Additive component performance optimization process method based on external magnetic field assistance

Abstract

The invention belongs to the technical field of additive manufacturing, and discloses an additive component performance optimization process method based on external magnetic field assistance. According to the method, a cold metal transition welding technology in an electric arc additive technology is adopted, in the forming process of the aluminum alloy thin-wall part, electromagnetic stirring is conducted through an external longitudinal magnetic field, so that the structure property and the mechanical property of metal are optimized, the surface forming precision is improved, and the effective deposition rate is increased; meanwhile, the porosity of the component is reduced, the grain structure is improved, and the microhardness and tensile strength are improved. The method provides an important technical reference for promoting application and development of electric arc additive manufacturing in the field of aluminum alloy thin-wall part forming.

Description

Technical Field

[0001] This invention relates to the field of electric arc additive manufacturing technology, and in particular to a process method for optimizing the performance of additive components based on external magnetic field assistance. Background Technology

[0002] As a widely used metal additive manufacturing technology, arc additive manufacturing has significant advantages such as low cost and high deposition efficiency, providing a new way for the rapid manufacturing and repair of large metal parts, and has great application prospects in fields such as shipbuilding, machinery manufacturing, and aerospace.

[0003] However, the molten zone in arc additive manufacturing is relatively large, and the deposited layer undergoes complex thermal cycles. This often results in potential defects such as coarse grains, significant anisotropy in mechanical properties, high residual stress and thermal deformation, and low forming accuracy, making it difficult to control the microstructure and properties of the components. To address these issues, traditional methods of adjusting deposition process parameters are time-consuming and costly in additive manufacturing, with limited performance improvement after optimization.

[0004] Therefore, a novel control method is needed to improve component performance, thereby saving manufacturing costs and accelerating production efficiency. Applying an external electromagnetic field to introduce interlayer electromagnetic stirring, as a control method in arc additive manufacturing, offers advantages such as lower device design and manufacturing costs and higher degrees of freedom. Interlayer stirring technology utilizes electromagnetic fields to promote or hinder the flow of molten metal, stirring the molten pool and refining the grain structure, effectively improving the component's hardness. Simultaneously, the magnetically induced heat generated by the electromagnetic field can reduce the temperature gradient in the molten pool region, decrease the anisotropy of transverse and longitudinal tensile strength, and reduce thermal stress and deformation of the component. Summary of the Invention

[0005] This invention proposes a process method for optimizing the performance of additive manufacturing components based on an external magnetic field. Its purpose is to address the problems of high porosity, interlayer segregation, and significant anisotropy of mechanical properties in thin-walled aluminum alloy parts manufactured by arc additive manufacturing. This provides new insights for the development and engineering application of arc additive manufacturing technology.

[0006] The specific technical solution of this invention is as follows:

[0007] A method for optimizing the performance of additive manufacturing components based on external magnetic field assistance, characterized by the following steps:

[0008] S1: Optimization process parameters for single-layer single-pass deposition of 2319 aluminum alloy by arc additive manufacturing under no magnetic field conditions.

[0009] S2: Optimization of excitation parameters for single-layer, single-channel deposition of 2319 aluminum alloy using electromagnetic stirring-assisted deposition.

[0010] S3: Experiment on 2319 aluminum alloy thin-walled parts produced by electric arc additive manufacturing with and without electromagnetic stirring.

[0011] S4: Microstructure observation and mechanical property analysis of 2319 aluminum alloy thin-walled parts produced by arc additive manufacturing with and without electromagnetic stirring.

[0012] Prioritizing the acquisition of optimized process parameters for single-layer, single-pass deposition of 2319 aluminum alloy using arc additive manufacturing under magnetic field-free conditions. Specifically, obtaining optimized deposition parameters is a prerequisite for subsequent experiments. For single-layer, single-pass deposition experiments of 2319 aluminum alloy using arc additive manufacturing, it is necessary to obtain optimal deposition current, deposition voltage, and deposition rate. This invention employs an orthogonal experimental method to optimize the deposition parameters of 2319 aluminum alloy using arc additive manufacturing. By observing the macroscopic morphology of each deposition layer, and ensuring minimal hump defects, minimal deposition spatter, and a low aspect ratio of the deposition layer, a combination of deposition parameters with optimal deposition effect is obtained.

[0013] Prioritizing the acquisition of optimized excitation parameters for single-layer, single-pass deposition of 2319 aluminum alloy under electromagnetic stirring-assisted arc additive manufacturing, this study focuses on obtaining optimal electromagnetic stirring effects for further interlayer electromagnetic stirring-assisted arc additive manufacturing experiments. Specifically, based on the obtained deposition parameters, a single-layer, single-pass deposition experiment under electromagnetic stirring-assisted conditions was designed to optimize various excitation parameters, including excitation frequency and excitation current, in order to achieve better electromagnetic stirring effects. Finally, also based on the macroscopic morphology of the deposited layer under interlayer electromagnetic stirring conditions, the spread and spatter of the deposited layer were observed to obtain optimal excitation parameters.

[0014] Prior to this, experiments were conducted on thin-walled 2319 aluminum alloy parts produced by arc additive manufacturing with and without electromagnetic stirring. Specifically, based on the obtained deposition and excitation parameters, two sets of experiments on thin-walled 2319 aluminum alloy parts produced by arc additive manufacturing with and without electromagnetic stirring were carried out.

[0015] Prioritizing the observation of the microstructure and mechanical property analysis of 2319 aluminum alloy thin-walled parts manufactured by arc additive manufacturing with and without electromagnetic stirring, the following steps were performed: Metallographic samples were prepared from the top, middle, and bottom of the thin-walled parts with and without interlayer electromagnetic stirring using an EDM machine, and the microstructure was observed. The pore size, second-phase morphology, and distribution characteristics of the arc-added 2319 aluminum alloy thin-walled structure were observed using a scanning electron microscope (SEM). SEM images of the middle region of the deposited part after natural cooling were taken, and micro-area composition analysis was performed using the energy dispersive spectroscopy (EDS) instrument integrated into the SEM. Vickers hardness measurements were performed along the centerline of the thin-walled part's cross-section from the substrate to the top. Furthermore, tensile properties were tested on transverse and longitudinal tensile samples of the 2319 aluminum alloy thin-walled parts manufactured by arc additive manufacturing with and without interlayer electromagnetic stirring, obtaining the transverse and longitudinal tensile strengths of the arc-added 2319 aluminum alloy thin-walled parts. Comprehensive analysis of the microstructure and mechanical properties of thin-walled parts verifies the reliability of the proposed method of adding electromagnetic stirring during the electric arc additive manufacturing process to improve the performance of the components.

[0016] Compared with existing technologies, the present invention has the following positive effects: The method for improving the performance of aluminum alloy components by introducing electromagnetic stirring in arc additive manufacturing, as claimed in this invention, can reduce the surface waviness of the components, break dendrites and second phases, weaken the conditions for porosity nucleation, and promote porosity overflow and equiaxed crystal transformation, thereby enhancing the average hardness of the components. Simultaneously, it improves the transverse and longitudinal tensile strength and elongation of the components, and reduces the anisotropy of tensile properties. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an electromagnetic stirring-assisted arc additive manufacturing process provided in a specific embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of an integrated electromagnetic stirring-assisted arc additive manufacturing system provided in a specific embodiment of the present invention;

[0019] Figure 3 This refers to the deposition of electrical signals in the ACTIVE mode provided in a specific embodiment of the present invention;

[0020] Figure 4 This invention provides optimized experimental parameters and corresponding macroscopic morphology for a single layer and single channel under electromagnetic stirring-free conditions, according to specific embodiments of the invention.

[0021] Figure 5 This is a characteristic excitation signal output diagram provided in a specific embodiment of the present invention;

[0022] Figure 6 The macroscopic morphology of the 2319 aluminum alloy thin-walled part produced by arc additive manufacturing according to specific embodiments of the present invention is as follows: (a) with interlayer electromagnetic stirring and (b) without interlayer electromagnetic stirring.

[0023] Figure 7 This is a schematic diagram of surface waviness calculation provided in a specific embodiment of the present invention.

[0024] Figure 8 The specific embodiments of the present invention provide the top, middle and bottom microstructures of the additive thin-walled part with and without interlayer electromagnetic stirring arc;

[0025] Figure 9 This is a specific embodiment of the invention providing the second phase distribution characteristics in the middle region of a thin-walled component under the presence or absence of interlayer electromagnetic stirring;

[0026] Figure 10 This is a specific embodiment of the invention providing the microhardness distribution along the center line of the deposition height with or without interlayer electromagnetic stirring;

[0027] Figure 11 This refers to the tensile properties provided by specific embodiments of the present invention under the presence or absence of interlayer electromagnetic stirring. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] The present invention will be described below based on embodiments. Those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes and are not necessarily drawn to scale.

[0030] Step 1: A process method for optimizing the performance of additive components based on external magnetic field assistance, the process design is as follows: Figure 1 As shown. First, a 2A12 aluminum alloy substrate with dimensions of 200mm (width) × 300mm (length) × 5mm (thickness) is used. ER2319 aluminum alloy welding wire with a diameter of 1.2mm is used for deposition. The substrate is polished with a grinding wheel to remove oxides. Then, acetone is used to wipe off the oil stains on the surface of the substrate and the welding wire.

[0031] The designed orthogonal process experimental scheme is shown in Table 1. Argon gas with a purity of 99.99% was used as the shielding gas, with a flow rate of 20 L / min, a wire extension of 10 mm, and a deposition length of 80 mm. The welding power source was selected in ACTIVE mode, and the deposition electrical signal was as follows: Figure 3 As shown.

[0032] Table 1 Optimized experimental parameters for a single-layer, single-channel system under conditions without electromagnetic stirring.

[0033]

[0034]

[0035] Furthermore, the deposition layer morphology corresponding to the optimized experimental parameters for a single layer and single channel under electromagnetic stirring conditions is as follows: Figure 4 As shown. Based on the single-layer single-channel deposition experiment, the macroscopic morphology of each deposition layer was observed. Under the conditions of minimizing hump defects, minimizing deposition splash, and ensuring a low aspect ratio of the deposition layer, the experimental parameters of group A08 were finally selected, namely, deposition current of 130A, deposition voltage of 18.2V, and deposition velocity of 0.6m / min, for subsequent deposition experiments. The other parameters of the remaining experiments were consistent with those of the single-layer single-channel deposition experiment under conventional conditions.

[0036] Step 2: Based on the optimized deposition parameters already obtained, in order to obtain better electromagnetic stirring effect and further carry out interlayer electromagnetic stirring assisted arc additive manufacturing experiments, a single-layer single-pass deposition experiment under electromagnetic stirring assisted conditions was first designed to optimize various excitation parameters, including excitation frequency and excitation current.

[0037] Furthermore, a self-designed external auxiliary longitudinal magnetic field device was introduced. This device mainly consists of a hollow DT4C iron core and an enameled coil, and can be connected to an external excitation power supply, generating a magnetic field with a maximum magnetic flux density exceeding 100mT. The excitation power supply used is an AN5010-MN type Annes power supply, with a square wave output signal. The self-designed magnetic field generator is mounted on the welding torch and coaxial with it, moving with the torch during the arc additive manufacturing process. Before each deposition pass, the excitation parameters are set and checked, and the excitation power supply is turned on. Simultaneously, an HT201 teslameter is used to measure the magnetic field strength at the welding wire tip to determine its stability. The excitation power supply is turned off during the interlayer cooling stage after each deposition layer to prevent excessive accumulation of resistive heat from the copper wire, which could cause changes in permeability and lead to electromagnetic field instability. The characteristics of the set excitation signal are as follows: Figure 5 As shown, the magnitude of the generated electromagnetic force remains constant, but its direction will continuously change to achieve a better electromagnetic stirring effect. The design scheme of the excitation parameters is shown in Table 2.

[0038] Table 2 Experimental parameters for single-layer, single-channel excitation parameter optimization

[0039]

[0040]

[0041] Furthermore, the macroscopic morphology corresponding to the experimental parameters for single-layer, single-channel excitation parameter optimization is as follows: Figure 4As shown. Finally, based on the macroscopic morphology of the deposited layer under the condition of introducing interlayer electromagnetic stirring, the spread and splashing of the deposited layer were observed. It was found that if the excitation current is too large, the splashing will be larger and the surface finish will be worse. If the excitation frequency is too large, the improvement of the droplet wettability by the electromagnetic field will be weakened. Finally, the experimental parameters of group B10, namely the excitation current of 1.5A and the excitation frequency of 80Hz, were selected to carry out the experiment of arc additive manufacturing of thin-walled components of 2319 aluminum alloy under electromagnetic stirring.

[0042] Step 3: Based on the optimized single-layer single-pass deposition parameters and the optimized electromagnetic stirring-assisted single-layer single-pass deposition excitation parameters, an arc additive manufacturing experiment of 2319 aluminum alloy with and without interlayer electromagnetic stirring was carried out using a reciprocating path with interlayer cooling strategy and the deposition process parameters shown in Table 3.

[0043] Table 3. Arc additive manufacturing parameters with and without interlayer electromagnetic stirring.

[0044]

[0045]

[0046] The deposition length was 200 mm, with a total of 60 layers. The interlayer cooling time in the actual experiment was extended to 90 s. The macroscopic morphology of the thin-walled part after deposition, with and without interlayer electromagnetic stirring, is shown below. Figure 6 As shown. Further, a cross-section of the thin-walled part with and without interlayer electromagnetic stirring is taken, and its surface waviness is calculated to characterize its surface accuracy and effective deposition rate. Specifically, a rectangle is taken within the stable forming region in the middle of the thin-walled part manufactured by arc additive manufacturing, inscribed in the inner wall of the thin-walled part, as shown. Figure 7 As shown, after introducing electromagnetic stirring, the electromagnetic force generated by the longitudinal electromagnetic field causes the molten metal to tend to diffuse towards both ends, thus reducing the height of the thin-walled part from 78.1 mm to 75.8 mm. Simultaneously, calculations show that the surface waviness decreased from 1.39 mm to 1.21 mm, a reduction of 12.9%. The reduction in surface waviness represents a decrease in the volume that needs to be removed by secondary machining, indicating that the introduction of interlayer electromagnetic stirring can improve the surface accuracy and effective deposition rate of the arc additive 2319 thin-walled part.

[0047] Step 4: Microscopic observation of the top, middle, and bottom sections of the thin-walled component with and without interlayer electromagnetic stirring. The metallographic morphology is as follows: Figure 8As shown, electromagnetic stirring causes some dendrite arms to break up and disappear, increases the dendrite spacing, and induces an equiaxed crystal transformation. Simultaneously, electromagnetic stirring has a particularly significant effect on the uniform distribution of the temperature field and the breaking up and stirring of dendrites, which is beneficial for promoting the formation of equiaxed crystals and refining the grains. Furthermore, the porosity distribution in the microstructure is significantly improved after the introduction of electromagnetic stirring. Before the introduction of electromagnetic stirring, pores mainly formed near the dendrite grain boundaries above the interlayer fusion line. After the introduction of interlayer electromagnetic stirring, due to the transformation of a large number of dendrites into equiaxed crystals, the morphology of the second phase also changed, thereby weakening the nucleation conditions for pores. At the same time, the disturbance of the molten pool by interlayer electromagnetic stirring causes many bubbles to overflow before the molten pool solidifies. Therefore, after electromagnetic stirring treatment, the overall porosity defect is significantly improved.

[0048] Furthermore, such as Figure 9 As shown, the introduction of electromagnetic stirring helps reduce Cu segregation along grain boundaries and alleviates the tendency for intergranular corrosion. Furthermore, in thin-walled parts with interlayer electromagnetic stirring, the second phase is mostly in the form of dots or short rods, which can improve the strength and hardness of the alloy, while a small amount is in the form of networks or filaments, which reduce the toughness and strength of the alloy. In contrast, the distribution of the second phase in thin-walled parts without interlayer electromagnetic stirring is the opposite. This indicates that the introduction of interlayer electromagnetic stirring can effectively improve the distribution of the second phase in aluminum alloy thin-walled parts manufactured by arc additive manufacturing, which will be beneficial for optimizing the performance of aluminum alloy arc additive manufactured components.

[0049] Furthermore, Figure 10 The hardness test results are for 2319 thin-walled parts manufactured by arc additive manufacturing with and without interlayer electromagnetic stirring. The average hardness of the thin-walled parts with interlayer electromagnetic stirring is 83.4 HV, while the average hardness of the thin-walled parts without interlayer electromagnetic stirring is 78.5 HV. The average hardness of the thin-walled parts with interlayer electromagnetic stirring is slightly higher than that of the parts without interlayer electromagnetic stirring.

[0050] Furthermore, Figure 11 This study compares the tensile properties of 2319 aluminum alloy thin-walled parts manufactured using arc additive manufacturing with and without interlayer electromagnetic stirring. After introducing interlayer electromagnetic stirring, both the transverse and longitudinal tensile strengths of the 2319 aluminum alloy thin-walled parts manufactured using arc additive manufacturing improved. Specifically, the average transverse tensile strength increased from 219.8 MPa to 232.5 MPa, and the average longitudinal tensile strength increased from 209.5 MPa to 239.0 MPa. The transverse and longitudinal elongations also increased from 7.2% and 6.8% to 9.8% and 10.7%, respectively. The transverse tensile strength increased by 5.8%, and the longitudinal tensile strength increased by 14.1%, with the longitudinal tensile strength showing a more significant improvement.

[0051] Analysis of the results from the embodiments shows that the method proposed in this invention for improving the performance of aluminum alloy components by introducing electromagnetic stirring in arc additive manufacturing solves problems such as high porosity, interlayer segregation, and large anisotropy of mechanical properties compared to traditional arc additive manufacturing of thin-walled aluminum alloy parts. While improving surface forming accuracy and effective deposition rate, the average microhardness of the arc-added aluminum alloy thin-walled parts is increased from 78.5 HV to 83.4 HV. Furthermore, both transverse and longitudinal tensile properties are improved, and the anisotropy of transverse and longitudinal tensile strength is reduced. This invention provides an important technical reference for promoting the development of arc additive manufacturing technology and its widespread application in the forming of thin-walled aluminum alloy parts, and has potential economic and social benefits.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process method for additive component performance optimization based on external magnetic field assistance, characterized by: In the process of arc additive manufacturing, electromagnetic stirring is introduced to further regulate the organization and performance of the components. The steps are as follows: S1: Obtain the process parameters of single-layer single-pass deposition of arc additive 2319 aluminum alloy under the condition of no magnetic field. S2: Obtain the excitation parameters of single-layer single-pass deposition of arc additive 2319 aluminum alloy under the condition of electromagnetic stirring assistance. S3: Arc additive 2319 aluminum alloy thin-walled part experiment with and without electromagnetic stirring. S4: Microstructure observation and mechanical property analysis test of arc additive 2319 aluminum alloy thin-walled part with and without electromagnetic stirring.

2. A method of improving the properties of an aluminum alloy component by introducing electromagnetic stirring in arc additive manufacturing according to claim 1, characterized in that: The substrate for arc additive manufacturing is a 5mm thick 2Al2 aluminum alloy plate, and the deposition material is ER2319 aluminum alloy wire with a diameter of 1.2mm; the protective gas is pure argon, the flow rate is 20L / min, the wire dry extension is 10mm, the layer lifting amount is 1.8mm, and the deposition length is 200mm; Using reciprocating path, the deposition current is 130A, the deposition voltage is 18.2V, the deposition speed is 0.6m, the excitation current is 1.5A, the excitation frequency is 80Hz, and the magnetic field direction is longitudinal.

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