Preparation method of titanium alloy quasi-in-situ EBSD tensile sample

Abstract

The invention belongs to the technical field of titanium alloy sample preparation, and particularly relates to a preparation method of a titanium alloy quasi-in-situ EBSD tensile sample. Comprising the following steps: polishing and cleaning a titanium alloy sample to obtain an initial EBSD tensile sample; the titanium alloy quasi-in-situ EBSD tensile sample is obtained through electrolytic polishing at the room temperature with an initial EBSD tensile sample as an anode, electrolytic polishing liquid used for electrolytic polishing is composed of perchloric acid, acetic acid and methyl alcohol with the volume ratio being (10-15): (70-75): (15-20), and in the electrolytic polishing process, the polishing voltage is 35-37.5 V, and the current is 0.6-1.0 A. According to the method, the preparation process is simplified by adding the methanol, regulating the ratio of the perchloric acid to the acetic acid to the methanol and regulating the electrolytic polishing voltage and current, the sample preparation process is safe, simple and easy to operate, and the calibration rate of the EBSD sample is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy sample preparation, and particularly relates to a method for preparing a titanium alloy quasi-in-situ EBSD tensile sample. Background Art

[0002] During the plastic deformation of titanium alloys, the dominant factors affecting the deformation process are different slip modes activated under different loading conditions and different twin variants. Under different loading conditions, the activated deformation modes and their proportions are also different. Therefore, in order to study the dominant plastic deformation modes under different strain conditions of titanium alloys, researchers have proposed quasi-in-situ tensile testing. For quasi-in-situ tensile testing of titanium and titanium alloys, this method combines an electronic universal testing machine, a scanning electron microscope (SEM), and electron backscatter diffraction (EBSD) to perform interrupted tests under different cumulative strains and analyze the deformation modes under different strains. Quasi-in-situ tensile testing has been widely used due to its advantages such as low technical requirements and simple experimental operation.

[0003] EBSD technology is a powerful microstructural analysis technique. It bombards the sample surface with an electron beam to produce a diffraction pattern, and reconstructs the atomic arrangement and crystal structure inside the sample by collecting these diffraction spots. The preparation techniques for EBSD samples include mechanical vibration polishing, ion polishing, focused ion beam polishing, and electrolytic polishing. Among them, although mechanical vibration polishing has a large polishable surface and good repeatability, it requires the sample to be mounted, has high requirements for the surface finish of the sample, and the polishing takes a long time. The heat generated by ion bombardment during ion polishing may cause damage to the sample surface, and the process produces waste gas. Focused ion beam polishing has a small polishing area, a long time, and high equipment and time costs. Electrolytic polishing is widely used because it is quick and easy to operate, has low requirements for the surface of the mechanically polished sample, and the polished sample does not need to be mounted.

[0004] Quasi-in-situ tensile specimens of titanium alloys cannot be mounted due to their large sample size, making it difficult to mechanically polish the samples. Therefore, electropolishing has become the first choice for preparing quasi-in-situ tensile EBSD specimens due to its simple operation and low equipment cost. However, the electropolishing solution commonly used for electropolishing of titanium alloys consists of perchloric acid and acetic acid solutions. Due to the large size of the tensile specimens, the electrolytic process parameters are unstable, making parameter determination more difficult. In addition, as the number of electropolishing times increases, the temperature of the electropolishing solution rises, resulting in excessive corrosion of the specimen surface, affecting the polishing quality and resulting in a low calibration rate for the backscattered electron diffraction Kikuchi pattern. Liquid nitrogen is often used to cool the electropolishing solution, which increases costs. Summary of the Invention

[0005] To address the above issues, the present invention provides a method for preparing titanium alloy quasi-in-situ EBSD tensile specimens. Based on the existing perchloric acid-acetic acid electrolytic polishing solution system, methanol is added, the ratio of perchloric acid, acetic acid, and methanol is adjusted, and the electrolytic polishing voltage and current are controlled to determine a stable electrolytic polishing sample preparation process window for titanium alloy quasi-in-situ tensile specimens, thereby improving sample preparation stability. This simplifies the preparation process, making it safe, simple, and easy to operate, eliminating the need for a mechanical polishing step, and effectively improving the calibration rate of EBSD specimens.

[0006] The present invention solves the above technical problems through the following technical solutions.

[0007] The present invention aims to provide a method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen, comprising the following steps: S1. Obtain a titanium alloy sample, polish and clean the titanium alloy sample, and obtain an initial EBSD tensile sample.

[0008] S2. Using the initial EBSD tensile specimen as the anode, electrolytic polishing was performed at room temperature to obtain a quasi-in-situ EBSD tensile specimen of the titanium alloy. The electrolytic polishing solution used for electrolytic polishing consisted of perchloric acid, acetic acid, and methanol in a volume ratio of 10-15:70-75:15-20. During the electrolytic polishing process, the polishing voltage was 35V-37.5V, and the polishing current was 0.6A-1.0A.

[0009] Furthermore, during the electrolytic polishing process, the polishing time is 90s to 120s.

[0010] Furthermore, the temperature of the electrolytic polishing solution is 15°C to 30°C.

[0011] Furthermore, during the electrolytic polishing process, the electrolytically polished surface of the initial EBSD tensile specimen is immersed in an electrolytic polishing solution using a metal clamp, and electrolytic polishing is performed at room temperature using a conductive metal as an auxiliary electrode.

[0012] Furthermore, one end of the metal clamp is connected to the positive pole of the DC power supply, one end of the auxiliary electrode is connected to the negative pole of the DC power supply, and the other end is placed in the electrolytic polishing liquid. The DC power supply voltage is 35V~37.5V, and the auxiliary electrode is TC4 titanium alloy.

[0013] Furthermore, when the distance between the initial EBSD tensile specimen and the auxiliary electrode is 50-100 mm.

[0014] Furthermore, during the electropolishing process, the initial EBSD tensile specimen is in a shaking state relative to the electropolishing solution. During the shaking process, the initial EBSD tensile specimen and the electropolishing solution are always in contact, and the shaking angle is 10° to 20°.

[0015] Furthermore, the sample surface was ground using 60#, 200#, 600#, 1000#, 1500# and 3000# grit sandpaper in sequence. The titanium alloy sample was rotated 90° after each grinding. After sandpaper grinding, it was washed with water and ethanol in sequence.

[0016] Furthermore, after the electrolytic polishing is completed, ultrasonic cleaning and drying are performed in sequence to obtain a titanium alloy quasi-in-situ EBSD tensile specimen.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The method for preparing a quasi-in-situ EBSD tensile specimen of a titanium alloy provided by the present invention is based on the existing perchloric acid-acetic acid electrolytic polishing liquid system. By adding methanol and adjusting the ratio of perchloric acid, acetic acid and methanol, on the one hand, the temperature of the electrolytic polishing liquid is lowered by methanol, and on the other hand, the viscosity of the electrolytic polishing liquid system is adjusted by methanol, so that during electrolytic polishing, a uniform liquid film is formed on the surface of the titanium alloy specimen. The liquid film selectively dissolves the protruding parts to achieve surface smoothing of the specimen and improve the surface finish. The efficiency of sample preparation is greatly improved, and the room temperature preparation of the quasi-in-situ EBSD specimen of titanium alloy is achieved. Based on the perchloric acid-acetic acid-methanol electrolytic polishing liquid system, electrolytic polishing is performed by adjusting the electrolytic polishing voltage and current, wherein the initial EBSD tensile specimen undergoes an anodic oxidation reaction, and the surface loses electrons to form titanium ions (Ti 4+ ), which then reacts with oxygen or water in the electrolyte to form a titanium dioxide (TiO2) passivation film. The raised areas of the initial EBSD tensile specimen are preferentially dissolved, while the recessed areas are protected by the passivation film, ultimately smoothing the surface. Methanol is used to prevent the passivation film from thickening with increasing polishing time and thus adhering to the surface of the initial EBSD tensile specimen. This prevents the raised areas that have not yet been completely dissolved from being dissolved, resulting in poor electropolishing results and a low Kikuchi pattern calibration rate for the test specimen, making it impossible to obtain crystallographic information in some areas. By regulating the electropolishing voltage and current, a stable electropolishing sample preparation process window for quasi-in-situ titanium alloy tensile specimens is determined, thereby improving sample preparation stability. This simplifies the preparation process, making it safe, simple, and easy to operate, without the need for a mechanical polishing step, and effectively improving the calibration rate of EBSD specimens. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a process flow chart of the EBSD tensile specimen prepared in the present invention.

[0019] Figure 2 This is a macroscopic image of the quasi-in-situ EBSD tensile specimens of the titanium alloys of Examples 1 and 2 of the present invention. Figure 2 Where a is Example 1, b is Example 2.

[0020] Figure 3 This is a macroscopic image of the quasi-in-situ EBSD tensile specimen of the titanium alloy prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] It should be noted that the technical terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of this invention. Unless otherwise specified, the various raw materials, reagents, instruments, and equipment used in the following examples of this invention can be purchased commercially or prepared by existing methods. The perchloric acid used herein is a commercially available aqueous solution of 70% to 72% by mass.

[0023] Due to the large size of titanium alloy quasi-in-situ tensile specimens, mounting is not possible, making mechanical polishing difficult. Therefore, electropolishing, with its simple operation and low equipment cost, has become the preferred method for preparing quasi-in-situ tensile EBSD specimens. However, the electropolishing solution commonly used for electropolishing of titanium alloys consists of a perchloric acid and acetic acid solution. While this solution system can dissolve raised areas on the titanium alloy surface and reduce surface roughness, the low viscosity of acetic acid can easily lead to uneven localized reactions, resulting in spots or streaks on the polished surface. Furthermore, as the electropolishing process continues, the temperature of the electropolishing solution increases, causing excessive corrosion on the specimen surface and compromising the polishing quality. Furthermore, due to the large size of the tensile specimens, unstable electropolishing parameters lead to unstable polishing surface quality, resulting in a low calibration rate for the Kikuchi pattern analysis of the specimens.

[0024] In view of the above problems, the present invention provides a method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen, comprising the following steps: S1. Obtain a titanium alloy sample, polish and clean the titanium alloy sample, and obtain an initial EBSD tensile sample.

[0025] S2. Using the initial EBSD tensile specimen as the anode, electrolytic polishing was performed at room temperature to obtain a quasi-in-situ EBSD tensile specimen of the titanium alloy. The electrolytic polishing solution used for electrolytic polishing consisted of perchloric acid, acetic acid, and methanol in a volume ratio of 10-15:70-75:15-20. During the electrolytic polishing process, the polishing voltage was 35V-37.5V, and the polishing current was 0.6A-1.0A.

[0026] The method for preparing a quasi-in-situ EBSD tensile specimen of a titanium alloy provided by the present invention is based on the existing perchloric acid-acetic acid electrolytic polishing liquid system. By adding methanol and adjusting the ratio of perchloric acid, acetic acid and methanol, on the one hand, the temperature of the electrolytic polishing liquid is lowered by methanol, and on the other hand, the viscosity of the electrolytic polishing liquid system is adjusted by methanol, so that during electrolytic polishing, a uniform liquid film is formed on the surface of the titanium alloy specimen, and the liquid film selectively dissolves the protruding parts to achieve surface smoothing of the specimen surface and improve the surface finish. The efficiency of sample preparation is greatly improved, and room temperature preparation of quasi-in-situ EBSD specimens of titanium alloys is achieved. The present invention is based on a perchloric acid-acetic acid-methanol electrolytic polishing liquid system, and electrolytic polishing is performed by adjusting the electrolytic polishing voltage and current, wherein the initial EBSD tensile specimen undergoes an anodic oxidation reaction, and the surface loses electrons to form titanium ions (Ti 4 + ), which then reacts with oxygen or water in the electrolyte to form a titanium dioxide (TiO2) passivation film. The raised areas of the initial EBSD tensile specimen are preferentially dissolved, while the recessed areas are protected by the passivation film, ultimately smoothing the surface. Methanol is used to prevent the passivation film from thickening with increasing polishing time and thus adhering to the surface of the initial EBSD tensile specimen. This prevents the raised areas that have not yet been completely dissolved from being dissolved, resulting in poor electropolishing results and a low Kikuchi pattern calibration rate for the test specimen, making it impossible to obtain crystallographic information in some areas. By regulating the electropolishing voltage and current, a stable electropolishing sample preparation process window for quasi-in-situ titanium alloy tensile specimens is determined, thereby improving sample preparation stability. This simplifies the preparation process, making it safe, simple, and easy to operate, without the need for a mechanical polishing step, and effectively improving the calibration rate of EBSD specimens.

[0027] In some embodiments, the electropolishing process has a polishing time of 90 seconds to 120 seconds. In the present invention, the polishing time is regulated based on the electropolishing voltage and current to determine a stable electropolishing sample preparation process window for the titanium alloy quasi-in-situ tensile specimen, thereby improving the stability of sample preparation.

[0028] In some embodiments, the temperature of the electrolytic polishing solution is 15° C. to 30° C. In the present invention, by adding methanol, which has a freezing point of -97° C., and adjusting the ratio of perchloric acid, acetic acid, and methanol, the temperature of the electrolytic polishing solution is lowered, thereby achieving room temperature preparation of titanium alloy quasi-in-situ EBSD samples.

[0029] In some embodiments, during the electropolishing process, the electropolished surface of the initial EBSD tensile specimen is immersed in an electropolishing solution using a metal holder, and electropolishing is performed at room temperature using a conductive metal as an auxiliary electrode.

[0030] In some embodiments, one end of the metal clamp is connected to the positive electrode of a DC power supply, one end of the auxiliary electrode is connected to the negative electrode of the DC power supply, and the other end is placed in the electrolytic polishing liquid. The DC power supply voltage is 35V to 37.5V, and the auxiliary electrode is TC4 titanium alloy.

[0031] In the present invention, Figure 1 As shown, the schematic diagram of clamping the initial EBSD tensile specimen for electrolytic polishing of the tensile specimen is shown in FIG. Figure 1 In the embodiment, the electrolytic polishing liquid 6 is placed in the container 1, the metal clamp 3 is a titanium alloy clamp, the titanium alloy clamp has excellent corrosion resistance, one end of the titanium alloy clamp is composed of two TC4 titanium alloy sheets with a size of 15mm×100mm×2mm, the non-polished part of the initial EBSD tensile specimen is clamped between the two TC4 titanium alloy sheets, and the two TC4 titanium alloy sheets are fixed by rubber bands, thereby clamping the non-polished part of the initial EBSD tensile specimen 2, fixing the initial EBSD tensile specimen 2, and connecting the other end to the positive pole of the DC power supply 4. The auxiliary electrode 7 is the cathode electrode. TC4 titanium alloy is used as the cathode material, which has better corrosion resistance and replaces traditional cathode materials such as stainless steel and aluminum sheets, thereby improving the service life of the cathode material and reducing the sample preparation cost. One end of the auxiliary electrode 7 is connected to the negative pole of the DC power supply, and the other end is placed in the electrolytic polishing liquid 6, wherein the auxiliary electrode 7 is a spoon-shaped auxiliary electrode, and the spoon handle end is connected to the negative pole of the DC power supply with a wire 5 with a metal clip. A path is formed by a DC power supply 4, a metal holder 3, an initial EBSD tensile specimen 2, an electrolytic polishing solution 6, and an auxiliary electrode 7. The electrolyte acts as a cathode to cause a cathode reduction reaction, and an anode to cause an anodic oxidation reaction. The initial EBSD tensile specimen undergoes an anodic oxidation reaction, and the surface loses electrons to form titanium ions (Ti 4+ ), which then reacts with oxygen or water in the electrolyte to form a titanium dioxide (TiO2) passivation film, thereby achieving the purpose of electrolytic polishing the surface of the tensile specimen.

[0032] In some embodiments, when the distance between the initial EBSD tensile specimen and the auxiliary electrode is 50 to 100 mm. In the present invention, the closer the distance between the anode metal specimen and the cathode auxiliary electrode spoon handle during the electrolytic polishing process, the greater the electric field strength at the same voltage, thereby accelerating electron migration, allowing more charges to pass through the electrolyte per unit time, and thus increasing the current, accelerating the anodic dissolution rate of the titanium alloy specimen. However, if the distance between the anode and the cathode is too small, it may cause the local current density to be too high, causing pitting or excessive corrosion. When the distance between the two electrodes is less than 50 mm, the polishing current is ≤0.6 A; when the distance between the two electrodes is 50~100 mm, the polishing current is 0.6~1.0 A, and when the distance between the two electrodes is ≥100 mm, the polishing current is >1.0 A. Therefore, during the polishing process, it is sufficient to keep the distance between the two at 50~100 mm and the current at about 0.75 A.

[0033] In some embodiments, during the electropolishing process, the initial EBSD tensile specimen is in a shaking state relative to the electropolishing liquid. During the shaking process, the initial EBSD tensile specimen and the electropolishing liquid are always in contact, and the shaking angle is 10° to 20°. Shaking the specimen during the polishing process causes the passivation film produced on the surface to fall off, ensuring that the shedding and production of the surface passivation film are always in a state of dynamic equilibrium, wherein the angle of the specimen shaking left and right is 10 to 20°, and ensuring that the surface to be polished of the tensile specimen is always placed in the electrolyte. Avoid the passivation film from thickening as the polishing time increases, thereby adhering to the surface of the specimen, making it impossible to dissolve the raised surface that has not been completely dissolved, resulting in poor electropolishing effect, low Kikuchi pattern analysis calibration rate of the test sample, and inability to obtain crystallographic information in some areas.

[0034] In some embodiments, the sample surface is ground using 60#, 200#, 600#, 1000#, 1500# and 3000# grit sandpaper in sequence. After each grinding, the titanium alloy sample is rotated 90°. After sandpaper grinding, the sample is washed with water and ethanol in sequence.

[0035] In the present invention, after each grinding, the sample is rotated 90° before the next grinding, in order to eliminate the grinding marks left by the previous grinding, thereby grinding off the wire cutting marks. During the mechanical grinding process, a three-point mode (left, middle, and right) is used to fix the sample to prevent uneven force on the sample, resulting in inconsistent gauge section thickness. After mechanical grinding, there should be no obvious scratches on the surface of the gauge section of the sample. Then, use clean water to rinse the titanium chips on the surface of the sample, wipe it with alcohol, and dry it.

[0036] Furthermore, after the electrolytic polishing is completed, ultrasonic cleaning and drying are performed in sequence to obtain a titanium alloy quasi-in-situ EBSD tensile specimen.

[0037] In the present invention, immediately after electropolishing, the sample is placed in water to rinse any residual electrolyte from the surface, preventing excessive corrosion of the test surface by the residual electrolyte. Furthermore, the misty film produced on the surface is scrubbed with non-marking rubber gloves. The electropolished tensile specimen is then placed in an ultrasonic cleaner for 180 seconds, with the test sample surface facing upward to protect the test surface from scratches. The ultrasonic cleaner contains anhydrous ethanol solution. After cleaning, the sample is dried, resulting in a mirror-like surface.

[0038] The following is further described through specific examples.

[0039] Example 1 A method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen comprises the following steps: S1. Prepare titanium alloy specimens of specific sizes by wire cutting, and grind the titanium alloy specimens. Use 60#, 200#, 600#, 1000#, 1500#, and 3000# grit sandpaper to mechanically grind the specimen surface. After each grinding, rotate the specimen 90° before the next grinding. The purpose is to eliminate the wear marks left by the previous grinding, thereby grinding off the wire cutting marks. During the mechanical grinding process, a three-point mode (left, middle, and right) is used to fix the specimen to prevent uneven force on the specimen, resulting in inconsistent gauge section thickness. There should be no obvious scratches on the surface of the gauge section of the specimen after mechanical grinding. Then use clean water to rinse the titanium chips on the surface of the sample, wipe it with alcohol, and dry it to obtain the initial EBSD tensile specimen.

[0040] S2. Electrolytic polishing is carried out in a 100ml beaker, where the electrolytic polishing solution consists of perchloric acid, acetic acid and methanol in a volume ratio of 10:75:15. The initial EBSD tensile specimen is used as the anode. A fixture consisting of two TC4 titanium alloy sheets with dimensions of 15mm×100mm×2mm is used to clamp the non-polished part of the initial EBSD tensile specimen between the two TC4 titanium alloy sheets. The two TC4 titanium alloy sheets are fixed with rubber bands. The initial EBSD tensile specimen is placed in the electrolytic polishing solution, one end of the spoon-shaped TC4 titanium alloy is placed in the electrolytic polishing solution, a metal clip wire is used to clamp one end of the fixture, and the fixture and the titanium alloy tensile specimen are connected to the positive electrode of the power supply. The spoon-shaped TC4 titanium alloy is connected to the negative electrode of the DC power supply with a wire with a metal clip for electrolytic polishing.

[0041] During S3 electropolishing, the voltage was controlled at 37.8 V, the current was maintained at 0.61 A, and the electropolishing time was 90 s. The distance between the anode metal specimen and the cathode auxiliary electrode was 50 mm, and the electropolishing solution was maintained at 15-20°C. During polishing, the specimen was shaken to remove the passive film on the surface, ensuring that the removal and generation of the passive film on the surface were always in a dynamic equilibrium.

[0042] S4. After the electrolytic polishing is completed, the sample is immediately placed in water to clean the residual electrolyte on the surface, and the residual passivation film on the surface is rubbed off with rubber gloves in the water. Then the electrolytically polished tensile sample is placed in an ultrasonic cleaning machine for cleaning for 180 seconds, with the surface of the sample to be tested facing up to protect the surface to be tested from being scratched. The ultrasonic cleaning machine contains anhydrous ethanol solution. After the sample is cleaned, it is dried. At this time, the surface of the sample is mirror-like, and a quasi-in-situ EBSD tensile specimen of titanium alloy is obtained.

[0043] Example 2 A method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen comprises the following steps: S1. Prepare titanium alloy specimens of specific sizes by wire cutting, and grind the titanium alloy specimens. Use 60#, 200#, 600#, 1000#, 1500#, and 3000# grit sandpaper to mechanically grind the specimen surface. After each grinding, rotate the specimen 90° before the next grinding. The purpose is to eliminate the wear marks left by the previous grinding, thereby grinding off the wire cutting marks. During the mechanical grinding process, a three-point mode (left, middle, and right) is used to fix the specimen to prevent uneven force on the specimen, resulting in inconsistent gauge section thickness. There should be no obvious scratches on the surface of the gauge section of the specimen after mechanical grinding. Then use clean water to rinse the titanium chips on the surface of the sample, wipe it with alcohol, and dry it to obtain the initial EBSD tensile specimen.

[0044] S2. Electrolytic polishing is carried out in a 100ml beaker, where the electrolytic polishing solution consists of perchloric acid, acetic acid and methanol in a volume ratio of 10:70:20. The initial EBSD tensile specimen is used as the anode. A fixture consisting of two TC4 titanium alloy sheets with dimensions of 15mm×100mm×2mm is used to clamp the non-polished part of the initial EBSD tensile specimen between the two TC4 titanium alloy sheets. The two TC4 titanium alloy sheets are fixed with rubber bands. The initial EBSD tensile specimen is placed in the electrolytic polishing solution, one end of the spoon-shaped TC4 titanium alloy is placed in the electrolytic polishing solution, a metal clip wire is used to clamp one end of the fixture, and the fixture and the titanium alloy tensile specimen are connected to the positive electrode of the power supply. The spoon-shaped TC4 titanium alloy is connected to the negative electrode of the DC power supply with a wire with a metal clip for electrolytic polishing.

[0045] During S3 electropolishing, the voltage was controlled at 37.5 V, the current was maintained at 0.75 A, and the electropolishing time was 105 s. The distance between the anode metal specimen and the cathode auxiliary electrode was 50 mm, and the electropolishing solution was maintained at 15-20°C. During polishing, the specimen was shaken to remove the passive film on the surface, ensuring that the removal and generation of the passive film on the surface were always in a dynamic equilibrium.

[0046] S4. After the electrolytic polishing is completed, the sample is immediately placed in water to clean the residual electrolyte on the surface, and the residual passivation film on the surface is rubbed off with rubber gloves in the water. Then the electrolytically polished tensile sample is placed in an ultrasonic cleaning machine for cleaning for 180 seconds, with the surface of the sample to be tested facing up to protect the surface to be tested from being scratched. The ultrasonic cleaning machine contains anhydrous ethanol solution. After the sample is cleaned, it is dried. At this time, the surface of the sample is mirror-like, and a quasi-in-situ EBSD tensile specimen of titanium alloy is obtained.

[0047] Example 3 A method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen comprises the following steps: S1. Prepare titanium alloy specimens of specific sizes by wire cutting, and grind the titanium alloy specimens. Use 60#, 200#, 600#, 1000#, 1500#, and 3000# grit sandpaper to mechanically grind the specimen surface. After each grinding, rotate the specimen 90° before the next grinding. The purpose is to eliminate the wear marks left by the previous grinding, thereby grinding off the wire cutting marks. During the mechanical grinding process, a three-point mode (left, middle, and right) is used to fix the specimen to prevent uneven force on the specimen, resulting in inconsistent gauge section thickness. There should be no obvious scratches on the surface of the gauge section of the specimen after mechanical grinding. Then use clean water to rinse the titanium chips on the surface of the sample, wipe it with alcohol, and dry it to obtain the initial EBSD tensile specimen.

[0048] S2. Electrolytic polishing is carried out in a 100ml beaker, where the electrolytic polishing solution consists of perchloric acid, acetic acid and methanol in a volume ratio of 10:70:20. The initial EBSD tensile specimen is used as the anode. A fixture consisting of two TC4 titanium alloy sheets with dimensions of 15mm×100mm×2mm is used to clamp the non-polished part of the initial EBSD tensile specimen between the two TC4 titanium alloy sheets. The two TC4 titanium alloy sheets are fixed with rubber bands. The initial EBSD tensile specimen is placed in the electrolytic polishing solution, one end of the spoon-shaped TC4 titanium alloy is placed in the electrolytic polishing solution, a metal clip wire is used to clamp one end of the fixture, and the fixture and the titanium alloy tensile specimen are connected to the positive electrode of the power supply. The spoon-shaped TC4 titanium alloy is connected to the negative electrode of the DC power supply with a wire with a metal clip for electrolytic polishing.

[0049] During S3 electropolishing, the voltage was controlled at 37.6 V, the current was maintained at 0.80 A, the electropolishing time was 100 s, the distance between the anode metal specimen and the cathode auxiliary electrode was 50 mm, and the electropolishing solution was maintained at 15-20°C. During polishing, the specimen was shaken to remove the passive film on the surface, ensuring that the removal and generation of the passive film on the surface were always in a dynamic equilibrium.

[0050] S4. After the electrolytic polishing is completed, the sample is immediately placed in water to clean the residual electrolyte on the surface, and the residual passivation film on the surface is rubbed off with rubber gloves in the water. Then the electrolytically polished tensile sample is placed in an ultrasonic cleaning machine for cleaning for 180 seconds, with the surface of the sample to be tested facing up to protect the surface to be tested from being scratched. The ultrasonic cleaning machine contains anhydrous ethanol solution. After the sample is cleaned, it is dried. At this time, the surface of the sample is mirror-like, and a quasi-in-situ EBSD tensile specimen of titanium alloy is obtained.

[0051] Example 4 A method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen comprises the following steps: S1. Prepare titanium alloy specimens of specific sizes by wire cutting, and grind the titanium alloy specimens. Use 60#, 200#, 600#, 1000#, 1500#, and 3000# grit sandpaper to mechanically grind the specimen surface. After each grinding, rotate the specimen 90° before the next grinding. The purpose is to eliminate the wear marks left by the previous grinding, thereby grinding off the wire cutting marks. During the mechanical grinding process, a three-point mode (left, middle, and right) is used to fix the specimen to prevent uneven force on the specimen, resulting in inconsistent gauge section thickness. There should be no obvious scratches on the surface of the gauge section of the specimen after mechanical grinding. Then use clean water to rinse the titanium chips on the surface of the sample, wipe it with alcohol, and dry it to obtain the initial EBSD tensile specimen.

[0052] S2. Electrolytic polishing is carried out in a 100ml beaker, where the electrolytic polishing solution consists of perchloric acid, acetic acid and methanol in a volume ratio of 10:70:20. The initial EBSD tensile specimen is used as the anode. A fixture consisting of two TC4 titanium alloy sheets with dimensions of 15mm×100mm×2mm is used to clamp the non-polished part of the initial EBSD tensile specimen between the two TC4 titanium alloy sheets. The two TC4 titanium alloy sheets are fixed with rubber bands. The initial EBSD tensile specimen is placed in the electrolytic polishing solution, one end of the spoon-shaped TC4 titanium alloy is placed in the electrolytic polishing solution, a metal clip wire is used to clamp one end of the fixture, and the fixture and the titanium alloy tensile specimen are connected to the positive electrode of the power supply. The spoon-shaped TC4 titanium alloy is connected to the negative electrode of the DC power supply with a wire with a metal clip for electrolytic polishing.

[0053] During S3 electropolishing, the voltage was controlled at 37.5 V, the current was maintained at 0.93 A, and the electropolishing time was 95 s. The distance between the anode metal specimen and the cathode auxiliary electrode was 50 mm, and the electropolishing solution was maintained at 15-20°C. During polishing, the specimen was shaken to remove the passive film on the surface, ensuring that the removal and generation of the passive film on the surface were always in a dynamic equilibrium.

[0054] S4. After the electrolytic polishing is completed, the sample is immediately placed in water to clean the residual electrolyte on the surface, and the residual passivation film on the surface is rubbed off with rubber gloves in the water. Then the electrolytically polished tensile sample is placed in an ultrasonic cleaning machine for cleaning for 180 seconds, with the surface of the sample to be tested facing up to protect the surface to be tested from being scratched. The ultrasonic cleaning machine contains anhydrous ethanol solution. After the sample is cleaned, it is dried. At this time, the surface of the sample is mirror-like, and a quasi-in-situ EBSD tensile specimen of titanium alloy is obtained.

[0055] Comparative Example 1 A method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen comprises the following steps: S1. Prepare titanium alloy specimens of specific sizes by wire cutting, and grind the titanium alloy specimens. Use 60#, 200#, 600#, 1000#, 1500#, and 3000# grit sandpaper to mechanically grind the specimen surface. After each grinding, rotate the specimen 90° before the next grinding. The purpose is to eliminate the wear marks left by the previous grinding, thereby grinding off the wire cutting marks. During the mechanical grinding process, a three-point mode (left, middle, and right) is used to fix the specimen to prevent uneven force on the specimen, resulting in inconsistent gauge section thickness. There should be no obvious scratches on the surface of the gauge section of the specimen after mechanical grinding. Then use clean water to rinse the titanium chips on the surface of the sample, wipe it with alcohol, and dry it to obtain the initial EBSD tensile specimen.

[0056] S2. Electrolytic polishing is carried out in a 100ml beaker, where the electrolytic polishing solution consists of perchloric acid and acetic acid in a volume ratio of 10:90. The initial EBSD tensile specimen is used as the anode. A fixture consisting of two TC4 titanium alloy sheets with dimensions of 15mm×100mm×2mm is used to clamp the non-polished part of the initial EBSD tensile specimen between the two TC4 titanium alloy sheets. The two TC4 titanium alloy sheets are fixed with rubber bands. The initial EBSD tensile specimen is placed in the electrolytic polishing solution, one end of the spoon-shaped TC4 titanium alloy is placed in the electrolytic polishing solution, a metal clip wire is used to clamp one end of the fixture, and the fixture and the titanium alloy tensile specimen are connected to the positive electrode of the power supply. The spoon-shaped TC4 titanium alloy is connected to the negative electrode of the DC power supply with a wire with a metal clip for electrolytic polishing.

[0057] During S3 electropolishing, the voltage was controlled at 37.5 V, the current was maintained at 0.75 A, and the electropolishing time was 90 s. The distance between the anode metal specimen and the cathode auxiliary electrode was 50 mm, and the temperature of the electropolishing solution was maintained at approximately 30°C as the polishing process continued. During polishing, the specimen was shaken to remove the passive film on the surface, ensuring that the removal and generation of the passive film on the surface were always in a dynamic equilibrium.

[0058] S4. After the electrolytic polishing is completed, the sample is immediately placed in water to clean the residual electrolyte on the surface, and the residual passivation film on the surface is rubbed off with rubber gloves in the water. Then the electrolytically polished tensile sample is placed in an ultrasonic cleaning machine for cleaning for 100 seconds, with the surface of the sample to be tested facing up to protect the surface to be tested from being scratched. The ultrasonic cleaning machine contains anhydrous ethanol solution. After the sample is cleaned, it is dried. At this time, the surface of the sample is mirror-like, and a quasi-in-situ EBSD tensile specimen of titanium alloy is obtained.

[0059] The analytical calibration rates of the quasi-in-situ EBSD tensile specimens of the titanium alloys prepared in Examples 1 to 4 and Comparative Example 1 were tested using EBSD backscattered electron diffraction. The results are shown in Table 1.

[0060] Table 1 Analysis calibration rate of titanium alloy quasi-in-situ EBSD tensile specimen As shown in Table 1, the EBSD tensile specimens prepared using the electrolytic polishing solution adopted in the present invention have a resolution rate of over 90%, while the perchloric acid-acetic acid system polishing solution used in the comparative example, without a cooling system, has a resolution rate of only 47.9%.

[0061] Figure 2 This is a macroscopic image of the quasi-in-situ EBSD tensile specimens of the titanium alloys of Examples 1 and 2 of the present invention. Figure 3 This is a macroscopic image of the quasi-in-situ EBSD tensile specimen of the titanium alloy prepared in Comparative Example 1 of the present invention. Figure 2 and Figure 3 As shown, the white areas are all phase areas that have not been resolved. Compared with Examples 1 and 2, the white areas in Comparative Example 1 are significantly larger.

[0062] It should be noted that when numerical ranges are mentioned in the present invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints may be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0063] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen, characterized in that: The following steps are involved: Obtain a titanium alloy sample, polish and clean the titanium alloy sample, and obtain an initial EBSD tensile sample; The initial EBSD tensile specimen was used as the anode and electrolytic polishing was performed at room temperature to obtain a quasi-in-situ EBSD tensile specimen of the titanium alloy. The electrolytic polishing solution used for electrolytic polishing consisted of perchloric acid, acetic acid and methanol in a volume ratio of 10-15:70-75:15-20. During the electrolytic polishing process, the polishing voltage was 35V-37.5V and the polishing current was 0.6A-1.0A.

2. The method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen according to claim 1, wherein: During the electrolytic polishing process, the polishing time is 90s to 120s.

3. The method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen according to claim 1, wherein: The temperature of the electrolytic polishing solution is 15°C to 20°C.

4. The method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen according to claim 1, wherein: During the electrolytic polishing process, the electrolytically polished surface of the initial EBSD tensile specimen was immersed in the electrolytic polishing solution using a metal clamp, and electrolytic polishing was performed at room temperature using a conductive metal as an auxiliary electrode.

5. The method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen according to claim 4, wherein: One end of the metal clamp is connected to the positive pole of the DC power supply, one end of the auxiliary electrode is connected to the negative pole of the DC power supply, and the other end is placed in the electrolytic polishing liquid. The DC power supply voltage is 35V~37.5V, and the auxiliary electrode is TC4 titanium alloy.

6. The method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen according to claim 5, wherein: When the distance between the initial EBSD tensile specimen and the auxiliary electrode is 50-100 mm.

7. The method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen according to claim 5, wherein: During the electropolishing process, the initial EBSD tensile specimen was in a shaking state relative to the electropolishing solution. During the shaking process, the initial EBSD tensile specimen and the electropolishing solution were always in contact, and the shaking angle was 10° to 20°.

8. The method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen according to claim 1, wherein: The sample surface was ground using 60#, 200#, 600#, 1000#, 1500# and 3000# grit sandpaper in sequence. The titanium alloy sample was rotated 90° after each grinding. After sandpaper grinding, it was washed with water and ethanol in sequence.

9. The method for preparing a titanium alloy quasi-in-situ EBSD tensile specimen according to claim 1, wherein: After electrolytic polishing, ultrasonic cleaning and drying were carried out in sequence to obtain the titanium alloy quasi-in-situ EBSD tensile specimen.

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