Method for testing copper diffusion depth of aluminum alloy clad aluminum plate
By analyzing the changes in Cu element concentration in aluminum alloy-clad aluminum sheets using energy dispersive spectroscopy line scanning, the problem of inaccurate copper diffusion depth testing in existing technologies has been solved, enabling accurate measurement of copper diffusion depth and ensuring the reliability of test results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHWEST ALUMINUM GRP
- Filing Date
- 2026-01-23
- Publication Date
- 2026-05-12
AI Technical Summary
Existing methods for testing the copper diffusion depth in aluminum alloy-clad aluminum sheets are inaccurate and easily affected by changes in etching conditions, leading to inaccurate test results.
Line scan analysis was performed using an energy dispersive spectroscopy (EDS) instrument. By detecting the change in Cu concentration on the surface of the aluminum alloy-clad aluminum sheet, the diffusion depth of copper was obtained, avoiding the influence of etching operations. After mechanical polishing, line scan Cu element curve analysis was performed under a scanning electron microscope.
This method enables accurate measurement of copper diffusion depth, avoids errors caused by etching, and ensures the accuracy and reliability of test results.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of aluminum alloy technology, and in particular to a method for testing the copper diffusion depth of aluminum alloy-clad aluminum sheets. Background Technology
[0002] Aluminum alloy-clad aluminum sheets are clad sheets made of alloyed aluminum material with a surface coating of pure aluminum. The alloyed aluminum material includes copper, primarily 2xxx series aluminum alloys. During high-temperature heat treatment, under the combined influence of elemental concentration difference and high temperature, copper diffuses and migrates towards the pure aluminum cladding layer, resulting in copper diffusion.
[0003] Currently, the metallographic method is used to test the copper diffusion depth in aluminum alloy cladding sheets. This method involves etching the aluminum alloy cladding to expose the grain boundaries where copper diffusion occurs, thus characterizing the Cu diffusion depth. However, changes in etching conditions may lead to insufficient exposure of copper diffusion or the etching out of the original grain boundaries of the cladding, both of which can result in inaccurate copper diffusion test results.
[0004] Therefore, it is of great significance to provide a detection method that can accurately reflect the diffusion depth of copper in the cladding layer of aluminum alloy-clad aluminum sheets. Summary of the Invention
[0005] The technical problem solved by this invention is to provide a test method for the copper diffusion depth of aluminum alloy-clad aluminum sheets, which can accurately detect the copper diffusion depth of aluminum alloy-clad aluminum sheets.
[0006] In view of this, this application provides a method for testing the copper diffusion depth of aluminum alloy-clad aluminum sheets, comprising the following steps:
[0007] Pre-treat the aluminum alloy-clad aluminum sheet;
[0008] The pretreated aluminum alloy-clad aluminum sheet was line-scanned using an energy dispersive spectroscopy (EDS) instrument, and the copper diffusion depth of the aluminum alloy-clad aluminum sheet was obtained based on the obtained Cu element curve.
[0009] In some specific embodiments, the pretreatment specifically involves mechanically polishing the surface of the aluminum alloy-clad aluminum sheet.
[0010] In some specific embodiments, the line scanning voltage of the energy dispersive spectrometer is 5~30kV.
[0011] In some specific embodiments, the line scanning voltage of the energy dispersive spectrometer is 10~20kV.
[0012] In some specific embodiments, the working distance between the energy dispersive spectrometer and the aluminum alloy-clad aluminum sheet is 5~15mm.
[0013] In some specific embodiments, the working distance between the energy dispersive spectrometer and the aluminum alloy-clad aluminum sheet is 8~10mm.
[0014] In some specific embodiments, the line scan time of the energy dispersive spectrometer is ≥100s.
[0015] In some specific embodiments, the line scan time of the energy dispersive spectrometer is 100~150s.
[0016] In some specific embodiments, the substrate of the aluminum alloy clad sheet is a 2-series aluminum alloy, and the cladding layer is a pure aluminum layer.
[0017] In some specific embodiments, the base material of the aluminum alloy clad aluminum sheet is 2024-T42 aluminum alloy or 2024-T62 aluminum alloy.
[0018] This application provides a method for testing the copper diffusion depth of aluminum alloy-clad aluminum sheets. First, the aluminum alloy-clad aluminum sheet is pretreated to ensure a clean surface and clear microstructure, preparing it for line scanning analysis using an energy dispersive spectrometer (EDS). Then, the pretreated sheet is subjected to a line scan using an EDS, and the copper diffusion depth is obtained based on the change in Cu concentration. In this method, the EDS is used to perform a line scan of the cladding layer of the aluminum alloy-clad aluminum sheet, with the electron beam analyzing Cu elements along the direction from the aluminum alloy substrate to the cladding layer. The fluctuations in the Cu element curve obtained from the line scan characterize the relative change in Cu concentration, thus reflecting the copper diffusion depth. This method avoids the influence of etching test conditions by not using etching. Furthermore, the Cu element curve obtained from the EDS line scan accurately reflects the Cu concentration gradient in the cladding layer, thus accurately characterizing the copper diffusion depth. Attached Figure Description
[0019] Figure 1 This is an electronic image of an aluminum alloy-clad aluminum sheet obtained by energy dispersive spectroscopy in Embodiment 1 of the present invention;
[0020] Figure 2 Metallographic photographs of aluminum alloy-clad aluminum sheets tested by the metallographic method in Comparative Example 1 of this invention.
[0021] Figure 3 This is an electronic image of an aluminum alloy-clad aluminum sheet obtained by energy dispersive spectroscopy in Embodiment 2 of the present invention;
[0022] Figure 4 The image shows a metallographic photograph of an aluminum alloy-clad aluminum sheet tested by the metallographic method in Comparative Example 2 of this invention. Detailed Implementation
[0023] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.
[0024] In view of the inaccuracy of metallographic detection of the diffusion depth of the cladding layer in aluminum alloy-clad aluminum sheets in the prior art, this application provides a method for testing the copper diffusion depth of aluminum alloy-clad aluminum sheets. This method utilizes energy dispersive spectroscopy (EDS) to detect the copper diffusion depth of the cladding layer in the aluminum alloy-clad aluminum sheet. This detection method does not involve etching of the aluminum alloy-clad aluminum sheet, thus it is unaffected by etching. Furthermore, the line scan analysis of the EDS can accurately characterize the concentration of Cu element. Therefore, the method for testing the copper diffusion depth of aluminum alloy-clad aluminum sheets provided in this application has high accuracy. Specifically, this invention discloses a method for testing the copper diffusion depth of aluminum alloy-clad aluminum sheets, including the following steps:
[0025] Pre-treat the aluminum alloy-clad aluminum sheet;
[0026] The pretreated aluminum alloy-clad aluminum sheet was scanned using an energy dispersive spectroscopy (EDS) instrument, and the copper diffusion depth of the aluminum alloy-clad aluminum sheet was obtained based on the change in Cu element concentration.
[0027] In the test method for copper diffusion depth of aluminum alloy-clad aluminum sheet provided in this application, the aluminum alloy-clad aluminum sheet is first pretreated. During this process, the aluminum alloy-clad aluminum sheet is any type of aluminum alloy-clad aluminum sheet known to those skilled in the art. Specifically, the substrate of the aluminum alloy-clad aluminum sheet is an aluminum alloy sheet, and the cladding layer is a pure aluminum layer. More specifically, the substrate of the aluminum alloy-clad aluminum sheet is a 2-series aluminum alloy, and the cladding layer is a pure aluminum layer. Even more specifically, the substrate of the aluminum alloy-clad aluminum sheet is 2024-T42 aluminum alloy or 2024-T62 aluminum alloy. The preparation scheme of the aluminum alloy-clad aluminum sheet is as known to those skilled in the art, and this application does not impose any particular limitations on it. The mechanical polishing is performed according to methods known to those skilled in the art, and this application does not impose any particular limitations on it. The mechanical polishing aims to make the cladding layer of the aluminum alloy-clad aluminum sheet clean and have a clear structure.
[0028] This application utilizes an energy dispersive spectroscopy (EDS) instrument to perform line scanning on the pretreated aluminum alloy-clad aluminum sheet. The copper diffusion depth of the aluminum alloy-clad aluminum sheet is obtained based on the obtained Cu element curve. During this process, the aluminum alloy cladding layer is located under a scanning electron microscope equipped with an EDS instrument. Cu element analysis is performed along a selected straight line using an EDS instrument scanning electron beam. Specifically, Cu element analysis is performed in the direction from the contact surface between the substrate and the cladding layer to the cladding layer. The relative change in Cu element concentration is characterized by the fluctuations in the line scan Cu element curve, thereby determining the depth of copper diffusion.
[0029] In this application, the substrate of the aluminum alloy clad aluminum sheet is a copper-containing 2-series aluminum alloy, and the cladding layer is pure aluminum without Cu. During high-temperature heat treatment (mainly solution treatment), Cu diffuses from the substrate to the cladding layer, increasing the Cu content in the cladding layer. This diffusion occurs from the inside out of the substrate to the cladding layer. Therefore, the Cu content in the cladding layer closer to the substrate is higher than that further away from the substrate, forming a concentration gradient. Thus, this application uses an energy dispersive spectroscopy (EDS) instrument to test the Cu concentration gradient in the cladding layer, thereby measuring the copper diffusion depth. In summary, after high-temperature treatment, Cu diffuses from the substrate into the cladding layer of the aluminum alloy clad aluminum sheet. Therefore, elemental analysis is performed using the scanning electron beam of an EDS instrument, starting from the interface between the substrate and the cladding layer, until Cu cannot be detected or analyzed by line scanning in the cladding layer. This provides the copper diffusion depth of the aluminum alloy clad aluminum sheet.
[0030] The line scanning voltage of the energy dispersive spectrometer is 5~30kV, specifically 10~20kV, and more specifically 12~18kV. The working distance between the energy dispersive spectrometer and the aluminum alloy-clad aluminum plate is 5~15mm, specifically 8~12mm; if the working distance is too far, it will affect the excitation and collection of electrons on the aluminum alloy-clad aluminum plate by the energy dispersive spectrometer, thus affecting the accuracy of the copper diffusion depth. The line scanning time of the energy dispersive spectrometer is ≥100s, specifically 100~200s, more specifically 100~150s, and more specifically 120~140s.
[0031] This invention provides a method for testing the copper diffusion depth of aluminum alloy-clad aluminum sheets. This method uses energy dispersive spectroscopy (EDS) line scanning to reflect the concentration gradient of Cu in the cladding layer of the aluminum alloy-clad aluminum sheet, avoiding the influence of etching and other experimental operations. This method can accurately reflect the copper diffusion depth of the cladding layer and ensure the accuracy of the test data.
[0032] To further understand the present invention, the method for testing the copper diffusion depth of aluminum alloy-clad aluminum plates provided by the present invention will be described in detail below with reference to embodiments. The scope of protection of the present invention is not limited by the following embodiments.
[0033] Example 1
[0034] The 2024-T42 aluminum alloy clad sheet (substrate: 2024-T42 aluminum alloy, cladding layer: pure aluminum layer) was mechanically polished to ensure a clean surface and clear microstructure. The pure aluminum layer was then located under a scanning electron microscope equipped with a scanner. Energy dispersive spectroscopy (EDS) was used to perform Cu element analysis by tracing the electron beam along the path from the substrate to the cladding layer. The scanning voltage was 20 kV, the working distance between the scanner and the aluminum alloy clad sheet was 10 mm, and the scanning time was 120 s. The relative change in Cu element concentration was characterized by the fluctuations in the Cu element curve obtained from the line scan, thus determining the depth of copper diffusion. Figure 1 As shown, Figure 1 The image shows an electron image of the aluminum alloy-clad aluminum sheet obtained by energy dispersive spectroscopy in this embodiment. As can be seen from the image, a Cu element curve appears within a 25.2 μm range from the surface of the 2024-T42 aluminum alloy substrate in contact with the cladding layer to the cladding layer. No Cu element appears at other locations. Therefore, it can be concluded that the copper diffusion depth of the 2024-T42 aluminum alloy-clad aluminum sheet in this embodiment is 25.2 μm.
[0035] Comparative Example 1
[0036] The 2024-T42 aluminum alloy clad sheet (the base material is 2024-T42 aluminum alloy, and the cladding layer is pure aluminum layer) is mechanically polished to make the surface of the aluminum alloy clean and the structure clear.
[0037] The mechanically polished aluminum alloy-clad sheet was immersed in a 25℃ etching solution for 25 seconds. Metallographic observation was performed after polishing, and the metallographic images are shown below. Figure 2 As shown, by Figure 2 Only a copper diffusion depth of 25 μm can be observed.
[0038] Example 2
[0039] The 2024-T62 aluminum alloy clad sheet (substrate: 2024-T62 aluminum alloy, cladding layer: pure aluminum layer) was mechanically polished to ensure a clean surface and clear microstructure. The pure aluminum layer was then located under a scanning electron microscope equipped with a scanner. Energy dispersive spectroscopy (EDS) was used to perform Cu elemental analysis by tracing the electron beam along the path from the substrate to the cladding layer. The scanning voltage was 20 kV, the working distance between the scanner and the aluminum alloy clad sheet was 10 mm, and the scanning time was 120 s. The relative change in Cu elemental concentration was characterized by the fluctuations in the Cu elemental curve obtained from the line scan, thus determining the depth of copper diffusion. Figure 3 As shown, Figure 3The image shows an electron image of the aluminum alloy-clad aluminum sheet obtained by energy dispersive spectroscopy in this embodiment. As can be seen from the image, a Cu element curve appears within a 26.1 μm range from the surface of the 2024-T42 aluminum alloy substrate in contact with the cladding layer to the cladding layer. No Cu element appears at other locations. Therefore, it can be concluded that the copper diffusion depth of the 2024-T62 aluminum alloy-clad aluminum sheet in this embodiment is 26.1 μm.
[0040] Comparative Example 2
[0041] The 2024-T62 aluminum alloy clad sheet (the base material is 2024-T62 aluminum alloy, and the cladding layer is pure aluminum layer) is mechanically polished to make the surface of the aluminum alloy clean and the structure clear.
[0042] The mechanically polished aluminum alloy-clad sheet was immersed in a 25℃ etching solution for 25 seconds. Metallographic observation was performed after polishing, and the metallographic images are shown below. Figure 4 As shown, by Figure 4 Only a copper diffusion depth of 25 μm can be observed.
[0043] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.
[0044] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for testing the copper diffusion depth of aluminum alloy-clad aluminum sheets, comprising the following steps: Pre-treat the aluminum alloy-clad aluminum sheet; The pretreated aluminum alloy-clad aluminum sheet was line-scanned using an energy dispersive spectroscopy (EDS) instrument, and the copper diffusion depth of the aluminum alloy-clad aluminum sheet was obtained based on the obtained Cu element curve.
2. The test method according to claim 1, characterized in that, The pretreatment specifically involves mechanically polishing the surface of the aluminum alloy-clad aluminum sheet.
3. The test method according to claim 1, characterized in that, The line scanning voltage of the energy dispersive spectrometer is 5~30kV.
4. The test method according to claim 1 or 3, characterized in that, The line scanning voltage of the energy dispersive spectrometer is 10~20kV.
5. The test method according to claim 1, characterized in that, The working distance between the energy dispersive spectrometer and the aluminum alloy-clad aluminum plate is 5~15mm.
6. The test method according to claim 1 or 5, characterized in that, The working distance between the energy dispersive spectrometer and the aluminum alloy-clad aluminum plate is 8~10mm.
7. The test method according to claim 1, characterized in that, The line scan time of the energy dispersive spectrometer is ≥100s.
8. The test method according to claim 1 or 7, characterized in that, The line scan time of the energy dispersive spectrometer is 100~150s.
9. The test method according to claim 1, characterized in that, The base material of the aluminum alloy clad sheet is a 2-series aluminum alloy, and the cladding layer is a pure aluminum layer.
10. The test method according to claim 9, characterized in that, The base material of the aluminum alloy clad aluminum sheet is 2024-T42 aluminum alloy or 2024-T62 aluminum alloy.