A method and device for preparing hydrophobic surface and strengthening forming by magnetic field force-assisted laser etching of aluminum alloy

Abstract

The present invention provides a method and device for preparing hydrophobic surface and strengthening forming by laser etching of aluminum alloy assisted by magnetic field force, comprising the following steps: fixing the two ends of the aluminum alloy on a fixture; a planar spiral coil and a laser are located directly above the surface of the aluminum alloy to be processed; the planar spiral coil generates a pulsed magnetic field, and the laser beam is located at the center of the pulsed magnetic field; laser etching is used to form a remelting groove and deposited spatter on the surface of the aluminum alloy to be processed, and the remelting groove and deposited spatter constitute a micro-nano multi-level structure; the pulsed magnetic field induces eddy currents on the surface of the aluminum alloy, and an induced magnetic field is formed by the eddy currents, the magnetic field direction of the induced magnetic field is opposite to the magnetic field direction of the pulsed magnetic field, and the repulsive force of the two magnetic fields causes the surface of the aluminum alloy to be processed to deform; the surface energy of the material is reduced by chemical modification of the processed surface of the aluminum alloy, and a curved aluminum alloy surface with super-hydrophobicity is obtained. The present invention can effectively prepare a curved reinforced aluminum alloy with a super-hydrophobic surface.

Description

Technical Field

[0001] The invention relates to the field of preparation of curved aluminum alloy functional surfaces, and in particular to a method and device for preparing hydrophobic surfaces and strengthening forming of aluminum alloys by laser etching assisted by magnetic field force. Background Art

[0002] Aviation aluminum alloys are important materials for civil aircraft due to their high performance and lightweight. However, the hydrophilic surface of aluminum alloys makes it easy for the aircraft surface to be covered with ice, which affects flight safety. Therefore, it is of great significance to develop methods for preparing aviation aluminum alloys with anti-icing properties.

[0003] There are currently many methods to achieve super-hydrophobicity on the surface of aluminum alloy materials, and common preparation methods include sol-gel method, electrochemical etching method, template method, etc. However, the above methods all have their own limitations, such as environmental pollution, complex process, poor stability, etc. In contrast, laser etching is simple and reliable to operate, and micro-nanoscale structures can be accurately constructed on the surface of various materials by simply adjusting various process parameters.

[0004] However, laser ablation is a process of heating and sudden cooling, which can easily introduce high tensile stress on the surface of aluminum alloy. Tensile stress is the driving force for fatigue crack propagation. In addition, because aluminum alloy is subjected to high-frequency vibration stress generated by thermal loads, strong noise loads and mechanical force loads during operation, fatigue cracks are relatively easy to occur, resulting in a higher risk of fatigue failure of aluminum alloy prepared by this method.

[0005] In addition, in order to meet the appearance requirements, aviation aluminum alloy materials generally have complex shape curvature. At the same time, aviation aluminum alloy is a high-strength metal material with a low forming limit and large deformation springback of formed parts. The current methods make it difficult to achieve high-stable super-hydrophobic surface preparation of aluminum alloys and enhanced forming of matrix materials. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a method and device for preparing hydrophobic surface and strengthening forming by laser etching of aluminum alloy assisted by magnetic field force. The aluminum alloy surface is irradiated by a high-energy laser beam, and the instantaneous high temperature causes the material to melt and gasify rapidly, and the remelted grooves and deposited spatters form a micro-nano multi-level structure on the material surface. At the same time, the magnetic field generated by the planar spiral coil being energized interacts with the magnetic field generated by the induced current, so that the axially distributed magnetic field force on the surface of the aluminum alloy is vertically compressed to the surface of the material, which not only reduces the sputtering effect of the melt, improves the surface smoothness of the aluminum alloy, and avoids the obvious difference in its hydrophobic performance in different directions and angles, but also forces the aluminum alloy remelting layer to flow radially plastically, reduces the tensile strain caused by cooling and shrinkage, improves the residual compressive stress of the remelting layer, and enhances the mechanical properties of the hydrophobic structure. In addition, the eddy current on the surface of the aluminum alloy induces a magnetic field that increases the entanglement spacing inside the material, reduces the stress required for dislocations in the material to get rid of entanglement, and the Joule heat generated by the flowing current causes the temperature of the aluminum alloy to rise and thermal softening occurs. Under the combined action of the two, the flow stress of the aluminum alloy decreases and the plasticity increases, thereby reducing the deformation and rebound of the aluminum alloy formed parts. And the magnetic field force causes the aluminum alloy to deform at high speed, and the high strain rate deformation improves the forming limit of the aluminum alloy. In addition, the high-amplitude magnetic field force refines the grains of the near-surface organization of the aluminum alloy material, and promotes the improvement of the mechanical properties of the matrix material. Therefore, the present invention can effectively prepare an arc-shaped reinforced aluminum alloy with a surface super-hydrophobicity.

[0007] The present invention achieves the above technical objectives through the following technical means.

[0008] A method for preparing a hydrophobic surface and strengthening the forming of an aluminum alloy by laser etching assisted by a magnetic field force comprises the following steps:

[0009] Fix both ends of the aluminum alloy on the fixture;

[0010] The planar spiral coil and the laser are located directly above the surface of the aluminum alloy to be processed; the planar spiral coil generates a pulsed magnetic field, and the laser generates a laser beam, and the laser beam is located at the center of the pulsed magnetic field;

[0011] The laser beam and the pulsed magnetic field act synchronously on the surface of the aluminum alloy to be processed, and laser etching is used to form a remelting groove and deposited spatter on the surface of the aluminum alloy to be processed, and the remelting groove and the deposited spatter constitute a micro-nano multi-level structure; the pulsed magnetic field induces eddy currents on the surface of the aluminum alloy, and an induced magnetic field is formed by the eddy currents. The magnetic field direction of the induced magnetic field is opposite to the magnetic field direction of the pulsed magnetic field, and the repulsive force of the two magnetic fields causes the surface of the aluminum alloy to be processed to deform;

[0012] The surface energy of the aluminum alloy is reduced by chemical modification on the processed surface, thereby obtaining a super-hydrophobic curved aluminum alloy surface.

[0013] Furthermore, the pulse magnetic field generated by the planar spiral coil being energized interacts with the magnetic field generated by the induced current, so that an axially distributed magnetic field force is generated on the surface of the aluminum alloy, which is used to vertically compress the surface of the material.

[0014] Furthermore, during the laser etching process, the induced magnetic field on the surface of the aluminum alloy is used to reduce the spattering of the melt and improve the smoothness of the surface of the aluminum alloy.

[0015] Furthermore, the planar spiral coil is parallel to the surface of the aluminum alloy to be processed, and the distance between the planar spiral coil and the surface of the aluminum alloy to be processed does not exceed 10 mm; the laser beam passes through the center of the planar spiral coil and is emitted into the surface of the aluminum alloy to be processed.

[0016] Furthermore, the planar spiral coil is powered by a power supply composed of energy storage pulse capacitors, the energy storage pulse capacitors have a discharge voltage of 4.5 to 6.5 kV, a capacitance of at least 320 μF, and a discharge frequency of 2.5 to 3.5 kHz; and the unfolded length of the planar spiral coil is at least 2 m.

[0017] Furthermore, the laser generates nanosecond laser to etch the surface of the aluminum alloy to be processed. The spot diameter of the nanosecond laser after focusing is 50μm. The nanosecond laser processing parameters are: wavelength 1064nm, laser power 45W, repetition frequency 30-50kHz, pulse width 100ns, and galvanometer scanning speed 200-400mm / s.

[0018] Furthermore, the method further includes pre-treating the surface of the aluminum alloy, specifically, grinding and polishing the surface of the plate with sandpaper of different particle sizes, and ultrasonically cleaning and drying the treated surface with anhydrous ethanol solution.

[0019] A processing device for the method of preparing hydrophobic surface and strengthening forming of aluminum alloy by laser etching assisted by magnetic field force is characterized in that it includes a planar spiral coil, a laser, a fixture and a controller; the laser is used to generate a laser beam; the planar spiral coil is used to generate a pulsed magnetic field; the laser emission end of the laser is installed in the center of the planar spiral coil; the laser beam passes through the center of the planar spiral coil so that the laser beam is located in the center of the pulsed magnetic field; the fixture is used to fix the two ends of the aluminum alloy; the fixture is installed on a translation mechanism, and the controller controls the movement of the translation mechanism to process the aluminum alloy along the moving path.

[0020] The beneficial effects of the present invention are:

[0021] 1. The method for preparing hydrophobic surface and strengthening forming by laser etching of aluminum alloy assisted by magnetic field force described in the present invention, by generating an instantaneous pulse magnetic field around the plane spiral coil when it is energized, so that the surface of the aluminum alloy induces current, i.e., eddy current, which further forms an induced magnetic field. Therefore, the aluminum alloy is in the pulse magnetic field and the induced magnetic field at the same time. Since there are eddy currents on the surface of the aluminum alloy, the aluminum alloy will be affected by the axially distributed magnetic field force. The magnetic field force generated by the induced magnetic field not only reduces the sputtering effect of the melt, improves the surface smoothness of the aluminum alloy, and avoids the obvious difference in its hydrophobic performance in different directions and angles, but also vertically compresses the remelted layer generated during the laser etching process, reduces the tensile strain generated by cooling and shrinkage, improves the residual compressive stress of the remelted layer, and effectively strengthens the mechanical stability of the hydrophobic structure.

[0022] 2. The method for preparing hydrophobic surface and strengthening forming by laser etching of aluminum alloy assisted by magnetic field force described in the present invention utilizes the magnetic field force generated by the interaction between the pulsed strong magnetic field and the current induced in the aluminum alloy to cause plastic deformation of the aluminum alloy. Since the electromagnetic force driving the deformation of the aluminum alloy is generated and consumed in an instant, the energy density is very high and the deformation speed is very fast. The large momentum generated by the high-speed deformation changes the stress distribution inside the aluminum alloy, making the strain distribution more uniform, thereby improving its forming limit. In addition, the induced magnetic field formed by the eddy current increases the entanglement spacing inside the aluminum alloy and reduces the potential barrier for dislocation movement in the aluminum alloy. At the same time, the Joule heat generated by the eddy current flowing inside the aluminum alloy induces the temperature rise of the aluminum alloy and thermal softening. The two together promote the decrease of the flow stress of the aluminum alloy and the increase of plasticity, thereby achieving the reduction of the stress rebound of the aluminum alloy. In addition, the magnetic field force generated by the induced magnetic field refines the grains of the near-surface structure of the aluminum alloy, achieving the effect of strengthening the comprehensive mechanical properties of the aluminum alloy after the preparation and forming of the hydrophobic surface;

[0023] 3. The method of preparing hydrophobic surface and strengthening forming by magnetic field force-assisted laser etching of aluminum alloy described in the present invention, all process parameters can be controlled in a computer, and has the advantages of simple operation, low cost and high efficiency; it overcomes the drawbacks of traditional laser etching process, completes the preparation of arc-shaped strengthened aluminum alloy with super-hydrophobic surface, is aimed at the service environment of aviation aluminum alloy, greatly improves the service life, and has broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a schematic diagram of the method for preparing a hydrophobic surface and strengthening forming by laser etching of aluminum alloy assisted by magnetic field force described in the present invention.

[0026] Figure 2 This is a traveling path diagram of the aluminum alloy surface to be processed in Example 1 of the present invention.

[0027] Figure 3 This is a diagram showing the actual forming effect and etching surface effect obtained in Example 1 of the present invention.

[0028] Figure 4 This is a SEM image of the hydrophobic morphology obtained in Example 1 of the present invention.

[0029] Figure 5 This is a comparison diagram of the contact angle of a liquid droplet on the aluminum alloy surface obtained in various embodiments of the present invention.

[0030] Figure 6 The figure is a comparison diagram of the residual stress on the aluminum alloy surface obtained in various embodiments of the present invention.

[0031] Figure 7 The following is a comparison diagram of the alloy profiles obtained in various embodiments of the present invention.

[0032] Figure 8 This is a comparison chart of the alloy deformation springback obtained in various embodiments of the present invention.

[0033] In the figure:

[0034] 1-power supply; 2-positioning fixture; 3-laser; 4-planar spiral coil; 5-fixture; 6-aluminum alloy. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] like Figure 1 and Figure 2 As shown, the method for preparing hydrophobic surface and strengthening forming of aluminum alloy by laser etching assisted by magnetic field force of the present invention comprises the following steps:

[0039] Fix the two ends of the aluminum alloy 6 on the fixture 5;

[0040] The planar spiral coil 4 and the laser 3 are located directly above the surface of the aluminum alloy 6 to be processed; the planar spiral coil 4 generates a pulsed magnetic field, and the laser 3 generates a laser beam, and the laser beam is located at the center of the pulsed magnetic field;

[0041] The laser beam and the pulsed magnetic field act synchronously on the surface of the aluminum alloy 6 to be processed, and laser etching is used to form a remelting groove and deposited spatter on the surface of the aluminum alloy 6 to be processed, and the remelting groove and deposited spatter constitute a micro-nano multi-level structure; the pulsed magnetic field induces eddy currents on the surface of the aluminum alloy 6, and uses the eddy currents to form an induced magnetic field, the magnetic field direction of the induced magnetic field is opposite to the magnetic field direction of the pulsed magnetic field, and the repulsive force of the two magnetic fields causes the surface of the aluminum alloy 6 to be processed to be deformed;

[0042] The surface energy of the aluminum alloy 6 is reduced by chemical modification on the processed surface, thereby obtaining a super-hydrophobic curved aluminum alloy surface.

[0043] The method for preparing hydrophobic surface and strengthening forming by laser etching of aluminum alloy assisted by magnetic field force of the present invention utilizes laser etching to form remelting grooves on the surface of aluminum alloy and deposit splashes to construct a micro-nano multi-level structure. At the same time, the magnetic field force generated by the induction magnetic field can not only reduce the sputtering effect of the melt and improve the surface smoothness of the aluminum alloy, thereby avoiding obvious differences in its hydrophobic properties in different directions and angles, but also reduce the tensile strain generated by the remelting layer on the surface of the aluminum alloy due to extreme heat and sudden cooling, increase its residual compressive stress level, and thus improve the mechanical stability of the hydrophobic structure. In addition, driven by the magnetic field force, the aluminum alloy can produce a strain rate of 10 2 s -1 The above high-speed deformation improves the forming limit of aluminum alloy, and the electroplasticity and Joule heat effect generated by the eddy current-induced magnetic field inside the aluminum alloy reduce the flow stress of the aluminum alloy and increase the plasticity of the aluminum alloy, thereby reducing the deformation springback of the aluminum alloy formed parts. In addition, under the action of the high-amplitude magnetic field force generated by the induced magnetic field, the grains of the near-surface structure of the aluminum alloy matrix are refined, which strengthens the comprehensive mechanical properties of the curved aluminum alloy with a super-hydrophobic surface.

[0044] In order to make the purpose, technical solutions and advantages of the present invention clearer, 2024-T351 aviation aluminum alloy is selected as a research object, and the present invention is described in detail in combination with specific embodiments.

[0045] Embodiment 1

[0046] The method for preparing a hydrophobic surface and strengthening forming by laser etching of aluminum alloy assisted by magnetic field force as described in Example 1 comprises the following steps:

[0047] S01: Cut 2024-T351 aviation aluminum alloy into 50mm×50mm×2mm square specimens, and grind the aluminum alloy surface with metallographic sandpaper of different mesh sizes, and then mechanically polish with a polishing machine and diamond polishing agent until the surface to be processed is smooth and scratch-free, and then use alcohol to ultrasonically clean the polished aluminum alloy and dry it;

[0048] S02: The two ends of the pretreated aluminum alloy in the length direction are respectively mounted on the fixture 5, and the aluminum alloy and the fixture 5 are connected with bolts to provide a pre-tightening force; the planar spiral coil 4 and the laser 3 are located directly above the surface to be processed of the aluminum alloy 6; the planar spiral coil 4 generates a pulsed magnetic field, and the laser 3 generates a laser beam, and the laser beam is located at the center of the pulsed magnetic field;

[0049] S03: Use a positioning fixture to fix the planar spiral coil 4 on the delivery end of the laser 3, so that the planar spiral coil 4 and the delivery end of the laser 3 are parallel and perpendicular to the surface of the aluminum alloy 3 to be processed, and keep the coupling gap between the planar spiral coil 4 and the surface of the aluminum alloy 3 to be processed at 10mm. The planar spiral coil 4 is powered on and starts laser processing synchronously, and the fixture 5 moves along the planned path; the power supply is composed of energy storage pulse capacitors, the discharge voltage is 4.5kV, the capacitance is 320μF, and the discharge frequency is 2.5kHz; the IPG-HP-100 nanosecond pulse laser is used to generate nanosecond laser, the spot diameter after focusing is 50μm, the wavelength is 1064nm, the laser power is 45W, the repetition frequency is 30kHz, the pulse width is 100ns, the galvanometer scanning speed is 200mm / s, and the overlap rate is 50%;

[0050] The laser beam and the pulsed magnetic field act synchronously on the surface of the aluminum alloy 6 to be processed, and laser etching is used to form a remelting groove and deposited spatter on the surface of the aluminum alloy 6 to be processed, and the remelting groove and deposited spatter constitute a micro-nano multi-level structure; the pulsed magnetic field induces eddy currents on the surface of the aluminum alloy 6, and uses the eddy currents to form an induced magnetic field, the magnetic field direction of the induced magnetic field is opposite to the magnetic field direction of the pulsed magnetic field, and the repulsive force of the two magnetic fields causes the surface of the aluminum alloy 6 to be processed to be deformed;

[0051] S04: Reduce the surface energy of the material through chemical modification to complete the preparation of arc-shaped reinforced aluminum alloy with super hydrophobic surface.

[0052] Example 1 The hydrophobic surface and forming effect of the aviation aluminum alloy sample prepared Figure 3 As shown in the figure, the remelted grooves and deposited splashes produced by laser etching on the aluminum alloy surface constitute a hydrophobic structure. After the surface energy of the structure is reduced, the average contact angle of the droplet (4μL) on the aluminum alloy surface reaches 167°, and the average rolling angle is 7.3°, as shown in the figure. Figure 5 As shown in the figure, the aluminum alloy surface processed by laser etching has good hydrophobic properties. At the same time, the magnetic field force generated by the interaction between the pulsed strong magnetic field and the current induced in the aluminum alloy causes the aluminum alloy to undergo plastic deformation. The aluminum alloy profile curves prepared with different discharge parameters and laser etching process parameters are shown in the figure. Figure 7 As shown, under traditional forming processes, such as shot peening, the maximum deformation depth of the aluminum alloy is only 1.86 mm, while the maximum deformation depth of the aluminum alloy prepared by the magnetic field force in Example 1 is 2.88 mm, which is about 54.8% higher than the maximum deformation depth of the aluminum alloy processed by shot peening. The high-speed deformation of the aluminum alloy under the action of the high-amplitude magnetic field force increases the forming limit of the aluminum alloy. Figure 4This is the SEM image of the hydrophobic morphology obtained in Example 1. The magnetic field force generated by the induced magnetic field reduces the sputtering effect of the melt, improves the surface smoothness of the aluminum alloy, and vertically compresses the remelted layer generated during the laser etching process, reducing the tensile strain caused by cooling and shrinkage, increasing the residual compressive stress of the remelted layer, and effectively enhancing the mechanical stability of the hydrophobic structure. The average residual stress of the super-hydrophobic surface of the aluminum alloy at a distance of 100 μm from the surface is as follows: Figure 6 As shown in the figure, the residual stress on the surface of the aluminum alloy prepared in Example 1 is 46MPa, which is about 57.4% lower than the residual stress of 108MPa on the surface of the aluminum alloy after laser etching. The magnetic field force generated by the induced magnetic field effectively reduces the tensile stress generated by the heating of the aluminum alloy remelting layer. The maximum deformation springback of the aluminum alloy formed part prepared in Example 1 is as follows: Figure 8 As shown in the figure, the maximum springback of the aluminum alloy formed by magnetic field force is 0.37mm, which is about 28.8% less than the maximum springback of the aluminum alloy formed by shot peening (0.52mm). The electroplasticity and Joule heating effect generated by the eddy current-induced magnetic field weaken the flow stress of the aluminum alloy and improve the plasticity of the aluminum alloy, thereby achieving the purpose of reducing the deformation springback of the sheet metal formed parts.

[0053] Experimental Example 2:

[0054] On the basis of Example 1, the discharge voltage in Example 2 is 5.5 kV, the capacitance is 320 μF, the discharge frequency is 3 kHz, the wavelength is 1064 nm, the laser power is 45 W, the repetition frequency is 40 kHz, the pulse width is 100 ns, the galvanometer scanning speed is 300 mm / s, and the overlap rate is 50%.

[0055] like Figure 5 As shown in Figure 2, the average contact angle of the aluminum alloy prepared in Example 2 after surface chemical modification reached 171°, and the average rolling angle was 6.0°, achieving good hydrophobicity on the aluminum alloy surface. Figure 6 As shown, the residual stress on the surface of the aluminum alloy prepared in Example 2 is 39MPa, which is about 15.2% lower than the residual stress of 46MPa on the surface of the aluminum alloy in Example 1. The axially distributed magnetic field force on the aluminum alloy effectively regulates the residual stress on the hydrophobic surface. The maximum deformation depth of the aluminum alloy prepared in Example 1 is 2.88mm, while the maximum deformation depth of the aluminum alloy formed by the magnetic field force in Example 2 is 3.50mm, which is about 21.5% higher than the maximum deformation depth of the aluminum alloy prepared in Example 1. The large momentum generated by high-speed forming changes the stress distribution of the aluminum alloy, making the strain distribution more uniform, thereby improving the forming limit of the aluminum alloy. The maximum deformation springback of the aluminum alloy prepared in Example 2 is shown in FIG. Figure 8As shown in the figure, it can be seen that the maximum deformation springback of the aluminum alloy prepared under the above process parameters is 0.23mm, which is reduced by about 37.8% compared with the maximum deformation springback of the aluminum alloy prepared in Example 1 of 0.37mm. The decrease in the flow stress of the aluminum alloy and the increase in plasticity effectively control the springback of the formed part.

[0056] Experimental Example 3:

[0057] On the basis of Example 2, the discharge voltage in Example 3 is 6.5 kV, the capacitance is 320 μF, the discharge frequency is 3.5 kHz, the wavelength is 1064 nm, the laser power is 45 W, the repetition frequency is 50 kHz, the pulse width is 100 ns, the galvanometer scanning speed is 400 mm / s, and the overlap rate is 50%.

[0058] like Figure 5 As shown in the figure, the surface contact angle of the aluminum alloy prepared in Example 3 after chemical modification reached 163°, and the rolling angle was 8.6°, realizing the preparation of super hydrophobic surface by laser etching. Figure 6 As shown in FIG. 1 , the residual stress on the surface of the aluminum alloy prepared in Example 3 is 34 MPa, which is about 12.8% lower than the residual stress of 39 MPa on the surface of the aluminum alloy in Example 2, thus achieving effective regulation of the residual stress on the hydrophobic surface by the magnetic field force. Figure 7 As shown, the maximum deformation depth of the aluminum alloy formed by the magnetic field force generated by the induction magnetic field in Example 3 is 3.84 mm, which is about 9.7% higher than that in Example 2 and about 33.3% higher than that in Example 1. The forming limit of the aluminum alloy is improved by forming with the instantaneous high-intensity magnetic field force. Figure 8 It can be seen that the maximum deformation springback of the aluminum alloy prepared under the above-mentioned pulsed magnetic field parameters and laser process parameters is 0.16 mm, which is about 30.4% less than the maximum deformation springback of the aluminum alloy prepared in Example 2 of 0.23 mm. The springback of the formed part is reduced by reducing the flow stress of the formed aluminum alloy and improving the plasticity of the aluminum alloy.

[0059] A processing device for a method of preparing a hydrophobic surface and strengthening forming by laser etching of an aluminum alloy assisted by a magnetic field force comprises a planar spiral coil 4, a laser 3, a fixture 5 and a controller; the laser 3 is used to generate a laser beam; the planar spiral coil 4 is used to generate a pulsed magnetic field; the laser emission end of the laser 3 is installed at the center of the planar spiral coil 4; the laser beam passes through the center of the planar spiral coil 4 so that the laser beam is located at the center of the pulsed magnetic field; the fixture 5 is used to fix both ends of the aluminum alloy 6; the fixture 5 is installed on a translation mechanism, and the controller controls the movement of the translation mechanism to process the aluminum alloy 6 along the moving path. The laser emission port of the laser 3 is inserted into the center of the spiral coil 4 through the positioning fixture 2.

[0060] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0061] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing hydrophobic surface and strengthening forming of aluminum alloy by laser etching assisted by magnetic field force, characterized in that: The steps include: Fixing both ends of the aluminum alloy (6) on the fixture (5); The planar spiral coil (4) and the laser (3) are located directly above the surface of the aluminum alloy (6) to be processed; the planar spiral coil (4) generates a pulsed magnetic field, and the laser (3) generates a laser beam, and the laser beam is located at the center of the pulsed magnetic field; The laser beam and the pulsed magnetic field act synchronously on the surface of the aluminum alloy (6) to be processed, and laser etching is used to form a remelting groove and deposited spatter on the surface of the aluminum alloy (6) to be processed, wherein the remelting groove and the deposited spatter constitute a micro-nano multi-level structure; the pulsed magnetic field induces eddy currents on the surface of the aluminum alloy (6), and an induced magnetic field is formed using the eddy currents. The magnetic field direction of the induced magnetic field is opposite to the magnetic field direction of the pulsed magnetic field, and the repulsive force of the two magnetic fields causes the surface of the aluminum alloy (6) to be processed to undergo plastic deformation; The surface energy of the material is reduced by chemically modifying the processed surface of the aluminum alloy (6), thereby obtaining a super-hydrophobic curved aluminum alloy surface.

2. The method for preparing hydrophobic surface and strengthening forming of aluminum alloy by laser etching assisted by magnetic field force according to claim 1, characterized in that: The pulse magnetic field generated by energizing the planar spiral coil (4) interacts with the magnetic field generated by the induced current, so that an axially distributed magnetic field force is generated on the surface of the aluminum alloy (6), which is used to vertically compress the surface of the material.

3. The method for preparing hydrophobic surface and strengthening forming of aluminum alloy by laser etching assisted by magnetic field force according to claim 1, characterized in that: During the laser etching process, the induced magnetic field on the surface of the aluminum alloy (6) is used to reduce the splashing of the melt and improve the surface smoothness of the aluminum alloy.

4. The method for preparing hydrophobic surface and strengthening forming of aluminum alloy by magnetic field force assisted laser etching according to claim 1, characterized in that: The planar spiral coil (4) is parallel to the surface of the aluminum alloy (6) to be processed, and the distance between the planar spiral coil (4) and the surface of the aluminum alloy (6) to be processed does not exceed 10 mm; the laser beam passes through the center of the planar spiral coil (4) and is emitted into the surface of the aluminum alloy (6) to be processed.

5. The method for preparing hydrophobic surface and strengthening forming of aluminum alloy by laser etching assisted by magnetic field force according to claim 1, characterized in that: The planar spiral coil (4) is powered by a power supply composed of an energy storage pulse capacitor, the energy storage pulse capacitor has a discharge voltage of 4.5-6.5 kV, a capacitance of 320 μF, and a discharge frequency of 2.5-3.5 kHz; the unfolded length of the planar spiral coil (4) is at least 2 m.

6. The method for preparing hydrophobic surface and strengthening forming of aluminum alloy by magnetic field force assisted laser etching according to claim 1, characterized in that: The laser generates nanosecond laser to etch the surface of the aluminum alloy (6) to be processed. The spot diameter of the nanosecond laser after focusing is 50 μm. The nanosecond laser processing parameters are: wavelength 1064 nm, laser power 45 W, repetition frequency 30-50 kHz, pulse width 100 ns, and galvanometer scanning speed 200-400 mm / s.

7. The method for preparing hydrophobic surface and strengthening forming of aluminum alloy by magnetic field force assisted laser etching according to claim 1, characterized in that: The method also includes pre-treating the surface of the aluminum alloy, specifically, grinding and polishing the surface of the plate with sandpaper of different particle sizes, and ultrasonically cleaning and drying the treated surface with an anhydrous ethanol solution.

8. A processing device according to the method for preparing hydrophobic surface and strengthening forming of aluminum alloy by laser etching assisted by magnetic field force according to any one of claims 5-6, characterized in that: The invention comprises a planar spiral coil (4), a laser (3), a fixture (5) and a controller; the laser (3) is used to generate a laser beam; the planar spiral coil (4) is used to generate a pulsed magnetic field; the laser emission end of the laser (3) is installed at the center of the planar spiral coil (4); the laser beam passes through the center of the planar spiral coil (4) so ​​that the laser beam is located at the center of the pulsed magnetic field; the fixture (5) is used to fix the two ends of the aluminum alloy (6); the fixture (5) is installed on a translation mechanism, and the controller controls the movement of the translation mechanism to enable the aluminum alloy (6) to be processed along a moving path.

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