5) The product that has undergone vacuum sintering is subjected to hot isostatic pressing at 850°C and 120MPa, and the initial product is obtained after holding the pressure for 5 hours.

[0056] (6) The outer surface is processed according to the product size, and the internal structure can be treated by sandblasting or abrasive flow to obtain copper alloy.

[0057] Example 2 This embodiment provides a short-cycle, low-cost, high-performance copper alloy, which is prepared by the following method: (1) Weigh high-purity oxygen-free copper and chromium-niobium master alloy (Cr 3.4wt%, Nb 3.0wt%, and Cu in the raw materials) according to the mass percentage, and carry out induction melting in a helium atmosphere at 1700℃. After the raw materials are melted, refine for 30 minutes to obtain the melt.

[0058] (2) The melt was rapidly cooled to room temperature by gas atomization to obtain alloy powder. After sieving, the alloy powder with a diameter of 30 μm was taken for later use. The gas used in the gas atomization method was argon, and the pressure was 5 MPa.

[0059] (3) The alloy powder is processed by 3DP spray printing according to the product drawings to obtain the copper alloy skeleton. The 3DP spray printing process includes the following steps: The powder is evenly spread on the forming platform using a scraper or roller, with a typical spreading speed of 30 mm / s and a powder layer thickness of 50 μm.

[0060] Use a piezoelectric or thermal foaming nozzle to spray the binder (such as polymer or silicone-based), with a droplet size of 50 pL; the binder content is approximately 2% of the powder weight, and the spraying frequency is 1 kHz.

[0061] After bonding, the material is dried by infrared or hot air (at a temperature of 60°C for 5 seconds) to prevent interlayer deformation and obtain a single-layer blank.

[0062] Repeat the steps of powder spreading, bonding and drying to obtain a green blank of copper alloy skeleton.

[0063] (4) The green blank of the copper alloy skeleton is subjected to a temperature of 900℃ for 10 minutes. -2 Vacuum sintering under pressure of Pa for 10 hours resulted in a product density of over 95%.

[0064] (5) The product that has undergone vacuum sintering is subjected to hot isostatic pressing at 900℃ and 130MPa, and the pressure is maintained for 4 hours to obtain the initial product.

[0065] (6) The outer surface is processed according to the product size, and the internal structure can be treated by sandblasting or abrasive flow to obtain copper alloy.

[0066] Example 3 This embodiment provides a short-cycle, low-cost, high-performance copper alloy, which is prepared by the following method: (1) Weigh high-purity oxygen-free copper and chromium-niobium master alloy (Cr 3.2wt%, Nb 2.8wt%, and Cu in the raw materials) according to the mass percentage, and carry out induction melting in a helium atmosphere at 1800℃. After the raw materials are melted, refine for 20 minutes to obtain the melt.

[0067] (2) The melt was rapidly cooled to room temperature by gas atomization to obtain alloy powder. After sieving, 50 μm alloy powder was taken for later use. The gas used in the gas atomization method was argon, and the pressure was 5 MPa.

[0068] (3) The alloy powder is processed by 3DP spray printing according to the product drawings to obtain the copper alloy skeleton. The 3DP spray printing process includes the following steps: The powder is evenly spread on the forming platform using a scraper or roller, with a typical spreading speed of 50 mm / s and a powder layer thickness of 100 μm.

[0069] Use a piezoelectric or thermal foaming nozzle to spray the binder (such as polymer or silicone-based), with a droplet size of 80 pL; the binder content is approximately 5% of the powder weight, and the spraying frequency is 2 kHz.

[0070] After bonding, the material is dried by infrared or hot air (at 80°C for 10 seconds) to prevent interlayer deformation and obtain a single-layer blank.

[0071] Repeat the steps of powder spreading, bonding and drying to obtain a green blank of copper alloy skeleton.

[0072] (4) The green blank of the copper alloy skeleton is subjected to a temperature of 950°C for 10 minutes. -2 Vacuum sintering at a pressure of Pa for 15 hours resulted in a product density exceeding 95%.

[0073] (5) The product that has undergone vacuum sintering is subjected to hot isostatic pressing at 950°C and 150MPa, and the initial product is obtained after holding the pressure for 5 hours.

[0074] (6) The outer surface is processed according to the product size, and the internal structure can be treated by sandblasting or abrasive flow to obtain copper alloy.

[0075] The copper alloys prepared in Examples 1-3 and copper alloys prepared by conventional processes were subjected to performance tests, and the results are shown in Table 1.

[0076] Table 1

[0077] In Table 1, the traditional processes are laser printing and hot isostatic pressing.

[0078] In summary, the preparation methods of Examples 1-3 of this application can all achieve the maximum degree of densification, thus ensuring consistent matrix continuity and consequently, consistent base strength values. Existing 3D printing copper alloy technologies inevitably suffer from alloy defects, necessitating hot isostatic pressing (HIP). This application achieves the same process effect without melt printing, and its method is lower in cost, higher in efficiency, and more stable.

[0079] Regarding conductivity, traditional laser printing processes introduce internal defects into the material, necessitating hot isostatic pressing (HIP) for 3D-printed copper alloys. However, HIP results in a loss of performance improvement. This application utilizes 3D printing technology, bonding powder with an adhesive to form a green body, followed by vacuum sintering and HIP, achieving the same performance as 3D printing but at a lower cost and higher efficiency.

[0080] In summary, the preparation method of this application has extremely high technological value, including in terms of production efficiency and equipment investment, precise control of scrap risk and cost, and efficient combination of material properties and production process. Firstly, compared with traditional laser powder-laying printing, 3DP spray printing has significant advantages in efficiency and equipment investment, specifically: (1) Order-of-magnitude improvement in printing efficiency: the forming rate of 3DP spray printing can reach 500cm. 3 / h~2000cm 3 / h, while laser powder-spread printing is typically only 5cm. 3 / h~50cm 3The former is 10 to 40 times more efficient than the latter. This high efficiency stems from the fact that 3DP does not require laser point-by-point melting. It achieves interlayer bonding by spraying adhesive as a whole, which greatly shortens the printing cycle of parts while ensuring the forming accuracy of complex structures. It is especially suitable for the short-cycle manufacturing needs of the aerospace field.

[0081] (2) Significant reduction in equipment costs: Entry-level 3DP equipment costs only RMB 1 million to RMB 2 million, while copper alloy laser powder deposition printing (SLM) requires high-power (≥1000W) or even multiple laser systems to overcome the high reflectivity of copper, with a single unit costing RMB 3 million to RMB 5 million, and maintenance costs increasing with the number of lasers. 3DP equipment has a simpler structure and control logic, and lower hardware performance requirements, directly reducing the cost threshold for equipment procurement and long-term operation and maintenance.

[0082] Secondly, due to the high added value of aerospace components, scrapping costs have a significant impact on overall economic efficiency. Therefore, the 3DP spray-on printing method used in this application has unique advantages in reducing scrapping risks. Laser powder-spreading printing requires melting metal powder point by point. If problems such as laser energy fluctuations or uneven powder spreading occur during the process, it can easily lead to printing interruptions or component cracking. For large and complex components, once scrapped, all initial material, time, and equipment investments are lost, resulting in extremely high costs. In contrast, 3DP spray-on printing achieves initial shaping by spraying adhesive, without the need for continuous high-energy heat sources, resulting in stronger process stability. Furthermore, due to its extremely high printing efficiency (500cm), it offers significant advantages. 3 / h~2000cm 3 Even with localized defects, the material and time loss from a single batch of printing is far less than that from laser printing (5cm). 3 / h~50cm 3 (The low efficiency of / h leads to long-term investment). Therefore, the combination of "low risk + high efficiency" in this application significantly reduces the scrapping cost of high value-added aerospace products.

[0083] Thirdly, this application uses high-temperature resistant CuCrNb material. Compared to traditional CuCrZr and CuCr alloys, the introduction of Nb element in CuCrNb alloy forms a high-temperature stable strengthening phase, maintaining high strength and resistance to softening even at temperatures above 600℃. This solves the core problem of easy deformation of traditional copper alloys at high temperatures, meeting the high-temperature resistance requirements of aerospace heat-bearing components. Furthermore, although 3DP spray printing and laser powder-laying printing have different forming principles, both ultimately require hot isostatic pressing (HIP). Under high temperature and pressure, HIP can eliminate internal porosity in parts formed by both processes, achieving a density of over 99.9%. Through diffusion homogenization, the final mechanical properties (such as high-temperature strength and thermal conductivity) are comparable. However, the efficiency and cost of the 3DP process are far superior to those of laser printing, achieving a comprehensive optimization of "high performance, low cost, and short cycle time" while ensuring equivalent performance.

[0084] While specific embodiments of this application have been described in detail, this should not be construed as limiting the scope of protection of this application. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this application.

Claims

1. A method for preparing a short-cycle, low-cost, high-performance copper alloy, characterized in that, Includes the following steps: CuCrNb alloy powder was prepared by gas atomization. The alloy powder was processed by 3DP spray printing to obtain a copper alloy skeleton; The copper alloy skeleton was subjected to vacuum sintering and hot isostatic pressing in sequence to obtain the initial product. After refining the initial product, a short-cycle, low-cost, high-performance copper alloy is obtained.

2. The method for preparing short-cycle, low-cost, high-performance copper alloys according to claim 1, characterized in that, The CuCrNb alloy powder contains 1.6wt% to 6.5wt% Cr, 1.5wt% to 5.8wt% Nb, and the balance is copper.

3. The method for preparing short-cycle, low-cost, high-performance copper alloys according to claim 1, characterized in that, The process of preparing CuCrNb alloy powder by gas atomization includes: Weigh out high-purity oxygen-free copper and chromium-niobium master alloy as raw materials; The raw material is induction melted at a temperature of 1600℃~1800℃ under an inert atmosphere, and then refined for 20min~40min to obtain the melt. The melt was rapidly cooled by gas atomization and then sieved to obtain CuCrNb alloy powder with a particle size of 10μm to 50μm; the gas used in the gas atomization method was argon, and the pressure was 4MPa to 6MPa.

4. The method for preparing short-cycle, low-cost, high-performance copper alloys according to claim 1, characterized in that, The 3DP spray printing process includes the following steps: The alloy powder is layered and spread, and an adhesive is sprayed onto the surface of the alloy powder for bonding. After drying, a single-layer blank is obtained. Repeat the steps of spreading powder, bonding and drying to obtain the green body.

5. The method for preparing short-cycle, low-cost, high-performance copper alloys according to claim 4, characterized in that, The thickness of a single layer of powder is 30μm to 100μm, and the powder spreading speed is 10mm / s to 50mm / s.

6. The method for preparing short-cycle, low-cost, high-performance copper alloys according to claim 4, characterized in that, The adhesive is a polymer adhesive or a silicone-based adhesive. The adhesive is sprayed using a piezoelectric or thermal foaming nozzle. The sprayed droplet size is 10 pL to 80 pL, the spraying frequency is 1 kHz to 20 kHz, and the mass of the adhesive is 0.5% to 5% of the mass of the alloy powder.

7. The method for preparing short-cycle, low-cost, high-performance copper alloys according to claim 4, characterized in that, The drying process is performed by infrared drying or hot air drying, with a drying temperature of 50℃~80℃ and a drying time of 5s~15s.

8. The method for preparing short-cycle, low-cost, high-performance copper alloys according to claim 1, characterized in that, The vacuum sintering process is carried out at a sintering temperature of 850℃~950℃, a sintering time of 8h~15h, and a pressure of 10. -2 Pa~10 -3 Pa.

9. The method for preparing short-cycle, low-cost, high-performance copper alloys according to claim 1, characterized in that, The heating temperature for the hot isostatic pressing process is 850℃~950℃, the pressure is 120MPa~150MPa, and the holding time is 3h~5h.

10. A short-cycle, low-cost, high-performance copper alloy, characterized in that, The short-cycle, low-cost, high-performance copper alloy obtained by the preparation method according to any one of claims 1 to 9 has a conductivity of 86% IACS to 88% IACS and a hardness of 90 HBW to 100 HBW.

Images