Preparation method of high-density copper-tungsten alloy component

Abstract

The invention discloses a preparation method of a high-density copper-tungsten alloy component, which comprises the following steps: manufacturing a tungsten blank in a binder jet 3D printing manner, and designing a printing model into a hollow porous skeleton structure; and a tungsten blank formed through printing is subjected to curing, degreasing and copper infiltration in sequence, and then the copper-tungsten alloy component is formed. In the step of copper infiltration, copper is placed on the degreased tungsten blank, and two-section type treatment is carried out. The two-stage treatment comprises sintering and infiltration; the sintering is carried out in a vacuum environment, the sintering temperature is 800-1000 DEG C, and the sintering heat preservation time is 0.5-3 hours; the infiltration is carried out in an argon and hydrogen mixed gas environment, the infiltration temperature is 1100-1400 DEG C, and the infiltration heat preservation time is 1-4 hours. The preparation method of the high-density copper-tungsten alloy component is not limited by the product structure and is wide in applicability, the copper phase distribution is more uniform, and the electric conductivity and the mechanical property are improved; and the infiltration stage is carried out in a protective gas environment, copper is effectively reduced, copper oxidation is prevented, and the quality of the copper-tungsten alloy component is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of copper-tungsten alloy preparation, and particularly to a method for preparing a high-density copper-tungsten alloy component. Background Art

[0002] Copper-tungsten alloy is a composite material composed of copper and tungsten, combining the high electrical conductivity and high thermal conductivity of copper and the high melting point and high strength of tungsten. Copper-tungsten materials are widely used in many fields due to their high electrical and thermal conductivity and good mechanical properties, such as the electrical contact contacts of power switches, the rocket nozzles of aerospace, and the heat dissipation materials of semiconductor integrated circuit chips.

[0003] In the prior art, the common manufacturing method of copper-tungsten alloy is to produce by die pressing and forming, and then form parts with the required structure through machining. However, this manufacturing method can only produce parts with simple shapes, and for parts with complex structures, their complex structures cannot be formed by machining. Due to the long production cycle and high cost of the die, this die pressing and forming production method is also not suitable for small-batch personalized customized products. In addition, there are defects in the uneven distribution of the copper phase during the subsequent copper infiltration process of the tungsten billet formed by die pressing, seriously affecting the production quality of copper-tungsten alloy products. Summary of the Invention

[0004] Based on this, in order to solve the above technical problems, the present invention provides a method for preparing a high-density copper-tungsten alloy component.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for preparing a high-density copper-tungsten alloy component, comprising the following steps:

[0007] 3D printing: adding tungsten powder and a binder into a 3D printer, and performing binder jet 3D printing according to a printing model; the printing model is designed as a porous skeleton structure;

[0008] Curing: putting the printed component model into a curing furnace for heating and curing, and obtaining a green tungsten blank after powder cleaning;

[0009] Debinding: putting the green tungsten blank into a debinding furnace for high-temperature debinding to obtain a debound tungsten blank;

[0010] Copper infiltration: putting the debound tungsten blank into an infiltration furnace, placing copper above the debound tungsten blank, and sequentially performing two-stage treatment by opening the infiltration furnace to obtain the copper-tungsten alloy component;

[0011] The two-stage treatment includes a sintering stage and an infiltration stage; the sintering stage is carried out in a vacuum environment, the sintering temperature is 800°C to 1000°C, and the sintering holding time is 0.5 h to 3 h; the infiltration stage is carried out in an environment of a mixed gas of argon and hydrogen, the infiltration temperature is 1100°C to 1400°C, and the infiltration holding time is 1 h to 4 h.

[0012] In one embodiment, before the 3D printing step, a tungsten powder preparation step is further included, and tungsten powder is prepared through coarse grinding, fine grinding, and drying processes; in the coarse grinding process, tungsten coarse materials are put into a crusher for crushing, and crushed materials of 5 μm to 100 μm are obtained through screening; in the fine grinding process, the crushed materials are put into a ball mill for ball milling, and three kinds of tungsten powders of 5 μm to 20 μm, 15 μm to 50 μm, and 40 μm to 80 μm are obtained through screening; at least one of the three kinds of tungsten powders of 5 μm to 20 μm, 15 μm to 50 μm, and 40 μm to 80 μm is selected for drying and subsequent printing.

[0013] In one embodiment, in the fine grinding process, the ball milling operation is carried out in an argon protection environment.

[0014] In one embodiment, in the fine grinding process, the rotational speed of the ball mill is 50 r / min to 300 r / min, and the ball milling time is 1 h to 15 h.

[0015] In one embodiment, the binder is a water-based low-residual-carbon binder, and the saturation is 50% to 100%.

[0016] In one embodiment, in the 3D printing step, the rotational speed of the lower powder feeder rod is 0.5 r / s to 5 r / s, the rotational speed of the powder spreading roller is 5 r / s to 15 r / s, and the printing layer thickness is 30 μm to 100 μm.

[0017] In one embodiment, in the curing step, the curing temperature is 150°C to 250°C, and the curing holding time is 1 h to 4 h.

[0018] In one embodiment, in the debinding step, the debinding temperature is 600°C to 900°C, and the debinding holding time is 2 h to 8 h.

[0019] In one embodiment, in the debinding step, the debinding furnace is evacuated to 1 Pa to 20 Pa, and nitrogen or argon is continuously introduced, and high-temperature debinding is carried out in an environment protected by nitrogen or argon.

[0020] In one embodiment, in the copper infiltration step, the weight ratio of copper to the debound tungsten blank is 1:2 to 3.

[0021] The method of the present invention has the following beneficial effects compared with the prior art:

[0022] The preparation method of the high-density copper-tungsten alloy component disclosed by the present invention sprays tungsten green bodies through binder jet 3D printing. The product structure is not restricted, and it is especially suitable for the rapid production of copper-tungsten alloy components with complex structures. At the same time, the binder jet 3D printing process makes the distribution of tungsten powder more uniform. Compared with the traditional copper infiltration technology for compacted green bodies, the copper phase distribution of this application is more uniform, and both the conductivity and mechanical properties are improved. The tungsten green body is printed into a porous skeleton with a hollow structure, which on the one hand helps to improve the uniformity of copper infiltration, on the other hand helps the volatilization of the binder, shortens the debinding time, and effectively avoids the subsequent sintering performance due to incomplete debinding of the binder. In addition, it effectively reduces the amount of binder used and reduces the printing cost.

[0023] The preparation method of the high-density copper-tungsten alloy component disclosed by the present invention performs ball milling grading on tungsten particles. By designing the particle size ratio of tungsten powder, the density of the tungsten green body can be effectively controlled, and the density of the copper-tungsten alloy component can be improved. The infiltration stage is carried out in an environment of a mixed gas of argon and hydrogen, which can effectively reduce copper, prevent copper oxidation, and improve the quality of the copper-tungsten alloy component. Specific Embodiments

[0024] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to related embodiments. The preferred embodiments of the present invention are given in the embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0026] An embodiment of the present invention discloses a preparation method of a high-density copper-tungsten alloy component, including the following steps:

[0027] S1. Tungsten powder preparation, including a coarse grinding process, a fine grinding and grading process, and a drying process.

[0028] In the coarse grinding process, tungsten coarse materials are put into a crusher for preliminary cutting and crushing, and crushed materials with a particle size of 5 μm to 100 μm are screened out.

[0029] In the fine grinding grading process, the crushed materials obtained from the crushing and screening in the coarse grinding process are placed in a planetary high-energy ball mill and milled in an argon gas protection environment to obtain relatively regular ball-milled granular tungsten powder. Among them, the milling medium can be stainless steel balls, the ball-to-material ratio can be 5-20:1, the rotation speed of the ball mill is set at 50 r / min - 300 r / min, and the ball milling time can be 1 h - 15 h. Screening the ball-milled tungsten material can obtain three different tungsten powders with particle sizes of 5 μm - 20 μm, 15 μm - 50 μm, and 40 μm - 80 μm. Select one or more of these three tungsten powders for grading to obtain tungsten powders with different density designs for printing tungsten blanks with required densities, such as W60, W65, W70, W75, W80, etc.

[0030] The tungsten powder needs to be dried before printing, and it can be dried before grading or after grading. The embodiments of the present invention do not make specific limitations on this.

[0031] S2. 3D printing, using binder jetting to 3D print the component model.

[0032] The printed model is designed as a porous skeleton hollow structure. This hollow design helps to improve the copper infiltration uniformity on the one hand and helps the binder to volatilize and shorten the debinding time on the other hand. In addition, this design can also effectively reduce the binder usage and save the printing cost. Add the tungsten powder graded and dried in step S1 to the powder spreader, and add the binder to the print head. This binder can be a water-based low residual carbon binder with a saturation of 50% - 100%. Generate a two-dimensional slice model according to the designed printed model and set the printing parameters. Among them, the rotation speed of the lower powder screw rod is set at 0.5 r / s - 5 r / s, and the powder feeding amount is controlled by the screw rod rotation speed, thereby controlling the density of the green tungsten blank; the rotation speed of the powder spreading roller is set at 5 r / s - 15 r / s, and the density of the green tungsten blank is controlled by the rotation speed of the powder spreading roller and the uniformity of the tungsten powder spreading is improved; the printing layer thickness is set at 30 μm - 100 μm.

[0033] Start the binder jetting 3D printer. The powder spreader evenly and smoothly lays a layer of tungsten powder on the printing bottom plate, and the print head sprays the binder onto the tungsten powder layer laid by the powder spreader according to the set path; after the printing platform descends by a printing layer thickness, the steps of powder spreading, inkjet (binder), and workbench descent are cycled until the printing is completed to form the component model.

[0034] S3. Curing, heating and curing the component model.

[0035] Put the component model formed by printing in step S2 together with the working box into a curing furnace for heating and curing. The curing temperature is 150°C - 250°C, the curing holding time is 1 h - 4 h, and the heating rate can be 5°C / min - 20°C / min. After curing, clear the powder to obtain the green tungsten blank.

[0036] S4. Degreasing, high-temperature degreasing of tungsten green compacts.

[0037] Put the tungsten green compacts obtained by curing and powder cleaning in step S3 into a degreasing furnace for sufficient degreasing to obtain degreased tungsten compacts. Among them, the degreasing process can specifically be: the degreasing furnace is evacuated to 1 Pa - 20 Pa, and nitrogen or argon is continuously introduced, and high-temperature degreasing is carried out in an atmosphere protected by nitrogen or argon; the gas flow rate of the introduced nitrogen or argon can be controlled at 2 L / min - 10 L / min; the degreasing temperature is 600 °C - 900 °C, and the degreasing holding time is 2 h - 8 h.

[0038] S5. Copper infiltration, two-stage treatment of degreased tungsten compacts.

[0039] Put the degreased tungsten compacts after the degreasing treatment in step S4 into an infiltration furnace, place copper blocks above the degreased tungsten compacts, and the weight ratio of copper to the degreased tungsten compacts is 1:2 - 3. Turn on the infiltration furnace to carry out two-stage treatment on the degreased tungsten compacts, and after furnace cooling, simple surface treatment can be carried out to obtain copper-tungsten alloy components.

[0040] This two-stage treatment includes a sintering stage and an infiltration stage in sequence. In the sintering stage, the furnace is evacuated and the temperature is relatively low, aiming to improve the mechanical properties of the tungsten compacts while discharging the gas in the pores of the tungsten compacts. In the infiltration stage, a mixed gas of argon and hydrogen is introduced into the furnace and the temperature is relatively high. In this stage, the copper blocks placed above the tungsten compacts melt and infiltrate into the porous skeleton structure of the tungsten compacts; and, due to the protection of this mixed gas, copper can be effectively reduced, preventing copper oxidation and improving the quality of the copper-tungsten alloy components.

[0041] Specifically, the sintering temperature in the sintering stage is 800 °C - 1000 °C, the holding time is 0.5 h - 3 h, and the heating rate is 3 °C / min - 10 °C / min. The infiltration temperature in the infiltration stage is 1100 °C - 1400 °C, the holding time is 1 h - 4 h, and the heating rate is 2 °C / min - 10 °C / min.

[0042] Example 1

[0043] A method for preparing a high-density copper-tungsten alloy component may include the following steps:

[0044] S1. Tungsten powder preparation

[0045] Put tungsten rough materials into a crusher for preliminary cutting and crushing and screen out crushed materials with a particle size of 5 μm - 100 μm. Place the crushed materials in a planetary high-energy ball mill and carry out ball milling in an argon protection environment to obtain relatively regular ball-milled granular tungsten powder. Screen the ball-milled tungsten materials to obtain three kinds of tungsten powders with particle sizes of 5 μm - 20 μm, 15 μm - 50 μm, and 40 μm - 80 μm.

[0046] Weigh 30% of tungsten powder with a particle size of 5μm - 20μm and 70% of tungsten powder with a particle size of 40μm - 80μm for grading. Before printing, place the graded tungsten powder in a vacuum oven and dry it at 100°C for 2 hours to make the tungsten powder completely dry.

[0047] S2. 3D Printing

[0048] The printed model is designed as a porous skeleton hollow structure. Add the graded and dried tungsten powder from step S1 into the powder spreading device, and add the binder into the print head. The binder is a water-based low residual carbon binder with a saturation of 60%. Input the two-dimensional slice model according to the designed printed model, set the printing parameters, and set the printing layer thickness to 100μm. Start the binder jet 3D printer. The powder spreading device evenly and flatly lays a layer of tungsten powder on the printing bottom plate, and the print head sprays the binder onto the tungsten powder layer laid by the powder spreading device according to the set path; after the printing platform descends by one printing layer thickness, repeat the steps of powder spreading, inkjet (binder), and workbench descent until the printing is completed to form a component model.

[0049] S3. Curing

[0050] Put the printing workbox together with the component model inside into the curing furnace, heat it up to 180°C at a speed of 10°C / min, keep it warm for 2 hours, and then cool it with the furnace and remove the excess loose powder to obtain a green tungsten blank. After testing, the density of the green tungsten blank in this example is 10.46 g / cm 3 , and the printed green blank is W80.

[0051] S4. Debinding

[0052] Put the green tungsten blank into the debinding furnace, evacuate the furnace to 20 Pa and introduce nitrogen or argon at a gas flow rate of 5 L / min. The debinding furnace is heated up to 900°C at a speed of 5°C / min and kept warm for 2 hours for sufficient debinding to obtain a debound tungsten blank.

[0053] S5. Copper Infiltration

[0054] Put the debound tungsten blank into the infiltration furnace, place a copper block above the debound tungsten blank, and the weight ratio of the copper block to the debound tungsten blank is 1:2 - 3, and the copper block is placed closely above the debound tungsten blank. Turn on the infiltration furnace and perform sintering and infiltration in sequence. After furnace cooling, perform simple surface treatment to obtain a copper-tungsten alloy component.

[0055] The sintering is vacuum sintering, heated up to 950°C at a speed of 5°C / min and kept warm for 2 hours. During the infiltration stage, a mixed gas of argon and hydrogen is introduced into the furnace at a flow rate of 5 L / min, the infiltration temperature is 1200°C, the holding time is 3 hours, and the heating rate is 2°C / min.

[0056] After testing, the density of the copper-tungsten alloy component prepared in this example can reach more than 98%.

[0057] Example 2

[0058] A method for preparing a high-density copper-tungsten alloy component may include the following steps:

[0059] S1. Tungsten powder preparation

[0060] Put the tungsten rough material into a crusher for preliminary cutting and crushing, and screen out the crushed material with a particle size of 5 μm to 100 μm. Place the crushed material in a planetary high-energy ball mill and perform ball milling in an argon gas protection environment to obtain relatively regular ball-milled granular tungsten powder. Screen the ball-milled tungsten material to obtain three kinds of tungsten powders with particle sizes of 5 μm to 20 μm, 15 μm to 50 μm, and 40 μm to 80 μm.

[0061] Weigh 27% of the tungsten powder with a particle size of 5 μm to 20 μm and 73% of the tungsten powder with a particle size of 15 μm to 50 μm for grading. Before printing, place the graded tungsten powder in a vacuum oven and dry it at 100 °C for 2 h to make the tungsten powder completely dry.

[0062] S2. 3D printing

[0063] The printed model is designed as a porous-skeleton hollow structure. Add the graded and dried tungsten powder in step S1 to the powder spreading device, and add the binder to the print head. The binder is a water-based low-residual-carbon metal binder with a saturation of 60%. Input the two-dimensional slice model according to the designed printed model, set the printing parameters, and set the printing layer thickness to 60 μm. Start the binder jet 3D printer. The powder spreading device evenly and smoothly lays a layer of tungsten powder on the printing bottom plate, and the print head sprays the binder onto the tungsten powder layer laid by the powder spreading device according to the set path; after the printing platform descends by one printing layer thickness, repeat the steps of powder spreading, inkjet (binder), and workbench descent until the printing is completed to form a component model.

[0064] S3. Curing

[0065] Put the printing workbox together with the component model inside into a curing furnace, heat it up to 200 °C at a rate of 10 °C / min, keep it warm for 2.5 h, and then cool it with the furnace and remove the excess loose powder to obtain a green tungsten blank. After testing, the density of the green tungsten blank in this example is 9.62 g / cm 3 , and the printed green blank is W75.

[0066] S4. Debinding

[0067] Put the green tungsten blank into a debinding furnace, evacuate the furnace to 20 Pa and introduce nitrogen or argon at a gas flow rate of 5 L / min. The debinding furnace is heated up to 600 °C at a rate of 10 °C / min and kept warm for 4 h for sufficient debinding to obtain a debound tungsten blank.

[0068] S5. Copper infiltration

[0069] Put the degreased tungsten blank into the impregnation furnace, place a copper block above the degreased tungsten blank, the weight ratio of the copper block to the degreased tungsten blank is 1:2 - 3, and the copper block is placed closely above the degreased tungsten blank. Turn on the impregnation furnace to carry out sintering and infiltration in sequence, and after furnace cooling, perform simple surface treatment to obtain a copper-tungsten alloy component.

[0070] The sintering is vacuum sintering, heating up to 1000°C at a rate of 3.5°C / min and holding for 3 hours. During the infiltration stage, a mixed gas of argon and hydrogen is introduced into the furnace at a flow rate of 5 L / min, the infiltration temperature is 1280°C, the holding time is 4 hours, and the heating rate is 2°C / min.

[0071] After testing, the density of the copper-tungsten alloy component prepared in this example can reach more than 98%.

[0072] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A preparation method of a high-density copper-tungsten alloy component, characterized in that, It includes the following steps: 3D printing: Add tungsten powder and binder into a 3D printer, and perform binder jetting 3D printing according to a printing model; The printing model is designed as a porous skeleton structure; Curing: Put the printed component model into a curing furnace for heating and curing, and obtain a green tungsten blank after powder cleaning; Debinding: Put the green tungsten blank into a debinding furnace for high-temperature debinding to obtain a debound tungsten blank; Copper infiltration: Put the debound tungsten blank into an infiltration furnace, place copper above the debound tungsten blank, and start the infiltration furnace for two-stage treatment to obtain the copper-tungsten alloy component; The two-stage treatment includes sintering and infiltration; the sintering is carried out in a vacuum environment, the sintering temperature is 800°C to 1000°C, and the sintering holding time is 0.5h to 3h; the infiltration is carried out in an environment of a mixed gas of argon and hydrogen, the infiltration temperature is 1100°C to 1400°C, and the infiltration holding time is 1h to 4h.

2. The method for preparing a high-density copper-tungsten alloy component according to claim 1, wherein, It further includes a tungsten powder preparation step. Before the 3D printing step, tungsten powder is prepared through coarse grinding, fine grinding, and drying processes; In the coarse grinding process, put tungsten coarse materials into a crusher for crushing, and screen to obtain crushed materials of 5μm to 100μm; In the fine grinding process, put the crushed materials into a ball mill for ball milling, and screen to obtain three kinds of tungsten powders of 5μm to 20μm, 15μm to 50μm, and 40μm to 80μm; Select one or more of the three kinds of tungsten powders of 5μm to 20μm, 15μm to 50μm, and 40μm to 80μm for drying and subsequent printing.

3. The preparation method of the high-density copper-tungsten alloy component according to claim 2, characterized in that, In the fine grinding process, the ball milling operation is carried out in an argon protection environment.

4. The preparation method of the high-density copper-tungsten alloy component according to claim 2, wherein In the fine grinding process, the rotation speed of the ball mill is 50r / min to 300r / min, and the ball milling time is 1h to 15h.

5. The preparation method of the high-density copper-tungsten alloy component according to claim 1, characterized in that, The binder is a water-based low-residual carbon binder, and the saturation is 50% to 100%.

6. The preparation method of the high-density copper-tungsten alloy component according to claim 1, characterized in that, In the 3D printing step, the rotation speed of the lower powder feeding rod is 0.5r / s to 5r / s, the rotation speed of the powder spreading roller is 5r / s to 15r / s, and the printing layer thickness is 30μm to 100μm.

7. The preparation method of the high-density copper-tungsten alloy component according to claim 1, characterized in that, In the curing step, the curing temperature is 150°C to 250°C, and the curing holding time is 1h to 4h.

8. The preparation method of the high-density copper-tungsten alloy component according to claim 1, characterized in that, In the debinding step, the debinding temperature is 600°C to 900°C, and the debinding holding time is 2h to 8h.

9. The preparation method of the high-density copper-tungsten alloy component according to claim 8, characterized in that, In the debinding step, the debinding furnace is evacuated to 1Pa to 20Pa, and nitrogen or argon is continuously introduced, and high-temperature debinding is carried out in an environment of nitrogen or argon protection.

10. The preparation method of the high-density copper-tungsten alloy component according to any one of claims 1-9, characterized in that, In the copper infiltration step, the weight ratio of copper to the debound tungsten blank is 1:2 to 3.