阅读说明：本技术 散斑的制备方法、具有散斑的材料及材料的测试方法 (Preparation method of speckles, material with speckles and testing method of material ) 是由 刘敬勇 向嘉奇 钟政烨 罗胜年 于 2019-10-08 设计创作，主要内容包括：本发明公开了一种散斑的制备方法、具有散斑的材料以及材料的测试方法。本发明散斑的制备方法包括：在目标散斑的载体的设定表面上附着作为散斑前体的银膜；将附着所述银膜的载体浸泡在含氯离子电解质溶液中使银膜转变成分散在所述设定表面上的银纳米散斑粒；进而由分散在所述设定表面上的银纳米散斑粒构成目标散斑。该方法操作简单方便,成本较低；制备的散斑对载体的设定表面的影响可控,容易满足EBSD测试的需求；纳米散斑粒粒径满足高分辨率DIC要求,并且纳米散斑粒粒径均匀,分布均匀性容易控制。(The invention discloses a preparation method of speckles, a material with the speckles and a test method of the material. The preparation method of the speckle of the invention comprises the following steps: attaching a silver film as a speckle precursor on a set surface of a carrier of the target speckle; soaking the carrier attached with the silver film in electrolyte solution containing chloride ions to convert the silver film into silver nano speckle grains dispersed on the set surface; and then the silver nanometer speckle grains dispersed on the set surface form the target speckle. The method is simple and convenient to operate and low in cost; the influence of the prepared speckles on the set surface of the carrier is controllable, and the requirements of an EBSD test are easily met; the grain size of the nanometer speckle grains meets the requirement of high-resolution DIC, and the nanometer speckle grains have uniform grain size and easy control of distribution uniformity.)

1. A method for producing speckle, comprising: attaching a silver film as a speckle precursor on a set surface of a carrier of the target speckle; soaking the carrier attached with the silver film in electrolyte solution containing chloride ions to convert the silver film into silver nano speckle grains dispersed on the set surface; and then the silver nanometer speckle grains dispersed on the set surface form the target speckle.

2. The method for producing speckle according to claim 1, wherein: the electrolyte solution containing chloride ions is specifically a sodium chloride solution.

3. The method for producing speckle of claim 2, wherein: the concentration of the sodium chloride solution is 0.2-2 wt.%, preferably 0.2-1.5 wt.%, more preferably 0.5-1 wt.%, still more preferably 1 wt.%.

4. The method for producing speckle according to claim 1, wherein: the thickness of the silver film is 5 to 40nm, preferably 5 to 25nm, more preferably 10 to 20nm, and still more preferably 15 nm.

5. The method for producing speckle according to any one of claims 1 to 6, wherein: the support to which the silver film is attached is ensured to be on the upper surface of the support during immersion in the chloride ion-containing electrolyte solution.

6. The method for producing speckle according to any one of claims 1 to 6, wherein: also included is cleaning the material having the support and the target speckle formed on the support to remove residual chloride-containing electrolyte solution.

7. The method for producing speckle according to any one of claims 1 to 6, wherein: and polishing and cleaning the set surface to remove the pollutants on the set surface before the silver film is attached on the set surface.

8. The method for producing speckle according to any one of claims 1 to 6, wherein: the particle size of the silver nanometer speckle grains is 1-100 nm.

9. A material having speckles, comprising a carrier and target speckles formed on a set surface of said carrier, characterized in that: the target speckle is prepared by the preparation method of the speckle of any one of claims 1 to 8.

10. A method of testing a material, comprising: acquiring the material with speckle of claim 9 and using the material as a sample in the following operations; performing EBSD characterization on the sample, wherein the calibration rate reaches more than 95%; shooting a speckle pattern of the sample before deformation, and shooting the speckle pattern of the sample after deformation after material deformation treatment; and comparing and analyzing the speckle pattern of the sample before deformation with the speckle pattern of the sample after deformation.

Technical Field

The invention relates to a preparation method of speckles, a material with speckles and a testing method of the material.

Background

With the continuous and deep research of material science, in the field of structural materials, researchers tend to analyze the properties of the materials from the microstructures of the materials, and further improve the mechanical properties of the materials by improving the microstructures. With the commercialization of EBSD (electron back scattering diffraction) technology, the introduction of this device since 1995 in our country has led to significant domestic EBSD progress over the twenty years. The technology can simultaneously analyze the grain size, grain orientation and texture of the material. However, due to the inherent limitations of EBSD, it is not possible to accurately and intuitively measure the displacement and strain of a material during deformation at a mesoscopic scale. Therefore, it is important to measure the displacement and strain of the material during deformation by a non-contact method.

Digital Image Correlation (DIC) has the characteristics of high measurement precision, multi-scale measurement, non-contact type and the like, and is gradually one of measurement methods for researching displacement and strain in the material deformation process. The digital image correlation method is that speckle which is distributed evenly is prepared on the surface of a sample, the speckle patterns of the sample before and after deformation of the material are shot, and displacement fields of two pictures are calculated by using correlation software, so that a strain field is obtained. Meanwhile, by combining the EBSD and the DIC, the evolution of the microstructure of the material in the deformation process can be obtained, and the changes of the displacement field and the strain field in the deformation process of the material can be visually obtained. The displacement strain field in the material deformation process is explained through the evolution of the microstructure, which is a great technical breakthrough in the scientific research history.

Currently, DIC is generally classified as optical or electronic imaging, in which nanometer-scale imaging is almost impossible due to technical limitations. The deformation information thus obtained is relatively macroscopic. In contrast, since electronic imaging can achieve extremely high resolution, it has been used by an increasing number of research teams for DIC imaging. This is a great improvement in the resolution technique, but how to make smaller speckles becomes a problem. Speckle patterns used by digital image correlation methods generally require that speckle grains are uniform in size, randomly distributed and have a certain contrast with a matrix. The size of the speckle grains determines the resolution, and the smaller the speckle grains, the more detailed information can be seen, and the more so-called high resolution is achieved. Generally, small speckle grains can be obtained by using nanoparticles (1-100nm) as the speckle grains, but because the specific surface energy of the nanoparticles is high, the actual speckle grains are often larger than 100nm due to the agglomeration of the nanoparticles, and are distributed unevenly, so that the purpose of high resolution cannot be achieved. The speckles serve as carriers of deformation information of the surface of the material, so that the quality of the speckles is a key factor for determining the success or failure of the test.

The EBSD technology requires that the surface of a tested sample has extremely high polishing degree, the traditional speckle manufacturing method, such as a paint spraying method, cannot meet the requirement of EBSD on the surface of a material, and if EBSD test is required, the speckle needs to be removed and the surface of the sample needs to be polished, so that the operation is complex, and the in-situ loading experiment cannot be met. Recently, Li Xue Zhen et al invented a method for preparing speckles and a method for characterizing material micro-domain deformation (Chinese patent publication No. CN109580677A), which simultaneously realized DIC and EBSD analysis, but it was not clear that the strain field near the slip band after deformation is seen in the strain diagram of DIC, and it can be seen from the scanned diagram that the size of the speckles is not in nanometer level, so it has not reached the requirement of high resolution. The secondary electron imaging also improves the Z-axis direction error caused by the deformation. Meanwhile, the manufacturing period of the method is relatively long. Further improvements are needed.

In short, some methods in the existing speckle preparation methods cannot meet the requirement of high resolution, some methods cannot meet the requirement of simultaneous analysis of EBSD and DIC, and some methods have longer speckle preparation period.

Disclosure of Invention

The invention aims to provide a preparation method of speckles, a material with the speckles and a testing method of the material.

According to one aspect of the invention, a method of producing speckle comprises: attaching a silver film as a speckle precursor on a set surface of a carrier of the target speckle; soaking the carrier attached with the silver film in electrolyte solution containing chloride ions to convert the silver film into silver nano speckle grains dispersed on the set surface; and then the silver nanometer speckle grains dispersed on the set surface form the target speckle.

The particle size of the nanometer speckle grains is generally 1-100 nm. In addition, the electrolyte solution containing chloride ions is generally a sodium chloride solution. The concentration of the sodium chloride solution may be 0.2 to 2 wt%, preferably 0.2 to 1.5 wt%, more preferably 0.5 to 1 wt%, still more preferably 1 wt%.

The thickness of the silver film may be 5 to 40nm, preferably 5 to 25nm, more preferably 10 to 20nm, still more preferably 15 nm. In order to control the formation and thickness of the silver film, the silver film may be attached to the set surface by a magnetron sputtering process, and the sputtering time in the magnetron sputtering process may be 5 to 35 seconds, preferably 10 to 30 seconds, more preferably 15 to 25 seconds, and still more preferably 20 seconds.

In addition, the silver film is preferably ensured to be on the upper surface of the carrier during the process of soaking the carrier attached with the silver film in the electrolyte solution, so that the uniformity of the dispersion of the nano-speckle grains on the set surface can be better ensured.

The above method may further include the operation of cleaning the material having the support and the target speckles formed thereon to remove residual chloride ion-containing electrolyte solution.

The method can also be used for polishing and cleaning the set surface to remove pollutants on the set surface before the silver film is attached on the set surface.

According to another aspect of the invention, a material with speckles comprises a carrier and target speckles formed on a set surface of the carrier, wherein the target speckles are prepared by a method for preparing any one of the speckles.

According to yet another aspect of the invention, a method of testing a material comprises: acquiring the material with speckles, and using the material as a sample in the following operation; performing EBSD characterization on the sample, wherein the calibration rate reaches more than 95%; shooting a speckle pattern of the sample before deformation, and shooting the speckle pattern of the sample after deformation after material deformation treatment; and comparing and analyzing the speckle pattern of the sample before deformation with the speckle pattern of the sample after deformation.

Experiments show that when the silver film is soaked in electrolyte solution containing chloride ions, Cl in the solution is^-Ions can destroy the integrity of the silver film; followed by reaction with Cl^-Under the action of the sensor, the silver particles can be migrated and aggregated into nano-level silver particles (namely silver nano speckle particles), and then the silver nano speckle particles dispersed on the set surface form the target speckle.

The preparation method of the speckle is simple and convenient to operate and low in cost; the influence of the prepared speckles on the set surface of the carrier is controllable, and the requirements of an EBSD test are easily met; the grain size of the nanometer speckle grains meets the requirement of high-resolution DIC, and the nanometer speckle grains have uniform grain size and easy control of distribution uniformity.

The invention is further described with reference to the following figures and detailed description. Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to assist in understanding the invention, and are included to explain the invention and their equivalents and not limit it unduly. In the drawings:

fig. 1 is an electron back scattering picture of example 1 of the present invention.

Fig. 2 is an electron back scattering picture of embodiment 2 of the present invention.

Fig. 3 is an electron back scattering picture of embodiment 3 of the present invention.

Fig. 4 is an electron back scattering picture of different materials of example 4 of the present invention.

FIG. 5 is an IPF plot of EBSD of pure nickel of example 5 of the present invention.

FIG. 6 is a graph of DIC strain field clouds at exx and exy orientations at different magnifications for nickel in example 5 of the present invention.

FIG. 7 is a back-scattered scanning electron (BSED) image of aluminum at different magnifications and the corresponding exx strain field cloud image in example 6 of the present invention.

Detailed Description

The invention will be described more fully hereinafter with reference to the accompanying drawings. Those skilled in the art will be able to implement the invention based on these teachings. Before the present invention is described in detail with reference to the accompanying drawings, it is to be noted that:

technical solutions and technical features provided in the respective portions including the following description in the present invention may be combined with each other without conflict.

In addition, the embodiments of the present invention described in the following description are generally only a partial embodiment of the present invention, and not all embodiments, and therefore, all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments of the present invention should fall within the protection scope of the present invention.

With respect to the terms and units in the present invention: the term "comprises" and any variations thereof in the description and claims of this invention and the related sections are intended to cover non-exclusive inclusions. In addition, other related terms and units in the invention can be reasonably construed based on the related contents of the invention.

The preparation method of the speckle of the embodiments 1 to 4 of the present invention includes:

1) coarse grinding different materials with sand paper, mechanically polishing, electropolishing, and ultrasonically oscillating and cleaning the materials with absolute ethyl alcohol for later use;

2) the polished surface of the material is placed upwards into a coating instrument, the silver film target material is fixed and then is subjected to magnetron sputtering, and the sputtering time is set according to the table 1.

3) Preparing sodium chloride solution with the concentration shown in table 1, pouring 50mL of deionized water into a beaker, weighing and analyzing pure sodium chloride particles according to table 1, pouring the sodium chloride particles into the beaker, and ultrasonically vibrating for 5min to completely dissolve the sodium chloride particles in the deionized water.

4) And (3) putting the material subjected to film coating into the sodium chloride solution prepared in the third step, performing soaking according to the table 1, and putting the material with the film coated side facing upwards without shaking in the soaking process.

5) And taking out the sample, washing the surface of the material by deionized water, and removing the residual sodium chloride solution on the surface. And obtaining speckles for performing EBSD test and DIC measurement simultaneously after the sample is dried.

TABLE 1

As shown in fig. 1, the speckle particle size gradually decreases with the increase of the coating time, and when the coating time is 20s, uniform and dense speckles are formed. Therefore, the optimum plating time was 20s (in this case, the thickness of the silver film was 15 nm).

As shown in fig. 2, there was no significant change in speckles as the soak time was extended. Theoretically, the silver film needs a certain time for recombination, when the time is short, the silver film is still relatively complete, and from the experimental result, the silver film is completely recombined after 2.5 hours. Thereafter, the silver speckle particles remain stable, increasing the soak time and not destroying the speckles.

As shown in fig. 3, when the solution concentration is less than 1 wt.%, no significant change in the speckle particle size occurs, and when the sodium chloride solution concentration reaches 2 wt.%, significant agglomeration of silver particles occurs, as indicated by the arrows, and at low power it can be seen that the agglomeration is distributed along the grains, which is not suitable for DIC analysis. The lower the concentration of the sodium chloride solution, the longer the required soaking time, which is the equilibrium soaking time, so a concentration of 1 wt.% is suitable.

Referring to fig. 1-3, the optimal speckle preparation conditions are coating time 20s, soaking time 2.5h, and sodium chloride solution concentration 1 wt.%. The experimental parameters are utilized to carry out the embodiment 4, the speckles on the surfaces of the four materials are uniformly distributed, and the particle diameters of the speckles on the surfaces of different materials are slightly different, but are all about 50 nm. Can be applied to high-resolution DIC.