阅读说明：本技术 一种提高反应润湿体系材料润湿铺展性能的方法 (Method for improving wetting and spreading performance of reaction wetting system material ) 是由 杨瑾 刘志杨 陈宗杰 徐佳宜 魏迪 陈捷狮 刘红兵 于治水 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种提高反应润湿体系材料润湿铺展性能的方法,采用超快激光加工技术在不锈钢基板表面上扫描加工得到条纹平均宽度为1.2～1.4μm且条纹平均间距为1.4～1.6μm的微纳米条纹织构；相同钎料在扫描加工后的不锈钢基板上的润湿角比未处理的不锈钢基板上的润湿角小0.9°～3.3°。本发明的方法,通过超快激光在反应润湿体系材料的表面进行微织构加工,改变反应润湿体系材料表面形貌,改变表面粗糙度,获得的独特的微纳米条纹织构的形貌,这种独特的微纳米条纹织构的形貌在钎料润湿铺展过程将极大地增强毛细作用,进而提高钎料在反应润湿体系材料的表面上润湿铺展动力,使得钎料与基板反应更充分,极具应用前景。(The invention discloses a method for improving the wetting and spreading performance of a reaction wetting system material, which comprises the steps of scanning and processing on the surface of a stainless steel substrate by adopting an ultrafast laser processing technology to obtain a micro-nano stripe texture with the average width of stripes of 1.2-1.4 mu m and the average interval of the stripes of 1.4-1.6 mu m; the wetting angle of the same solder on the stainless steel substrate after scanning processing is 0.9-3.3 degrees smaller than that on the untreated stainless steel substrate. According to the method, the ultrafast laser is used for carrying out microtexture processing on the surface of the reaction wetting system material, the surface appearance of the reaction wetting system material is changed, the surface roughness is changed, and the obtained unique micro-nano stripe texture appearance greatly enhances the capillary action in the solder wetting and spreading process, so that the wetting and spreading power of the solder on the surface of the reaction wetting system material is improved, the solder and a substrate are enabled to react more fully, and the method has a wide application prospect.)

1. A method for improving the wetting and spreading performance of a reaction wetting system material is characterized in that a ultrafast laser processing technology is adopted to scan and process on the surface of a stainless steel substrate to obtain a micro-nano stripe texture with the average width of stripes of 1.2-1.4 mu m and the average interval of the stripes of 1.4-1.6 mu m;

the wetting angle of the same solder on the stainless steel substrate after scanning processing is 0.9-3.3 degrees smaller than that on the untreated stainless steel substrate.

2. The method for improving the wetting and spreading performance of the material in the reaction wetting system according to claim 1, wherein the specific operations of scanning and processing on the surface of the stainless steel substrate by using the ultrafast laser processing technology are as follows: after the stainless steel substrate is placed on a workbench, an ultrafast laser is focused on a part to be processed of the stainless steel substrate, and then a microtexture is scanned and processed on the surface of the stainless steel substrate.

3. The method of claim 2, wherein the ultrafast laser comprises a laser emitter, a mirror, an aperture, an attenuator, a shutter, and a scanning galvanometer;

the laser transmitter is used for transmitting laser;

the reflecting mirror is used for adjusting a laser light path;

and the laser light path is irradiated to the part to be processed through the aperture, the attenuator, the shielding plate and the scanning galvanometer in sequence.

4. The method for improving the material wetting and spreading performance of the reaction wetting system according to claim 1, wherein the stainless steel substrate is ultrasonically cleaned in an absolute ethanol solution for 10-15 min before being processed;

the stainless steel comprises the components of Fe-17.2Cr-11.6Ni-2.7Mo-0.8Si-1.5 Mn.

5. The method for improving the wetting and spreading performance of the material in the reaction wetting system according to claim 2, wherein the laser power of the ultrafast laser is 0.9-1.5W, the scanning rate is 1m/s, the number of repetition times is 1-20, the pulse energy is 2.1-3.8 muJ, and the energy density is 0.12-0.23J/cm²。

6. A method of improving the wet spreading properties of a reactive wetting system material according to claim 5, wherein the laser beam is parallel lines at a distance of 1.5 μm during processing.

Technical Field

The invention belongs to the technical field of material surface modification, and relates to a method for improving the wetting and spreading performance of a reaction wetting system material.

Background

The 316 stainless steel is steel with Fe, Cr, Ni and Mo as main components, has the advantages of strong corrosion resistance, high heat resistance and the like, has good welding performance, and is widely applied to the industrial fields of ships, oceans, aerospace and the like. However, although 316 stainless steel has a good application prospect, in practical applications, it is often required to be connected with aluminum and aluminum alloy for use (for example, a conduit structure of an aerospace propeller, a cylinder structure of aluminum alloy and stainless steel, and a pot bottom structure of stainless steel and aluminum alloy in a pressure cooker, which take advantage of the connection of dissimilar materials), but the stainless steel and the aluminum alloy have great differences in thermal physical properties (melting point, thermal conductivity, thermal expansion coefficient, etc.) and material mechanical properties, which greatly affects the further application of 316 stainless steel.

The wettability of the surface of the material is an important characteristic between connecting pieces, and the wettability between the stainless steel and the aluminum alloy is improved, so that the connecting performance of the stainless steel and the aluminum alloy can be ensured. However, for the two connecting materials of 316 stainless steel and aluminum alloy, due to the characteristics of the materials, the two connecting materials are often in the form of welding, and chemical/metallurgical reaction necessarily occurs at the interface during welding, namely the system of the two connecting materials is a reaction wetting system.

The method for improving the wettability of the reaction wetting system material by the person skilled in the art is as follows: 1) different microstructures can be processed on the surface of the material by a traditional long pulse or continuous laser processing method, so that the surface roughness is changed to improve the wettability, but the processing precision is low, and the heat affected zone is large; 2) the surface of the substrate is subjected to surface coating treatment by physical or chemical methods such as plasma coating, vapor deposition, electrochemical deposition, etc., to improve wettability. However, the metal coating material has a complex manufacturing process and may react with the substrate to generate a brittle compound, thereby reducing the interface performance; 3) microstructures with different appearances can be etched on the surface of the substrate by a chemical etching method so as to improve the wetting performance, but the etching line width is difficult to control and precision etching cannot be carried out; 4) the coating of the brazing filler metal on the substrate is realized on the surface of the material through chemical plating, the wetting and spreading performance of the brazing filler metal on the surface of the material is improved, but the chemical plating is slow in plating speed and complex in operation, and a large number of resources are consumed for maintaining the working temperature of the chemical plating.

Therefore, the development of a method for improving the wetting and spreading performance of the reaction wetting system material, which has the advantages of high preparation speed, simple preparation process, small processing influence area and high processing precision, has a practical significance.

Disclosure of Invention

The invention aims to overcome the defects of complex operation, low preparation speed, low precision and easy generation of brittle compounds in the prior art, and provides a method for improving the wetting and spreading performance of a reaction wetting system material, which has the advantages of high preparation speed, simple and convenient preparation process, small processing influence area and high processing precision.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for improving the wetting and spreading performance of a reaction wetting system material comprises the steps of scanning and processing on the surface of a stainless steel substrate by adopting an ultrafast laser processing technology to obtain a micro-nano stripe texture with the average width of stripes of 1.2-1.4 mu m and the average interval of the stripes of 1.4-1.6 mu m; the micro-nano stripes are compact and continuous, a layered structure is formed among the stripes, the capillary action force is enhanced by the layered structure, the transportation of the liquid brazing filler metal is effectively improved, and the wettability is further improved; if the average width or the average distance of the stripes is too large, the compactness and the continuity between the stripes are poor, the transportation of the liquid brazing filler metal is hindered, the wetting and spreading power of the liquid brazing filler metal on the surface of the substrate is reduced, and the wettability of the brazing filler metal is further reduced; if the average width or the average distance of the stripes is too small, the average width or the average distance is not obviously changed compared with the roughness of the original surface, the power of wetting and spreading the liquid brazing filler metal on the surface of the substrate cannot be obviously improved, the wettability cannot be effectively improved, and uncertainty is brought to the change of the wettability;

the wetting angle of the same solder on the stainless steel substrate after scanning processing is 0.9-3.3 degrees smaller than that on the untreated stainless steel substrate.

According to the method, the ultrafast laser is used for carrying out microtexture processing on the surface of the reaction wetting system material, the surface appearance of the reaction wetting system material is changed, the surface roughness is changed, the obtained unique micro-nano stripe texture appearance is improved, the wetting and spreading power of the brazing filler metal on the surface of the reaction wetting system material is improved, the wetting and spreading capacity of the brazing filler metal is improved, the microstructure of a connecting interface is improved, the connecting performance is improved, the stability and reliability of connection between stainless steel and aluminum alloy can be obviously improved, and the method has a good practical significance for expanding the connecting application range of the stainless steel and the aluminum alloy. Compared with other prior art for changing the wetting and spreading performance of the reaction wetting system material, the invention provides a new technical idea for improving the wetting and spreading performance of the reaction wetting system material.

As a preferred technical scheme:

the method for improving the wetting and spreading performance of the reaction wetting system material comprises the following specific operations of scanning and processing on the surface of the stainless steel substrate by adopting the ultrafast laser processing technology: after the stainless steel substrate is placed on a workbench, an ultrafast laser is focused on a part to be processed of the stainless steel substrate, and then a microtexture is scanned and processed on the surface of the stainless steel substrate.

The method for improving the material wetting and spreading performance of the reaction wetting system comprises the steps that the ultrafast laser comprises a laser emitter, a reflector, an aperture, an attenuator, a shutter and a scanning galvanometer;

the laser transmitter is used for transmitting laser;

the reflecting mirror is used for adjusting a laser light path;

and the laser light path is irradiated to the part to be processed through the aperture, the attenuator, the shielding plate and the scanning galvanometer in sequence. The structure of the ultrafast laser of the present invention is not limited thereto, and only one possible technical solution is given here, and those skilled in the art can select a suitable ultrafast laser to process the reaction wetting system material according to actual needs.

According to the method for improving the wetting and spreading performance of the reaction wetting system material, the stainless steel substrate is ultrasonically cleaned in an absolute ethyl alcohol solution for 10-15 min before being processed to remove surface oil stains;

the stainless steel comprises the components of Fe-17.2Cr-11.6Ni-2.7Mo-0.8Si-1.5 Mn. The scope of the invention is not limited thereto, and the composition of the stainless steel is not limited thereto, and only one proven solution is given here, and stainless steels of other compositions may be suitable for the invention.

The method for improving the wetting and spreading performance of the reaction wetting system material comprises the following steps that the laser power of the ultrafast laser is 0.9-1.5W, the scanning speed is 1m/s, the repetition times are 1-20, the pulse energy is 2.1-3.8 muJ, and the energy density is 0.12-0.23J/cm². If the laser power is too high, an obvious groove-shaped texture morphology can be formed, the power of wetting and spreading is reduced, and the wetting and spreading of the liquid brazing filler metal is hindered; the laser power is too low, the change of the texture morphology of the substrate surface is not obvious, and the wettability is not effectively improved. The pulse energy and the energy density influence the appearance of the micro-texture, and the micro-nano stripe texture is formed by the mutual coupling of laser pulses and surface plasmas because the pulse energy and the energy density are small and cannot play a role in obviously removing materials.

In the method for improving the wetting and spreading performance of the reaction wetting system material, the laser beam is parallel lines during processing, and the distance between the parallel lines is 1.5 mu m. The parallel line spacing of the present invention is not limited thereto, and those skilled in the art can adjust the spacing within a certain range according to the actual situation.

Has the advantages that:

according to the method for improving the wetting and spreading performance of the reaction wetting system material, the ultrafast laser is used for carrying out microtexture processing on the surface of the reaction wetting system material, the surface appearance of the reaction wetting system material is changed, the surface roughness is changed, and the obtained unique micro-nano stripe texture appearance is obtained, so that the capillary action of the unique micro-nano stripe texture appearance is greatly enhanced in the solder wetting and spreading process, the wetting and spreading power of the solder on the surface of the reaction wetting system material is further improved, the solder and a substrate are enabled to react more fully, the microstructure of a connecting interface is improved, and the connecting performance is improved. Compared with other prior art for changing the wetting and spreading performance of the reaction wetting system material, the method provides a new technical idea for improving the wetting and spreading performance of the reaction wetting system material, and because most reaction wetting systems are easy to generate intermetallic compounds to improve brittleness, the method changes the wetting and spreading performance of the reaction wetting system material, even can control the generation of the intermetallic compounds of the reaction wetting system, and has important significance for the research of the reaction wetting system.

Drawings

FIG. 1 is a schematic diagram of ultrafast laser machining for preparing surface microtexture;

FIG. 2 is a schematic illustration of an in situ wet spread test;

FIG. 3 is a graph showing temperature change curves of in-situ wetting tests of the reference group and the test group;

FIG. 4 is a schematic surface topography of the original surface and the microtextured surface of the reference group and the test group under an optical microscope, a three-dimensional super-depth-of-field microscope and a scanning electron microscope, respectively;

FIG. 5 shows the Al-5Si solder on the original surface and the microtextured surface of the reference group and the test group before heating, before spreading, after spreading and after solidification;

FIG. 6 is a schematic cross-sectional view under an optical microscope of reference and test sets of pristine and microtextured surfaces after wet spreading;

FIG. 7 is a schematic cross-sectional view under a scanning electron microscope of the reference and test sets of pristine and microtextured surfaces;

in fig. 4, a1 to a3 are the original surface features of the reference group under the optical microscope, the three-dimensional super-depth-of-field microscope and the scanning electron microscope, respectively, and b1 to b3 are the microtextured surface features of the test group under the optical microscope, the three-dimensional super-depth-of-field microscope and the scanning electron microscope;

in fig. 6 and 7, a is a schematic view of the reference group, and b is a schematic view of the test group.

Detailed Description

The following further describes the embodiments of the present invention with reference to the attached drawings.