A method for improving mechanical properties of thin-walled CuCrZr alloy parts manufactured by additive manufacturing

Abstract

The application discloses a method for improving mechanical properties of an additive manufacturing thin-wall CuCrZr alloy part, and comprises the following steps: S1, pretreatment, S2, metal additive manufacturing, and S3, deep cooling treatment; the method is first proposed to combine the deep cooling treatment with the metal additive manufacturing process to cooperatively improve the mechanical properties of the thin-wall CuCrZr alloy part, compared with a traditional solid solution + aging treatment mode in the additive manufacturing, the deep cooling treatment can effectively reduce the deformation of the thin-wall part in the method, and the mechanical properties and the conductivity of the additive manufacturing thin-wall CuCrZr alloy part are significantly improved.

Description

Technical Field

[0001] This invention relates to the fields of powder metallurgy and metal additive manufacturing technology, specifically to a method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts. Background Technology

[0002] CuCrZr alloy is an age-hardening alloy that maintains high strength while retaining excellent electrical and thermal conductivity, thermal stability, and oxidation resistance, making it an important structural material. It is widely used in aerospace and other fields, particularly suitable for heat exchange equipment and components such as rocket engine combustion chamber liners. Traditional casting, forging, machining, and welding techniques for manufacturing thin-walled CuCrZr alloy parts with complex shapes face problems such as high scrap rates and long production cycles. Additive manufacturing can easily produce complex parts that are difficult to form using traditional material processing techniques. However, additive manufacturing of complex-shaped thin-walled CuCrZr alloy parts typically requires solution treatment followed by aging to improve their performance. When dealing with complex shapes such as thin walls, heat treatment can lead to deformation and warping. In contrast, cryogenic treatment achieves the same effect in improving the performance of copper alloy parts without the deformation caused by high-temperature treatment, thus offering unique advantages in improving the performance of additive-manufactured copper alloy parts. Cryogenic treatment significantly improves the room-temperature Vickers hardness of additively manufactured thin-walled CuCrZr alloy parts, increasing the Vickers hardness by 30%. It significantly improves the anisotropy of thin-walled CuCrZr alloy parts, increasing the maximum elongation by about 40% and the tensile strength by about 6%. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts.

[0004] The technical solution of this invention is: a method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts, comprising the following steps:

[0005] S1, Preprocessing

[0006] CuCrZr alloy powder was placed in a vacuum drying oven at 80–120°C for 2–10 hours to obtain CuCrZr alloy particles for later use.

[0007] S2, Metal Additive Manufacturing

[0008] The CuCrZr alloy particles obtained in step S1 were printed layer by layer using a metal additive manufacturing process to melt and solidify them, thereby producing CuCrZr alloy parts with a wall thickness of 0.1 to 10 mm.

[0009] S3, Cryogenic Treatment

[0010] The CuCrZr alloy parts obtained in step S2 are immersed in liquid nitrogen at a temperature of -196℃ for cryogenic treatment for 1 to 10 days. After the treatment is completed, they are dried to obtain thin-walled CuCrZr alloy parts.

[0011] Description: This invention is the first to propose combining cryogenic treatment with metal additive manufacturing to jointly improve the mechanical properties of thin-walled CuCrZr alloy parts. Compared with the traditional solution treatment + aging treatment method in additive manufacturing, this method uses cryogenic treatment to significantly improve the room temperature Vickers hardness of additively manufactured thin-walled CuCrZr alloy parts, increasing the Vickers hardness by about 30%. It also significantly improves the anisotropy of thin-walled CuCrZr alloy parts, increases the maximum elongation by about 40%, and increases the tensile strength by about 6%. At the same time, it does not cause problems such as deformation and warping of parts that require further post-processing.

[0012] Further, in step S1, the CuCrZr alloy powder that meets the requirements comprises, by weight percentage: Cr: 0.5-1.5%, Zr: 0.05-0.25%, O: ≤0.06%, Fe: ≤0.05%, Si: ≤0.05%, P: ≤0.01%, with the balance being Cu and a small amount of unavoidable impurities;

[0013] Note: According to the experimental data, the proportion of each element in CuCrZr alloy powder within the above-mentioned conditions has better mechanical properties, and thin-walled CuCrZr alloy parts with better performance can be prepared.

[0014] Furthermore, the CuCrZr alloy powder has a particle size of 15–106 μm and a purity of 99.9%.

[0015] Note: The above-mentioned limitations on CuCrZr alloy powder can ensure an increase in the absorption rate of the powder to the laser beam during additive manufacturing, further promoting the additive manufacturing reaction and improving the mechanical properties of thin-walled CuCrZr alloy parts.

[0016] Furthermore, the CuCrZr alloy powder is homogenized for 1-2 hours;

[0017] The homogenization process is as follows: 1) First, the CuCrZr alloy powder is divided into three types of powder according to the particle size: 15-35μm, 36-70μm, and 71-106μm, for later use.

[0018] 2) Take CuCrZr alloy powder with a particle size of 15-35 μm and put the grinding balls and CuCrZr alloy powder into a ball mill jar at a ball-to-powder ratio of 2-3:1 to obtain the first mixture; then add the control agent to the ball mill jar at a mass ratio of 1-2:0.5-0.7 of the first mixture to the control agent, evacuate the ball mill jar to a vacuum degree of -0.08 to -0.1 MPa, and place the ball mill jar into a planetary ball mill for grinding for 15-20 min to obtain the first grinding material; the control agent is anhydrous ethanol;

[0019] 3) Add CuCrZr alloy powder with a particle size of 36-70 μm to the first grinding material, and mix them at a ball-to-material ratio of 2-3:1.2-1.4 to obtain a second mixture. Adjust the vacuum degree to -0.08--0.1 MPa again, and continue grinding the second mixture for 15-20 min to obtain the second grinding material. Add CuCrZr alloy powder with a particle size of 71-106 μm to the second grinding material, and mix them at a ball-to-material ratio of 2-3:1.8-2 to obtain a third mixture. Adjust the vacuum degree to -0.08--0.1 MPa again, and continue grinding the third mixture for 15-20 min to obtain the third grinding material.

[0020] 4) Pour out the third grinding material from the ball mill jar to obtain CuCrZr alloy homogenized particles with a particle size of 25-85μm;

[0021] 5) The CuCrZr alloy homogenized particles were sieved using a sieve plate with a particle size of 53 μm to obtain first homogenized particles with a particle size of 25–53 μm and second homogenized particles with a particle size of 53–85 μm.

[0022] Note: The above-mentioned homogenization treatment of CuCrZr alloy can effectively improve the uniformity of CuCrZr alloy powder. By adjusting the ball-to-powder ratio and the synergistic mixing method between various grinding materials, the ball milling effect can be further improved. The shape and size of the metal particles are more uniform, which enhances the homogenization degree of CuCrZr alloy powder, improves the quality of the product, and further improves the mechanical properties of CuCrZr alloy.

[0023] Furthermore, after step 4), the CuCrZr alloy homogenized particles are subjected to a modification treatment;

[0024] The modification treatment method is as follows: CuCrZr alloy homogenized particles are divided into 3 to 5 groups, and laid layer by layer from bottom to top, with each layer being 1 to 3 mm thick. For each layer, 10 to 15 mL / dm is applied to the surface of the CuCrZr alloy homogenized particles. 2A layer of reinforcing agent is sprayed until all the CuCrZr alloy homogenized particles are used up to obtain a mixed powder. Then, the mixed powder is ultrasonically treated at an ultrasonic frequency of 30-50kHz for 15-30 minutes to obtain a modified powder. The reinforcing agent, by mass percentage, includes 45-55% SiC, 8-10% rare earth oxide nitrate, and the balance ethanol.

[0025] Explanation: The above method can improve the absorption rate of CuCrZr alloy and enhance the performance of CuCrZr alloy parts. Silicon carbide can be well dispersed in ethanol solution. With the flow of ethanol, it enters the interior of CuCrZr alloy powder layer, thereby increasing the surface roughness, which allows for multiple laser reflections and improves absorption, significantly enhancing the absorption irradiance of the powder to the laser. Nitric acid oxide rare earth is a mixture prepared by reacting nitric acid and rare earth element oxides. It has strong oxidizing properties. With the flow of ethanol, it is distributed in different positions in each powder layer, which can also improve the surface roughness of the powder layer, further enhancing the absorption irradiance of CuCrZr alloy powder to the laser.

[0026] Furthermore, in step S2, the metal additive manufacturing process is a laser additive manufacturing process or an electron beam powder bed melting process;

[0027] Note: Laser additive manufacturing or electron beam additive manufacturing processes can produce thin-walled CuCrZr alloy parts better than other additive manufacturing methods.

[0028] Furthermore, when printing samples using laser additive manufacturing, the first homogenized particles are selected; the process parameters are: laser power of 200-500W, scanning speed of 200-1000mm / s, melting gap of 50-120μm, and powder layer thickness of 30-100μm.

[0029] Note: Laser printing with a particle size greater than 53μm is difficult to form and has too many defects. The above parameters allow the powder to be fully melted, thereby improving the preparation efficiency of CuCrZr alloy parts.

[0030] Furthermore, when printing samples using electron beam powder bed melting technology, second homogenized particles are selected; the printing process is as follows: CuCrZr alloy particles are laid on a horizontally placed base plate inside the forming chamber, and a vacuum is drawn inside the forming chamber until the vacuum degree of the forming chamber reaches 10. -2 When Pa is reached, start filling with helium and preheat the base plate to 50-500°C. After setting the printing parameters, start printing.

[0031] The printing parameters are: electron beam current of 15-20 mA, scanning speed of 2-6 mm / s, melting gap of 50-100 μm, and powder layer thickness of 50-100 μm;

[0032] Note: Electron beam printing particle size needs to be greater than 53μm; if it is too small, it is easy to blow powder. Preheating the substrate is an effective way to eliminate residual stress in additive manufacturing components. If the energy density of the electron beam is too high, the liquid molten pool may be unstable and defects may occur. If the energy density of the electron beam is too low, the powder may not be fully melted. At the same time, the introduction of inert gas can generate submicroscopic pores during laser processing, which leads to a local increase in the electric field intensity of the laser beam, thereby improving the absorption rate.

[0033] Furthermore, in step S3, the CuCrZr alloy parts are pretreated before cryogenic treatment;

[0034] The pretreatment method is as follows: first, use a shot peening machine to grind the CuCrZr alloy parts for 20-30 minutes, then spray deionized water onto the surface of the CuCrZr alloy parts 3-5 times at a rate of 15-20 mL / time, continue grinding for 15-25 minutes, and finally put them in a refrigerator at -18 to -20℃ for 1-1.2 hours.

[0035] Note: Dry grinding of CuCrZr alloy parts using a shot peening machine followed by wet grinding can improve the efficiency and quality of shot peening, while ensuring residual compressive stress on the surface and deep layers, and extending the service life of the metal workpiece. Placing it in a refrigerator to stand can act as a buffer, preventing rapid temperature changes from affecting the performance of thin-walled CuCrZr alloy parts.

[0036] Furthermore, the parameters of the shot peening device are: a spray angle of 85-95°, a spray distance of 195-205 mm, a spray frequency of 3-5 times, and a travel speed of 15-25 mm / min;

[0037] Note: The experimental results show that using the above parameters to grind CuCrZr alloy parts can effectively remove defects such as burrs, welding slag, sharp corners, dirt and impurities from the workpiece surface, improve the cleanliness of the workpiece surface, and enhance the adhesion of the workpiece surface, so that the workpiece surface can better bond with the treatment liquid, further improving the effect of cryogenic treatment.

[0038] The beneficial effects of this invention are:

[0039] (1) The present invention provides a method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts. The method involves first preparing CuCrZr alloy powder through electron beam or laser additive manufacturing process, and then placing it into liquid nitrogen for cryogenic treatment to improve the mechanical properties of thin-walled CuCrZr alloy parts, thereby avoiding deformation of thin-walled parts caused by aging heat treatment. In the cryogenic treatment process, the precipitation of nano-Cr phase significantly improves the mechanical properties of thin-walled CuCrZr alloy parts, and the electrical conductivity of thin-walled CuCrZr alloy parts is increased with the consumption of solid solution elements.

[0040] (2) The homogenization treatment of CuCrZr alloy powder in this invention can effectively improve the uniformity of CuCrZr alloy powder. By adjusting the ball-to-powder ratio and the synergistic mixing method between various grinding materials, the ball milling effect can be further improved, the homogenization degree of CuCrZr alloy can be enhanced, and the mechanical properties of CuCrZr alloy can be further improved.

[0041] (3) The process of CuCrZr alloy homogenization particle modification in this invention effectively improves the absorption rate of CuCrZr alloy and enhances the performance of CuCrZr alloy parts. Silicon carbide can be well dispersed in ethanol solution. As the ethanol flows into the CuCrZr alloy powder layer, the addition of rare earth oxide nitric acid can further increase the surface roughness, so that the laser is reflected multiple times to improve absorption and significantly improve the absorption irradiance of the powder to the laser. Attached Figure Description

[0042] Figure 1 These are thin-walled CuCrZr alloy samples prepared using electron beam additive manufacturing technology.

[0043] Figure 2 This is a schematic diagram showing the temperature changes over different cryogenic treatment times. Detailed Implementation

[0044] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0045] Example 1

[0046] A method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts includes the following steps:

[0047] S1, Preprocessing

[0048] CuCrZr alloy powder was placed in a vacuum drying oven at 100℃ for 7 hours to obtain CuCrZr alloy particles for later use. The required CuCrZr alloy, by weight percentage, includes Cr: 1%, Zr: 0.12%, O: ≤0.06%, Fe: ≤0.05%, Si: ≤0.05%, P: ≤0.01%, with the balance being Cu and a small amount of unavoidable impurities. The particle size of the CuCrZr alloy is 15-106 μm, and the purity is 99.9%.

[0049] S2, Metal Additive Manufacturing

[0050] The CuCrZr alloy particles obtained in step S1 were printed layer by layer using a metal additive manufacturing process to melt and solidify them, thus producing a CuCrZr alloy part with a wall thickness of 5 mm.

[0051] The metal additive manufacturing process is laser additive manufacturing; when printing samples using laser additive manufacturing, the first homogenized particles are selected; the process parameters are: laser power of 350W, scanning speed of 600mm / s, melting gap of 85μm, and powder layer thickness of 65μm.

[0052] S3, Cryogenic Treatment

[0053] First, the CuCrZr alloy parts were polished with a shot peening device for 25 minutes. Then, deionized water was sprayed onto the surface of the CuCrZr alloy parts 4 times at a rate of 18 mL / time, and polishing continued for 20 minutes. Finally, the parts were placed in a refrigerator at -19℃ and left to stand for 1.1 hours. Then, the obtained CuCrZr alloy parts were immersed in liquid nitrogen at a temperature of -196℃ for deep cryogenic treatment for 5 days. After the treatment, thin-walled CuCrZr alloy parts were obtained. The parameters of the shot peening device were: spray angle of 90°, spray distance of 200 mm, number of sprays of 4, and travel speed of 20 mm / min.

[0054] Example 2

[0055] Unlike Example 1, in step S1, the particles are then placed in a vacuum drying oven at 80°C for 10 hours to obtain CuCrZr alloy particles for later use.

[0056] Example 3

[0057] Unlike Example 1, in step S1, the particles are then placed in a vacuum drying oven at 120°C for 2 hours to obtain CuCrZr alloy particles for later use.

[0058] Example 4

[0059] Unlike Example 1, in step S1, the CuCrZr alloy powder that meets the requirements includes, by weight percentage, Cr: 0.5%, Zr: 0.05%, O: ≤0.06%, Fe: ≤0.05%, Si: ≤0.05%, P: ≤0.01%, with the balance being Cu and a small amount of unavoidable impurities.

[0060] Example 5

[0061] Unlike Example 1, in step S1, the CuCrZr alloy powder that meets the requirements includes, by weight percentage, Cr: 1.5%, Zr: 0.25%, O: ≤0.06%, Fe: ≤0.05%, Si: ≤0.05%, P: ≤0.01%, with the balance being Cu and a small amount of unavoidable impurities.

[0062] Example 6

[0063] Unlike Example 1, in step S1, the CuCrZr alloy powder is homogenized for 1 hour; the homogenization method is as follows:

[0064] 1) First, divide the CuCrZr alloy powder into three types of powder according to particle size: 15-35μm, 36-70μm, and 71-106μm, and set them aside for later use;

[0065] 2) Take CuCrZr alloy powder with a particle size of 15-35μm and put the grinding balls and CuCrZr alloy powder into a ball mill jar at a ball-to-powder ratio of 2:1 to obtain the first mixture; then add the control agent to the ball mill jar at a mass ratio of 1:0.5 of the first mixture to the control agent, evacuate the ball mill jar to a vacuum degree of -0.08MPa, and grind the ball mill jar in a planetary ball mill for 25 minutes to obtain the first grinding material; the control agent is anhydrous ethanol;

[0066] 3) Add CuCrZr alloy powder with a particle size of 36-70 μm to the first grinding material, and mix them at a ball-to-material ratio of 2:1.2 to obtain a second mixture. Adjust the vacuum degree to -0.08 MPa again, and continue grinding the second mixture for 25 min to obtain the second grinding material. Add CuCrZr alloy powder with a particle size of 71-106 μm to the second grinding material, and mix them at a ball-to-material ratio of 2:1.8 to obtain a third mixture. Adjust the vacuum degree to -0.08 MPa again, and continue grinding the third mixture for 25 min to obtain the third grinding material.

[0067] 4) Pour out the third grinding material from the ball mill jar to obtain CuCrZr alloy homogenized particles with a particle size of 25-85μm;

[0068] 5) The CuCrZr alloy homogenized particles were sieved using a sieve plate with a particle size of 53 μm to obtain first homogenized particles with a particle size of 25–53 μm and second homogenized particles with a particle size of 53–85 μm.

[0069] Example 7

[0070] Unlike Example 1, in step S1, the CuCrZr alloy powder is homogenized for 1.5 hours; the homogenization method is as follows:

[0071] 1) First, divide the CuCrZr alloy powder into three types of powder according to particle size: 15-35μm, 36-70μm, and 71-106μm, and set them aside for later use;

[0072] 2) Take CuCrZr alloy powder with a particle size of 15-35μm and put the grinding balls and CuCrZr alloy powder into a ball mill jar at a ball-to-powder ratio of 2.5:1 to obtain the first mixture; then add the control agent to the ball mill jar at a mass ratio of 1.5:0.6 for the first mixture and the control agent, evacuate the ball mill jar to a vacuum degree of -0.09MPa, and grind the ball mill jar in a planetary ball mill for 35 minutes to obtain the first grinding material; the control agent is anhydrous ethanol.

[0073] 3) Add CuCrZr alloy powder with a particle size of 36-70 μm to the first grinding material, and mix them at a ball-to-material ratio of 2.5:1.3 to obtain a second mixture. Adjust the vacuum degree to -0.09 MPa again, and continue grinding the second mixture for 35 min to obtain the second grinding material. Add CuCrZr alloy powder with a particle size of 71-106 μm to the second grinding material, and mix them at a ball-to-material ratio of 2.5:1.9 to obtain a third mixture. Adjust the vacuum degree to -0.09 MPa again, and continue grinding the third mixture for 35 min to obtain the third grinding material.

[0074] 4) Pour out the third grinding material from the ball mill jar to obtain CuCrZr alloy homogenized particles with a particle size of 25-85μm;

[0075] 5) The CuCrZr alloy homogenized particles were sieved using a sieve plate with a particle size of 53 μm to obtain first homogenized particles with a particle size of 25–53 μm and second homogenized particles with a particle size of 53–85 μm.

[0076] Example 8

[0077] Unlike Example 1, in step S1, the CuCrZr alloy powder is homogenized for 2 hours;

[0078] The homogenization process is as follows: 1) First, the CuCrZr alloy powder is divided into three types of powder according to the particle size: 15-35μm, 36-70μm, and 71-106μm, for later use.

[0079] 2) Take CuCrZr alloy powder with a particle size of 15-35μm and put the grinding balls and CuCrZr alloy powder into a ball mill jar at a ball-to-powder ratio of 3:1 to obtain the first mixture; then add the control agent to the ball mill jar at a mass ratio of 2:0.7 of the first mixture to the control agent, evacuate the ball mill jar to a vacuum degree of -0.1MPa, and grind the ball mill jar in a planetary ball mill for 40 minutes to obtain the first grinding material; the control agent is anhydrous ethanol;

[0080] 3) Add CuCrZr alloy powder with a particle size of 36-70 μm to the first grinding material, and mix them at a ball-to-material ratio of 3:1.4 to obtain a second mixture. Adjust the vacuum degree to -0.1 MPa again, and continue grinding the second mixture for 40 min to obtain the second grinding material. Add CuCrZr alloy powder with a particle size of 71-106 μm to the second grinding material, and mix them at a ball-to-material ratio of 3:2 to obtain a third mixture. Adjust the vacuum degree to -0.1 MPa again, and continue grinding the third mixture for 40 min to obtain the third grinding material.

[0081] 4) Pour out the third grinding material from the ball mill jar to obtain CuCrZr alloy homogenized particles with a particle size of 25-85μm;

[0082] 5) The CuCrZr alloy homogenized particles were sieved using a sieve plate with a particle size of 53 μm to obtain first homogenized particles with a particle size of 25–53 μm and second homogenized particles with a particle size of 53–85 μm.

[0083] Example 9

[0084] Unlike Example 7, the CuCrZr alloy homogenized particles were modified after step 4).

[0085] The modification treatment method is as follows: The CuCrZr alloy homogenized particles are divided into 3 groups and laid layer by layer from bottom to top, each layer being 10 μm thick. After each layer is laid, the surface of the CuCrZr alloy homogenized particles is treated with a spray of 1.5 mL / cm. 2 A layer of reinforcing agent is sprayed until all the CuCrZr alloy homogenized particles are used up to obtain a mixed powder. Then, the mixed powder is ultrasonically treated at an ultrasonic frequency of 30kHz for 30 minutes to obtain modified powder.

[0086] Example 10

[0087] Unlike Example 7, the CuCrZr alloy homogenized particles were modified after step 4).

[0088] The modification treatment method is as follows: The CuCrZr alloy homogenized particles are divided into 4 groups and laid layer by layer from bottom to top, each layer being 2 mm thick. After each layer is laid, spray 12 mL / dm onto the surface of the CuCrZr alloy homogenized particles. 2 A layer of reinforcing agent is sprayed until all the CuCrZr alloy homogenized particles are used up to obtain a mixed powder. The mixed powder is then ultrasonically treated at an ultrasonic frequency of 40kHz for 23 minutes to obtain modified powder.

[0089] Example 11

[0090] Unlike Example 7, the CuCrZr alloy homogenized particles were modified after step 4).

[0091] The modification treatment method is as follows: The CuCrZr alloy homogenized particles are divided into 5 groups and laid layer by layer from bottom to top, each layer being 20 μm thick. For each layer, the surface of the CuCrZr alloy homogenized particles is treated with a spray of 2.5 mL / cm². 2 A layer of reinforcing agent is sprayed until all the CuCrZr alloy homogenized particles are used up to obtain a mixed powder. Then, the mixed powder is ultrasonically treated at an ultrasonic frequency of 50kHz for 15 minutes to obtain modified powder.

[0092] Example 12

[0093] Unlike Example 10, in step S2, the metal additive manufacturing process is an electron beam powder bed melting process; when printing samples using the electron beam powder bed melting process, the second homogenized particles are selected; the printing process is as follows: CuCrZr alloy particles are laid on a horizontally placed base plate inside the forming chamber, and a vacuum is drawn inside the forming chamber until the vacuum degree of the forming chamber reaches 10. -2 When Pa is reached, helium gas is introduced and the base plate is preheated to 500°C. After setting the printing parameters, printing begins. The printing parameters are: electron beam current of 15mA, scanning speed of 2mm / s, melting gap of 50μm, and powder layer thickness of 50μm.

[0094] Example 13

[0095] Unlike Example 10, in step S2, the metal additive manufacturing process is an electron beam powder bed melting process; when printing samples using the electron beam powder bed melting process, the second homogenized particles are selected; the printing process is as follows: CuCrZr alloy particles are laid on a horizontally placed base plate inside the forming chamber, and a vacuum is drawn inside the forming chamber until the vacuum degree of the forming chamber reaches 10. -2 When Pa is reached, helium gas is introduced and the base plate is preheated to 275°C. After setting the printing parameters, printing begins. The printing parameters are: electron beam current of 18mA, scanning speed of 4mm / s, melting gap of 75μm, and powder layer thickness of 75μm.

[0096] Example 14

[0097] Unlike Example 10, in step S2, the metal additive manufacturing process is an electron beam powder bed melting process; when printing samples using the electron beam powder bed melting process, the second homogenized particles are selected; the printing process is as follows: CuCrZr alloy particles are laid on a horizontally placed base plate inside the forming chamber, and a vacuum is drawn inside the forming chamber until the vacuum degree of the forming chamber reaches 10. -2 When Pa is reached, helium gas is introduced and the base plate is preheated to 50°C. After setting the printing parameters, printing begins. The printing parameters are: electron beam current of 20mA, scanning speed of 6mm / s, melting gap of 100μm, and powder layer thickness of 100μm.

[0098] Example 15

[0099] Unlike Example 10, in step S2, the reinforcing agent comprises, by mass percentage, 45% SiC, 8% rare earth oxide nitrate, and the balance ethanol.

[0100] Example 16

[0101] Unlike Example 10, in step S2, the reinforcing agent comprises, by mass percentage, 55% SiC, 10% rare earth oxide nitrate, and the balance ethanol.

[0102] Example 17

[0103] Unlike Example 10, in step S3, the CuCrZr alloy parts are first polished with a shot peening machine for 20 minutes, then deionized water is sprayed onto the surface of the CuCrZr alloy parts 3 times at a rate of 15 mL / time, polishing is continued for 25 minutes, and finally the parts are placed in a refrigerator at -18°C for 1 hour.

[0104] Example 18

[0105] Unlike Example 10, in step S3, the CuCrZr alloy parts are first polished with a shot peening machine for 30 minutes, then deionized water is sprayed onto the surface of the CuCrZr alloy parts 5 times at a rate of 20 mL / time, polishing is continued for 15 minutes, and finally the parts are placed in a refrigerator at -20°C for 1.2 hours.

[0106] Example 19

[0107] Unlike Example 10, in step S3, the obtained CuCrZr alloy parts are then immersed in liquid nitrogen at a temperature of -196°C for one day for cryogenic treatment. After the treatment is completed, thin-walled CuCrZr alloy parts are obtained.

[0108] Example 20

[0109] Unlike Example 10, in step S3, the obtained CuCrZr alloy parts are then immersed in liquid nitrogen at a temperature of -196°C for cryogenic treatment for 10 days. After the treatment is completed, thin-walled CuCrZr alloy parts are obtained.

[0110] Example 21

[0111] Unlike Example 10, in step S3, the parameters of the shot peening device are: spray angle of 85°, spray distance of 195mm, number of sprays of 3, and travel speed of 15mm / min.

[0112] Example 22

[0113] Unlike Example 10, in step S3, the parameters of the shot peening device are: spray angle of 95°, spray distance of 205mm, number of sprays of 5, and travel speed of 25mm / min.

[0114] Example 23

[0115] Unlike Example 1, in step S2, the metal additive manufacturing process is a laser additive manufacturing process; when printing samples using the laser additive manufacturing process, the first homogenized particles are selected; the process parameters are: laser power of 200W, scanning speed of 200mm / s, melting gap of 50μm, and powder layer thickness of 30μm.

[0116] Example 24

[0117] Unlike Example 1, in step S2, the metal additive manufacturing process is a laser additive manufacturing process; when printing samples using the laser additive manufacturing process, the first homogenized particles are selected; the process parameters are: laser power of 500W, scanning speed of 1000mm / s, melting gap of 120μm, and powder layer thickness of 100μm.

[0118] Comparison Example

[0119] Comparative Example 1: Unlike Example 1, in step S1, the CuCrZr alloy powder that meets the requirements includes, by weight percentage, Cr: 0.4%, Zr: 0.03%, O: ≤0.06%, Fe: ≤0.05%, Si: ≤0.05%, P: ≤0.01%, with the balance being Cu and a small amount of unavoidable impurities.

[0120] Comparative Example 2: Unlike Example 10, the reinforcing agent, by mass percentage, comprises 50% SiC and the balance ethanol.

[0121] Comparative Example 3: Unlike Example 10, in step S3, the obtained CuCrZr alloy parts are then immersed in liquid nitrogen at a temperature of -196°C for cryogenic treatment for 0 days. After the treatment is completed, thin-walled CuCrZr alloy parts are obtained.

[0122] Experimental Example

[0123] Five thin-walled CuCrZr alloy parts prepared in Examples 1-24 and Comparative Examples 1-3 were taken as samples, and their mechanical properties were tested. The average value of the five samples was used as a reference. The results are as follows:

[0124] 1. Investigate the effect of the proportion of Cr and Zr in CuCrZr alloy on the properties of thin-walled CuCrZr alloy.

[0125] Table 1. Comparison of the properties of CuCrZr alloys prepared in Examples 1, 4-5, and Comparative Example 1

[0126]

[0127] Conclusion: As shown in Table 1, when the proportion of Cr and Zr in the CuCrZr alloy is lower than the range protected by this scheme, the properties of the thin-walled CuCrZr alloy will decline. This is because the amount of nano-precipitates is reduced, which makes the mechanical properties of the thin-walled CuCrZr alloy parts decline compared with the optimal range of this scheme. At the same time, the consumption of solid solution elements is also significantly reduced, which makes the electrical conductivity of the thin-walled CuCrZr alloy parts significantly reduced. The thin-walled CuCrZr alloy parts prepared in Examples 1 and 4-5 have better performance. Considering all factors, Example 1 is the optimal scheme.

[0128] 2. Investigating the effect of homogenization treatment on the properties of thin-walled CuCrZr alloys.

[0129] Table 2 Comparison of the properties of CuCrZr alloys prepared in Examples 1, 6-8 and Comparative Example 2

[0130]

[0131] Conclusion: As shown in Table 2, the homogenization treatment of the mixed powder has an impact on the performance of the manufactured CuCrZr alloy parts. Compared with no homogenization treatment, the homogenization treatment is more effective. This is because the homogenization method used in Examples 6-8 can enhance the dispersion effect of CuCrZr alloy powder, and at the same time make the shape and size of metal particles more uniform, further improving the quality of the product, thereby improving the uniformity of the thin-walled CuCrZr alloy and thus improving its performance. Compared with Example 1, Example 7 has advantages in all aspects of performance. Examples 9-11 are modified based on Examples 6-8, and their performance is slightly improved compared with Example 7. Therefore, overall, the thin-walled CuCrZr alloy prepared in Example 10 has better performance.

[0132] 3. Investigating the effect of rare earth oxides in nitric acid on the properties of thin-walled CuCrZr alloys.

[0133] Table 3 Comparison of the properties of CuCrZr alloys prepared in Examples 10, 15-16 and Comparative Example 2

[0134]

[0135] Conclusion: As shown in Table 3, the lack of rare earth nitrate oxide in the reinforcing agent in Comparative Example 2 led to a decrease in the performance of the thin-walled CuCrZr alloy. However, a comparison of the data from Examples 7 and 14-15 shows that the performance of the thin-walled CuCrZr alloy was optimal in Example 7. In Example 15, the performance decreased with the increase of rare earth nitrate oxide. This is because rare earth nitrate oxide is a mixture prepared by reacting nitric acid and rare earth element oxides. It has strong oxidizing properties and can improve the surface roughness of the powder layer by distributing it at different positions in each powder layer with the flow of ethanol. However, since it may generate oxygen during the reaction, the stabilizing effect of the inert gas is limited when oxygen is excessive, resulting in the generation of a large number of defects. This not only fails to promote the absorption rate of the powder but also hinders it. Therefore, considering all factors, Example 7 is the optimal solution.

[0136] 4. Investigating the effect of cryogenic treatment time on the properties of thin-walled CuCrZr alloys

[0137] Table 4 Comparison of the properties of CuCrZr alloys prepared in Examples 7, 19-20 and Comparative Example 3

[0138]

[0139]

[0140] Conclusion: Table 4 shows that, compared to Example 3 where no cryogenic treatment was performed on the additively manufactured thin-walled CuCrZr alloy parts, the mechanical properties of the thin-walled CuCrZr alloy parts are significantly reduced. Furthermore, the data indicates that cryogenic treatment significantly improves the room-temperature Vickers hardness of the additively manufactured thin-walled CuCrZr alloy parts, increasing it by 30%. It also significantly improves the anisotropy of the thin-walled CuCrZr alloy parts, increasing the maximum elongation by approximately 40% and the tensile strength by approximately 6%. The data in the table show that with increasing cryogenic treatment time, Vickers hardness and elongation tend to increase, but yield strength, tensile strength, and electrical conductivity all show a trend of first increasing and then decreasing with increasing cryogenic time. Therefore, considering all factors, Example 10 is the optimal solution.

Claims

1. A method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts, characterized in that, Includes the following steps: S1, Preprocessing CuCrZr alloy powder was placed in a vacuum drying oven at 80~120℃ for 2~10 hours to obtain CuCrZr alloy particles for later use. S2, Metal Additive Manufacturing The CuCrZr alloy particles obtained in step S1 were printed layer by layer using a metal additive manufacturing process to melt and solidify them, thereby producing CuCrZr alloy parts with a wall thickness of 0.1~10mm. S3, Cryogenic Treatment The CuCrZr alloy parts obtained in step S2 are immersed in liquid nitrogen at a temperature of -196℃ for cryogenic treatment for 1 to 10 days. After the treatment is completed, thin-walled CuCrZr alloy parts are obtained. In step S1, the CuCrZr alloy powder comprises, by weight percentage: Cr: 0.5~1.5%, Zr: 0.05~0.25%, O: ≤0.06%, Fe: ≤0.05%, Si: ≤0.05%, P: ≤0.01%, with the balance being Cu; The CuCrZr alloy powder has a particle size of 15~106μm and a purity of 99.9%. The CuCrZr alloy powder was homogenized for 1-2 hours; The homogenization process is as follows: 1) First, separate the CuCrZr alloy powder into three types of powder according to particle size: 15~35μm, 36~70μm, and 71~106μm, and set them aside for later use; 2) Take CuCrZr alloy powder with a particle size of 15~35μm and put the grinding balls and CuCrZr alloy powder into a ball mill jar at a ball-to-powder ratio of 2~3:1 to obtain the first mixture; then add the control agent to the ball mill jar at a mass ratio of 1~2:0.5~0.7 of the first mixture to the control agent, evacuate the ball mill jar to a vacuum degree of -0.08~-0.1MPa, and grind the ball mill jar in a planetary ball mill for 15~20min to obtain the first grinding material; the control agent is anhydrous ethanol; 3) Add CuCrZr alloy powder with a particle size of 36~70μm to the first grinding material, and mix them at a ball-to-material ratio of 2~3:1.2~1.4 to obtain a second mixture. Adjust the vacuum degree to -0.08~-0.1MPa again, and continue grinding the second mixture for 15~20min to obtain the second grinding material. Add CuCrZr alloy powder with a particle size of 71~106μm to the second grinding material, and mix them at a ball-to-material ratio of 2~3:1.8~2 to obtain a third mixture. Adjust the vacuum degree to -0.08~-0.1MPa again, and continue grinding the third mixture for 15~20min to obtain the third grinding material. 4) Pour out the third grinding material from the ball mill jar to obtain CuCrZr alloy homogenized particles with a particle size of 25~85μm; 5) The CuCrZr alloy homogenized particles were sieved using a sieve plate with a particle size of 53 μm to obtain first homogenized particles with a particle size of 25~53 μm and second homogenized particles with a particle size of 53~85 μm. After step 4), the CuCrZr alloy homogenized particles are subjected to modification treatment. The modification treatment method is as follows: CuCrZr alloy homogenized particles are divided into 3-5 groups and laid layer by layer from bottom to top, with each layer being 1-3 mm thick. For each layer, 10-15 mL / dm is applied to the surface of the CuCrZr alloy homogenized particles. 2 A layer of reinforcing agent is sprayed until all the CuCrZr alloy homogenized particles are used up to obtain a mixed powder. Then, the mixed powder is ultrasonically treated at an ultrasonic frequency of 30~50kHz for 15~30min to obtain a modified powder. The reinforcing agent, by mass percentage, includes 45~55% SiC, 8~10% rare earth oxide nitrate, and the balance ethanol.

2. The method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts according to claim 1, characterized in that, In step S2, the metal additive manufacturing process is either laser additive manufacturing or electron beam powder bed melting.

3. The method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts according to claim 2, characterized in that, When printing samples using laser additive manufacturing, the first homogenized particles are selected; the process parameters are: laser power of 200~500W, scanning speed of 200~1000mm / s, melting gap of 50~120μm, and powder layer thickness of 30~100μm.

4. The method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts according to claim 2, characterized in that, When printing samples using electron beam powder bed fusion technology, the second homogenized particles are selected. The printing process is as follows: CuCrZr alloy particles are laid on a horizontally placed base plate inside the forming chamber, and a vacuum is drawn into the forming chamber until the vacuum degree of the forming chamber reaches 10. -2 When Pa is reached, start filling with helium and preheat the base plate to 50~500℃. After setting the printing parameters, start printing. The printing parameters are: electron beam current of 15~20mA, scanning speed of 2~6mm / s, melting gap of 50~100μm, and powder layer thickness of 50~100μm.

5. A method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts according to claim 1, characterized in that, In step S3, the CuCrZr alloy parts are pretreated before cryogenic treatment. The pretreatment method is as follows: first, use a shot peening machine to grind the CuCrZr alloy parts for 20-30 minutes, then spray deionized water onto the surface of the CuCrZr alloy parts 3-5 times at a rate of 15-20 mL / time, continue grinding for 15-25 minutes, and finally place them in a refrigerator at -18~-20℃ for 1-1.2 hours.

6. A method for improving the mechanical properties of additively manufactured thin-walled CuCrZr alloy parts according to claim 5, characterized in that, The parameters of the shot peening device are: spray angle of 85~95°, spray distance of 195~205mm, number of sprays of 3~5, and travel speed of 15~25mm / min.

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