CN1944713A - Method for producing multiple material micro part - Google Patents

Abstract

The invention discloses a method for manufacturing multi-material micro-parts, which comprises the following steps: putting metal-based materials into a crucible, sealing and melting them for use, respectively putting multi-material powders into containers of a powder supply device, sealing the vacuum chamber, start the injection environment measurement and control system, jet injection control system, droplet/powder joint deposition control system, keep the crucible injection pressure at 40KPa, add charging voltage and deflection voltage, so that the uniform metal droplet flow is deflected and deposited according to the design; control The nozzle sprays the powder into the "melt pool" formed by the accumulation of droplets, and at the same time relies on the heat generated by the accumulation of droplets and the surface tension of the molten metal liquid to dissolve with the metal droplets or directly embed the powder into the molten metal; Cool the part in an oxygen-free environment. Since multiple control systems are used to simultaneously control molten droplets and at least two different powders, low-cost manufacturing of multi-material micro-parts with complex material distribution or material composition can be formed.

Description

Manufacturing method of multi-material micro-parts

technical field

The invention relates to a manufacturing method of a multi-material micro-part.

Background technique

Due to its unique physical and mechanical properties, high-performance multi-material micro-parts have broad application prospects and potential markets in the micro-structures of various aerospace vehicles, special parts of micro-aircraft, load-bearing parts of space power systems, and the nuclear industry. . The traditional preparation methods of metal multi-material parts mainly include vapor deposition method, coating method, laser cladding method, powder metallurgy method, self-propagating high-temperature combustion synthesis method, etc. The preparation of multi-material parts, such as the self-propagating high-temperature combustion synthesis method, requires molds, and the material composition is single, which cannot form complex parts such as tiny metal multi-material turbines with complex internal flow channels. In addition, because other technologies involve high-power laser equipment, the processing cost is expensive and the process is complicated. Therefore, people continue to explore the method of integrating the design and manufacture of multi-material micro-parts to realize low-cost and high-efficiency manufacturing of multi-material micro-parts.

Uniform Droplet Discharge Technology (UDS) is a new metal rapid prototyping method proposed by the MIT Droplet based Manufacture (DBM) laboratory. The basic principle is to use mechanical disturbance to discretize the laminar capillary metal jet into a uniform At the same time, the generated molten droplets are selectively charged, and then the high-voltage electrostatic field is used to precisely position the metal molten droplets, and they are piled up layer by layer to form the workpiece to be formed. This method can directly deposit metal, which provides a way of thinking for the rapid preparation of metal parts and metal-based multi-material parts. However, uniform droplet spray deposition can only deposit metals such as aluminum, zinc, and copper with low melting points, so the method of using uniform droplet joint deposition of different materials to prepare multi-material tiny parts can only be used to prepare limited low-temperature parts. Melting point metal multi-material tiny parts.

The literature "W.B.Cao, S.Kirihara, Y.Miyamoto, K.Matsuura, M.Kudoh.evelopment of freeform fabrication method for Ti-Al-Ni intermetallics.Intermetallics 10 2002:879-885." A rapid preparation method of high-temperature intermetallic compounds combining droplet jetting and droplet/powder high-temperature self-propagating synthesis (SHS) technology. It accurately deposits aluminum droplets on the substrate covered with uniform titanium powder, and uses uniform aluminum droplets to deposit into the metal powder preheated at 300 degrees to generate high-temperature self-propagating synthesis (SHS) reaction to produce aluminum-titanium metal The intermetallic compound is then powdered and deposited again, and the aluminum-titanium intermetallic compound material is prepared through repeated powdering and deposition. The technology is designed to rapidly deposit intermetallic materials, which have a higher melting point than titanium metal. However, it has no deposited parts, and since the powder material on the substrate cannot be changed as required during the forming process, it is impossible to form multi-material tiny parts with various complex material compositions and distributions.

Contents of the invention

In order to overcome the deficiency that the prior art cannot form multi-material micro-parts with various complex material components, the present invention provides a method for manufacturing multi-material micro-parts.

The technical solution adopted by the present invention to solve its technical problem is: a kind of manufacturing method of multi-material tiny parts, it is characterized in that comprising the following steps:

1) Put the metal material into the crucible, seal it and melt it for use, put the multi-material powder into the container of the powder supply device respectively, adjust the powder supply device, make the powder nozzle be filled with powder, and the whole preparation process is carried out in the vacuum chamber;

2) Seal the vacuum chamber, start the injection environment measurement and control system to deoxygenate the gas in the chamber, and reduce the oxygen content in the vacuum chamber to below 10PPM after 2 to 4 hours of deoxygenation treatment;

3) Start the jet injection control system to maintain the injection pressure of the crucible at 40KPa to ensure the stability of the jet flow. Add the charging voltage and deflection voltage, observe the shape of the droplet flow through a high-speed CCD camera, and adjust the excitation signal to obtain a uniform droplet flow. The uniform metal droplet flow is deflected and deposited according to the design;

4) Start the droplet/powder joint deposition control system, control the nozzle to spray the powder into the "melt pool" formed by the droplet accumulation process, and rely on the heat generated by the droplet accumulation and the surface tension of the molten metal liquid and the metal droplet Miscibility or direct embedding of powders into molten metals;

5) Where support is required, heat-gasified powder and metal droplets are used for joint spraying to form a foam-like metal support structure. After the forming is completed, the part is cooled in an oxygen-free environment to form a foam-like metal support structure. It is removed by mechanical means to obtain multi-material tiny parts.

The beneficial effect of the present invention is that due to the adoption of the injection environment measurement and control system, the jet injection control system, and the droplet/powder joint deposition control system to control the droplet and at least two different powders at the same time, it can form complex material distribution or material composition. Integrated manufacturing of multi-material tiny parts. The method has simple procedures and no expensive equipment, can break through the bottleneck of manufacturing cost of metal multi-material tiny parts at the present stage, and realize low-cost and high-efficiency preparation of multi-material tiny parts.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the device used in the manufacturing method of multi-material micro-parts of the present invention.

In the figure, 1. Exciting source 2. Crucible 3. Resistance wire 4. Jet 5. Charging electrode 6. Deflecting electrode 7. Powder storage container 8. Powder nozzle 9. Part 10. Three-dimensional substrate 11. Circulating cooling water 12. Recovery tank 13. High-speed CCD camera 14. Droplet/powder joint deposition control system 15. Injection environment measurement and control system 16. Jet injection control system 17. Vacuum chamber.

Detailed ways

Example 1: Referring to FIG. 1 , an Al-Li-Si multi-material motion-bearing tiny component with wear resistance and fatigue crack propagation resistance is formed. The workpiece is a 1×1×1cm cube, and part of it is a wear-resistant part. Since high-silicon aluminum alloy has excellent wear resistance and corrosion resistance, the material is selected as Al-18Si alloy; then the material gradually transitions to other parts of Al -3.8Li alloy, Al-3.8Li alloy is a low-density high-lithium alloy, which not only greatly reduces the weight of the component, but also has a good resistance to fatigue crack propagation, and can be used as a cyclic load-bearing component; firstly, according to the shape and Establish the digital model of the workpiece according to the distribution of materials, generate discrete files of the rapid deposition system according to the model, and combine the droplet deposition system to generate three-dimensional substrate motion trajectory data files; at the same time, formulate powder supply and droplet charging deflection according to the type and distribution state of the material Deposited data files. Put the aluminum ingot into the crucible 2, put the silicon powder and lithium powder into the powder storage container 7 of the powder supply device, debug the powder supply device, make the powder nozzle place full of powder; start the injection environment measurement and control system 15, and seal the vacuum chamber 17 , carry out deoxygenation of the gas until the oxygen content is reduced to below 10PPM; seal the crucible 2, energize the resistance wire 3, heat the crucible 2 to 650 degrees, and keep the temperature constant; apply an air pressure of 40KPa to the crucible, establish a jet 4, and then When the 3KHz sinusoidal disturbance is generated by the excitation 1, the shape of the droplet flow is observed through the high-speed CCD camera 13, and the frequency of the sinusoidal signal is adjusted until a uniform droplet flow is generated; the charging voltage is applied to the charging electrode 5, and the deflection electrode 6 Adding the deflection voltage, the jet injection control system 16 starts the droplet/powder joint deposition control system 14, deflects the aluminum droplet to be deposited onto the three-dimensional substrate 10 according to the design, and the excess aluminum droplet enters the recovery tank 12; Spray into the "melting pool" formed by the accumulation of droplets, and rely on the heat generated by the accumulation of droplets and the surface tension of the molten metal liquid to dissolve with the metal droplets or directly embed the powder into the metal in the molten state; at the same time, through the powder The spray head 8 sprays the silicon powder to be deposited to the droplet deposition point, and controls the powder feeding amount by controlling the powder injection rate to realize the combination of aluminum and silicon to obtain Al-18Si alloy; the combined deposition process follows the three-dimensional substrate 10 motion track data file , powder feeding and droplet charge deflection deposition data files are performed. Gradually control the amount of powder to control the gradient change of silicon content in the material. When the aluminum-lithium alloy part is reached, the powder supply device replaces the powder material with lithium powder. Repeat the above process to obtain the Al-3.8Li alloy. Where support is required, heat-gasified powder and metal droplets are used to jointly spray to form a foam-like metal support structure. After the forming is completed, the foam-like metal support structure is removed by a mechanical method, that is, a multi-material micro-manufacturing system is obtained. pieces. During the multi-material deposition process, double cooling by using the circulating cooling water 11 on the substrate and the airflow spraying the powder ensures no segregation of the alloy composition. After the deposition of the part is completed, the part is cooled in an oxygen-free environment to obtain an Al-Li-Si multi-material micro-part 9 with partial wear resistance and partial resistance to fatigue crack propagation.

Embodiment 2: Referring to FIG. 1 , Al-Cu/SiC particle-reinforced metal-based multi-material micro-parts with gradient materials are formed. Al-Cu alloys with different SiC volume fractions have different mechanical properties. For example, with the increase of SiC volume fraction, the elastic modulus E of Al-Cu alloys increases linearly, while the elongation δ decreases monotonously. Volume fraction changes can be made into multi-material tiny parts whose material properties change as required. The workpiece is a 1×1×1cm cube. Firstly, the digital model of the workpiece is established according to the shape of the workpiece and the distribution of materials, and the discrete file of the rapid deposition system is generated according to the model. Combined with the droplet deposition system, the three-dimensional substrate motion trajectory data file is generated. ; At the same time, formulate the data files of powder supply and droplet charging deflection deposition according to the type of material and distribution state. Put the aluminum-copper alloy with a copper content of 5% into the crucible 2, put the SiC powder into the powder storage container 7 of the powder supply device; start the injection environment measurement and control system 15, seal the vacuum chamber 17, and carry out gas deoxygenation until Reduce the oxygen content to less than 10PPM; seal the crucible, heat the crucible to 900 degrees, and keep the temperature constant; apply an air pressure of 50KPa to the crucible, establish a jet, and then generate a 3KHz sinusoidal disturbance by the excitation 1, through a high-speed CCD camera 13 Observe the shape of the droplet flow, adjust the frequency of the sinusoidal signal until a uniform droplet flow is generated; add the charging voltage and the deflection voltage, deflect the aluminum droplet to be deposited onto the three-dimensional substrate 10 according to the design, and pass through the powder nozzle at the same time 8 Spray the SiC powder to be deposited to the droplet deposition point at a certain initial velocity, and control the powder delivery amount by controlling the powder injection rate to realize the injection of the reinforcement phase and obtain AL-Cu/SiC particle-reinforced metal materials; combined deposition process The process is carried out according to the data file of the motion trajectory of the three-dimensional substrate 10, the data file of powder supply and droplet charge deflection deposition. Gradually control the amount of powder to control the gradient change of SiC content in the material, and obtain Al-Cu/SiC particle-reinforced metal-based multi-material micro-parts with different SiC volume fractions, and use the circulating cooling water on the substrate and the airflow of sprayed powder for double cooling. It can ensure timely cooling of alloy droplets. After the deposition of the parts is completed, the parts are cooled in an oxygen-free environment to obtain Al-Cu/SiC particle-reinforced metal-based multi-material micro parts with material gradient changes.

Two or more metal or non-metal powders can be stored in the powder storage container 7 as required.

Claims (1)

1. A method for manufacturing a multi-material micro-part, characterized in that it comprises the following steps: 1) Put the metal material into the crucible, seal it and melt it for use, put the multi-material powder into the container of the powder supply device respectively, adjust the powder supply device, make the powder nozzle be filled with powder, and the whole preparation process is carried out in the vacuum chamber; 2) Seal the vacuum chamber, start the injection environment measurement and control system to deoxygenate the gas in the chamber, and reduce the oxygen content in the vacuum chamber to below 10PPM after 2 to 4 hours of deoxygenation treatment; 3) Start the jet injection control system to maintain the injection pressure of the crucible at 40KPa to ensure the stability of the jet flow. Add the charging voltage and deflection voltage, observe the shape of the droplet flow through a high-speed CCD camera, and adjust the excitation signal to obtain a uniform droplet flow. The uniform metal droplet flow is deflected and deposited according to the design; 4) Start the droplet/powder joint deposition control system, control the nozzle to spray the powder into the "melt pool" formed by the droplet accumulation process, and rely on the heat generated by the droplet accumulation and the surface tension of the molten metal liquid and the metal droplet Miscibility or direct embedding of powders into molten metals; 5) Where support is required, heat-gasified powder and metal droplets are used for joint spraying to form a foam-like metal support structure. After the forming is completed, the part is cooled in an oxygen-free environment to form a foam-like metal support structure. It is removed by mechanical means to obtain multi-material tiny parts.

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