Subsurface damage mapping method based on polarization laser scattering method

Abstract

The invention discloses a subsurface damage mapping method based on a polarization laser scattering method. The subsurface damage mapping method comprises the following steps: preparing samples with different subsurface damage depths; detecting samples with different subsurface damage depths; acquiring a sample detection signal; detecting surface roughness data of the sample; obtaining the subsurface damage depth of the sample; and obtaining a sample damage mapping relation. According to the method, the mapping relation between the polarization laser detection signal and the subsurface damage depth can be established through a simple grinding experiment, according to the mapping relation, the subsurface damage depth information can be directly obtained through the detection signal, and quantitative expression of the subsurface damage information is achieved. According to the method, the problem that only other physical quantities can indirectly represent the subsurface damage depth in a nondestructive testing method is solved, the mapping relation between other physical quantities and the subsurface damage depth is established, and other physical quantities indirectly representing the subsurface damage depth can be mapped into the subsurface damage depth value.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to a sub-surface damage mapping method based on a polarized laser scattering method. Background Art

[0002] Currently, various methods exist in the field of subsurface damage detection that can directly or indirectly measure subsurface damage depth. Nondestructive testing methods can indirectly measure subsurface damage depth without damaging the specimen, but these methods rely on other physical quantities, such as light intensity and voltage, to indirectly measure subsurface damage depth. These methods can only qualitatively indicate subsurface damage depth and distribution, but cannot quantitatively analyze it. Therefore, establishing a mapping relationship between these physical quantities and subsurface damage depth is crucial.

[0003] Among existing subsurface damage nondestructive testing technologies, polarized laser nondestructive testing (NDT) can achieve damage detection over a wide range with high efficiency (e.g., CN109781665A discloses a device for detecting subsurface damage in semiconductor materials using polarized laser scattering). Some technologies can also detect subsurface damage on the surfaces of three-dimensional components (e.g., CN 118501173 A discloses a device and method for detecting subsurface damage signals from a fused silica hemispherical resonator). However, all of these technologies characterize the subsurface damage depth of the sample by detecting optical signals, and no mapping relationship between the detection signal and the subsurface damage depth has been established. Although these technologies can qualitatively indicate the depth and location of subsurface damage, they cannot quantitatively determine the specific value of the subsurface damage depth. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention designs a sub-surface damage mapping method based on polarized laser scattering method, which can fill the gap in the field of non-destructive testing of polarized laser scattering method in mapping the detection signal into sub-surface damage information.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: A subsurface damage mapping method based on polarized laser scattering method comprises the following steps:

[0006] A. Prepare samples with different subsurface damage depths;

[0007] B. Detect samples with different subsurface damage depths;

[0008] C. Obtaining sample detection signals;

[0009] D. Detect sample surface roughness data;

[0010] E. Obtain the subsurface damage depth of the sample;

[0011] F. Obtain sample damage mapping relationship.

[0012] Furthermore, the method for preparing samples with different subsurface damage depths in step A is as follows:

[0013] Several groups of samples with smooth surfaces and no subsurface damage are fixed on a counterweight block, and the samples are pressed on the grinding disc surface of the grinder. They are ground using grinding fluids of different particle sizes, and the grinding fluid particle sizes are 1μm, 5μm, 10μm, 15μm, 20μm or similar abrasive particle sizes with certain differences, to prepare test samples with subsurface damage of different depths.

[0014] Furthermore, the method for detecting samples with different subsurface damage depths in step B is as follows:

[0015] Place the test sample on the mobile platform of the polarized laser detection platform, use a computer to control the mobile platform through a motion controller so that the polarized laser is irradiated on the sample surface; control the mobile platform to move along the X-axis and Y-axis in an S-shaped route so that the polarized laser completes the detection of the sample surface.

[0016] Furthermore, the method for obtaining the sample detection signal in step C is as follows:

[0017] The computer collects the electrical signals measured by the photoelectric detector in the polarized laser nondestructive testing system collected by the data acquisition card, analyzes and processes the collected electrical signals, and uses them as detection signals of the sample surface.

[0018] Furthermore, the method for detecting the surface roughness data of the sample in step D is as follows:

[0019] The surface roughness of each test sample was tested using a surface profilometer to obtain the roughness data of the surfaces of all samples.

[0020] Furthermore, the method for obtaining the subsurface damage depth of the sample in step E is as follows:

[0021] The subsurface damage depth of the sample is calculated according to the formula of the surface roughness and subsurface damage depth of the sample, and a schematic diagram of the abrasive grain size corresponding to the subsurface damage depth is drawn.

[0022] Furthermore, the method for obtaining the sample damage mapping relationship in step F is as follows:

[0023] Use the exponential formula D = AS n +B fits the detection signal and subsurface damage depth curve of the sample, and maps the detection signal data of the sample into subsurface damage depth data according to this curve.

[0024] Where D represents the damage depth in μm; S represents the detection signal value in μW; A, n, and B are all fitting parameters of the formula.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention realizes that a mapping relationship between the polarized laser detection signal and the sub-surface damage depth can be established through a simple grinding experiment. According to this mapping relationship, the sub-surface damage depth information can be directly obtained through the detection signal, thereby realizing the quantitative representation of the sub-surface damage information.

[0027] 2. The present invention solves the problem that nondestructive testing methods can only indirectly represent the sub-surface damage depth by other physical quantities, realizes the establishment of a mapping relationship between other physical quantities and the sub-surface damage depth, and can map other physical quantities that indirectly represent the sub-surface damage depth into sub-surface damage depth values.

[0028] 3. The present invention requires a small amount of experiment, is simple to operate, and produces reliable results, and is applicable to a variety of non-destructive testing methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A flow chart illustrating the present invention.

[0030] Figure 2 Schematic diagram showing the preparation of samples according to the present invention.

[0031] Figure 3 A schematic diagram showing the polarized laser nondestructive detection of subsurface damage according to the present invention.

[0032] Figure 4 Schematic diagram showing the subsurface damage signal of a nondestructive testing sample according to the present invention.

[0033] Figure 5 Schematic diagram showing the subsurface damage depth corresponding to the abrasive grain size of the present invention.

[0034] Figure 6 The figure shows the subsurface damage depth and the polarization laser nondestructive testing signal fitting curve of the present invention.

[0035] Figure 7 Shows the subsurface damage map of the sample of the present invention.

[0036] In the figure: 1. Grinding disc, 2. Sample, 3. Counterweight, 4. Grinding fluid, 5. Moving platform, 6. Grinding sample, 7. Polarized laser detection equipment. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be further described below with reference to the accompanying drawings.

[0038] like Figure 1-5As shown, a subsurface damage mapping method based on polarized laser scattering method includes the following steps:

[0039] The first step is to prepare five (or more) groups of polished samples, each group of three (or more) pieces, such as Figure 2 As shown, each group of samples 2 was fixed to a counterweight 3, which was used to press the sample 2 onto a grinding disc 1. A grinding liquid 4 was dripped onto the grinding disc 1 at a flow rate of 25 mL / min. The grinding disc was rotated at 30 rpm and ground for 1 hour to prepare five groups of ground samples. The grinding liquid particle size of each of the five groups of samples was different. The grinding liquid particle sizes of groups 1 to 5 were 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm, respectively.

[0040] The second step is Figure 3 As shown, the five groups of ground samples 2 prepared in the first step are placed on the mobile platform 5 in sequence, and the ground samples 6 are tested one by one using the polarized laser detection device 7 to obtain the polarized laser non-destructive detection signal value of each sample. The polarized laser non-destructive detection signal mean of each group of ground samples is obtained by computer analysis and processing as shown in FIG. Figure 4 As shown, the mean values ​​of the polarized laser nondestructive testing signals from group 1 to group 5 are 0.75μw, 5.32μw, 7.03μw, 7.09μw, and 7.69μw, respectively.

[0041] The third step is to use a surface profiler to measure the average surface roughness of each group of samples. According to the formula Depth of SSD = 9.1Ra, it can be calculated and plotted as follows: Figure 5 The schematic diagram of the subsurface damage depth corresponding to the abrasive grain size shown is as follows: abrasive grain sizes of 1μm, 5μm, 10μm, 15μm, and 20μm correspond to damage depths of 0.93μm, 1.11μm, 1.41μm, 1.74μm, and 2.74μm, respectively.

[0042] The fourth step is as follows Figure 6 As shown, according to the five sets of polarized laser nondestructive testing signal values ​​and subsurface damage depth values ​​obtained in the second and third steps, the formula D=AS n +B fitting to obtain the polarized laser nondestructive testing signal and subsurface damage depth mapping curve D = 2.20 × 10 -4 S 4.78 +1.11.

[0043] In the fifth step, the polarized laser nondestructive testing signal value measured in the second step is mapped to the subsurface damage depth value using the mapping curve obtained in the fourth step. Figure 7 Subsurface damage map shown.

[0044] The main function of the mapping curve is to map the sample subsurface damage detection signal measured during polarized laser nondestructive testing into the sample's actual subsurface damage depth through the mapping curve. During actual sample testing, the damage mapping relationship can be added to the signal collection and processing part of the polarized laser nondestructive testing system, and the collected data indirectly representing the sample subsurface damage depth can be mapped one by one to the sample's actual subsurface damage depth, thereby directly obtaining data used to represent the sample's subsurface damage depth through testing by the polarized laser nondestructive testing system.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A subsurface damage mapping method based on polarized laser scattering, characterized by: The following steps are involved: A. Prepare samples with different subsurface damage depths; B. Detect samples with different subsurface damage depths; C. Obtaining sample detection signals; D. Detect sample surface roughness data; E. Obtain the subsurface damage depth of the sample; F. Obtain sample damage mapping relationship.

2. The subsurface damage mapping method based on polarized laser scattering according to claim 1, characterized in that: The method for preparing samples with different subsurface damage depths described in step A is as follows: Several groups of samples with smooth surfaces and no subsurface damage are fixed on a counterweight block, and the samples are pressed on the grinding disc surface of the grinder. They are ground using grinding fluids of different particle sizes, and the grinding fluid particle sizes are 1μm, 5μm, 10μm, 15μm, 20μm or similar abrasive particle sizes with certain differences, to prepare test samples with subsurface damage of different depths.

3. The subsurface damage mapping method based on polarized laser scattering according to claim 1, characterized in that: The method for detecting samples with different subsurface damage depths in step B is as follows: Place the test sample on the mobile platform of the polarized laser detection platform, use a computer to control the mobile platform through a motion controller so that the polarized laser is irradiated on the sample surface; control the mobile platform to move along the X-axis and Y-axis in an S-shaped route so that the polarized laser completes the detection of the sample surface.

4. The subsurface damage mapping method based on polarized laser scattering according to claim 1, characterized in that: The method for obtaining the sample detection signal in step C is as follows: The computer collects the electrical signals measured by the photoelectric detector in the polarized laser nondestructive testing system collected by the data acquisition card, analyzes and processes the collected electrical signals, and uses them as detection signals of the sample surface.

5. The subsurface damage mapping method based on polarized laser scattering according to claim 1, characterized in that: The method for detecting the surface roughness data of the sample in step D is as follows: The surface roughness of each test sample was tested using a surface profilometer to obtain the roughness data of the surfaces of all samples.

6. The subsurface damage mapping method based on polarized laser scattering according to claim 1, characterized in that: The method for obtaining the subsurface damage depth of the sample in step E is as follows: The subsurface damage depth of the sample is calculated according to the formula of the surface roughness and subsurface damage depth of the sample, and a schematic diagram of the abrasive grain size corresponding to the subsurface damage depth is drawn.

7. The subsurface damage mapping method based on polarized laser scattering according to claim 1, characterized in that: The method for obtaining the sample damage mapping relationship in step F is as follows: Use the exponential formula D = AS n +B fits the detection signal and subsurface damage depth curve of the sample, and maps the detection signal data of the sample into subsurface damage depth data according to this curve; Where D represents the damage depth in μm; S represents the detection signal value in μW, and A, n, and B are all formula fitting parameters.

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