Additive manufacturing method for gradient composite material magnetic shielding structure

Abstract

The invention provides an additive manufacturing method for a gradient composite material magnetic shielding structure. The additive manufacturing method comprises the steps that a FeNi50 soft magnetic alloy material is adopted as a magnetic conductive layer, and 12Cr13 high-strength steel is adopted as a magnetic isolation layer and a structure reinforcing layer; a laser melting deposition process method is adopted for forming a three-dimensional conformal magnetic shielding structure, a FeNi50-12Cr13-FeNi50 sandwich structure is formed, the method is suitable for manufacturing a shielding structure shell with the thickness range of 0.4 mm-2mm, and the optimal thickness ratio of a gradient structure layer is FeNi50: 12Cr13: FeNi50 = 1: 2: 1. The magnetic shielding structure material structure integrated design and additive manufacturing method can be applied to manufacturing of ultrathin, high-performance and three-dimensional shape-following magnetic shielding structures, and it is guaranteed that precise instruments and equipment such as spaceflight optical fiber gyroscopes and satellite rubidium clocks play the optimal working performance.

Description

Technical Field

[0001] The invention relates to the field of preparation of gradient material functional structures, and relates to an additive manufacturing method for a gradient composite material magnetic shielding structure. Background Art

[0002] The electromagnetic environment in which precision aerospace instruments and equipment are located is becoming increasingly complex, and their shielding materials need to meet the requirements of magnetic field shielding in a wide frequency range, such as aerospace fiber optic gyroscopes, satellite rubidium clocks, etc. Existing research focuses on the structural design of single-layer shielding bodies. However, due to the limitations of traditional manufacturing processes such as diffusion welding and vacuum hot pressing, the prepared shielding structure is large in size and weight, making it difficult to adapt to the complex structural appearance of spacecraft products. Based on the principle of multi-layer magnetic layer grading and shunting to attenuate the magnetic field and gradient structure multiple absorption and reflection of electromagnetic waves, the multi-layer shielding structure has a natural advantage over the single-layer shielding structure.

[0003] Laser melting deposition forming technology can realize the free forming of complex shaped structures. The forming process software is used to slice and layer the three-dimensional model of the structure. Based on the two-dimensional cross-section of each layer, the high-energy beam laser is used to melt the synchronously transported powder material, overlap the layers, and finally form a three-dimensional structure. This technology has been widely used in the production of structural materials and devices. Compared with traditional manufacturing or processing methods, it has the advantages of no mold, no restrictions on part structure and materials, and rapid response to design changes. It provides a technical approach to realize the "structural design-manufacturing-functional integration" of complex structural functional metal components, and is particularly suitable for gradient structure forming and manufacturing.

[0004] In existing research, a manufacturing method of magnetic shielding structural materials based on SLM forming, as described in CN 114939672 A (Yang Jiaoxi, Zhu Qing, Wang Zekang, etc.), is based on the manufacturing of magnetic shielding structural materials formed by SLM. The method reduces the consumption of printing raw materials through a dot matrix filling method, reduces the weight of the magnetic shielding structure, improves its manufacturing efficiency, and obtains a soft magnetic alloy with high magnetic permeability by controlling the process conditions, thereby improving the shielding effectiveness of the magnetic shielding structure. This method is suitable for the preparation of small magnetic shielding structural parts. The bonding strength between different layer structures is weak, and the middle layer is easily mixed with powder excess and is difficult to remove cleanly, which cannot meet the excess protection requirements in aerospace and other fields.

[0005] A multi-layered electromagnetic shielding composite material and its preparation method and application, as described in CN 112793269 A (Ran Xianghai, Wang Chunbo, Fu Chao, etc.), the method provides an electromagnetic shielding composite material, including an absorption layer and a reflection layer composited on the absorption layer, using specific layer materials, and combining the absorption layer-reflection layer stacking structure to obtain an electromagnetic shielding composite material with a specific structure and composition. This method uses a non-metallic composite material as a magnetic shielding structural material, which is suitable for use in a normal temperature environment and has a low structural strength.

[0006] A friction stir solid state additive manufacturing device and method for laminated composite components, as described in CN 116551155 A (Shi Lei, Zhang Xiankun, Dai Guoxin, etc.). This method proposes a friction stir solid state additive manufacturing device and method for laminated composite components, which can avoid the problems of a relatively thick intermetallic compound layer existing in the laminated additive manufacturing of materials with large differences, and when adding a high melting point material layer, due to excessive frictional heat generation, the low melting point material remelts, resulting in a reduction in the forming accuracy and performance of the additive manufactured component. This method is mainly applicable to the preparation of large-scale gradient material structures and is not applicable to the preparation of precision instrument housing structures.

[0007] In summary, there is currently no structural design of a metal material magnetic shielding cover with ultra-thin and high shielding performance and a process method that can achieve three-dimensional conformal manufacturing at home and abroad. Summary of the Invention

[0008] The purpose of the present invention is to provide a friction stir solid state additive manufacturing method for a gradient composite material magnetic shielding structure, which solves the problems of insufficient performance of a single-layer shielding body, the preparation of a multi-layer shielding body being restricted by manufacturing processes such as traditional diffusion welding and vacuum hot pressing, having a large volume and weight, and being difficult to adapt to the complex structures of spacecraft products.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] The present invention provides a friction stir solid state additive manufacturing method for a gradient composite material magnetic shielding structure, using FeNi50 soft magnetic alloy material as the magnetic conductive layer, and using 12Cr13 high-strength steel as the magnetic isolation layer and structural strengthening layer; a three-dimensional conformal magnetic shielding structure is formed by using the laser melting deposition process method to form a FeNi50-12Cr13-FeNi50 sandwich structure.

[0011] As an embodiment of the present invention, the thickness range of the shielding structure is 0.4 mm to 2 mm.

[0012] As an embodiment of the present invention, a sandwich structure arranged in the order of FeNi50-12Cr13-FeNi50 is formed, and the thickness of the single FeNi50 structure layer is not less than 0.1 mm, and the thickness of the single 12Cr13 structure layer is not less than 0.2 mm. As some implementation examples, the gradient structure layer forms a sandwich structure arranged in the order of FeNi50-12Cr13-FeNi50, the thickness of the single FeNi50 structure layer is 0.1 mm - 0.5 mm, and the thickness of the single 12Cr13 structure layer is 0.2 mm - 1 mm.

[0013] As an embodiment of the present invention, the composition of the FeNi50 soft magnetic alloy material is Ni: 46.8 - 51.2 wt%, C: 0.002 - 0.006 wt%, O: 0.020 - 0.032 wt%, S: 0.001 - 0.004 wt%, P: 0.005 - 0.012 wt%, Fe: Bal.

[0014] As an embodiment of the present invention, for the laser melting deposition forming process of the FeNi50 soft magnetic alloy, the laser power ≤ 800 W, the spot diameter ≤ 1 mm, and the lift amount ≤ 0.1 mm. It is prepared alternately in different forming directions. The forming direction of the first layer needs to be parallel to the surface of the shielded part, and the subsequent forming layers are perpendicular to the surface of the shielded part.

[0015] As an embodiment of the present invention, for the laser melting deposition forming process of the 12Cr13 high-strength steel, the laser power ≤ 1000 W, the spot diameter ≤ 1.5 mm, and the lift amount ≤ 0.2 mm.

[0016] As an embodiment of the present invention, an FeNi50 - 12Cr13 - FeNi50 sandwich structure is formed. This method is applicable to manufacturing a shield structure housing with a thickness range of 0.4 mm to 2 mm, and the thickness ratio of the gradient structure layer is FeNi50: 12Cr13: FeNi50 = 1:2:1.

[0017] The gradient composite magnetic shielding structure prepared by the method of the present invention belongs to the protection scope of the present invention.

[0018] As an embodiment of the present invention, the method of the present invention can realize the manufacturing of a three-dimensional conformal shielding cover layer by layer from the inside to the outside according to the shape of the protective product, and can realize the preparation of any thickness of the FeNi50 material layer and the 12Cr13 material layer based on the requirements of magnetic shielding performance and the matching of structural strength.

[0019] As an embodiment of the present invention, the thickness range of the cover body structure of the gradient composite magnetic shielding structure is 0.4 mm to 2 mm, and the optimal thickness ratio of the gradient structure layer is FeNi50: 12Cr13: FeNi50 = 1:2:1.

[0020] The application of the gradient composite magnetic shielding structure of the present invention in aerospace fiber optic gyroscopes or satellite rubidium clocks also belongs to the protection scope of the present invention.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The FeNi50-12Cr13-FeNi50 structural magnetic shielding layer described in the present invention is integrally prepared in-situ, featuring high interlayer metallurgical bonding strength and no risk of peeling or delamination. It is difficult to prepare ultra-thin and conformal structures using non-metallic materials such as ceramic layers and fiberglass as magnetic isolation layers. The shielding layer has a large weight, which will increase the payload and cause loss of instrument operation function.

[0023] 2) The laser melting deposition process method of the present invention adopts a method of alternately preparing by combining multiple materials, different thicknesses, and different forming directions, providing a feasible way for the preparation of ultra-thin, multi-layer composite, and complex conformal magnetic shielding structures.

[0024] 3) The present invention can manufacture a three-dimensional conformal shielding cover according to the shape of the protected product. The shielding cover has the advantages of ultra-thin, high strength, resistance to high and low temperatures, and excellent performance. Brief Description of the Drawings

[0025] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects, and advantages of the present invention will become more apparent:

[0026] Figure 1 Schematic diagram of the magnetic shielding structure prepared by the additive manufacturing method of the gradient composite material magnetic shielding structure of the present invention;

[0027] Figure 2 Schematic flow chart of the additive manufacturing of the gradient composite material magnetic shielding structure of the present invention. Detailed Description of the Embodiments

[0028] The following further elaborates on an additive manufacturing method for a gradient composite material magnetic shielding structure proposed by the present invention in conjunction with the drawings and specific embodiments. According to the following description and claims, the advantages and features of the present invention will become clearer. It should be noted that the drawings are all in a very simplified form and supplemented with physical representations and performance measurement results to illustrate the operation process and actual effects of the present invention, including but not limited to the proposed material combinations and structural forms.

[0029] Example 1

[0030] The magnetic shielding structure of this example is as Figure 1 shown. The FeNi50 soft magnetic alloy material is used as the magnetic conduction layer, and 12Cr13 high-strength steel is used as the magnetic isolation layer and structural reinforcement layer to form a FeNi50-12Cr13-FeNi50 sandwich structure. The raw material FeNi50 soft magnetic alloy is in powder form, and the main chemical composition test results are Ni: 48.2wt%, C: 0.002wt%, O: 0.022wt%, S: 0.002wt%, P: 0.005wt%, Fe: Bal.

[0031] The additive manufacturing method of the magnetic shielding structure is as follows Figure 2 shown. First, the first layer of FeNi50 soft magnetic alloy layer is formed. The laser melting deposition forming process parameters used are laser power = 600W, spot diameter = 0.3mm, lift = 0.1mm, and the thickness of the formed part is 0.4mm. The forming direction of the first layer needs to be parallel to the outer surface of the part to be shielded. The magnetic properties of the formed part are tested to be the saturation magnetic induction intensity B S = 1.1T, and the maximum magnetic permeability is μ m = 4.88mH / m; then the 12Cr13 high-strength steel magnetic isolation layer is formed by laser melting deposition. The forming process parameters are laser power = 1000W, spot diameter = 0.4mm, lift = 0.2mm. Multiple passes are overlapped to form the intermediate layer, and the forming thickness is 0.8mm; finally, the second layer of FeNi50 soft magnetic alloy layer is formed. The laser melting deposition forming process parameters used are laser power = 800W, spot diameter = 0.4mm, lift = 0.2mm, and the forming thickness is 0.4mm. The final shielding layer forms a sandwich structure with 12Cr13 high-strength steel in the middle and FeNi50 soft magnetic alloy on both sides. The total thickness is 1.6mm. The middle 12Cr13 high-strength steel layer has good structural strength, and the FeNi50 soft magnetic alloy on both sides has excellent magnetic conductivity. The double magnetic conductivity layer structure can achieve the function of hierarchical shunt attenuation of the magnetic field. Combining the principle of multiple absorption and reflection of electromagnetic waves at the gradient structure interface, this structure has excellent magnetic shielding performance. According to the shape of the protected product, a three-dimensional conformal shielding cover can be manufactured. In the case of the present invention, the magnetic shielding performance of the shielding cover is tested by using the shielding cover method, and the magnetic shielding coefficient (Shielding Factor, SF) is used to characterize the magnetic shielding effect of the structure. The definition of the magnetic shielding coefficient is as follows:

[0032]

[0033] wherein, H0 is the magnetic field intensity measured without the shielding cover, and H S is the magnetic field intensity measured with the magnetic shielding cover. The magnetic field intensity is measured by using the FVM-400 type fluxgate meter produced by the MEDA company. The magnetic field intensity at the same point is tested, and the measured SF is 13.2. Compared with the conventional metal single-layer shielding cover structure, the magnetic shielding effect is improved by about 3 times.

[0034] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present invention.

Claims

1. An additive manufacturing method for a magnetic shielding structure of a gradient composite material, characterized in that, The FeNi50 soft magnetic alloy material is used as the magnetic conduction layer, and the 12Cr13 high-strength steel is used as the magnetic isolation layer and the structural strengthening layer; the three-dimensional conformal magnetic shielding structure is formed by using the laser melting deposition process method to form a FeNi50-12Cr13-FeNi50 sandwich structure.

2. The additive manufacturing method of the gradient composite material magnetic shielding structure according to claim 1, characterized in that The thickness range of the shielding structure is 0.4 mm to 2 mm.

3. The additive manufacturing method of the gradient composite magnetic shielding structure according to claim 1, characterized in that The gradient structure layer forms a sandwich structure arranged in the order of FeNi50-12Cr13-FeNi50. The thickness of the FeNi50 single structure layer is 0.1 mm - 0.5 mm, and the thickness of the 12Cr13 single structure layer is 0.2 mm - 1 mm.

4. The additive manufacturing method for the gradient composite material magnetic shielding structure according to claim 1, characterized in that, The composition of the FeNi50 soft magnetic alloy material is Ni: 46.8 - 51.2 wt%, C: 0.002 - 0.006 wt%, O: 0.020 - 0.032 wt%, S: 0.001 - 0.004 wt%, P: 0.005 - 0.012 wt%, Fe: Bal.

5. The additive manufacturing method for a gradient composite magnetic shielding structure according to claim 1, characterized in that, For the laser melting deposition forming process of the FeNi50 soft magnetic alloy, the laser power ≤ 800 W, the spot diameter ≤ 1 mm, and the lift amount ≤ 0.1 mm.

6. The additive manufacturing method for the gradient composite magnetic shielding structure according to claim 1, characterized in that, For the laser melting deposition forming process of the 12Cr13 high-strength steel, the laser power ≤ 1000 W, the spot diameter ≤ 1.5 mm, and the lift amount ≤ 0.2 mm.

7. A gradient composite material magnetic shielding structure prepared by the method according to claim 1.

8. The gradient composite material magnetic shielding structure according to claim 7, characterized in that, According to the shape of the protective product, the three-dimensional conformal shielding cover is manufactured layer by layer from the inside to the outside. Based on the requirements of magnetic shielding performance and the matching of structural strength, the preparation of any thickness of the FeNi50 material layer and the 12Cr13 material layer is realized.

9. The gradient composite magnetic shielding structure according to claim 7, characterized in that, The thickness range of the cover body structure is 0.4 mm to 2 mm, and the optimal thickness ratio of the gradient structure layer is FeNi50:12Cr13:FeNi50 = 1:2:

1.

10. An application of the gradient composite material magnetic shielding structure as claimed in claim 7 in an aerospace fiber optic gyroscope or a satellite rubidium clock.

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