Laser additive manufacturing device and method for nickel-based magnetic functional composite material

Abstract

The invention discloses a laser additive manufacturing device and method for a nickel-based magnetic functional composite material. The laser additive manufacturing device comprises a multi-axis mechanical arm, a laser device, a forming base table, two sets of powder cylinders and a mixing cabin. Wherein a laser processing head of the laser is arranged at the execution tail end of the multi-axis mechanical arm; the forming base table is arranged below the laser processing head; the two groups of powder cylinders are respectively filled with nickel matrix powder and magnetic particle powder; the mixing cabin comprises a stirrer connected with the two groups of powder cylinders and a powder feeder used for connecting the mixing cabin and the laser processing head; in addition, electromagnetic generators are arranged at the two ends of the stirrer, liquid metal is contained in the stirrer, and the liquid metal assists the nickel matrix powder and the magnetic particle powder to be mixed under the action of the electromagnetic generators.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and in particular relates to a laser additive manufacturing device and method for a nickel-based magnetic functional composite material. Background Art

[0002] Particle-reinforced metal matrix composites are a general term for composite materials that use metal or alloy as the matrix and carbide, oxide, nitride, graphite or even metal particles as reinforcement. Because of the high specific stiffness, specific strength, wear resistance, high temperature resistance and low specific gravity of this type of material, it is suitable for the repair / remanufacturing of aircraft engines or lightweight automotive parts, greatly reducing manufacturing costs.

[0003] In particular, nickel-based composite materials have excellent mechanical properties and are heterogeneous composite materials with great development potential. However, there are few reports on the technology of additive manufacturing of nickel-based composite materials reinforced with magnetic particle powder. During the additive manufacturing process, there is a serious interface reaction at the interface between the two phases, the finished product is prone to cracks, it is difficult to achieve a high-density structure, the workpiece forming quality is poor, and it is difficult to accurately control the powder mixing and powder feeding stages. The above technical problems are the primary difficulties restricting the application and development of additive manufacturing technology for metal parts. In the actual application process, the forming quality will be difficult to control, which will eventually lead to the inability to effectively complete the entire additive manufacturing process of nickel-based composite materials reinforced with magnetic particle powder within a reasonable time, which seriously restricts the development of nickel-based composite material additive technology.

[0004] In view of this, the present invention aims to propose a laser additive manufacturing device and method for nickel-based magnetic functional composite materials, which can reduce the risks in the preparation process, simplify the process flow, reduce costs, and improve the quality and performance of the composite materials. Summary of the invention

[0005] In order to overcome the technical problems described in the prior art, the purpose of the present invention is to provide a laser additive manufacturing device and method for a nickel-based magnetic functional composite material.

[0006] In a first aspect, the present invention provides a laser additive manufacturing device for a nickel-based magnetic functional composite material, comprising:

[0007] Multi-axis robotic arm;

[0008] A laser, including a laser processing head disposed at the execution end of the multi-axis multi-axis robotic arm;

[0009] A molding base, arranged below the laser processing head;

[0010] Two sets of powder cylinders, respectively containing nickel matrix powder and magnetic particle powder;

[0011] A mixing chamber, comprising a stirrer connected to the two sets of powder cylinders, and a powder feeder for connecting the mixing chamber and the laser processing head;

[0012] Wherein, electromagnetic generators are arranged at both ends of the stirrer, and liquid metal is contained in the stirrer. Under the action of the electromagnetic generator, the liquid metal assists the nickel matrix powder and the magnetic particle powder to be mixed.

[0013] As a preferred technical solution, the electromagnetic generator includes a power module, a waveform module generator, a power amplifier and a magnetic field coil, and the electromagnetic generator can generate an oscillating magnetic field with a sinusoidal alternating waveform.

[0014] As a preferred technical solution, the peak intensity of the oscillating magnetic field is not less than 50mT.

[0015] As a preferred technical solution, the stirrer is made of polyethylene and coated with a lead titanate film on its surface, and the stirring paddle in the stirrer performs circular motion at an angular velocity of not less than 30 rad / s.

[0016] As a preferred technical solution, it also includes a protective gas protection device for ensuring that the additive manufacturing is carried out in a protective gas atmosphere, and the protective gas is N2 or an inert gas.

[0017] As a preferred technical solution, the light source of the laser processing head comes from a solid laser with a laser wavelength of 1064 nm, which contains three gas channels, and the beam energy is Gaussian distributed in space.

[0018] In a second aspect, based on the laser additive manufacturing device of the nickel-based magnetic functional composite material, the present invention also provides an additive manufacturing method, comprising the following steps:

[0019] Prepare raw materials: put nickel matrix powder and magnetic particle powder as initial materials into corresponding powder cylinders, and put liquid metal into a stirrer;

[0020] Powder mixing operation: nickel matrix powder and magnetic particle powder fall from the powder cylinder into the agitator filled with liquid metal, and the liquid metal is used to encapsulate the magnetic particle powder; the electromagnetic generator is turned on to use the alternating oscillating magnetic field to reduce powder mixing defects, and the strong eddy current effect of the liquid metal promotes uniform powder mixing;

[0021] Part forming: The powder feeder feeds the mixture into powder, and the multi-axis robot arm and laser are turned on for additive manufacturing.

[0022] As a preferred technical solution, when the front layer is manufactured, the nickel matrix powder and the magnetic particle powder need to maintain a constant mixing ratio.

[0023] As a preferred technical solution, the spot diameter of the laser processing head is no more than 3 mm, and the multi-axis robotic arm moves along the planned path at a moving speed of no less than 10 mm / s.

[0024] As a preferred technical solution, the nickel matrix powder is IN718, and the magnetic particle powder is NdFeB.

[0025] In summary, the present invention has the following technical effects:

[0026] The present invention discloses a laser additive manufacturing device and method for a nickel-based magnetic functional composite material. The laser additive manufacturing device comprises a multi-axis mechanical arm, a laser, a molding base, two groups of powder cylinders and a mixing chamber. The laser processing head of the laser is arranged at the execution end of the multi-axis mechanical arm. The molding base is arranged below the laser processing head. The two groups of powder cylinders are respectively filled with nickel matrix powder and magnetic particle powder. The mixing chamber comprises a stirrer connected to the two groups of powder cylinders, and a powder feeder for connecting the mixing chamber and the laser processing head. In addition, electromagnetic generators are arranged at both ends of the stirrer. Liquid metal is contained in the stirrer. The liquid metal assists the nickel matrix powder and the magnetic particle powder to be mixed under the action of the electromagnetic generator. The additive manufacturing method using the above-mentioned device has the following technical advantages: 1. The present invention has a simple structure and strong operability. It innovatively proposes liquid metal encapsulation of magnetic particle powder, thereby enhancing the compatibility of magnetic particle powder with the alloy matrix and effectively avoiding interface reaction; 2. The present invention uses an alternating magnetic field to quickly magnetize the magnetic particle powder in situ, and realizes flexible proportional stirring, powder mixing and precise control of magnetic particle powder and nickel matrix powder based on the alternating Lorentz force, effectively reducing powder mixing defects and achieving dispersed and uniform powder mixing; 3. In the additive manufacturing process of the present invention, when interlayer thermal stress produces microcracks, the high surface tension of the liquid metal induces the directional movement of the magnetic particle powder, realizing the self-healing of cracks in the nickel matrix composite material, and providing a new idea for high-density functional alloy gradient additive molding. Therefore, compared with the existing additive manufacturing technology, the present invention has obvious technical advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 is a schematic structural diagram of a laser additive manufacturing device according to an embodiment of the present invention;

[0029] Figure 2 is a schematic diagram of a crack healing mechanism of a nickel-based composite material according to an embodiment of the present invention;

[0030] The meanings of the reference numerals are as follows:

[0031] 11-Multi-axis robotic arm, 12-Laser processing head;

[0032] 2-molding abutment;

[0033] 31-powder cylinder, 32-mixing chamber, 321-agitator, 322-electromagnetic generator, 33-powder feeder;

[0034] 4-Protective gas protection device. DETAILED DESCRIPTION

[0035] The following will be combined with the accompanying drawings in this embodiment to clearly and completely describe the technical solution in this embodiment. The present embodiment described herein is only for illustrative purposes and is not intended to limit the scope of protection of the present invention. Therefore, it should be understood that various modifications and changes can be made to this embodiment without departing from the scope of protection of the present invention.

[0036] In the description of the present invention, unless otherwise clearly specified and limited, the term "and / or" includes any and all combinations of one or more associated listed items. Unless otherwise specified or explained, the terms "connection", "fixed", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] Further, in the description of the present invention, it should be understood that the directional words described in the present embodiment are described at the angles shown in the accompanying drawings and should not be understood as limiting the present embodiment. It should also be understood that in the context, when it is mentioned that an element or feature is connected to another element (one or more), it can not only be directly connected to the other (one or more) elements, but also indirectly connected to the other (one or more) elements through an intermediate element.

[0038] Before introducing the technical solution of the present invention, it is necessary to explain the background of the invention of the present invention. It is common that there are few reports on the technology of additive manufacturing of nickel-based composite materials reinforced with magnetic particle powder. In the additive manufacturing process, there is a serious interface reaction at the interface between the two phases, the finished product is prone to cracks, it is difficult to achieve a high-density structure, the workpiece forming quality is poor, and it is difficult to accurately control the powder mixing and powder feeding stages. The above technical problems are the primary difficulties restricting the application and development of additive manufacturing technology for metal parts. In the actual application process, the forming quality will be difficult to control, which will eventually lead to the inability to effectively complete the entire additive manufacturing process of nickel-based composite materials reinforced with magnetic particle powder within a reasonable time, which seriously restricts the development of nickel-based composite material additive technology. In view of this, the present invention aims to propose a laser additive manufacturing device and method for nickel-based magnetic functional composite materials, which can reduce the risks in the preparation process, simplify the process flow, reduce costs, and improve the quality and performance of composite materials.

[0039] See also Figure 1 The present invention first provides a laser additive manufacturing device for nickel-based magnetic functional composite materials. The laser additive manufacturing device includes a multi-axis robot 11, a laser, a molding base 2, two groups of powder cylinders 31 and a mixing chamber 32; wherein, the laser processing head 12 of the laser is arranged at the execution end of the multi-axis robot 11; the molding base 2 is arranged below the laser processing head 12; the two groups of powder cylinders 31 are respectively filled with nickel matrix powder and magnetic particle powder; the mixing chamber 32 includes a stirrer 321 connected to the two groups of powder cylinders 31, and a powder feeder 33 for connecting the mixing chamber 32 and the laser processing head 12; in addition, electromagnetic generators 322 are arranged at both ends of the stirrer 321, and liquid metal is contained in the stirrer 321. The liquid metal assists the nickel matrix powder and the magnetic particle powder to mix powder under the action of the electromagnetic generator 322. In some embodiments, the electromagnetic generator 322 includes a power module, a waveform module generator, a power amplifier and a magnetic field coil, and the electromagnetic generator 322 can generate an oscillating magnetic field with a sinusoidal waveform alternating. As a preferred technical solution, the laser additive manufacturing device of the present invention further includes a protective gas protection device 4 for ensuring that additive manufacturing is carried out in a protective gas atmosphere, wherein the protective gas is N2 or an inert gas. As a preferred technical solution, the light source of the laser processing head 12 comes from a solid laser with a laser wavelength of 1064nm, which contains three gas channels, and the beam energy is Gaussian distributed in space.

[0040] In the powder mixing process, the possibility and multi-directionality of the interface reaction between the nickel matrix powder and the magnetic particle powder in direct contact will directly affect the interface bonding state in the composite material, and ultimately have a significant impact on the performance of the composite material. In order to reduce the serious impact of the interface characteristics on the performance of the composite material, the laser additive manufacturing device with the above structure creatively proposes liquid metal encapsulation of magnetic particle powder, such as Figure 2 As shown, the liquid metal encapsulates the magnetic particle powder, so that the magnetic particle powder enhances the compatibility with the nickel matrix powder, thereby effectively reducing the interface reaction.

[0041] As an excellent technical solution, a sinusoidal current is passed through the magnetic field coil of the electromagnetic generator 322 to generate an oscillating magnetic field whose magnetic field strength changes with time gradient. The peak strength of the magnetic field is 50mT. An alternating oscillating magnetic field is used to quickly magnetize the magnetic particle powder in situ, and the alternating Lorentz force is used to achieve flexible proportional stirring, powder mixing and precise control of the magnetic particle powder and the nickel matrix powder, effectively reducing powder mixing defects and achieving dispersed and uniform powder mixing. Under the alternating oscillating magnetic field, due to the strong eddy current effect of the liquid metal, the liquid metal can promote the Brownian motion between the magnetic particle powders to achieve uniform powder mixing through its own magnetic induction heating ability.

[0042] Further, such as Figure 2 As shown, the liquid metal is fixed to the surface of the magnetic particle powder by high surface tension to avoid the risk of collapse of the magnetic particle powder under the action of the alternating Lorentz force and the strong magnetic mutual attraction, and to maintain the characteristics of the magnetic particle powder itself to the maximum extent; further, the alternating oscillating magnetic field can also be used to promote the self-assembly of the magnetic particle powder that does not undergo Brownian motion in the liquid metal into a three-dimensional oriented and branched magnetic network structure to enhance the magnetic sensitivity of the functional alloy. In addition, when microcracks are generated by interlayer thermal stress, the high surface tension of the liquid metal induces the directional movement of the magnetic particle powder. The liquid metal is attached to the surface of the magnetic particle powder. Its high surface tension can pull the hard magnetic particle powder to the crack area during printing, realize the self-healing of the printed part, and break through the bottleneck of insufficient precision of the existing technology.

[0043] In some embodiments, the agitator 321 is made of polyethylene and coated with a PbTiO3 (lead titanate) thin film. The ferroelectric skyrmion effect of PbTiO3 at room temperature without an external field can be used to prevent magnetothermal damage to the surface of the agitator 321 and prevent the adhesion of magnetic particle powder. The stirring paddle in the agitator 321 can perform circular motion at an angular velocity of not less than 30 rad / s to perform stirring and powder mixing steps.

[0044] Preferably, the melting point of the liquid metal used in the present invention is not higher than room temperature, such as liquid GaInSn (gallium indium tin alloy, a low melting point alloy).

[0045] It should be noted that the nickel matrix powder used in the present invention is preferably IN718 (a nickel-based alloy with high strength and high temperature resistance), which has excellent mechanical properties and corrosion resistance and is widely used in aerospace, energy and other fields. The magnetic particle powder used in the present invention is preferably NdFeB (NdFeB). NdFeB particle powder has extremely high magnetic energy product and coercive force, which enables the particle powder to generate a strong magnetic field after being magnetized by a magnetizing device, and its magnetization effect shows significant advantages in many applications.

[0046] Second, see Figure 1 and Figure 2 Based on the laser additive manufacturing device of the nickel-based magnetic functional composite material, the present invention also provides an additive manufacturing method, comprising the following steps:

[0047] Step 1: 3D modeling of the printed part, and complete model slicing, path planning, and component partitioning;

[0048] Step 2, preparing raw materials: selecting nickel matrix powder and magnetic particle powder as initial materials for additive manufacturing and placing them into corresponding powder cylinders 31;

[0049] The particle size of the nickel matrix powder is preferably 15 μm to 40 μm, and the particle size of the magnetic particle powder is preferably 12 μm to 30 μm;

[0050] Step 3, powder mixing operation: drop the nickel matrix powder and the magnetic particle powder into a stirring tank filled with liquid metal, turn on the electromagnetic generator 322 to set the magnetic field parameters, and the stirring paddle in the stirring tank moves in a circular motion at an angular velocity of not less than 30 rad / s;

[0051] Preferably, the powder mixing is started with the weight ratio of the magnetic particle powder to the mixed material being 20wt%;

[0052] The liquid metal assists the nickel matrix powder and the magnetic particle powder to mix under the action of the electromagnetic generator 322;

[0053] The principle of the above process is as follows: liquid metal encapsulates magnetic particle powder to enhance the compatibility of magnetic particle powder with nickel matrix powder, so as to effectively reduce interface reaction; at the same time, liquid metal is fixed to the surface of magnetic particle powder by high surface tension to avoid the risk of collapse of magnetic particle powder under collision under the action of alternating Lorentz force and strong magnetic mutual attraction, so as to maximize the maintenance of the characteristics of magnetic particle powder itself; further, alternating oscillating magnetic field can also be used to promote magnetic particle powder that does not undergo Brownian motion to self-assemble into a three-dimensional oriented, branched magnetic network structure in liquid metal to enhance the magnetic sensitivity of functional alloys; in addition, when interlayer thermal stress produces microcracks, the high surface tension of liquid metal induces directional movement of magnetic particle powder, and the surface of magnetic particle powder is attached with liquid metal, and its high surface tension can pull hard magnetic particle powder to the crack area during printing, so as to achieve self-healing of printed parts.

[0054] Step 4, part forming: the powder feeder 33 feeds powder at a powder feeding rate of not less than 6 g / min, and the laser is turned on, and the multi-axis robot arm 11 drives the laser processing head 12 to move along the planned path to complete the current layer manufacturing;

[0055] Furthermore, the implementation of step 3 also includes turning on the protective gas protection device 4 to ensure that the additive manufacturing is performed in a protective gas atmosphere;

[0056] It should be noted that the nickel matrix powder is IN718, and the magnetic particle powder is NdFeB.

[0057] As a preferred technical solution, when the current layer is manufactured, the nickel matrix powder and the magnetic particle powder need to maintain a certain mixing ratio; after the current layer is manufactured, the weight ratio of the magnetic particle powder to the mixed material is increased by 20wt% and then mixed, while increasing the oscillating magnetic field strength to continue mixing.

[0058] As a preferred technical solution, the spot diameter of the laser processing head 12 is no larger than 3 mm, and the multi-axis robot arm 11 moves along the planned path at a moving speed of no less than 10 mm / s.

[0059] In a third aspect, the present invention further provides a nickel-based magnetic functional composite material, which is prepared by the above-mentioned laser additive manufacturing device or the above-mentioned additive manufacturing method. The nickel-based magnetic functional composite material is specifically a magnetic particle powder reinforced nickel-based composite material, which has excellent molding quality, excellent specific stiffness, specific strength, wear resistance, high temperature resistance and low specific gravity.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser additive manufacturing device for nickel-based magnetic functional composite materials, characterized in that: include: Multi-axis robotic arm; A laser, including a laser processing head disposed at the execution end of the multi-axis multi-axis robotic arm; A molding base, arranged below the laser processing head; Two sets of powder cylinders, respectively containing nickel matrix powder and magnetic particle powder; A mixing chamber, comprising a stirrer connected to the two sets of powder cylinders, and a powder feeder for connecting the mixing chamber and the laser processing head; Wherein, electromagnetic generators are arranged at both ends of the stirrer, and liquid metal is contained in the stirrer. Under the action of the electromagnetic generator, the liquid metal assists the nickel matrix powder and the magnetic particle powder to be mixed.

2. The laser additive manufacturing device according to claim 1, characterized in that: The electromagnetic generator comprises a power module, a waveform module generator, a power amplifier and a magnetic field coil, and the electromagnetic generator can generate an oscillating magnetic field with alternating sinusoidal waveforms.

3. The laser additive manufacturing device according to claim 1, characterized in that: The peak intensity of the oscillating magnetic field is not less than 50mT.

4. The laser additive manufacturing device according to claim 1, characterized in that: The stirrer is made of polyethylene and coated with a lead titanate film on its surface. The stirring paddle in the stirrer performs circular motion at an angular velocity of not less than 30 rad / s.

5. The laser additive manufacturing device according to claim 1, characterized in that: It also includes a protective gas protection device for ensuring that the additive manufacturing is carried out in a protective gas atmosphere, wherein the protective gas is N2 or an inert gas.

6. The laser additive manufacturing device according to claim 1, characterized in that: The light source of the laser processing head comes from a solid laser with a laser wavelength of 1064nm, and the laser processing head contains three gas channels inside, and the beam energy is Gaussian distributed in space.

7. An additive manufacturing method based on the laser additive manufacturing device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Prepare raw materials: put nickel matrix powder and magnetic particle powder as initial materials into corresponding powder cylinders, and put liquid metal into a stirrer; Powder mixing operation: nickel matrix powder and magnetic particle powder fall from the powder cylinder into the agitator filled with liquid metal, and the liquid metal is used to encapsulate the magnetic particle powder; the electromagnetic generator is turned on to use the alternating oscillating magnetic field to reduce powder mixing defects, and the strong eddy current effect of the liquid metal promotes uniform powder mixing; Part forming: The powder feeder feeds the mixture into powder, and the multi-axis robot arm and laser are turned on for additive manufacturing.

8. The additive manufacturing method according to claim 7, characterized in that: When the front layer is manufactured, the nickel matrix powder and the magnetic particle powder must maintain a certain mixing ratio.

9. The additive manufacturing method according to claim 7, characterized in that: The spot diameter of the laser processing head is no more than 3 mm, and the multi-axis robotic arm moves along the planned path at a speed of no less than 10 mm / s.

10. The additive manufacturing method according to claim 7, characterized in that: The nickel matrix powder is IN718, and the magnetic particle powder is NdFeB.

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