Oxide dispersion strengthened metal powder for 3D printing and preparation method of oxide dispersion strengthened metal powder

Abstract

The invention discloses oxide dispersion strengthened metal powder for 3D printing and a preparation method of the oxide dispersion strengthened metal powder. The preparation method comprises the following steps that S1, the smelting process is conducted, specifically, a metal ingot is put into a vacuum smelting furnace or a feeding system integrated with powder manufacturing equipment, vacuumizing and high-temperature melting are conducted to be in a molten state, and a melt is obtained; s2, the atomization process is conducted, specifically, the melt is put into powder manufacturing equipment, small metal liquid drops are generated in a reaction chamber through the melt, fine spherical metal powder is formed, and the fine spherical metal powder with the needed particle size is collected through screening under the protective atmosphere; wherein oxygen is doped in the smelting process and / or the atomization process. The oxide particles can be dispersed inside and outside the metal powder, the problem that oxide can only be added on the surface through thermal oxidation and mechanical grinding is solved, meanwhile, the laser absorptivity is improved, and the 3D printing performance of the metal powder is improved.

Description

Oxide dispersion strengthened metal powder for 3D printing and preparation method thereof TECHNICAL FIELD

[0001] The present application relates to 3D printing materials, in particular to an oxide dispersion strengthened metal powder for 3D printing and a preparation method thereof. BACKGROUND

[0002] 3D printing technology can directly process metal powder raw materials into the required shape without post-processing steps, which has high requirements for the strength of the printed material, and the metal raw powder determines the strength of the printed material. Traditional pure metals cannot be directly used in many applications due to their low strength, while alloy materials can exhibit high strength performance, but are limited by the cumbersome pre-alloying step and the increased cost of subsequent heat treatment. In recent years, nano-particle dispersion reinforced metals have attracted much attention due to their need for no heat treatment and significant improvement in strength, and are currently very friendly metal raw materials for 3D printing technology. In addition, materials with high reflectivity to infrared light, such as copper, silver, gold, and aluminum, are very important metal materials in the industry, and 3D printing technology generally uses infrared light wavelengths, which makes it difficult for laser 3D printing technology to process high-reflectivity material components with high density due to insufficient energy input, which greatly limits the development of high-reflectivity materials in the field of 3D printing. Nanoparticles in metal powder play a role in increasing absorption, improving the absorption of laser energy by metal powder. Traditional 3D printing powder oxide particle addition methods, such as mechanical grinding and thermal oxidation, can only add oxide particles to the surface, and it is difficult to achieve uniform dispersion of oxide particles inside and outside the powder, which has disadvantages in strengthening effect, powder flowability, etc., affecting the 3D printing precision and performance.

[0003] It should be noted that the information disclosed in the above BACKGROUND section is only for understanding the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art.

[0004] SUMMARY

[0005] The main purpose of the present application is to provide an oxide dispersion strengthened metal powder for 3D printing and a preparation method thereof to solve the problem of poor printing performance of 3D printing metal powder materials.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A preparation method of an oxide dispersion strengthened metal powder for 3D printing, comprising the following steps:

[0008] S1, smelting process: the metal ingot is put into a vacuum smelting furnace or a feeding system integrated with a powdering device, and is melted into a molten state at high temperature under vacuum to obtain a melt;

[0009] S2, atomization process: the melt is put into a powdering device, and the melt generates metal droplets in a reaction chamber to form fine spherical metal powder, which is sieved under a protective atmosphere to collect fine spherical metal powder of a desired particle size;

[0010] In the smelting process and / or the atomization process, oxygen is doped.

[0011] Further, the oxygen doping in the smelting process includes: when the metal blank is heated and melted, 1000-10000 ppm of oxygen is added to make the melt absorb oxygen in the environment.

[0012] Further, the oxygen doping in the atomization process includes: using a vacuum atomization technology, 1000-10000 ppm of oxygen is added in an inert gas carrier, or using a non-vacuum atomization technology, 1000-10000 ppm of oxygen is added in air carrier.

[0013] Further, the way to maintain the oxygen partial pressure includes: using a partial pressure valve to control the addition of oxygen, or using a constant flow of CO2-H2 gas mixture to control the oxygen partial pressure and adjust the oxygen content, or using a constant flow of O2-He gas mixture to control the oxygen partial pressure and adjust the oxygen content.

[0014] Further, the way to dope oxygen includes: adding oxygen in the smelting chamber and / or the atomization chamber in the form of environmental oxygenation or in the form of nozzle gas injection.

[0015] Further, when the nozzle gas injection is used to dope oxygen, the temperature of the injected gas is 10-50℃; when the environmental oxygenation is used, the temperature in the smelting process is 500-3000℃, and the temperature in the atomization process is 300-2000℃.

[0016] Further, the heating method of smelting includes: resistance heating, electromagnetic induction heating or plasma heating.

[0017] Further, the atomization method includes: high-pressure water atomization, gas atomization or ultrasonic vibration atomization.

[0018] Further, the atomization process includes primary atomization and secondary atomization, the primary atomization includes: the molten metal flows along the tip of the electrode rod to form metal droplets; the secondary atomization includes: when the metal droplets are impacted by inert gas in the nozzle, they are further broken down into smaller droplets, and finally form metal powder.

[0019] An oxide dispersion strengthened metal powder for 3D printing is prepared by the preparation method.

[0020] Further, the oxygen content of the metal powder is 1000-10000 ppm.

[0021] Further, the oxide of the metal powder is a nanoparticle with a diameter of 10-200 nm.

[0022] The present application has the following advantages:

[0023] The present application provides an oxide dispersion strengthened metal powder for 3D printing and a preparation method thereof, which can produce high-strength metal powder at low cost. The metal powder has nanoparticles dispersed inside and outside, and has improved laser absorption rate, high melt viscosity and high wettability. The metal powder has the advantages of high sphericity, good flowability, narrow particle size distribution, controllable oxygen content, controllable oxide size, controllable oxide layer thickness, and high laser absorption rate, which improves the printing performance as a 3D printing metal powder material.

[0024] Compared with the prior art, the preparation method has the following advantages:

[0025] Compared with the prior art, the preparation method has the following advantages:

[0026] The method of the present application can achieve dispersion of oxide particles inside and outside the metal powder, solving the problem of surface addition of oxide particles by thermal oxidation and mechanical grinding, and improving the 3D printing performance of the metal powder.

[0027] The method of the present application directly uses the steps in the powdering process to increase the oxide content in the powder, and the process innovation does not require expensive modification of existing mature equipment, which is low in cost and suitable for popularization.

[0028] Other advantages of the embodiments of the present application will be further described below. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a morphology diagram of a pure copper powder not using the method of the present application;

[0030] Figure 2 is a morphology diagram of the oxide dispersion strengthened pure copper powder prepared in Example 1 of the present application;

[0031] Fig. 3 is a comparison of laser reflectivity of the oxide dispersion strengthened pure copper powder prepared in Example 1 of the present application and the control group pure copper powder, green is the pure copper powder, and red is the oxide dispersion strengthened pure copper powder;

[0032] Fig. 4 is an SEM and TEM morphology diagram of the oxide distribution inside the oxide dispersion strengthened pure copper powder prepared in Example 1 of the present application and the surface oxide layer;

[0033] Fig. 5 is a theoretical formula related to the CO2-H2 gas mixture for controlling the oxygen partial pressure of the present application;

[0034] Fig. 6 is a schematic diagram of a vacuum gas atomization device for preparing the pure copper powder for laser 3D printing in Example 1 of the present application. DETAILED DESCRIPTION

[0035] The embodiments of the present application are described in detail below. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present application and its applications.

[0036] The embodiments of the present application provide a preparation method of an oxide dispersion strengthened metal powder for 3D printing, comprising the following steps:

[0037] S1, a melting process: a metal ingot is put into a feeding system integrated with a powder preparation device in a vacuum melting furnace, and is melted into a molten state by vacuum high temperature melting to obtain a melt;

[0038] S2, an atomization process: the melt is put into a powder preparation device, and the melt generates small metal droplets in a reaction chamber to form a fine spherical metal powder, which is sieved under a protective atmosphere to collect fine spherical metal powder of a desired particle size;

[0039] In the melting process and / or the atomization process, oxygen is doped.

[0040] The embodiments of the present application also provide an oxide dispersion strengthened metal powder for 3D printing, which is prepared by using the preparation method.

[0041] In a preferred embodiment, the oxygen content of the metal powder is 1000 ppm-10000 ppm.

[0042] In a preferred embodiment, the oxide of the metal powder is a nanoparticle with a diameter of 10 nm-200 nm.

[0043] The embodiment of the present application provides an oxide dispersion strengthened metal powder and a preparation method thereof. The metal powder has the characteristics of low cost and high strength, and is suitable for 3D printing application. Compared with traditional oxide particle adding techniques (such as mechanical grinding and thermal oxidation), the present application can ensure that the oxide particles are uniformly distributed inside and outside the metal powder, thereby overcoming the limitation that the traditional method can only form an oxide layer on the surface, and significantly improving the 3D printing applicability of the powder.

[0044] The metal powder of the present application has multiple advantages: high sphericity, excellent fluidity, narrow particle size distribution, and precisely controlled oxygen content, oxide size and oxide layer thickness, high laser absorption rate, high melt viscosity and high wettability. These characteristics work together to make the metal powder of the present application perform well in the 3D printing process, improving the quality and performance of the printed part.

[0045] The preparation method of the present application precisely controls the oxygen content in the gas during the powder making process, achieving fine control of the oxide characteristics. The process innovation of the method of the present application does not require expensive modification of the existing mature process equipment, thus having a lower production cost, and is very suitable for wide application and promotion in industrial production.

[0046] The specific embodiments of the present application are further described below.

[0047] An oxide dispersion strengthened metal powder for 3D printing, the oxygen content of the metal powder can be 1000 ppm-10000 ppm.

[0048] The preparation method of the oxide dispersion strengthened metal powder comprises the following steps:

[0049] Step one: put the metal ingot into the feeding system of the vacuum melting furnace or the powder making equipment integration, vacuumize and melt at high temperature to obtain a melt, this process is called melting process, and oxygen can be doped in this process;

[0050] Step two: put the melt into the powder making equipment, the melt generates small metal droplets in the reaction chamber to form fine spherical metal powder, and the fine spherical metal powder of the required particle size is collected by sieving under a protective atmosphere, this process is called atomization process, and oxygen can be doped in this process.

[0051] In some embodiments, the atomization method of the powder making equipment includes: high-pressure water atomization, gas atomization, ultrasonic vibration atomization.

[0052] In some embodiments, the heating method of the powder making equipment includes: resistance heating, electromagnetic induction heating, and plasma heating.

[0053] In some embodiments, the way of doping a certain amount of oxygen includes:

[0054] The oxygen is absorbed from the environment during the melting process, i.e. 1000-10000 ppm of oxygen is added when the metal blank is heated and melted, so that the melt absorbs oxygen from the environment; or

[0055] The oxygen is doped in a certain amount in inert gas or air during the atomization process, wherein 1000-10000 ppm of oxygen is added in the inert gas carrier gas in the vacuum atomization technology, and 1000-10000 ppm of oxygen is added in the air carrier gas in the non-vacuum atomization technology.

[0056] In some embodiments, the oxygen control method includes: adding oxygen by using a partial pressure valve; or adjusting the oxygen content by using a constant flow of CO2-H2 gas mixture to control the oxygen partial pressure; or adjusting the oxygen content by using a constant flow of O2-He gas mixture to control the oxygen partial pressure. The oxygen partial pressure can be maintained by directly adding oxygen in the vacuum chamber by using a partial pressure valve, or by adding carbon dioxide and hydrogen to adjust the oxygen partial pressure.

[0057] In some embodiments, the oxygen adding method includes: adding oxygen in the vacuum chamber (including the melting chamber and the atomization chamber) in an environmental oxygen adding manner, or adding oxygen through a gas jet nozzle.

[0058] In some embodiments, the oxygen adding stage includes two stages of adding oxygen in the melting process and the atomization process respectively.

[0059] In some embodiments, when the nozzle sprays oxygen, the temperature of the sprayed gas is 10-50℃. When the oxygen is added in an environmental manner, the temperature in the melting process is 500-3000℃, and the temperature in the atomization process is 300-2000℃.

[0060] Example 1:

[0061] Preparation of oxide dispersion strengthened pure copper powder by using a vacuum gas atomization method and an atomization chamber for oxygen addition

[0062] An oxide dispersion strengthened pure copper powder for 3D printing, wherein the oxygen content of the metal powder is 2000-4000 ppm.

[0063] Referring to FIG. 6, the preparation process of the oxide dispersion strengthened pure copper powder includes:

[0064] Step 1: Pretreatment

[0065] The pure copper ingot is made into a cylinder as an electrode copper rod, and one end of the electrode copper rod is processed into a 30-60 degree cone. The surface roughness Ra of the electrode rod is 10-20 μm, and the other end of the electrode rod is processed into a ring-shaped clamping groove near the top end.

[0066] The electrode rod material tip is vertically installed downward in the electrode induction melting chamber, the conical tip is 4-8 cm away from the upper nozzle of the atomization chamber, and the rod material / melting chamber induction coil / atomization chamber are coaxial.

[0067] Step two: after vacuum extraction, fill with protective gas

[0068] The induction melting chamber / atomization chamber / powder collection device is vacuumed, filled with inert gas mixed with oxygen gas, the oxygen content is 2000-4000 ppm, and the gas pressure is maintained at 0.005-0.1 MPa;

[0069] Step three: electrode induction melting

[0070] Adjust the electrode rod material to rotate at the center at a speed of 2-12 r / min; at the same time, turn on the electrode induction power supply, and make the melting power reach 40-120 KW.

[0071] Step four: inert gas atomization

[0072] When the electrode tip becomes bright, the molten pure copper droplets start to flow along the tip of the electrode rod material, and at the same time, the rod material moves downward (500 μm-900 μm / s) and the atomizing nozzle atomizing gas pressure is 1.0-10.0 MPa, the gas temperature when the nozzle sprays is 10-50℃, so that the inert gas sprayed is gathered to the conical tip of the rod material and impacts the molten pure copper droplets, forming pure copper powder in the atomization chamber;

[0073] Step five: metal powder collection and screening

[0074] The prepared pure copper metal powder is collected by using a two-stage powder collection device; the pure copper powder is classified and screened and stored in vacuum.

[0075] Figure 2 shows the morphology of the oxide dispersion strengthened pure copper powder prepared in Example 1. Figure 3 shows the laser reflectivity comparison of the oxide dispersion strengthened pure copper powder prepared in Example 1 and the control group pure copper powder, green is pure copper powder, red is oxide dispersion strengthened pure copper powder. Figure 4 shows the SEM and TEM morphology of the internal oxide distribution and surface oxide layer of the oxide dispersion strengthened pure copper powder prepared in Example 1.

[0076] Example 2:

[0077] Using a vacuum gas atomization method to prepare oxide dispersion strengthened pure copper powder using a nozzle to add oxygen

[0078] An oxide dispersion strengthened pure copper powder for 3D printing, the metal powder contains 2000-4000 ppm of oxygen.

[0079] Step one: pretreatment

[0080] The pure copper ingot is made into a cylindrical body as an electrode copper rod, and one end of the electrode copper rod is processed into a 30-60 degree cone, the surface roughness of the electrode rod is Ra=10 μm-Ra20=μm, and the other end of the electrode rod is processed into a ring-shaped clamping groove near the top end.

[0081] The electrode rod tip is vertically installed downward in the electrode induction melting chamber, the cone top end is 4-8 cm away from the upper nozzle of the atomization chamber, and the rod / melting chamber induction coil / atomization chamber are coaxial.

[0082] Step two: after vacuum extraction, fill in the protective gas

[0083] The induction melting chamber / atomization chamber / powder collecting device is vacuumed, inert gas is filled in, and the gas pressure is kept at 0.005-0.1 MPa;

[0084] Step three: electrode induction melting

[0085] The electrode rod is adjusted to rotate around the center at a speed of 2-12 r / min; at the same time, the electrode induction power supply is turned on, and the melting power reaches 40-120 KW.

[0086] Step four: inert gas atomization

[0087] When the electrode tip becomes bright, the molten pure copper droplets start to flow along the tip of the electrode rod, and at the same time, the rod moves downward (500 μm-900 μm / s) and the atomizing nozzle atomizing gas pressure is 1.0-10.0 MPa, the atomizing nozzle sprays inert gas mixed with oxygen gas, the oxygen content is 2000-4000 ppm, and the gas temperature is 10-50℃ when the nozzle sprays, so that the sprayed inert gas converges to the conical top end of the rod and impacts the molten pure copper droplets, forming pure copper powder in the atomization chamber;

[0088] Step five: metal powder collection and screening

[0089] The prepared pure copper metal powder is collected by using a two-stage powder collecting device; the pure copper powder is classified and screened and is stored in vacuum.

[0090] Compared with the prior art, the embodiments of the present application have the following advantages:

[0091] Compared with the traditional 3D printing powder oxide particle adding method, such as mechanical grinding, thermal oxidation, etc., the method of the present application can realize that the oxide particles are dispersed inside and outside the metal powder, solves the problem that thermal oxidation and mechanical grinding can only add oxide particles on the surface, and at the same time improves the laser absorption rate and improves the 3D printing performance of the metal powder.

[0092] The method of the present application controls the content and size of the oxides in the finally generated powder by adding a quantitatively controllable oxygen content in the gas, has good controllability of the oxygen content, oxide size and oxide layer thickness, and produces high-strength metal powder with high sphericity, good flowability, narrow particle size distribution and high laser absorption rate.

[0093] The method of the present application directly uses the step in the powdering process to increase the oxides in the powder, and the process innovation improvement does not need expensive modification of the existing mature process equipment, has low cost and is suitable for promotion.

[0094] The above is a further detailed description of the present application in combination with specific / preferred embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, they can make several substitutions or modifications to the described embodiments, and these substitutions or modifications shall be considered as belonging to the protection scope of the present application. In the description of the present application, the description of the terms "one embodiment", "some embodiments", "preferred embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the case of no mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples. Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made in the present application without departing from the scope of protection of the patent application.

Claims

1. A method for the production of oxide dispersion strengthened metal powder for 3D printing, characterized in that, The method comprises the following steps: S1, smelting process: put the metal ingot into the feeding system of the vacuum smelting furnace or the integrated powder making equipment, and melt at high temperature under vacuum to obtain a melt; S2, atomization process: put the melt into the powder making equipment, and generate metal droplets in the reaction chamber to form fine spherical metal powder, and sieve under a protective atmosphere to collect fine spherical metal powder with a desired particle size; In the smelting process and / or the atomization process, oxygen is doped.

2. The production method according to claim 1, wherein In the smelting process, 1000-10000 ppm of oxygen is added when the metal blank is heated and melted, so that the melt absorbs oxygen in the environment.

3. The production method according to claim 1 or 2, characterized by, In the atomization process, 1000-10000 ppm of oxygen is added in the inert gas carrier gas by using vacuum atomization technology, or 1000-10000 ppm of oxygen is added in the air carrier gas by using non-vacuum atomization technology.

4. The production method according to any one of claims 1 to 3, characterized by, The method for maintaining the oxygen partial pressure includes: controlling the addition of oxygen by using a partial pressure valve; or adjusting the oxygen content by using a constant flow of CO2-H2 gas mixture to control the oxygen partial pressure; or adjusting the oxygen content by using a constant flow of O2-He gas mixture to control the oxygen partial pressure.

5. The production method according to any one of claims 1 to 4, wherein The method for doping oxygen includes: adding oxygen in the form of environmental oxygenation in the smelting chamber and / or the atomization chamber, or in the form of nozzle gas injection.

6. The production method according to claim 5, wherein When the nozzle gas injection is used for oxygenation, the temperature of the injected gas is 10-50℃; when the environmental oxygenation is used, the temperature in the smelting process is 500-3000℃, and the temperature in the atomization process is 300-2000℃.

7. The production method according to any one of claims 1 to 6, wherein The heating method for smelting includes resistance heating, electromagnetic induction heating or plasma heating; the atomization method includes high-pressure water atomization, gas atomization or ultrasonic vibration atomization.

8. The production method according to any one of claims 1 to 7, wherein The atomization process includes primary atomization and secondary atomization, the primary atomization includes: the molten metal flows along the tip of the electrode rod to form metal droplets; the secondary atomization includes: the metal droplets are further broken into smaller droplets when impacted by the inert gas in the nozzle, and finally form metal powder.

9. An oxide dispersion strengthened metal powder for 3D printing, characterized in that, The metal powder is prepared by using the preparation method according to any one of claims 1-8.

10. The oxide dispersion-strengthened metal powder of claim 9 wherein, The oxygen content of the metal powder is 1000-10000 ppm.

11. The oxide dispersion-strengthened metal powder of claim 9, wherein the oxide particles have an average diameter of 0.1 to 1.0 μm. The oxide of the metal powder is a nanoparticle with a diameter of 10-200 nm.

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