Method for preparing ultrafast laser surface micro-nano structure

Abstract

The application discloses a method for preparing a micro-nano structure on a surface by using ultrafast laser, and the method comprises the following steps: constructing a structure model matched with a target material according to characteristic parameters of the target material and application requirements, wherein the characteristic parameters comprise a material type and structure parameters, and the application requirements comprise geometric characteristics and functional requirements; obtaining ultrafast laser strengthening process parameters of the target material from a material femtosecond laser strengthening database according to the material type, wherein the process parameters comprise laser power, scanning speed, repetition frequency and spot lap rate; designing a processing path of the ultrafast laser based on the structure model and in combination with the geometric characteristics and the functional requirements; and processing the micro-nano structure based on the ultrafast laser strengthening process parameters and the processing path, so as to obtain the micro-nano structure.

Description

Technical Field

[0001] This invention relates to the field of ultrafast laser processing technology, and in particular to a method for preparing ultrafast laser surface micro / nano structures. Background Technology

[0002] Traditional micro / nano structure fabrication techniques, such as photolithography, electron beam etching, ion beam etching, and machining, while still important in some applications, have significant limitations. These techniques often cause varying degrees of damage to the material surface, such as increased surface roughness, introduction of chemical contamination, lattice damage, and the creation of heat-affected zones. These problems significantly reduce the mechanical, optical, electrical, and corrosion resistance properties of materials, limiting their application in high-end manufacturing.

[0003] Ultrafast laser texturing technology, especially femtosecond and picosecond lasers, can achieve high-precision micro- and nanostructure processing on material surfaces due to its extremely high peak power and extremely short pulse duration. The core advantage of this technology lies in its non-thermally fusible processing characteristics, avoiding the heat-affected zone problem in traditional laser processing, thus achieving cold processing of materials. Ultrafast laser processing offers advantages such as high precision, non-contact processing, material versatility, and flexibility, making it suitable for fields such as microelectronics, biomedical devices, and optical component manufacturing, demonstrating enormous application potential.

[0004] The information disclosed in the background section is only for enhancing the understanding of the background of this invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides a method for fabricating ultrafast laser surface micro / nano structures and the micro / nano structures themselves. While achieving high-precision processing, it effectively protects and even enhances the surface properties of materials. By precisely controlling laser parameters and introducing real-time monitoring and feedback control, it not only achieves high-precision micro / nano structure processing but also significantly improves the mechanical properties, wear resistance, and corrosion resistance of materials, providing an efficient and reliable solution for the field of micro / nano manufacturing.

[0006] A method for fabricating ultrafast laser surface micro / nano structures includes: Step S1: Based on the characteristic parameters of the target material and the application requirements, construct a structural model that matches the target material. The characteristic parameters include material type and structural parameters, and the application requirements include geometric features and functional requirements. Step S2: Based on the material type, obtain the ultrafast laser strengthening process parameters of the target material from the material femtosecond laser strengthening database, including laser power, scanning speed, repetition frequency and spot overlap rate; Step S3: Based on the structural model, and combining the geometric features and functional requirements, design the ultrafast laser processing path. Step S4: Based on the ultrafast laser strengthening process parameters and processing path, the micro-nano structure is processed to obtain the micro-nano structure.

[0007] In the method for fabricating ultrafast laser surface micro / nano structures, step S1 includes: Step S101: Construct a three-dimensional structural model of the target material using CAD software based on the structural parameters; Step S102: Determine the interface structure type of the target functional requirements based on the application requirements, and determine the interface structure model parameters in conjunction with the target material surface location. Step S103: Based on the interface structure model parameters, construct a micro / nano structure model on the surface of the three-dimensional structure model; Step S104: Perform functional characteristic simulation tests on the surface micro / nano structure model, optimize the surface structure parameters, and obtain the optimized surface micro / nano structure model. Step S105: The three-dimensional structural model is fused with the optimized surface micro / nano structure model to obtain the final structural model.

[0008] In the aforementioned method for fabricating ultrafast laser surface micro / nano structures, the functional requirements include wear resistance parameters or hydrophilic / hydrophobic parameters.

[0009] In the aforementioned method for fabricating ultrafast laser surface micro / nano structures, before ultrafast laser processing, the component undergoes surface cleaning and drying treatment. Step S3 further includes... Step S301: Use an ultrasonic cleaner to perform ultrasonic cleaning on the components. Step S302: Perform a secondary cleaning of the cleaned component surface using an ethyl acetate solution. Step S303: Dry the parts after the second cleaning.

[0010] In the method for fabricating ultrafast laser surface micro / nano structures, the ultrafast laser includes femtosecond lasers and picosecond lasers.

[0011] In the method for fabricating ultrafast laser surface micro / nano structures, the target materials include metals, ceramics, and polymers.

[0012] A micro / nano structure is prepared by the method described above.

[0013] Compared with existing technologies, this invention has the following advantages: This invention achieves high-precision surface micro / nanostructure processing using ultrafast laser technology, significantly improving various functional properties of materials, such as wear resistance, hydrophilicity / hydrophobicity, and corrosion resistance. Simultaneously, it utilizes laser-induced residual compressive stress to enhance surface integrity and extend product lifespan. This method is applicable to various materials, including metals, ceramics, and polymers, and through optimized processing paths and parameters, ensures high controllability and consistency in the processing. Compared with traditional methods, ultrafast laser processing has a smaller heat-affected zone, requires no chemical reagents, causes less environmental pollution, and offers high processing efficiency and low cost. Furthermore, this invention solves the technical challenges of uncontrollable processing structures and easy damage to surface properties in traditional surface treatment methods, possessing broad application prospects, especially in aerospace, biomedicine, and microelectronics fields, providing an efficient, environmentally friendly, and powerful solution for the preparation of high-performance material surfaces. This invention achieves high-precision processing of micro / nanostructures on material surfaces and significantly improves various functional properties of materials. It provides optimized laser processing parameters to ensure high efficiency and consistency in the processing. This multi-level, multi-dimensional synergistic mechanism ensures the effective realization of the technical results. Laser surface processing induces plasma shock waves, refining the grain size of the material surface and inducing residual compressive stress, thereby strengthening the material surface. Furthermore, by varying the processing trajectory and the number of scans, functional structures can be fabricated, achieving a balance between strengthening and other effects. Attached Figure Description

[0014] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0015] In the attached diagram: Figure 1 This is a flowchart of a preferred embodiment of the present invention.

[0016] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0017] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0018] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0019] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0020] like Figure 1 As shown, the method for fabricating ultrafast laser surface micro / nano structures includes the following steps: Step S1: Based on the characteristic parameters of the target material and application requirements, construct a structural model matching the target material. Characteristic parameters include material type and structural parameters, while application requirements include geometric features and functional requirements. Further, the material type includes chemical composition, hardness, and elastic modulus, and the structural parameters include three-dimensional dimensions. Functional requirements and geometric features refer to the design of different micro / nano structures to address different needs such as friction, lubrication, and sealing. Examples include striped structures to reduce friction and columnar micro / nano structures for sealing. Matching involves designing different structural models based on the specific requirements.

[0021] Step S2: Based on the material type, obtain the ultrafast laser strengthening process parameters of the target material from the material femtosecond laser strengthening database, including laser power, scanning speed, repetition rate, and spot overlap rate; further, the material femtosecond laser strengthening database includes laser strengthening processing of titanium alloys using a wavelength of 1030nm, a laser power of 1.2W, a scanning speed of 80mm / s, a spot overlap rate of 75%, and a repetition rate of 50KHz. Based on the corresponding material being processed, determine the femtosecond laser strengthening process parameters.

[0022] Step S3: Based on the structural model, combined with the geometric features and functional requirements, design the ultrafast laser processing path, process the wear-resistant stripe periodic structure through the flow path, design the stripe spacing, width and depth according to simulation analysis, and design the laser to use different scanning intervals and scanning times to process the required morphology.

[0023] Step S4 involves processing micro / nano structures based on the ultrafast laser strengthening process parameters and processing path to obtain the micro / nano structures. These micro / nano structures simultaneously exist at the micrometer and nanometer scales, with the micrometer portion reaching 30-100 micrometers and the nanometer portion not exceeding 500 nanometers. Laser surface processing induces plasma shock waves, refining the material surface grains and inducing residual compressive stress, thus strengthening the material surface. Furthermore, by adjusting the processing trajectory and number of scans, functional structures can be fabricated, achieving the fabrication of micro / nano structures that simultaneously achieve strengthening effects.

[0024] In a preferred embodiment of the ultrafast laser surface micro / nanostructure fabrication method, step S1 includes: Step S101: Construct a three-dimensional structural model of the target material using CAD software based on the structural parameters; Step S102: Determine the interface structure type of the target functional requirements based on application needs, and determine the interface structure model parameters in conjunction with the surface position of the target material; the interface structure type is the micro-nano structure size characteristics to be processed. Different structural models are designed according to different requirements, and the structural parameters are optimized based on mechanical simulation to obtain the final three-dimensional size parameters of the structural model. Step S103: Based on the interface structure model parameters, construct a micro / nano structure model on the surface of the three-dimensional structure model; Step S104 involves performing functional characteristic simulation tests on the surface micro / nano structure model, optimizing the surface structure parameters, and obtaining an optimized surface micro / nano structure model. For the fabrication optimization of the sealing and bonding functional micro / nano structure, simulation software is used to further optimize the model. In the finite element method (FEM) calculation, the failure of the cohesive model is based on the stress-displacement separation criterion, which assumes the material is linearly elastic and that material elements can undergo tensile separation along the thickness direction, shear separation perpendicular to the thickness direction, or a hybrid of both. The maximum nominal strain criterion is used for cohesive failure.

[0025] In the specific simulation, the adhesive layer is set as a zero-thickness cohesive element, and there is only one layer of adhesive element along the thickness direction. SDEG represents the damage factor of the element; when the damage factor reaches a certain value, the element will fail. The minimum damage factor is 0, meaning no damage, and the maximum value is 1, meaning complete damage failure. When the damage factor reaches 1, it means that the strain energy release rate of the element is equal to the crack energy of the element, and the crack energy is equal to the area enclosed by the stress-displacement curve and the x-axis. Based on the feasibility of calculation, the maximum damage factor is set to 0.99. Inputting a series of parameters such as the material's elastic modulus and Poisson's ratio, the fracture energy is calculated according to the designed structural dimensions, and then reverse optimization is performed.

[0026] Step S105: The three-dimensional structural model is fused with the optimized surface micro / nano structure model to obtain the final structural model.

[0027] In a preferred embodiment of the ultrafast laser surface micro / nano structure fabrication method, the functional requirements include wear resistance parameters or hydrophilic / hydrophobic parameters.

[0028] In a preferred embodiment of the ultrafast laser surface micro / nano structure fabrication method, before ultrafast laser processing, the component undergoes surface cleaning and drying treatment. Step S3 further includes... Step S301: Use an ultrasonic cleaner to perform ultrasonic cleaning on the components. Step S302: Perform a secondary cleaning of the cleaned component surface using an ethyl acetate solution. Step S303: Dry the parts after the second cleaning.

[0029] In a preferred embodiment of the method for fabricating ultrafast laser surface micro / nano structures, the ultrafast laser includes femtosecond lasers and picosecond lasers.

[0030] In a preferred embodiment of the ultrafast laser surface micro / nanostructure fabrication method, the target material includes metals, ceramics, and polymers.

[0031] A micro / nano structure is prepared by the method described above.

[0032] In one embodiment, the method includes, S1. Based on the characteristic parameters of the target material (including material type and structural parameters) and application requirements (such as wear resistance, hydrophobicity, and other functional requirements), construct a structural model that matches the target material. Specific steps include: S101. Based on the structural parameters, a three-dimensional structural model of the target material is constructed using CAD software. S102, determine the interface structure type of the target functional characteristics (such as wear resistance, hydrophobicity, etc.) according to the application requirements, and determine the interface structure model parameters in combination with the material surface location information; S103, based on the interface structure model parameters, constructs a micro-nano structure model on the surface of a three-dimensional structure model; S104, Perform functional characteristic simulation tests (such as wear resistance and hydrophilicity / hydrophobicity tests) on the surface micro-nano structure model, optimize the surface structure parameters, and obtain the optimized surface micro-nano structure model; S105 combines the three-dimensional structural model with the optimized surface micro / nano structure model to obtain the final structural model.

[0033] S2, based on the material type of the component, obtain the target femtosecond laser strengthening process parameters that match the component from a preset material femtosecond laser strengthening database, including laser power, scanning speed, repetition frequency, and spot overlap rate.

[0034] S3, based on the S1 structural model, combines the geometric features and functional requirements of the structural model to design the corresponding femtosecond laser processing path to ensure the processing of micro and nano structures.

[0035] Before performing femtosecond laser processing, the S301 component needs to undergo surface cleaning and drying to remove surface impurities and organic matter. Specific steps include: 1. Use an ultrasonic cleaner to clean the parts.

[0036] 2. Use ethyl acetate solution to perform a second cleaning on the surface of the cleaned parts.

[0037] 3. Dry the parts after the second cleaning.

[0038] After cleaning, the thickness of the component needs to be remeasured to ensure that the laser energy can be precisely focused on the surface, thereby achieving efficient femtosecond laser processing.

[0039] S4, based on the determined femtosecond laser enhancement process parameters and processing path, performs micro-nano structure processing.

[0040] Example 1 In the aerospace field, the wear resistance and corrosion resistance of material surfaces are crucial. For example, aircraft engine blades are susceptible to wear and corrosion during high-speed operation, affecting their performance and lifespan.

[0041] Implementation steps: Titanium alloy was chosen as the target material because of its high strength, corrosion resistance, and high temperature resistance.

[0042] Based on the physical properties of titanium alloys, a three-dimensional structural model of the engine blade was constructed using CAD software. The wear resistance and corrosion resistance requirements of the blade surface were determined, and a corresponding periodic corrugated micro / nano structure model was designed.

[0043] The laser strengthening process parameters for titanium alloys are obtained from a pre-defined femtosecond laser strengthening database, including laser power, scanning speed, repetition frequency, and spot overlap rate. The process parameters that can be used are: wavelength 1030 nm, pulse width 290 fs, repetition frequency 1 MHz, energy density 1.2 J / cm², and scanning speed 80 mm / s.

[0044] The blades are cleaned using an ultrasonic cleaner to remove surface impurities and organic matter, and then dried.

[0045] Based on the designed processing path, femtosecond lasers are used to fabricate micro / nano structures on the blade surface to ensure improved wear resistance and corrosion resistance. The surface hardening layer and periodic lip slab micro / nano structures enhance wear resistance, while fabricating structures such as nanopillars kills surface bacteria and reduces bacterial adhesion, improving the material's antibacterial properties. Ultrafast laser processing significantly improves the wear resistance and corrosion resistance of titanium alloy blade surfaces, extending engine blade life, reducing maintenance costs, and enhancing flight safety. Blades strengthened with laser micro / nano structures can extend service life by 150%.

[0046] Example 2: In the biomedical field, the surface properties of implant materials have a significant impact on biocompatibility and antibacterial properties. For example, the surface of artificial joints needs to have good wear resistance and antibacterial properties to reduce infection and wear.

[0047] Implementation steps: Medical-grade stainless steel was chosen as the target material because of its good biocompatibility and mechanical properties.

[0048] Based on the geometry of the artificial joint, a three-dimensional structural model was constructed using CAD software. The wear resistance and antibacterial properties of the joint surface were determined, and corresponding nano-columnar micro / nano-structure models were designed.

[0049] The laser strengthening process parameters for medical stainless steel are obtained from a pre-set femtosecond laser strengthening database, including laser power, scanning speed, repetition frequency, and spot overlap rate. Processing can be carried out using process parameters of wavelength 1030 nm, pulse width 290 fs, repetition frequency 1 MHz, energy density 2 J / cm², and scanning speed 50 mm / s.

[0050] Artificial joints are cleaned using an ultrasonic cleaner to remove surface impurities and organic matter, and then dried.

[0051] Based on the designed processing path, femtosecond lasers are used to process micro-nano structures on the surface of artificial joints to ensure improved wear resistance and antibacterial properties.

[0052] Ultrafast laser processing significantly improves the wear resistance and antibacterial properties of the surface of medical stainless steel artificial joints, reducing the risk of infection after implantation, extending the lifespan of the artificial joint, and improving the quality of life for patients.

[0053] Example 3: Applications in the field of microelectronics Application scenarios: In the field of microelectronics, the surface properties of electronic components have a significant impact on conductivity and heat dissipation performance. For example, the surface of heat sinks for integrated circuits needs to have good heat dissipation and conductivity to improve the performance and reliability of electronic components.

[0054] Implementation steps: Copper was chosen as the target material because of its excellent electrical conductivity and heat dissipation.

[0055] Based on the geometry of the heat sink, a three-dimensional structural model was constructed using CAD software. The heat dissipation and electrical conductivity requirements of the heat sink surface were determined, and a corresponding micro / nano flower-like hierarchical micro / nano structure model was designed.

[0056] The laser strengthening process parameters for copper are obtained from a pre-defined femtosecond laser strengthening database, including laser power, scanning speed, repetition rate, and spot overlap rate. The process parameters can be processed using a wavelength of 1030 nm, a pulse width of 800 fs, a repetition rate of 200 kHz, an energy density of 1.5 J / cm², and a scanning speed of 100 mm / s.

[0057] The heat sink is cleaned using an ultrasonic cleaner to remove surface impurities and organic matter, and then dried.

[0058] Based on the designed processing path, femtosecond lasers are used to process micro- and nano-structures on the surface of the heat sink to ensure improved heat dissipation and conductivity.

[0059] Although embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of the present invention, and all of these are within the scope of protection of the present invention.

Claims

1. A method for fabricating ultrafast laser surface micro / nano structures, characterized in that, Includes the following steps: Step S1: Based on the characteristic parameters of the target material and the application requirements, construct a structural model that matches the target material. The characteristic parameters include material type and structural parameters, and the application requirements include geometric features and functional requirements. Step S2: Based on the material type, obtain the ultrafast laser strengthening process parameters of the target material from the material femtosecond laser strengthening database, including laser power, scanning speed, repetition frequency and spot overlap rate; Step S3: Based on the structural model, and combining the geometric features and functional requirements, design the ultrafast laser processing path. Step S4: Based on the ultrafast laser strengthening process parameters and processing path, the micro-nano structure is processed to obtain the micro-nano structure.

2. The method for fabricating ultrafast laser surface micro / nano structures according to claim 1, characterized in that, Preferably, step S1 includes, Step S101: Construct a three-dimensional structural model of the target material using CAD software based on the structural parameters; Step S102: Determine the interface structure type of the target functional requirements based on the application requirements, and determine the interface structure model parameters in conjunction with the target material surface location. Step S103: Based on the interface structure model parameters, construct a micro / nano structure model on the surface of the three-dimensional structure model; Step S104: Perform functional characteristic simulation tests on the surface micro / nano structure model, optimize the surface structure parameters, and obtain the optimized surface micro / nano structure model. Step S105: The three-dimensional structural model is fused with the optimized surface micro / nano structure model to obtain the final structural model.

3. The method for fabricating ultrafast laser surface micro / nano structures according to claim 1, characterized in that, Functional requirements include abrasion resistance parameters or hydrophilic / hydrophobic parameters.

4. The method for fabricating ultrafast laser surface micro / nano structures according to claim 1, characterized in that, Before ultrafast laser processing, the parts undergo surface cleaning and drying. Step S3 also includes... Step S301: Use an ultrasonic cleaner to perform ultrasonic cleaning on the components. Step S302: Perform a secondary cleaning of the cleaned component surface using an ethyl acetate solution. Step S303: Dry the parts after the second cleaning.

5. The method for fabricating ultrafast laser surface micro / nano structures according to claim 1, characterized in that, Ultrafast lasers include femtosecond lasers and picosecond lasers.

6. The method for fabricating ultrafast laser surface micro / nano structures according to claim 1, characterized in that, The target materials include metals, ceramics, and polymers.

7. A micro / nano structure, characterized in that, It is prepared by the method described in any one of claims 1-6.

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