Method for rapidly displaying metal tungsten crystal grains based on femtosecond laser processing

Abstract

The invention relates to a fast display method for metal tungsten crystal grains based on femtosecond laser processing, which comprises the following steps: cutting a metal tungsten sample, carrying out femtosecond laser ablation and post-treatment on the cut section of the metal tungsten sample, and then carrying out microstructure observation. According to the method, the ground metal tungsten surface is ablated based on the femtosecond laser, the tungsten grain boundary is rapidly displayed through different effects of the tungsten grain boundary and a matrix in the femtosecond laser ablating process, and reference is provided for structural analysis in the metal tungsten material research and development and application process. According to the method, traditional chemical etching can be replaced, the machining process is free of pollution, the working procedure is simple, the stability is high, the tungsten surface only needs to be subjected to simple abrasive paper polishing treatment before grain boundary display, the working procedure is greatly shortened, and the preparation efficiency is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal tungsten crystal grain display, and in particular to a metal tungsten crystal grain rapid display method based on femtosecond laser processing. Background Art

[0002] Metal tungsten is a commonly used metal material with the highest melting point. It has excellent properties such as high density, high hardness, strong corrosion resistance, and radiation resistance. It is widely used in the fields of electricity, nuclear energy, aerospace, electronics, etc. During the forming and service process of tungsten, in order to analyze the change mechanism of tungsten performance, it is necessary to characterize and analyze the microstructure of tungsten. For single-phase metal tungsten, the internal grain boundary morphology and grain size are the key points of the microstructure analysis of metal tungsten.

[0003] Traditional metallographic preparation of tungsten usually starts with rough polishing with mechanical sandpaper, followed by mechanical fine polishing with polishing cloth + polishing liquid, and finally direct chemical corrosion using solutions such as potassium hydroxide and potassium ferrocyanide, or electrochemical corrosion using a 10% mass fraction NaOH solution. This metallographic preparation process is complex, has poor stability, is easy to pollute the environment, and is harmful to the human body. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a method for rapid display of metal tungsten grains based on femtosecond laser processing, which ablates the polished metal tungsten surface based on femtosecond laser. Through the different effects of tungsten grain boundaries and matrix during femtosecond laser ablation, rapid display of tungsten grain boundaries is achieved, providing a reference for the organizational analysis of the research and development and application process of metal tungsten materials.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention first provides a method for quickly displaying metal tungsten grains based on femtosecond laser processing, which comprises the following steps: cutting a metal tungsten sample, performing femtosecond laser ablation on the cut section of the metal tungsten sample, and performing microstructure observation after post-processing.

[0006] The present invention is based on femtosecond laser ablation of the polished metal tungsten surface. During the femtosecond laser ablation process, the tungsten grain boundary and the matrix act differently to achieve rapid display of the tungsten grain boundary, providing a reference for the organizational analysis of the research and development and application process of metal tungsten materials. The method of the present invention can replace traditional chemical etching, has a pollution-free processing process, a simple process, and high stability. Before the grain boundary is displayed, the tungsten surface only needs to be simply sanded, which greatly shortens the process and significantly improves the preparation efficiency.

[0007] As a further improvement of the above solution of the present invention, the metal tungsten sample is tungsten or a tungsten alloy.

[0008] As a further improvement of the above solution of the present invention, a galvanometer scanning laser processing system is used to perform femtosecond laser ablation on the cut cross section of the metal tungsten sample.

[0009] As a further improvement of the above solution of the present invention, the laser power of the femtosecond laser is 10-100W, the spot diameter is 25-60μm, the scanning rate is 200-1500mm / s, the linear filling spacing is 0.01-0.05mm, and the number of scans is 5-20 times.

[0010] As a further improvement of the above solution of the present invention, before performing femtosecond laser ablation on the cut cross-section of the metal tungsten sample, the method further includes a step of polishing the cut cross-section of the metal tungsten sample.

[0011] As a further improvement of the above solution of the present invention, the polishing is to mechanically polish the cut cross section of the metal tungsten sample using sandpaper.

[0012] As a further improvement of the above solution of the present invention, the post-treatment is to place the metal tungsten sample in an alcohol solution for ultrasonic cleaning, and the cleaning time is 3-15 minutes.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention is based on femtosecond laser ablation of the polished metal tungsten surface. During the femtosecond laser ablation process, the tungsten grain boundary and the matrix act differently to achieve rapid display of the tungsten grain boundary, providing a reference for the organizational analysis of the research and development and application process of metal tungsten materials. The method of the present invention can replace traditional chemical etching, has a pollution-free processing process, a simple process, and high stability. Before the grain boundary is displayed, the tungsten surface only needs to be simply sanded, which greatly shortens the process and significantly improves the preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a photo of the tungsten metallographic structure displayed by femtosecond laser ablation in Example 1 of the present invention; Figure 2 This is a scanning tissue photograph of tungsten displayed by femtosecond laser ablation in Example 1 of the present invention; Figure 3 This is a metallographic photograph of the tungsten surface morphology after sandpaper polishing in Comparative Example 1 of the present invention; Figure 4 This is a photo of the tungsten metallographic structure displayed by femtosecond laser ablation in Comparative Example 2 of the present invention; Figure 5 This is a photograph of the tungsten metallographic structure displayed by femtosecond laser ablation in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0015] For ease of understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0017] This embodiment provides a method for quickly displaying metal tungsten grains based on femtosecond laser processing, which specifically includes the following steps: a. Cut the metal tungsten sample (tungsten or tungsten alloy), and then mechanically grind the cut section of the metal tungsten sample flat with sandpaper; b. Perform femtosecond laser ablation on the cut section of the metal tungsten sample using a galvanometer scanning laser processing system. The laser power of the femtosecond laser is 10-100W, the spot diameter is 25-60μm, the scanning rate is 200-1500mm / s, the linear filling spacing is 0.01-0.05mm, and the number of scans is 5-20 times; c. Place the metal tungsten sample in an alcohol solution for ultrasonic cleaning for 3-15 minutes to remove the surface laser ablation products; d. Use a microscope and / or scanning electron microscope to conduct microstructural observation.

[0018] This embodiment is based on femtosecond laser ablation to achieve rapid display of grain boundaries on the tungsten surface. By utilizing the difference in the action process of tungsten grain boundaries and grains under the action of femtosecond laser, the laser processing parameters are reasonably adjusted to quickly display the grain boundaries on the tungsten surface, providing a reference for the organizational analysis of the research and development and application process of metal tungsten materials, which can replace the traditional chemical etching method and avoid environmental pollution. Before the grain boundaries are displayed, the tungsten surface only needs to be simply polished with sandpaper, which greatly shortens the process, significantly improves the preparation efficiency, and has high stability.

[0019] Next, the present invention is further described with reference to specific examples.

[0020] Example a. Cut the forged pure tungsten, and then mechanically grind the cut section of the forged pure tungsten to make it smooth by sandpaper; b. The cut section of the forged pure tungsten was subjected to femtosecond laser ablation using a galvanometer scanning laser processing system. The laser power of the femtosecond laser was 130 W, the spot diameter was 30 μm, the scanning rate was 1000 mm / s, the linear filling spacing was 0.02 mm, and the number of scans was 12 times. c. Place the forged pure tungsten after femtosecond laser ablation in an alcohol solution for ultrasonic cleaning for 5 minutes to remove the surface laser ablation products; d. Microstructure observation was carried out using metallographic microscope and scanning electron microscope respectively.

[0021] Figure 1 The metallographic morphology of the tungsten surface after femtosecond laser ablation in this embodiment is shown in FIG. Figure 1 It can be seen that after femtosecond laser ablation, the grain boundary morphology of the tungsten surface is clear without any pollutants or scratch defects.

[0022] Figure 2 This is a scanning electron microscope photo of the tungsten surface after femtosecond laser ablation in this embodiment. Figure 2 It can be seen that femtosecond laser ablation induces laser periodic surface structure (LIPSS) on the tungsten surface. The scratches and other defects caused by the original mechanical grinding of the tungsten surface are covered by the LIPSS structure. Since the segregation of impurity elements such as oxygen is prone to occur at the tungsten grain boundaries, the material is significantly removed and the grain boundary structure is revealed.

[0023] Comparative Example 1 a. Cut the forged pure tungsten, and then mechanically grind the cut section of the forged pure tungsten to make it smooth by sandpaper; b. Use a metallographic microscope to observe the surface morphology of polished titanium pure tungsten.

[0024] Figure 3 This is the metallographic morphology of the pure titanium tungsten surface after sandpaper polishing in this comparative example. Since the tungsten surface was only coarsely polished with sandpaper, a large number of staggered scratches can be observed in the metallographic photograph of the tungsten surface before femtosecond laser ablation, and the tungsten grain boundary is not visible.

[0025] Comparative Example 2 a. Cut the forged pure tungsten, and then mechanically grind the cut section of the forged pure tungsten to make it smooth by sandpaper; b. Femtosecond laser ablation was performed on the cut section of forged pure tungsten using a galvanometer scanning laser processing system, with a laser power of 10 W, a spot diameter of 30 μm, a scanning rate of 1500 mm / s, a linear filling spacing of 0.01 mm, and a scanning number of 10 times; c. Place the forged pure tungsten after femtosecond laser ablation in an alcohol solution for ultrasonic cleaning for 3 minutes to remove the surface laser ablation products; d. Use a metallographic microscope to observe the microstructure of the tungsten surface after femtosecond laser ablation.

[0026] Figure 4 This is the metallographic morphology of the tungsten surface after femtosecond laser ablation in this comparative example. Figure 4 It can be seen that due to the low laser energy density and small number of scans, the scratches on the tungsten surface are not completely shielded and the tungsten grain boundaries are not obvious.

[0027] Comparative Example 3 a. Cut the forged pure tungsten, and then mechanically grind the cut section of the forged pure tungsten to make it smooth by sandpaper; b. Femtosecond laser ablation was performed on the cut section of forged pure tungsten using a galvanometer scanning laser processing system, with a laser power of 50 W, a spot diameter of 30 μm, a scanning rate of 1000 mm / s, a linear filling spacing of 0.02 mm, and a scanning number of 25 times; c. Place the forged pure tungsten after femtosecond laser ablation in an alcohol solution for ultrasonic cleaning for 10 minutes to remove the surface laser ablation products; d. Use a metallographic microscope to observe the microstructure of the tungsten surface after femtosecond laser ablation.

[0028] Figure 5 This is the metallographic morphology of the tungsten surface after femtosecond laser ablation in this comparative example. Figure 5 It can be seen that due to the high laser energy density and the large number of scanning times, a lot of tungsten surface material is removed, the structure produced by laser ablation is highly oxidized, and there may be a certain amount of oxidation on the tungsten surface after laser ablation, and the tungsten grain boundaries appear fuzzy.

[0029] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0030] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for rapid display of metal tungsten grains based on femtosecond laser processing, characterized in that: It includes the following steps: The metal tungsten sample is cut, and the cut cross section of the metal tungsten sample is subjected to femtosecond laser ablation. After post-processing, microstructure observation is performed.

2. The method for rapid display of metal tungsten grains based on femtosecond laser processing according to claim 1 is characterized in that: The metal tungsten sample is tungsten or a tungsten alloy.

3. The method for rapid display of metal tungsten grains based on femtosecond laser processing according to claim 1, characterized in that: A galvanometer scanning laser processing system is used to perform femtosecond laser ablation on the cut cross section of the metal tungsten sample.

4. The method for rapid display of metal tungsten grains based on femtosecond laser processing according to claim 1, characterized in that: The femtosecond laser has a laser power of 10-100W, a spot diameter of 25-60 μm, a scanning rate of 200-1500 mm / s, a linear filling spacing of 0.01-0.05 mm, and a scanning number of 5-20 times.

5. The method for rapid display of metal tungsten grains based on femtosecond laser processing according to claim 1, characterized in that: Before performing femtosecond laser ablation on the cut cross section of the metal tungsten sample, the method further includes a step of polishing the cut cross section of the metal tungsten sample.

6. The method for rapid display of metal tungsten grains based on femtosecond laser processing according to claim 5, characterized in that: The grinding is to mechanically grind the cut section of the metal tungsten sample using sandpaper.

7. The method for rapid display of metal tungsten grains based on femtosecond laser processing according to claim 1, characterized in that: The post-treatment is to place the metal tungsten sample in an alcohol solution for ultrasonic cleaning, and the cleaning time is 3-15 minutes.

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