Laser combined machining method of infrared stealth micro-nano structure based on life retention

Abstract

The application provides a kind of infrared stealth micro-nano structure laser combined machining method based on life retention, uses laser strengthening-micro-nano structure machining combined process, first laser shock peening is carried out on the surface of high-temperature alloy, a certain depth of compressive stress layer is formed in the material, then micro-nano structure is machined within the depth of compressive stress layer, stress concentration degree at the size change of micro-nano structure is reduced, and life retention performance is improved. Laser shock peening simulation is adopted, laser shock peening process parameters are developed based on traditional test and simulation, first, the finite element analysis method is used to verify the strengthening effect of iterative process parameters simulation, to provide process parameter development direction for traditional test. The application has the advantages that the strengthening problem of infrared stealth micro-nano structure is solved, the problem of coating difficulty of laser shock peening absorption layer after machining micro-nano structure in the past is solved, the service life of component with stealth coating is improved, and the manufacturing of long-life infrared stealth micro-nano structure of aero-engine is realized.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular to a laser combined processing method for infrared stealth micro-nano structures based on lifetime maintenance. Background Technology

[0002] Mechanisms and methods for maintaining the service life of micro- and nanostructures: Micro- and nanostructures have a large equivalent area and low mechanical strength. When operating in aero-engines, they are subjected to huge thermal loads and airflow scouring, and are also subject to dust and carbon deposits, making them extremely prone to losing functionality. Therefore, it is crucial to improve the chemical and mechanical stability of micro- and nanostructures and maintain their service life.

[0003] Micro / nano structure fabrication: Utilizing submicron (1-5 μm) micro / nano structures made of high-temperature alloys, including arrays of moth-eye-shaped papillae, positive cones, and inverted cones, to control electromagnetic wave reflection, biomimetic Bragg stacking interference, and plasma resonance, precise selective infrared radiation control is achieved. Micro / nano structures Summary of the Invention

[0004] The purpose of this invention is to propose a method for manufacturing and strengthening micro / nano structures on the surface of high-temperature alloys, which solves the problem that the strengthening absorption layer is difficult to bond and coat after the manufacturing of micro / nano structures, resulting in poor strengthening effect. This method places the entire micro / nano structure in a compressive stress layer, thereby improving the lifespan of the micro / nano structure.

[0005] This application proposes a laser shock osmosis strengthening method, which uses laser-induced strain hardening to strengthen micro / nanostructures, resisting high-speed airflow erosion, thereby protecting the micro / nanostructure configuration and improving its service life. This invention employs a Gaussian laser energy distribution combined with laser scanning path planning to scan and fabricate submicron papillae and microcone arrays to achieve the fabrication of micro / nanostructures.

[0006] This invention provides a laser combined processing method for infrared stealth micro-nano structures based on lifetime preservation, characterized in that: the laser combined processing method for infrared stealth micro-nano structures based on lifetime preservation firstly performs laser shock strengthening on the surface of a high-temperature alloy to form a compressive stress layer inside the high-temperature alloy, and then processes the micro-nano structure within the depth of the compressive stress layer;

[0007] Laser shock peening was performed on the surface of high-temperature alloys. The laser shock peening process parameters were developed based on traditional experiments and simulations.

[0008] Laser shock peening process: An absorber layer is applied to the high-temperature alloy part to be processed, and the non-strengthened areas are protected; the part is clamped onto the gripper of a robotic arm, and the robotic arm is adjusted to the processing position where the laser indicator light is in its initial state, and the thickness of the constraint layer is adjusted; a trial run of the planned processing path is conducted to check for any areas not covered by the constraint layer during equipment operation; the range of process parameters for laser shock peening is determined.

[0009] Laser energy E: 10–28 J;

[0010] Laser pulse width τ: 15ns;

[0011] The shapes of the light spots include: circles and squares;

[0012] Laser incident angle θ: 0~20°;

[0013] Spot sizes: 3mm, 4mm, 5mm; where this size corresponds to the diameter in a circular spot and the side length in a square spot.

[0014] Overlap rate: 5%~50%.

[0015] Micro / nano structure fabrication solutions:

[0016] Determine the geometry of the micro / nano structure and design the laser galvanometer scanning path based on the geometry;

[0017] Process parameter range:

[0018] Laser energy E: 10–28 J;

[0019] Laser pulse width τ: 15ns;

[0020] Light spot shape: circular;

[0021] Overlap rate: 5%~50%.

[0022] After laser shock peening, the development of processing parameters for micro and nanostructures requires controlling the thickness of the remelted layer to avoid affecting the morphology of the micro and nanostructures and subsequent coating.

[0023] Compared with the prior art, the advantages of this invention are:

[0024] The laser combined processing method for infrared stealth micro-nano structures based on lifetime preservation described in this invention solves the problem of strengthening infrared stealth micro-nano structures. It proposes a laser combined processing method to solve the problem of difficult coating of laser shock strengthening absorption layer after processing micro-nano structures in the past, improves the service life of components with stealth coating, and realizes the manufacturing of long-life infrared stealth micro-nano structures for aero-engines. Attached Figure Description

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0026] Figure 1 This is a schematic diagram illustrating the principle of laser shock peening.

[0027] Figure 2 This is a schematic diagram of micro / nano structure fabrication.

[0028] In the figure, 1 is the absorption layer, 2 is the high-temperature alloy, 3 is the laser beam, 4 is the high-pressure plasma, 5 is the shock wave propagation path into the material, 6 is the surface micro-nano structure, 7 is the laser movement direction, and 8 is the compressive stress layer. Detailed Implementation

[0029] The present invention will be further explained below with reference to specific implementation schemes, but it is not limited to the present invention. The structures, proportions, sizes, etc. shown in the accompanying drawings are only used to complement the content disclosed in the specification, so as to enable those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0030] Combination Figure 1 , Figure 2 The method of the present invention is described in the following steps:

[0031] After being emitted from the laser, laser beam 3 undergoes focusing and shaping via an external optical path; its direction of movement is shown in [reference needed]. Figure 1 The laser moves in the direction 7, passes through the confinement layer, and acts on the absorption layer 1 to form a high-pressure plasma 4 shock wave. See the shock wave propagation path 5 into the material. Under the action of the confinement layer, the shock wave propagates along the material interior, causing plastic deformation in the material and forming the surface micro-nano structure 6 in the compressive stress layer 8, thereby introducing residual compressive stress to improve lifespan.

[0032] The aforementioned laser-based combined processing method for infrared stealth micro / nano structures based on lifetime retention uses a laser strengthening-micro / nano structure processing combined process. First, the surface of the high-temperature alloy 2 is subjected to laser shock strengthening to form a compressive stress layer with a certain depth inside the material. Then, micro / nano structures are processed within the depth of the compressive stress layer. This avoids the problem of difficulty in bonding the laser shock strengthening absorption layer after processing the micro / nano structure first, reduces the stress concentration at the micro / nano structure size change points, and improves its lifetime retention performance.

[0033] Laser shock strengthening simulation was adopted. The development of laser shock strengthening process parameters is based on traditional experiments and simulation. First, the process parameters were iteratively verified using the finite element analysis method to verify the strengthening effect through simulation, which provides a direction for the development of process parameters for traditional experiments. Traditional experiments then improved and optimized the process parameters based on the simulation.

[0034] Process parameter development:

[0035] I. Reference Figure 1 The compressive stress distribution and compressive stress layer depth under different laser energies, spot sizes, and overlap rates were simulated in the simulation software. Appropriate laser shock strengthening parameters were then selected.

[0036] Second, conduct experiments based on the process parameters in section one, compare the simulation results with the experimental results, and optimize the process parameters.

[0037] 3. Micro- and nano-structures are fabricated on the surface of parts after laser shock peening, and the morphology of the micro- and nano-structures under different laser parameters is detected to optimize the process parameters.

[0038] Parts machining:

[0039] 1. Press on the surface of the part Figure 1 The absorbent layer is pasted as shown.

[0040] 2. Conduct a trial run of the processing path, check for any areas not covered by the constraint layer, and ensure proper protection of non-processing areas.

[0041] III. Begin laser shock peening.

[0042] 4. Move the parts away from the laser to a safe location.

[0043] 5. Peel off the absorbent layer from the surface of the part and wipe the surface of the part dry with a wiping paper.

[0044] 6. Replace the laser and move the part back to the processing position.

[0045] VII. Begin fabrication of micro / nano structures.

[0046] 8. Move the parts away from the laser to a safe location.

[0047] 9. Remove the parts and complete the machining.

[0048] Laser shock peening processing scheme: Apply an absorption layer to the part to be processed, and protect the non-penetrated areas; clamp the part onto the gripper of the robotic arm, adjust the robotic arm's posture until the laser indicator light is in the initial processing position, and adjust the constraint layer thickness; conduct a trial run of the processing plan path to check for any areas not covered by the constraint layer during equipment operation; determine the main process parameter ranges based on the part and the experiment.

[0049] Laser energy E: 10–28 J;

[0050] Laser pulse width τ: 15ns;

[0051] Light spot shape: circular, square;

[0052] Laser incident angle θ: 0~20;

[0053] Spot sizes: 3mm, 4mm, 5mm, with the diameter corresponding to the circle and the side length corresponding to the square;

[0054] Overlap rate: 5%~50%.

[0055] The development of laser shock peening process parameters requires controlling the depth of the compressive stress layer after laser shock peening, and the compressive stress depth should exceed the processing depth of the micro-nano structure.

[0056] After laser shock peening, the development of laser micro-nano structure processing parameters also requires controlling the thickness of the remelted layer to avoid affecting the morphology of the micro-nano structure and subsequent coating.

[0057] Matters not covered in this invention are common knowledge.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laser-based combined processing method for infrared stealth micro / nano structures based on lifetime preservation, characterized in that: The laser combined processing method for infrared stealth micro / nano structures based on lifetime maintenance firstly involves laser shock strengthening of the surface of a high-temperature alloy to form a compressive stress layer inside the high-temperature alloy, and then processing the micro / nano structure within the depth of the compressive stress layer. Laser shock peening was performed on the surface of high-temperature alloys. The laser shock peening process parameters were developed based on traditional experiments and simulations.

2. The laser combined processing method for infrared stealth micro / nano structures based on lifetime preservation according to claim 1, characterized in that: Laser shock peening process: An absorber layer is applied to the high-temperature alloy part to be processed, and the non-strengthened areas are protected; the part is clamped onto the gripper of a robotic arm, and the robotic arm is adjusted to the processing position where the laser indicator light is in its initial state, and the thickness of the constraint layer is adjusted; a trial run of the planned processing path is conducted to check for any areas not covered by the constraint layer during equipment operation; the range of process parameters for laser shock peening is determined. Laser energy E: 10–28 J; Laser pulse width τ: 15ns; The shapes of the light spots include: circles and squares; Laser incident angle θ: 0~20°; Spot sizes: 3mm, 4mm, 5mm; where this size corresponds to the diameter in a circular spot and the side length in a square spot. Overlap rate: 5%~50%.

3. The laser combined processing method for infrared stealth micro / nano structures based on lifetime preservation according to claim 1, characterized in that: Micro / nano structure fabrication solutions: Determine the geometry of the micro / nano structure and design the laser galvanometer scanning path based on the geometry; Process parameter range: Laser energy E: 10–28 J; Laser pulse width τ: 15ns; Light spot shape: circular; Overlap rate: 5%~50%.

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