Method for rapidly preparing ultrathin-wall nanocrystalline micro-part through laser shock

Abstract

The invention discloses a method for rapidly preparing an ultra-thin-wall nanocrystalline micro part through laser shock, belongs to the field of ultra-thin nanocrystalline foil microstructure laser shock processing, and aims to solve the problems that the nanocrystalline foil is difficult to deform when the ultra-thin-wall nanocrystalline micro part is processed due to the performance difference of materials when the existing ultra-thin-wall nanocrystalline micro part is processed, and the processing quality of the ultra-thin-wall nanocrystalline micro part is influenced. According to the invention, a laser emitter generates a high-energy laser pulse, the laser pulse passes through a transparent material of a restraint layer and directly reaches an ablation layer, and the ablation layer instantaneously absorbs the high-energy-density pulse laser and instantaneously vaporizes and ionizes the pulse laser to form a high-energy shock wave; under the limitation of the restraint layer, the peak pressure of the shock wave is increased instantly, can reach the GPa level and is far beyond the yield limit of the nanocrystalline foil, so that the nanocrystalline foil generates ultra-high-speed plastic deformation to be attached to a microarray mold, and preparation and production of various nanocrystalline micro parts are completed. The method is mainly used for preparing the ultrathin-wall nanocrystalline micro-part.

Description

Technical Field

[0001] The invention belongs to the field of ultra-thin nanocrystalline foil microstructure laser shock processing, and in particular relates to a method for rapidly preparing ultra-thin-wall nanocrystalline micro parts by laser shock. Background Art

[0002] With the advancement of science and technology and the development of precision manufacturing technology, the demand for micro parts in major fields such as electronics, medical, automobiles and aerospace is becoming more and more extensive. Their design and manufacturing can meet the needs of higher integration and functionality, thereby promoting the development of related industries. At present, most microstructure materials are still based on coarse-grained materials, and their strength, hardness, wear resistance and corrosion resistance are gradually unable to meet the needs of industry development. The development and application of high-performance materials with excellent mechanical properties and good processing performance are of great significance to the improvement of parts quality and performance.

[0003] Nanocrystalline materials have small grain sizes and a huge number of grain boundaries, which can significantly improve the strength, hardness, wear resistance and corrosion resistance of the material. Higher strength can significantly reduce the thickness of the foil used to prepare microstructures and reduce the weight of micro parts. At the same time, the improvement of wear resistance and corrosion resistance can effectively extend the service life of parts, and has great application potential in the field of microstructure parts manufacturing.

[0004] At present, the preparation and production of most micro-structured parts mainly rely on micro-stamping, micro-stretching and micro-machining, which mainly rely on mold matching or material reduction processing. When using the above methods to prepare nanocrystalline materials, especially ultra-thin-walled nanocrystalline materials, processing is more difficult due to the difference in the properties of the materials themselves. Therefore, it is very practical to develop a relatively novel processing method for micro-parts. Summary of the invention

[0005] The present invention aims to solve the problem that the nanocrystalline foil is difficult to deform and the processing of the ultra-thin nanocrystalline micro-parts is difficult due to the difference in the performance of the materials themselves during the processing of the existing ultra-thin nanocrystalline micro-parts, and thus provides a method for rapidly preparing ultra-thin nanocrystalline micro-parts with laser shock.

[0006] A method for rapidly preparing ultra-thin-wall nanocrystalline micro-parts by laser shock, the method being achieved by the following steps:

[0007] Step 1: Preparation of nanocrystalline foil: Use mechanical processing to cut the entire nanocrystalline material to obtain the shape of the micro-part to be prepared, grind and surface treat the cut nanocrystalline material foil to obtain the nanocrystalline foil layer to be impacted;

[0008] Step 2: Selecting the laser shock confinement layer and the laser shock ablation layer used in the laser shock strengthening process; the laser shock confinement layer is made of a solid material with high light transmittance or a flexible liquid with high light transmittance, and the laser shock ablation layer is made of a material with excellent light absorption and a relatively low melting point;

[0009] Step 3: stacking the laser shock constraint layer and the laser shock ablation layer selected in step 2 and the nanocrystalline foil layer to be impacted prepared in step 1 from top to bottom to form an impacted body, and ensuring that two adjacent layers in the impacted body are perfectly fitted;

[0010] Step 4: Preparation before laser shock forming: place the impacted body obtained in step 3 in the forming mold, constrain the impacted body through the forming mold to ensure the stability of the impacted body during the laser shock forming process, and after the impacted body and the forming mold are assembled, move the forming mold with the impacted body to a high-precision three-dimensional moving platform;

[0011] Step 5: Install a high-energy laser transmitter on a high-precision three-dimensional mobile platform, and the high-energy pulse laser instantaneously excites the high-energy pulse laser with a constant pulse, and driven by the high-precision three-dimensional mobile platform, impacts the impacted body located in the forming mold according to a predetermined impact path, so as to achieve impact strengthening forming of the nanocrystalline foil layer to be impacted in the impacted body;

[0012] Step 6: After the impact is completed, the impacted body after the laser impact is removed from the forming mold, and then the laser impact ablation layer in the impacted body is peeled off from the nanocrystalline foil layer to obtain the formed ultra-thin-wall nanocrystalline micro-parts, and then ultrasonically cleaned to obtain clean and high-strength nanocrystalline materials;

[0013] Furthermore, the whole nanocrystalline material in step 1 is prepared by one of vapor deposition, electrochemical deposition, magnetron sputtering and severe plastic deformation, ensuring that the grain size inside the nanocrystalline material is within the range of nanocrystalline polycrystalline material, while its thickness is maintained at an ultra-thin level;

[0014] Furthermore, the mechanical processing in step 1 is performed by wire cutting, laser cutting or punching;

[0015] Furthermore, the grinding treatment in step 1 is to use different types of sandpaper to mechanically grind the surface of the nanocrystalline material foil obtained after shearing, and the surface treatment mainly includes ultrasonic cleaning in alcohol, acetone, acid solution or alkaline solution to ensure that the impurity particles and oil stains on the surface of the nanocrystalline material foil are fully removed. The washed nanocrystalline material to be impacted is rinsed with a large amount of clean water, and finally dried with a hair dryer to obtain a nanocrystalline material layer to be impacted for standby use. The thickness of the nanocrystalline material layer to be impacted is between 1μm-500μm, and the ultrasonic cleaning time is 20-40min;

[0016] Furthermore, in step 2, the laser shock confinement layer is a highly light-transmitting solid material confinement layer, and the thickness of the laser shock confinement layer is 500 μm-5 mm, specifically K9 glass or PMMA resin;

[0017] Furthermore, in step 2, the laser shock confinement layer is a highly light-transmitting flexible liquid confinement layer, and the thickness of the laser shock confinement layer is 500 μm-5 mm, specifically a water layer or an oil layer;

[0018] Further, in step 2, the thickness of the laser shock ablation layer is 100nm-5mm, specifically black paint, black tape or aluminum foil;

[0019] Furthermore, the forming mold in step 4 includes an upper mold, a core mold and a lower mold, a groove for accommodating the core mold is processed at the top center of the lower mold, the core mold is arranged in the lower mold and movably connected to the lower mold, the upper mold is arranged on the top of the lower mold and is detachably connected to the upper mold by bolts, the depth dimension of the groove in the lower mold is greater than the height dimension of the core mold, the core mold is used to carry the impacted body formed by stacking the laser impact constraint layer, the laser impact ablation layer and the nanocrystalline material layer, and a light-transmitting hole is processed at the top center of the upper mold, and the light-transmitting hole is used to guide the laser beam to impact the impacted body;

[0020] Furthermore, the output parameters of the high energy pulse laser in step 5 are a wavelength of 1064 nm, a laser energy of 5 to 40 J, a pulse duration of 30 to 100 ns, a spot diameter of 4 to 20 mm, and an output laser density of 10 5 ~10 10 W / cm 2 ;

[0021] Furthermore, in step 6, the ultra-thin-wall nanocrystalline micro-parts are cleaned using an organic solvent in an ultrasonic environment, and the treatment time is 5-10 minutes.

[0022] The beneficial effects of this application compared to the prior art are as follows:

[0023] The present application provides a method for rapidly preparing ultra-thin-wall nanocrystalline micro-parts by laser shock, which has the advantage of cleverly combining the laser shock process with the preparation of ultra-thin nanocrystalline foils, thereby realizing the production and preparation of various ultra-thin-wall nanocrystalline microstructures. The use of this method to prepare ultra-thin-wall nanocrystalline micro-parts can greatly improve the forming efficiency, while overcoming the problems of difficult deformation caused by the high strength and hardness of the nanocrystalline material itself, and also avoiding the substantial increase in economic costs caused by the preparation and production of high-precision complex punches. In addition, laser shock forming belongs to flexible forming, and the complexity of the prepared parts can be improved to a certain extent;

[0024] As a relatively advanced processing technology, laser shock technology has been widely studied and applied in recent years. The powerful impact force it generates instantly can reach the GPa level, which can effectively overcome the deformation resistance of the material and cause the nanocrystalline material to deform. The forming process has greater flexibility and strong adaptability. At the same time, the deformation produced by this technology is instantaneous, and its strain rate can reach more than 106s-1. The deformation speed is extremely fast and the production efficiency is extremely high. Therefore, this technology shows great application potential in the field of micro-parts manufacturing, especially in the preparation of nanocrystalline super-strong materials;

[0025] In addition, the strong impact force generated by laser shock will generate an ordered 9R phase structure inside the grains of the nanocrystalline foil. As a more stable structure compared to dislocation entanglement, dislocation wall, stacking fault and twin, the 9R phase can more effectively hinder the movement of dislocations, so that dislocations can accumulate inside the nanocrystalline grains that cannot accumulate, thereby obtaining higher material strength at the same grain size. In addition, fewer dislocations interact with grain boundaries, which will reduce the occurrence of dislocation-induced grain boundary sliding, grain rotation and grain boundary migration, and reduce the grain growth driven by dislocations under quasi-static and high-speed impact conditions, thereby effectively suppressing the reduction in strength from the perspective of grain size. Furthermore, while suppressing grain growth, the larger grains inside the material will be broken under the strong energy generated by the laser, which is conducive to suppressing grain growth. The strengthening effect of the 9R phase and the suppression of grain growth can effectively improve the strength of nanocrystalline materials. It should be emphasized here that under normal conditions (quasi-static or high strain rate), strong forces will cause nanocrystalline grains to grow significantly, and the ultra-high strain rate generated by laser shock allows the material to effectively overcome this. The use of laser shock to prepare nanocrystalline micro-parts can design the impact strengthening area and related paths according to needs, while closing the macro defects such as holes in the nanocrystalline material, and enhancing the material's wear resistance, corrosion resistance, and fatigue resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of preparing ultra-thin-wall nanocrystalline micro-parts by laser shock in this application;

[0027] Figure 2 This is a crystal phase structure diagram of the 9R phase formed inside the nanocrystalline foil in this application after being impacted by laser (in the figure, A, B, and C all represent atomic layers, and each letter indicates that all atoms in the atomic layer are arranged in the same manner):

[0028] Figure 3 This is a curve diagram of the strength improvement of the nanocrystalline foil in this application after laser shock;

[0029] In the figure, 1 is a high-energy laser beam, 2 is a laser shock confinement layer, 3 is an upper mold, 4 is a laser shock ablation layer, 5 is a nanocrystalline foil layer, 6 is a core mold, 7 is a lower mold and 8 is a bolt. DETAILED DESCRIPTION

[0030] Specific implementation method 1: Combination Figure 1 This embodiment describes a method for rapidly preparing ultra-thin-wall nanocrystalline micro-parts by laser shock, which is achieved by the following steps:

[0031] Step 1: Preparation of nanocrystalline foil: cutting the whole nanocrystalline material by mechanical processing to obtain the shape of the micro-part to be prepared, grinding and surface treating the cut nanocrystalline foil to obtain the nanocrystalline foil layer 5 to be impacted;

[0032] Step 2: Selecting the laser shock confinement layer 2 and the laser shock ablation layer 4 used in the laser shock strengthening process; the laser shock confinement layer 2 is made of a solid material with high light transmittance or a flexible liquid with high light transmittance, and the laser shock ablation layer 4 is made of a material with excellent light absorption and a relatively low melting point;

[0033] Step 3: stack the laser shock confinement layer 2 and the laser shock ablation layer 4 selected in step 2 and the nanocrystalline foil layer 5 to be impacted prepared in step 1 from top to bottom to form an impacted body, and ensure that the two adjacent layers in the impacted body are perfectly fitted;

[0034] Step 4: Preparation before laser shock forming: place the impacted body obtained in step 3 in the forming mold, constrain the impacted body through the forming mold to ensure the stability of the impacted body during the laser shock forming process, and after the impacted body and the forming mold are assembled, move the forming mold with the impacted body to a high-precision three-dimensional moving platform;

[0035] Step 5: Install a high-energy laser transmitter on a high-precision three-dimensional mobile platform, and the high-energy pulse laser instantaneously excites the high-energy pulse laser with a constant pulse, and driven by the high-precision three-dimensional mobile platform, impacts the impacted body in the forming mold according to a predetermined impact path, so as to achieve impact strengthening forming of the nanocrystalline foil layer 5 to be impacted in the impacted body;

[0036] Step 6: After the impact is completed, the impacted body after laser impact is removed from the forming mold, and then the laser impact ablation layer 4 in the impacted body is peeled off from the nanocrystalline foil layer 5 to obtain the formed ultra-thin-wall nanocrystalline micro-parts, and then ultrasonically cleaned to obtain clean and high-strength nanocrystalline materials.

[0037] The present embodiment provides a method for rapidly preparing ultra-thin-wall nanocrystalline micro-parts by laser shock. The working principle is that a laser transmitter generates a high-energy laser pulse, and the laser pulse passes through the transparent material of the constraint layer and directly reaches the ablation layer. The ablation layer instantly absorbs the high-energy density pulse laser and instantly vaporizes and ionizes to form a high-energy shock wave. Under the restriction of the constraint layer, the peak pressure of the shock wave instantly increases and can reach the GPa level, far exceeding the yield limit of the nanocrystalline foil, so that it produces ultra-high-speed plastic deformation and fits the microarray mold, completing the preparation and production of various nanocrystalline micro-parts.

[0038] The core of this application is to apply laser impact technology to the forming process of ultra-thin-wall nanocrystalline micro-parts, which can effectively overcome the processing difficulty of nanocrystalline foil that is difficult to deform, and at the same time can greatly reduce the mold processing cost and quickly realize the production of ultra-thin-wall nanocrystalline micro-parts. While reducing the overall weight of the micro-parts, it ensures the strength, hardness, wear resistance, corrosion resistance and fatigue resistance of the micro-parts. It is a forming method with great application prospects.

[0039] Specific implementation method 2: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the whole nanocrystalline material in step 1 is prepared by one of vapor deposition, electrochemical deposition, magnetron sputtering and severe plastic deformation, ensuring that the grain size inside the nanocrystalline material is within the range of nanocrystalline polycrystalline materials, and its thickness is maintained at an ultra-thin level. Other components and connection methods are the same as those in the first embodiment.

[0040] In this embodiment, the grain size inside the nanocrystalline material is guaranteed to be below 100 nm.

[0041] Specific implementation method three: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the mechanical processing method in step 1 is wire cutting, laser cutting or punching, etc. The other components and connection methods are the same as those in the first embodiment.

[0042] In this embodiment, it is taken into consideration that the surface flatness of the nanocrystalline material cut by mechanical processing is uneven, and directly using it in the laser shock strengthening process will affect the strengthening effect of the final nanocrystalline material. Therefore, it is necessary to use different types of sandpaper to perform surface mechanical grinding on the cut nanocrystalline material. The nanocrystalline material to be impacted after grinding has a higher flatness and can avoid the occurrence of obvious warping.

[0043] Specific implementation method four: Combination Figure 1This embodiment is described. The difference between this embodiment and the specific embodiment 1 is that the grinding treatment in step 1 is to use different types of sandpaper to mechanically grind the surface of the nanocrystalline material foil obtained after shearing. The surface treatment mainly includes ultrasonic cleaning in alcohol, acetone, acid solution or alkaline solution to ensure that the impurity particles and oil stains on the surface of the nanocrystalline material foil are fully removed. The washed nanocrystalline material to be impacted is rinsed with a large amount of clean water, and finally dried with a hair dryer to obtain a nanocrystalline material layer to be impacted for standby use. The thickness of the nanocrystalline material layer to be impacted is between 1μm-500μm, and the ultrasonic cleaning time is 20-40min. Other components and connection methods are the same as those in the specific embodiment 1.

[0044] Specific implementation method five: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the laser shock confinement layer 2 in step 2 is a highly light-transmitting solid material confinement layer, and the thickness of the laser shock confinement layer 2 is 500 μm-5 mm, specifically K9 glass or PMMA resin. The other components and connection methods are the same as those in the first embodiment.

[0045] Specific implementation method six: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the laser shock confinement layer 2 in step 2 is a highly light-transmitting flexible liquid confinement layer, and the thickness of the laser shock confinement layer 2 is 500 μm-5 mm, specifically a water layer or an oil layer. The other components and connection methods are the same as those in the first embodiment.

[0046] In combination with the description of specific implementation methods four to five, the solid material constraint layer has high strength and hardness, and can greatly increase the pressure brought by the shock wave. The flexible liquid constraint layer has extremely high flexibility, which can increase the pressure brought by the shock wave while replenishing the constraint layer in time, and effectively carry out continuous impact. The specific type of laser shock constraint layer 2 is selected by the staff. The thickness of the laser shock constraint layer 2 is between 100μm-10mm, which can effectively limit the shock wave and increase the shock wave pressure.

[0047] Specific implementation method seven: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the thickness of the laser shock ablation layer 4 in step 2 is 10nm-5mm, specifically black paint, black tape or aluminum foil. The other components and connection methods are the same as those in the first embodiment.

[0048] In this embodiment, the laser shock ablation layer 4 mainly absorbs high-energy lasers, thereby instantly exploding to generate plasma and generating the impact force required for the forming process. It mainly includes materials with strong light absorption and low melting points such as black paint, black tape, and aluminum foil. During the forming process, it must be tightly combined with the constraint layer and nanocrystalline foil. In addition, its thickness needs to be selected according to its material properties and impact energy. The thickness is generally between 10nm-1mm, and it is necessary to ensure that all impact positions are covered.

[0049] Specific implementation method eight: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the forming mold in step 4 includes an upper mold 3, a core mold 6 and a lower mold 7. A groove for accommodating the core mold 6 is processed at the top center of the lower mold 7. The core mold 6 is arranged in the lower mold 7 and is movably connected to the lower mold 7. The upper mold 3 is arranged on the top of the lower mold 7 and is detachably connected to the upper mold 7 by bolts 8. The depth dimension of the groove in the lower mold 7 is greater than the height dimension of the core mold 6. The core mold 6 is used to carry the impacted body formed by stacking the laser impact confinement layer 2, the laser impact ablation layer 4 and the nanocrystalline material layer 5. A light-transmitting hole is processed at the top center of the upper mold 3. The light-transmitting hole is used to guide the laser beam to impact the impacted body. Other components and connection methods are the same as those in the first embodiment.

[0050] When a forming mold provided in the present embodiment is used, first, the lower mold 7 is fixed to the working surface of the three-dimensional high-precision platform, and the core mold 6 for forming is placed in the lower mold 7. Then, the laser shock constraint layer 2, the laser shock ablation layer 4 and the nanocrystalline foil layer 5 to be impacted are stacked on the core mold 6 from top to bottom in sequence, and then the upper mold 3 is laid on the top of the lower mold 7 and fixed with bolts 8. It is worth noting here that the size of the light-transmitting hole at the top of the upper mold 3 is smaller than the size of the laser shock constraint layer 2, and the contour area of ​​the light-transmitting hole in the upper mold 3 forms a pressure edge to limit the impacted body as a whole on the core mold 6 to ensure the stability of the impacted body during subsequent laser impact.

[0051] Specific implementation method nine: Combination Figure 1 The present embodiment is different from the first embodiment in that the output parameters of the high energy pulse laser in step 5 are a wavelength of 1064 nm, a laser energy of 5 to 40 J, a pulse duration of 30 to 100 ns, a spot diameter of 4 to 20 mm, and an output laser density of 10 5 ~10 10 W / cm 2 The other components and connection methods are the same as those in the first embodiment.

[0052] Step 5 in this embodiment is the core step, which cleverly combines laser shock forming with the strengthening of nanocrystalline materials to achieve the improvement of the strength, hardness and other properties of nanocrystalline foil. The high-energy laser beam 1 passes through the laser shock confinement layer 2 and irradiates the laser shock ablation layer 3. After the pulsed laser is absorbed by the laser shock ablation layer 3, the laser shock ablation layer 3 is rapidly vaporized and ionized to generate plasma. The plasma rapidly expands under the action of laser energy to generate a high-energy shock wave. Under the constraint of the laser shock confinement layer 2, the instantaneous peak pressure of the high-energy shock wave can reach the GPa level. The shock wave generated by the laser shock ablation layer 3 is quickly transmitted to the nanocrystalline material layer 5, so that the nanocrystalline material layer 5 is squeezed into contact with the core mold 6 to complete the forming of the ultra-thin nanocrystalline micro-parts. At the same time as the ultra-thin nanocrystalline micro-parts are formed, the ultra-thin nanocrystalline micro-parts can also be strengthened under the action of laser shock, which can achieve the effect of killing two birds with one stone.

[0053] Specific implementation method ten: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the ultra-thin-wall nanocrystalline micro-parts are cleaned in an ultrasonic environment using an organic solvent in step 6 for 5-10 minutes. The other components and connection methods are the same as those in the first embodiment.

[0054] In this embodiment, ultrasonic cleaning is performed on the strengthened nanocrystalline foil, which is beneficial to removing impurities on the surface of the strengthened nanocrystalline foil and ensuring the neatness of the strengthened nanocrystalline foil.

[0055] The present invention has been disclosed as above with preferred implementation cases, but it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above implementation cases based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention. Specific embodiment:

[0057] Take the strengthening process of nanocrystalline nickel-cobalt foil by laser shock strengthening as an example;

[0058] Step 1: Use electrochemical deposition to prepare ultra-thin nanocrystalline NiCo foil, which is about 33μm thick and has internal grains below 100nm, which is a typical nanocrystalline material. Use punching to process the prepared foil into a predetermined shape, and use 3000# sandpaper to carefully grind the surface of the cut foil to ensure that the foil has a high degree of flatness. Then put the ground foil into acetone solution and use ultrasonic cleaning for 25 minutes to ensure that the oil and impurities on the surface are completely removed to facilitate the attachment of the ablation layer. Then rinse with plenty of clean water and blow dry with a hair dryer to ensure that the thickness of the final nanocrystalline material foil to be impacted is 33μm;

[0059] Step 2: Select aluminum foil as the laser shock ablation layer. The thickness of the aluminum foil is 120μm. The aluminum foil has the characteristics of good light absorption and low melting point, and can effectively generate high-energy shock waves. At the same time, it can block the transfer of heat to the surface of ultra-thin nanocrystalline NiCo to ensure the stability of the nanocrystalline material. Select highly transparent K9 glass as the laser shock confinement layer during the laser shock process. K9 glass has high hardness and good light transmittance, which can effectively suppress the explosive expansion of plasma, provide extremely high impact force, and ensure the forming effect of nanocrystalline NiCo foil;

[0060] Step 3: stack the highly light-transmitting K9 glass, aluminum foil and the ultra-thin nanocrystalline NiCo foil after polishing and cleaning from top to bottom to form an impact-receiving body, and ensure that the two adjacent layers fit perfectly and are tightly attached;

[0061] Step 4: Use carbide steel as the material of the mold, use ultra-precision CNC processing equipment to precisely process and manufacture the mold to ensure that the mold has good surface quality and behavior accuracy. The extremely high strength and hardness can effectively ensure the progress of the forming process. Place the processed core mold in the groove on the lower mold, place the impact body obtained in step 3 on the core mold, and finally place the upper mold on the lower mold and use bolts to mechanically connect the upper mold and the lower mold to ensure that each part has high stability during the forming process. Then place the forming mold with the impact body on a three-dimensional high-precision mobile platform;

[0062] Step 5: Use a high-energy pulse laser and a three-dimensional high-precision mobile platform to impact the impacted body according to the predetermined impact path. The parameters of the pulse laser are wavelength 1064nm, laser energy 10J, pulse width 45ns, spot diameter 5mm, output laser density 10 8 W / cm 2The high-energy laser beam irradiates the aluminum foil through the K9 glass layer, and the aluminum foil quickly vaporizes and ionizes into plasma and expands rapidly to form a super strong shock wave. Under the constraint of the K9 glass, the shock wave is efficiently transmitted to the ultra-thin nanocrystalline NiCo foil, making it fit with the core mold at an ultra-high speed, completing the laser shock preparation of ultra-thin-walled nano NiCo alloy micro parts;

[0063] Step 6: The prepared micro-parts are prepared into target parts by micro-punching, and then placed in an acetone solution for ultrasonic cleaning for 10 minutes, followed by rinsing with plenty of clean water and then drying.

[0064] After testing, the ultra-thin-wall nanocrystalline NiCo alloy micro-parts prepared by the present application have good shape accuracy, light weight, and their strength can be increased by 10% to 20%. At the same time, the wear resistance, corrosion resistance and fatigue resistance can be improved.

Claims

1. A method for rapidly preparing ultra-thin-wall nanocrystalline micro-parts by laser shock, characterized in that: The method is achieved by the following steps: Step 1: Preparation of nanocrystalline foil: using mechanical processing to cut the whole piece of nanocrystalline material to obtain the shape of the micro-part to be prepared, grinding and surface treating the cut nanocrystalline material foil to obtain a nanocrystalline foil layer to be impacted (5); Step 2: Selecting the laser shock confinement layer (2) and the laser shock ablation layer (4) used in the laser shock strengthening process; the laser shock confinement layer (2) is selected from a solid material with high light transmittance or a flexible liquid with high light transmittance, and the laser shock ablation layer (4) is selected from a material with excellent light absorption and a relatively low melting point; Step 3: stacking the laser shock confinement layer (2) and the laser shock ablation layer (4) selected in step 2 and the nanocrystalline foil layer (5) to be impacted prepared in step 1 from top to bottom in sequence to form an impacted body, and ensuring that two adjacent layers in the impacted body are perfectly fitted; Step 4: Preparation before laser shock forming: place the impacted body obtained in step 3 in the forming mold, constrain the impacted body through the forming mold to ensure the stability of the impacted body during the laser shock forming process, and after the impacted body and the forming mold are assembled, move the forming mold with the impacted body to a high-precision three-dimensional moving platform; Step 5: installing a high-energy laser transmitter on a high-precision three-dimensional mobile platform, and the high-energy pulse laser instantaneously excites the high-energy pulse laser with a constant pulse, and driven by the high-precision three-dimensional mobile platform, impacts the impacted body located in the forming mold according to a predetermined impact path, so as to achieve impact strengthening forming of the nanocrystalline foil layer (5) to be impacted in the impacted body; Step 6: After the impact is completed, the impacted body after the laser impact is removed from the forming mold, and then the laser impact ablation layer (4) in the impacted body is peeled off from the nanocrystalline foil layer (5) to obtain the formed ultra-thin-wall nanocrystalline micro-parts, and then ultrasonically cleaned to obtain clean and high-strength nanocrystalline materials.

2. The method for rapidly preparing ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: The whole piece of nanocrystalline material in step 1 is prepared by one of vapor deposition, electrochemical deposition, magnetron sputtering and severe plastic deformation, ensuring that the grain size inside the nanocrystalline material is within the range of nanocrystalline polycrystalline material, while its thickness is maintained at an ultra-thin level.

3. The method for rapidly preparing ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: The mechanical processing method in step 1 is wire cutting, laser cutting or punching.

4. The method for rapidly preparing ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: The grinding treatment in step 1 is to use sandpaper of different types to mechanically grind the surface of the nanocrystalline material foil obtained after shearing. The surface treatment mainly includes ultrasonic cleaning in alcohol, acetone, acid solution or alkaline solution to ensure that the impurity particles and oil stains on the surface of the nanocrystalline material foil are fully removed. The nanocrystalline material to be impacted after cleaning is rinsed with a large amount of clean water, and finally dried with a hair dryer to obtain a nanocrystalline material layer to be impacted for standby use. The thickness of the nanocrystalline foil layer (5) to be impacted is between 1μm and 500μm, and the ultrasonic cleaning time is 20-40min.

5. The method for rapidly preparing ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: In the step 2, the laser shock confinement layer is a highly light-transmitting solid material confinement layer, and the thickness of the laser shock confinement layer is 500 μm-5 mm, specifically K9 glass or PMMA resin.

6. The method for rapidly preparing ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: In the step 2, the laser shock confinement layer is a flexible liquid confinement layer with high light transmittance, and the thickness of the laser shock confinement layer is 500 μm-5 mm, specifically a water layer or an oil layer.

7. The method for rapidly preparing ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: The thickness of the laser shock ablation layer in step 2 is 100 nm-5 mm, specifically black paint, black tape or aluminum foil.

8. The method for rapid preparation of ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: The forming mold in step 4 comprises an upper mold (3), a core mold (6) and a lower mold (7); a hole system for accommodating the core mold (6) is processed at the top center of the lower mold (7); the core mold (6) is arranged in the lower mold (7) and is movably connected to the lower mold (7); the upper mold (3) is arranged on the top of the lower mold (7) and is detachably connected to the upper mold (7) by bolts; the depth dimension of the hole system in the lower mold (7) is greater than the height dimension of the core mold (6); the core mold (6) is used to support the impacted body formed by stacking the laser impact confinement layer (2), the laser impact ablation layer (4) and the nanocrystalline material layer (5); a light-transmitting hole is processed at the top center of the upper mold (3); the light-transmitting hole is used to guide the laser beam to impact the impacted body.

9. The method for rapid preparation of ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: The output parameters of the high-energy pulse laser in step 4 are: wavelength of 1064nm, laser energy of 5-40J, pulse duration of 30-100ns, spot diameter of 4-20mm, output laser density of 10 5 ~10 10 W / cm 2 .

10. The method for rapid preparation of ultra-thin-wall nanocrystalline micro-components by laser shock according to claim 1, characterized in that: In step 6, the ultra-thin-wall nanocrystalline micro-parts are cleaned using an organic solvent in an ultrasonic environment for 5-10 minutes.

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