CN107252967B - Method for manufacturing high-absorptivity ferrous metal by modifying ultrashort pulse laser surface structure - Google Patents
Method for manufacturing high-absorptivity ferrous metal by modifying ultrashort pulse laser surface structure Download PDFInfo
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- CN107252967B CN107252967B CN201710616090.0A CN201710616090A CN107252967B CN 107252967 B CN107252967 B CN 107252967B CN 201710616090 A CN201710616090 A CN 201710616090A CN 107252967 B CN107252967 B CN 107252967B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/0093—Working by laser beam, e.g. welding, cutting or boring combined with mechanical machining or metal-working covered by other subclasses than B23K
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/352—Working by laser beam, e.g. welding, cutting or boring for surface treatment
- B23K26/355—Texturing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2223/00—Investigating materials by wave or particle radiation
- G01N2223/05—Investigating materials by wave or particle radiation by diffraction, scatter or reflection
- G01N2223/052—Investigating materials by wave or particle radiation by diffraction, scatter or reflection reflection
Abstract
The invention discloses a method for manufacturing high-absorptivity ferrous metal by modifying an ultrashort pulse laser surface structure. The method can realize the rapid and large-area uniform surface modification of the area, and can also realize the surface modification of the mu m-order area by changing the focusing degree of laser focusing. In addition, the method can also carry out surface modification on magnetron sputtering, vacuum ion plating and plasma spraying plating under the condition of not influencing the substrate.
Description
Technical Field
The invention relates to the technical field of materials, in particular to a method for manufacturing high-absorptivity ferrous metal by modifying an ultrashort pulse laser surface structure.
Background
In modern warfare, the key to win or lose is dependent on who first discovers the other party and destroys it, so stealth technology has become one of the key advanced technologies in modern warfare. Submarines are indispensable heavy weapons in modern wars, where the main advantage is concealment. However, with the rapid development of object detection technology in modern military technology, various countries have formed anti-dive reconnaissance systems for air, water and underwater environments. The most important reconnaissance means in military is a radar reconnaissance system at present, which is to measure by means of characteristics of radar waves reflected by an object to find a target. When the submarine is sailing under water, the periscope and the radar antenna of the submarine need to work under the condition of exposing the water surface frequently. Particularly, for a conventional power submarine, the submarine is periodically floated on the water surface to work and rest, so that the submarine is always in an exposed state and is easy to be found by an enemy radar. This is because metals are good conductors, and their polished surfaces have high reflectivity to electromagnetic waves. Currently, a more effective anti-reconnaissance measure is to coat these weapons with radar absorbing materials, such as XFT-2 type radar absorbing paint. The general radar wave-absorbing paint mainly consists of base material and absorbent. And because the submarine is required to navigate underwater for a long time, under the condition of high water pressure, the coated wave-absorbing paint can crack or even fall off on the surface of the submarine, and the radar detection prevention capability is seriously affected.
Femtosecond laser has the advantages of high energy density, definite ablation threshold, negligible heat affected zone under low laser measurement, high accuracy, no shock wave and the like, and is widely applied to the fields of material processing and material surface modification. The femtosecond laser is used for directly modifying the surface material of the key parts of the submarine, so that the absorptivity of the surface material is increased. Our experiments show that the surface of low Z metal material aluminum (Al), noble metal material copper (Cu), medium Z metal material molybdenum (Mo) and high Z metal material tungsten (W) is modified by using femtosecond laser, and the surface absorptivity of the metal material can be increased to more than 95% by selecting proper laser parameters. In addition, the laser material surface modification technology has strong environmental adaptability, and can achieve the purpose of increasing the absorptivity by directly interacting with the modified material, avoid the use of base materials and absorbents, avoid the phenomena of cracking, falling off and the like on the surface of the submarine, and greatly improve the detection prevention capability of the submarine.
In addition, physical and chemical adsorption of the metal material in the atmosphere inevitably occurs. For the most commonly used structural materials, such as steel materials, adsorbed H 2 O can form a micro battery system with local iron and carbon, and the chemical reactions such as electrolysis, oxidization and the like can occur. Long-time electrolysis and oxidation tend to corrode metal materials, and the mechanical properties and the service life of the metal materials are affected.
Disclosure of Invention
In order to prolong the service life of structural steel and improve the oxidation resistance and mechanical properties of the structural steel, a thin film can be deposited on the surface of the material by using plasma coating and plasma spraying technology, for example, the surface of the steel material is coated by using metal with strong oxidation resistance. Considering the advantage that the thermal effect of the femtosecond laser under low laser metering is negligible, the femtosecond laser can be used for carrying out surface modification on the metal surface coating, so that the optical performance of the metal surface coating is optimized without causing any influence on a substrate. Our experiments show that the use of femtosecond laser can realize the modification of the surface performance of the surface metal material under the condition of damaging the nanometer level surface metal material, which is similar to a nondestructive modification method. The invention can also modify the surface of the coating material, and increase the corrosion resistance and mechanical property and the absorptivity.
The invention provides a method for manufacturing high-absorptivity ferrous metal by modifying an ultrashort pulse laser surface structure, which comprises the following steps:
(1) Triggering an FPGA time sequence module by using a data acquisition analysis computer;
(2) Triggering an ultrashort pulse ablation laser and a processing machine tool as well as an electromagnetic wave emitter and an electromagnetic wave detector according to the set time sequence;
(3) The laser emitted by the ultra-short pulse ablation laser is expanded by the laser beam expander, so that the damage probability of the laser to the optical element can be reduced; secondly, the laser can be focused to the mu m level through a parabolic mirror, and thirdly, the self-focusing phenomenon of the laser in the air can be reduced for fs laser;
(4) The expanded laser regulates and controls the laser energy through the half wave plate and the polarization cube by rotating the angle of the half wave plate, and the advantage of the method is that experimental errors caused by the change of the beam diameter under different laser energy are reduced, and one part of the split two laser beams is used for ablating a deposited film and the other part of the laser beams enter a residual laser absorber;
(5) The femtosecond laser transmitted through the polarization cube is focused by a parabolic mirror to reach the processed material and modify the processed material;
(6) Detecting the absorptivity of the modified material by using a group of electromagnetic wave emitters and electromagnetic wave detectors, and transmitting the acquired signals to a data acquisition analysis computer for data acquisition and processing;
(7) The data acquisition analysis computer processes the collected signals, calculates the difference between the signal intensity ratio of the electromagnetic wave detector and the electromagnetic wave emitter and a set threshold value (the threshold value is determined according to the modification target, if the modification target is that the modified material needs to absorb 95% of electromagnetic waves, the threshold value is 1 minus 0.95, namely 0.05 or 5%), gives a qualified result, if the difference is larger than 0, the result is disqualified, if the difference is smaller than or equal to 0, the modification of the material is finished, if the difference is qualified, the FPGA time sequence module is continuously triggered, and the next round of modification is carried out.
The beneficial effects are that: the invention can directly modify the material to achieve the purpose of enhancing the surface absorptivity, and avoids the use of base materials and absorbents when modifying the key parts of the deep sea submarines, and the phenomena of cracking, falling off and the like on the surfaces of the submarines can not occur due to the characteristic of direct modification, so that the detection prevention capability and the service capability of the submarines can be greatly improved. The invention can also carry out surface modification on the coating material without influencing the matrix material, and produce functional materials with excellent output and different optical properties. In addition, since the method is an optical modification method, the remote and micro-area modification can be performed by selecting and optimizing the optical device.
Drawings
FIG. 1 is a schematic diagram of a method for manufacturing high absorptivity ferrous metal by modifying the surface structure of an ultra-short pulse laser according to the present invention.
FIG. 2 is a schematic diagram of an apparatus for the method of producing high absorptivity ferrous metal by surface structure modification with ultra-short pulse laser according to the present invention.
FIG. 3 shows the result of a typical 6fs ultrashort pulse surface modification to enhance surface absorptivity, (a) untreated raw surface, absorptivity of 41.3%; (b) modified surface morphology, absorptivity of 95.5%; (c) The laser surface modification enhances the relationship of the surface absorptivity and the treatment laser pulse.
The attached drawings are identified:
a1 is a data acquisition and analysis module, and the function of the module is (1) that electromagnetic wave signals are acquired and analyzed; (2) evaluating results; (3) and controlling the time sequence module to work. A2 is a time sequence control module which has the functions of (1) triggering the laser to work and controlling the pulse number of the laser; (2) triggering the lathe to work according to the set speed; (3) the trigger result detection module starts working. A3 is a femtosecond laser, and the function of the femtosecond laser is to modify a material. A4 is a femtosecond laser energy regulation and control module, and the function of the regulation and control module is to regulate and control the laser energy under the condition that the spatial distribution of the facula energy is kept unchanged. A5 is an electromagnetic wave detector, which functions to detect electromagnetic waves reflected via the modifying material emitted by the electromagnetic wave emitter. A6 is an electromagnetic wave emitter whose function is to emit electromagnetic waves to be detected. A7 is a material to be modified. A8 is processing equipment.
B1. A data acquisition and analysis computer; B2.FPGA time sequence control module; B3. an ultrashort pulse ablation laser and a B4. processing machine tool; B5. a laser beam expander; B6. a half-wave plate; B7. a polarizing cube; B8. a residual laser absorber; B9. parabolic mirror; B10. a material to be modified; B11. a modified material; B12. an electromagnetic wave emitter; B13. an electromagnetic wave detector.
Detailed Description
In order to make the technical problems solved by the invention, the technical scheme adopted and the technical effects achieved clearer, the invention is further described in detail below with reference to the accompanying drawings and the embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the matters related to the present invention are shown in the accompanying drawings.
The principle of the invention: referring to fig. 1, the present invention mainly includes the following modules: a timing control module A2; a femtosecond laser module A3; a processing device A8; and a data acquisition and processing module A1.
The femtosecond excitation wavelength is not limited at all, but is preferably ultraviolet laser for material surface modification. Ultrashort pulse laser 1) can reduce or even avoid laser heat affected zone (Heating Affect Zone, HAZ); 2) The laser ablation depth can be accurately controlled, the processing accuracy of the technology is improved, and the surface of the coating material can be modified under the condition of not damaging a matrix; 3) Processing defects caused by resolidification of surface elements of the material due to thermal effects during short pulse laser ablation can be avoided. The time sequence control module 1) is used for triggering the modified laser and optimizing the number of modified laser pulses so as to achieve the purpose of enhancing the metal absorptivity through surface modification; 2) And simultaneously triggering the machine tool module to move at a set speed, and modifying the material in a pipelining manner. In the method, the laser energy is optimized through the polarization cube and the half-wave plate according to different materials to be modified, so that the purposes of modifying the materials and the coating materials are achieved. In order to avoid uncontrollable processing area caused by uneven energy distribution of laser beams due to spherical aberration of a traditional lens, the modified laser is focused by using a parabolic mirror, and the parabolic mirror 1) can avoid uneven light beams caused by spherical aberration; 2) The laser beam can be focused to the order of μm to micro-region modify the material. The invention uses an electromagnetic wave emitter and an electromagnetic wave detector in the normal direction to monitor the absorptivity of the modified material to electromagnetic waves in real time. The collected signals are transmitted to a data collection and processing module to process the data, a result whether the requirements are met is given, if yes, the modification of the block is completed, and if not, the data processing module continues to send the signals to a time sequence control module to carry out next modification processing.
Examples:
the method for manufacturing the high-absorptivity ferrous metal by modifying the surface structure of the ultrashort pulse laser comprises the following steps:
(1) Triggering an FPGA time sequence module B2 by using a data acquisition analysis computer B1;
(2) Triggering an ultra-short pulse ablation laser B3 and a processing machine tool B4, an electromagnetic wave emitter B12 and an electromagnetic wave detector B13 according to the set time sequence;
(3) The laser emitted by the ultra-short pulse ablation laser B3 is expanded by the laser expander B5, so that the damage probability of the laser to the optical element can be reduced; secondly, the laser can be focused to the mu m level through the parabolic mirror B9, and thirdly, the self-focusing phenomenon of the laser in the air can be reduced for fs laser;
(4) The expanded laser regulates and controls the laser energy through the half wave plate B6 and the polarization cube B7 by rotating the angle of the half wave plate, which has the advantages of reducing experimental errors caused by the change of the beam diameter under different laser energy, and the two separated laser beams are used for ablating a part of laser of the deposited film and enter (8) a residual laser absorber;
(5) The femtosecond laser transmitted through the polarization cube B7 is focused by a parabolic mirror B9, reaches the processed material and modifies the processed material;
(6) The modified material B11 is detected in absorptivity by using a group of electromagnetic wave emitters B12 and electromagnetic wave detectors B13, and acquired signals are transmitted to a data acquisition analysis computer B1 for data acquisition and processing;
(7) The data acquisition analysis computer B1 processes the collected signals, calculates the difference between the signal intensity ratio of the electromagnetic wave detector B13 and the electromagnetic wave emitter B12 and a set threshold value (the threshold value is determined according to the modification target, if the modification target is that the modified material needs to absorb 95% of electromagnetic waves, the threshold value is 1 minus 0.95, namely 0.05 or 5%), gives a result whether the signal is qualified or not, if the difference is larger than 0, the signal is disqualified, if the difference is smaller than or equal to 0, the material modification is finished, if the signal is qualified, the FPGA time sequence module B2 is continuously triggered, and the next round of modification is carried out.
FIG. 3 is a graph of the results of a typical 6fs ultrashort pulse surface modification to enhance surface absorptivity, (a) untreated raw surface, absorptivity of 41.3%; (b) modified surface morphology, absorptivity of 95.5%; (c) a laser modified cross-sectional view; (d) Laser surface modification enhances the relationship of surface absorptivity to the processing laser pulses. The material was modified experimentally using low laser metrology, and no heat affected zone was found in its 3-dimensional spatial distribution, as shown in fig. 3 (c).
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments is modified or some or all of the technical features are replaced equivalently, so that the essence of the corresponding technical scheme does not deviate from the scope of the technical scheme of the embodiments of the present invention.
Claims (1)
1. The method for manufacturing the high-absorptivity ferrous metal by modifying the surface structure of the ultrashort pulse laser comprises the following steps:
(1) Triggering an FPGA time sequence module (B2) by using a data acquisition analysis computer (B1);
(2) Triggering an ultrashort pulse ablation laser (B3), a processing machine tool (B4), an electromagnetic wave emitter (B12) and an electromagnetic wave detector (B13) according to the set time sequence;
(3) Laser emitted by the ultra-short pulse ablation laser (B3) is expanded by a laser beam expander (B5), and is focused to the mu m level by a parabolic mirror (B9);
(4) The energy of the expanded laser is regulated and controlled through the half wave plate (B6) and the polarization cube (B7) by rotating the angle of the half wave plate, and one part of the split laser is used for ablating a deposited film and the other part of the split laser enters the residual laser absorber (B8);
(5) The femtosecond laser transmitted through the polarization cube (B7) is focused by a parabolic mirror (B9) to reach the processed material and modify the processed material;
(6) Detecting the absorptivity of the modified material (B11) by using a group of electromagnetic wave emitters (B12) and electromagnetic wave detectors (B13), and transmitting the acquired signals to a data acquisition analysis computer (B1) for data acquisition and processing;
(7) The data acquisition analysis computer (B1) processes the collected signals, calculates the difference value between the signal intensity ratio of the electromagnetic wave detector (B13) and the electromagnetic wave emitter (B12) and a set threshold value to give a qualified result, if the difference value is larger than 0, the result is disqualified, if the difference value is smaller than or equal to 0, the result is qualified, if the difference value is smaller than or equal to 0, the material modification is finished, if the difference value is unqualified, the FPGA time sequence module (B2) is continuously triggered, and the next round of modification is carried out.
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| CN2137781Y (en) * | 1992-06-16 | 1993-07-07 | 李士瑛 | Photoelectric detecting device |
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