Batch preparation method of EBSD samples

Abstract

The invention provides an EBSD sample batch preparation method, and relates to the technical field of metallographic structure detection, the preparation method comprises the following steps: S1, sample cutting: cutting a raw material sample into a round bar with a diameter of 8-10 mm, and then cutting the round bar into a round cake with a thickness of 6-8 mm; s2, sample clamping: clamping the cut round cake in a sample rack; s3, grinding and polishing the sample: loading the clamped sample and the sample holder into an automatic grinding and polishing clamp, and mechanically grinding and polishing the sample; after mechanical grinding and polishing are finished, the sample and the sample holder are subjected to ultrasonic cleaning and blow-drying together in alcohol, and then the sample and the sample holder are placed in vibration polishing equipment together to be subjected to vibration polishing. The method solves the technical problems that in the prior art, the sample preparation efficiency is low, and batch sample preparation cannot be achieved, and meanwhile the sample preparation cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallographic structure detection, and particularly relates to an EBSD sample batch preparation method. BACKGROUND

[0002] EBSD (Electron Backscatter Diffraction) technology is a powerful material analysis tool and is widely applied to the field of material science research. EBSD technology is mainly used for the research of material microstructure. At present, when EBSD detection is performed, a sample needs to be pasted to an inclined surface with an angle of 70 degrees. Since steel and high-temperature alloy have large density, in order to ensure the stability of the detection process, the sample needs to be as small as possible, generally with a diameter of less than 10 mm and a thickness of less than 5 mm.

[0003] In the current EBSD sample preparation method, the sample preparation efficiency is low, batch sample preparation cannot be met, and the cost is relatively high. In order to ensure the effectiveness of the detection, multiple samples need to be prepared for the same batch of samples. Therefore, it is necessary to design a method for rapidly and batch-preparing EBSD samples. SUMMARY

[0004] The present application aims to provide an EBSD sample batch preparation method to solve the technical problems of low sample preparation efficiency and inability to realize batch sample preparation in the prior art, and to reduce the sample preparation cost.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions: The present application provides an EBSD sample batch preparation method, comprising the following steps: S1, sample cutting: cutting a raw sample into a round bar with a diameter of 8-10 mm, and then cutting the round bar into a round cake with a thickness of 6-8 mm; S2, sample clamping: clamping the cut round cake in a sample holder; S3, sample grinding and polishing: clamping the clamped sample together with the sample holder in an automatic grinding and polishing clamp, and mechanically grinding and polishing the sample; after the mechanical grinding and polishing is completed, the sample together with the sample holder is ultrasonically cleaned in alcohol and dried, and then the sample together with the sample holder is placed in a vibration polishing device for vibration polishing.

[0006] Further, the raw sample in step S1 is steel or high-temperature alloy.

[0007] Further, the raw sample cutting in step S1 adopts electric spark wire cutting, and / or the round bar cutting adopts metallographic cutting machine cutting.

[0008] Further, the sample holder in step S2 comprises a base, a plurality of sample holes recessed downward along the base axis on one end surface of the base, bolt holes extending from the side wall of the base to the inside of the base along the base radial direction and communicated with the sample holes, and machine screws matched with the bolt holes.

[0009] Further, the base is made of stainless steel or copper material, and is a cylinder with a diameter of 38-42 mm and a height of 20-25 mm.

[0010] Further, the sample holes are drilled on one end surface of the base, the sample holes have a diameter of 10 mm and a depth of 4 mm, and the sample holes are uniformly distributed around the center of the base.

[0011] Further, bolt holes are processed at the corresponding positions of the sample holes, and the bolt holes have a diameter of 3-5 mm.

[0012] Further, in step S3, the mechanical polishing comprises five steps of rough polishing, fine polishing, rough polishing, fine polishing, and alumina polishing.

[0013] Further, in step S3, the alcohol is analytical pure alcohol, the cleaning time of ultrasonic cleaning in alcohol is 5-10 min, and the power of ultrasonic waves is 1500-2000 W.

[0014] Further, in step S3, the vibration frequency of vibration polishing is 90-110 HZ, and the polishing time is 1.5-2 h.

[0015] The EBSD sample batch preparation method provided by the application has the following beneficial effects: 1) The cutting method combining electric spark wire cutting and metallographic cutting machine can ensure the uniformity of the sample cutting size.

[0016] 2) The sample is clamped on the designed sample holder, which can avoid the small sample being inconvenient for mechanical polishing by an automatic polishing machine, and multiple samples can be prepared at the same time.

[0017] 3) The sample does not need to be removed from the sample holder during mechanical polishing and vibration polishing, and can be removed for EBSD detection after the whole process is completed. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0019] Figure 1 The sample size after cutting of the wire cut electrical discharge machining device provided by the embodiment of the present application; Figure 2 The sample size after cutting of the metallographic cutting machine provided by the embodiment of the present application; Figure 3 The sample holder appearance provided by the embodiment of the present application, wherein 1 is a base, 2 is a sample hole, and 3 is a machine screw; Figure 4 The grain boundary appearance map of the steel EBSD sample provided by the embodiment of the present application; Figure 5 The IPF map of the steel EBSD sample provided by the embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application. It should be understood by those skilled in the art that the embodiments are only used to help understand the present application and should not be regarded as a specific limitation on the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. The process parameters not specified in the following embodiments are usually according to the conventional conditions.

[0021] The endpoints of the ranges and any values in the present application are not limited to the precise values stated. The ranges and values should be interpreted as approximately between the stated values. For ranges, the endpoints are included between each respective range; the endpoints are included in the respective range or ranges; and each respective range is a separate and independent range. The various independent ranges can be combined.

[0022] The present application provides a batch preparation method of EBSD sample, comprising the following steps: S1, sample cutting: cutting the raw material sample into a round bar with a diameter of 8-10 mm, and then cutting the round bar into a round cake with a thickness of 6-8 mm; S2, sample clamping: clamping the cut round cake in a sample holder; S3, sample grinding and polishing: clamping the clamped sample together with the sample holder in an automatic grinding and polishing clamp, and mechanically grinding and polishing the sample; after the mechanical grinding and polishing is completed, the sample together with the sample holder is ultrasonically cleaned in alcohol and dried, and then the sample together with the sample holder is placed in a vibration polishing device for vibration polishing.

[0023] The application can cut many same round cake samples according to actual experimental needs, and the samples can be clamped in the sample holder to be polished, the sample is convenient to take and place in the sample holder, and additional inlaying and bonding steps are not needed; the sample holder does not affect the normal operation of the vibration polishing equipment, and the sample holder is equivalent to the added counterweight block during conventional sample preparation.

[0024] In the application, the original sample cutting can adopt a Boma electric spark wire cutting, and the key parameters are core electrical parameters (determining the discharge energy and cutting effect). These parameters are directly adjusted on the operation panel, and directly affect the cutting speed, surface quality and electrode wire loss. A large pulse width (such as 20-40 µs) is used for sample rough machining, and a small pulse width (such as 2-6 µs or even smaller) is used for finishing to obtain good smoothness. The parameter that most affects the cutting speed is the peak current, increasing the peak current, the discharge energy increases dramatically, the cutting speed is significantly improved, but the surface is rougher, the gap is larger, the wire consumption increases, and even the wire may be broken. Therefore, it is necessary to adjust carefully according to the thickness and material of the workpiece, the peak current can be appropriately increased when cutting thick pieces, and the peak current must be reduced when finishing. The open circuit voltage applied between the electrode wire and the workpiece is called the no-load voltage, the higher the voltage, the larger the discharge gap, the better the chip removal condition, the higher the machining stability, but the precision is slightly reduced; high voltage is helpful for cutting and cutting materials with oxide skin and non-conductive inclusions. The wire speed affects chip removal, cooling and electrode wire loss; too slow speed can easily lead to local large loss and wire breakage; too fast speed can increase vibration, so the wire speed is usually set according to the thickness and cutting current of the workpiece, and a higher wire speed is used for thick workpieces and large current.

[0025] The circular bar with a diameter of 8-10 mm is cut into a 6-8 mm round cake using a metallographic cutting machine; according to the size of the original sample, a suitable cutting machine model is selected, and the 8-10 mm circular bar is cut using a cutting machine with a maximum cutting diameter / cross section of ø50 mm, and the parameter setting is mainly based on: 1. Select the correct cutting blade according to the material (the most important step). 2. Use sufficient and clean cooling liquid (always turn on double injection). 3. Use appropriate speed and lower feed force / speed to avoid excessive heat generated by pressure and friction. 4. For heat-sensitive or hard and brittle materials, it is necessary to use “multi-step cutting method”: first, use a thicker and coarser cutting blade to quickly remove most of the excess (away from the target surface), and then use a thin and fine precision cutting blade to complete the final cutting with low feed.

[0026] As an optional embodiment of the application, the raw material sample in step S1 is steel or a high-temperature alloy.

[0027] The high-temperature alloy in the application refers to a kind of metal material taking iron, nickel and / or cobalt as the base, which can work at high temperature above 600℃ and under certain stress for a long time. For example: GH4169, GH2909, etc.

[0028] The steel in the present application includes all steel brands, which are not specifically limited in the present application.

[0029] As an optional embodiment of the present application, the raw material sample cutting in step S1 adopts wire electrical discharge machining; and / or, the round bar cutting adopts metallographic cutting machine cutting.

[0030] As an optional embodiment of the present application, the sample holder in step S2 includes a base 1, a plurality of sample holes 2 recessed downward along the base axis at one end surface of the base 1, bolt holes extending from the side wall of the base 1 to the inside of the base 1 along the radial direction of the base 1 and communicating with the sample holes 2, and machine screws 3 matched with the bolt holes, which are specifically shown in Figure 3 .

[0031] Specifically, the base 1 can be made of stainless steel or copper material, which is a cylinder with a diameter of 38-42 mm and a height of 20-25 mm. The two end surfaces of the cylinder are the end surfaces of the base 1, and the sample holes 2 are arranged on one of the end surfaces.

[0032] Specifically, the sample holes 2 are drilled at one end surface of the base 1, with a diameter of 10 mm and a depth of 4 mm. The sample holes 2 are uniformly distributed around the center of the end surface of the base 1. In order to ensure that the sample size is large enough and the detection surface size is sufficient, and to prevent the sample from falling off during automatic grinding and polishing due to being too small, usually up to 4 sample holes are arranged on one sample holder. A bolt hole with a diameter of 3-5 mm is arranged at the corresponding position of the sample hole, and a flat head machine screw is screwed into the bolt hole. The corresponding position of the sample hole is a position extending from the side wall of the base to the inside of the base along the radial direction of the base and communicating with the sample hole.

[0033] The sample clamping method of the present application is very simple. Only the cut round cake sample is placed in the sample hole, and then the flat head machine screw is tightened to fix it.

[0034] In a specific embodiment of the present application, one sample holder can load 4 samples at a time, and the existing automatic grinding and polishing machine (model Saphir X-Change, brand QATM) is used for mechanical grinding and polishing. The clamp of this type of automatic grinding and polishing machine can simultaneously load 6 such sample holders, so that 24 EBSD samples can be prepared at a time, realizing batch sample preparation.

[0035] As an optional embodiment of the present application, in step S3, the mechanical grinding and polishing includes five steps of rough grinding, fine grinding, rough polishing, fine polishing, and alumina polishing.

[0036] The five steps of mechanical grinding and polishing in the present application are automatically completed by the full-automatic grinding and polishing machine. Related parameters are set on the equipment.

[0037] The parameters of the rough grinding step are as follows: the grinding amount of the rough grinding is 0.5-2 mm, preferably 1 mm, the grinding force is 200-400 N, preferably 300 N; the rotating speed of the grinding disc is 1000-2000 rpm, preferably 1500 rpm, the rotating speed of the fixture seat is 100-200 rpm, preferably 150 rpm, the grinding disc and the fixture seat rotate in the same direction, the sample is rough ground by using the grinding wheel according to the preset parameters, the granularity of the grinding wheel is 100-300 mesh, preferably 150 mesh; after the rough grinding step is completed, high-pressure water is automatically used for cleaning for 0.5-3 minutes, preferably 1 minute, so as to prevent the rough grinding particles from being brought into the next grinding and polishing process.

[0038] The parameters of the fine grinding step are as follows: the grinding time of the fine grinding is 3-10 minutes, preferably 6 minutes, the grinding force is set to 300-450 N, preferably 350 N; the rotating speed of the grinding disc is 100-200 rpm, preferably 150 rpm, the rotating speed of the fixture seat is 100-200 rpm, preferably 150 rpm, the grinding disc and the fixture seat rotate in the same direction. The sample is fine ground by using diamond polishing liquid, water-based cooling lubricating liquid and diamond grinding disc, the diamond polishing liquid is 9-micron diamond polishing liquid, the granularity of the diamond grinding disc is 300-500 mesh, preferably 400 mesh; after the fine grinding step is completed, high-pressure water is automatically used for cleaning for 1-4 minutes, preferably 2 minutes, so as to prevent the fine grinding particles from being brought into the next grinding and polishing process.

[0039] The parameters of the rough polishing step are as follows: the rough polishing time is 4.5 minutes, the grinding force is set to 250 N; the rotating speed of the grinding disc is 100-200 rpm, preferably 150 rpm; the rotating speed of the fixture seat is 100-200 rpm, preferably 150 rpm; the grinding disc and the fixture seat rotate in the same direction. The sample is rough polished by using 3-micron diamond polishing liquid, alcohol-based cooling lubricating liquid and woolen cloth; after the rough polishing step is completed, high-pressure water is automatically used for cleaning for 2-4.5 minutes, preferably 2.5 minutes, so as to prevent the rough polishing particles from being brought into the next grinding and polishing process.

[0040] The parameters of the fine polishing step are as follows: the fine polishing time is 4 minutes, the grinding force is set to 150-400 N, preferably 250 N; the rotating speed of the grinding disc is 100-200 rpm, preferably 150 rpm; the rotating speed of the fixture seat is 100-200 rpm, preferably 150 rpm; the grinding disc and the fixture seat rotate in the same direction. The sample is fine polished by using 1-micron diamond polishing liquid, alcohol-based cooling lubricating liquid and short woolen cloth; after the fine polishing step is completed, high-pressure water is automatically used for cleaning for 2.5 minutes, and compressed air is blown for 30 seconds, so as to remove the fine polishing particles.

[0041] The present application adds the last step of polishing alumina on the basis of conventional metallographic sample preparation, the alumina particles are finer and more uniform, the particle size of the alumina particles is about 0.05 microns, and the scratches after polishing by 1 micron diamond polishing solution can be effectively removed, so that the sample after polishing can meet the use requirements.

[0042] As an optional embodiment of the present application, in step S3, the alcohol is analytical pure alcohol; the cleaning time of ultrasonic cleaning in alcohol is 5-10 min; and the power of ultrasonic wave is 1500-2000 W.

[0043] As an optional embodiment of the present application, in step S3, the vibration frequency of vibration polishing is 90-110 HZ, and the polishing time is 1.5-2 h. The sample holder of the present application is suitable for the vibration polishing equipment of Qpol Vibro type.

[0044] The vibration polishing of the present application is used to remove the residual stress of the detection surface, and after the vibration polishing is finished, the sample can be directly unloaded from the sample holder, which is convenient and easy to obtain. In the traditional sample preparation method, basically, a single sample is embedded and then mechanically polished, the sample requires to be relatively thin and small in weight, and a counterweight needs to be added during vibration polishing to further polish, so that only one sample can be vibration polished at a time, and the efficiency is low. The preparation method of the present application does not need to add a counterweight because the sample clamp plays the role of the counterweight in the present application.

[0045] The present application will be further described in detail in combination with specific embodiments. Embodiment

[0046] 1. Sample cutting: 1.1 According to the requirement of the detection part, the steel is cut into a round bar with a diameter of 9±1 mm by using electric spark wire, and the length can be selected according to the original size of the sample or the number of samples to be prepared. The size of the sample after cutting is shown in the attached Figure 1 .

[0047] 1.2 The round bar in 1.1 is cut into a round cake with a thickness of 6±1 mm by using a metallographic cutting machine. The size of the sample after cutting is shown in the attached Figure 2 .

[0048] 2. Sample clamping: 2.1 The cut sample is clamped into the sample hole of the sample holder, wherein the diameter of the sample hole is 10 mm, and the depth is 4 mm. The cross section of the sample holder loaded with the sample is shown in the attached Figure 3 . The sample holder comprises a base 1, a plurality of sample holes 2 recessed downward along the base axis at one end face of the base 1, screw holes extending from the side wall of the base 1 to the inside of the base 1 along the radial direction of the base 1 and communicating with the sample holes 2, and machine screws 3 matched with the screw holes.

[0049] 2.2 Insert the flat head machine screw into the bolt hole and tighten, the sample is fixed in the sample hole of the sample holder.

[0050] 3. Sample grinding and polishing: 3.1 Clamp 4 samples on a single sample holder, clamp 6 sample holders (24 samples in total) together in the automatic grinding and polishing machine clamp of model Saphir X-Change, brand QATM.

[0051] 3.2 Set the parameters of the automatic grinding and polishing machine and start mechanical grinding and polishing. The automatic grinding and polishing sample includes five steps of coarse grinding, fine grinding, coarse polishing, fine polishing and alumina polishing.

[0052] The parameters of the coarse grinding step are set as follows: the grinding amount of the coarse grinding is 1 mm, the grinding force is 300 N; the rotation speed of the grinding disc is 1500 rpm, the rotation speed of the clamp seat is 150 rpm, the grinding disc and the clamp seat rotate in the same direction, the grinding disc is used to grind the sample according to the preset parameters, the granularity of the grinding disc is 150 mesh; after the coarse grinding step, high-pressure water is used to clean automatically for 1 minute to prevent coarse grinding particles from being brought into the next grinding and polishing process.

[0053] The parameters of the fine grinding step are set as follows: the grinding time of the fine grinding is 6 minutes, the grinding force is set to 350 N; the rotation speed of the grinding disc is 150 rpm, the rotation speed of the clamp seat is 150 rpm, and the grinding disc and the clamp seat rotate in the same direction. The fine grinding step uses diamond polishing liquid, water-based cooling lubricant and diamond grinding disc to grind the sample, the diamond polishing liquid is 9 microns of diamond polishing liquid, and the granularity of the diamond grinding disc is 400 mesh; after the fine grinding step, high-pressure water is used to clean automatically for 2 minutes to prevent fine grinding particles from being brought into the next grinding and polishing process.

[0054] The parameters of the coarse polishing step are set as follows: the coarse polishing time is 4.5 minutes, the grinding force is set to 250 N; the rotation speed of the grinding disc is 150 rpm; the rotation speed of the clamp seat is 150 rpm; the grinding disc and the clamp seat rotate in the same direction. The coarse polishing step uses 3 microns of diamond polishing liquid, alcohol-based cooling lubricant and woolen cloth to polish the sample; after the coarse polishing step, high-pressure water is used to clean automatically for 2.5 minutes to prevent coarse polishing particles from being brought into the next grinding and polishing process.

[0055] The parameters of the fine polishing step are set as follows: the fine polishing time is 4 minutes, the grinding force is set to 250 N; the rotation speed of the grinding disc is 150 rpm; the rotation speed of the clamp seat is 150 rpm; the grinding disc and the clamp seat rotate in the same direction. The fine polishing step uses 1 micron of diamond polishing liquid, alcohol-based cooling lubricant and short woolen cloth to polish the sample; after the fine polishing step, high-pressure water is used to clean automatically for 2.5 minutes and compressed air is used to blow for 30 seconds to remove fine polishing particles.

[0056] The alumina particles used in the alumina polishing process have a particle size of approximately 0.05 micrometers.

[0057] 3.3 After mechanical polishing, the sample and fixture were ultrasonically cleaned with alcohol and then dried. The alcohol used was analytical grade, the ultrasonic power was 1800W, and the cleaning time was 8 minutes.

[0058] 3.4 The sample, along with its holder, is placed in a vibratory polishing device for vibratory polishing to remove residual prestress on the test surface. The vibration frequency of the vibratory polishing is 100 Hz, and the polishing time is 1.5 hours.

[0059] 3.5 After the vibration polishing is completed, the sample can be removed from the sample holder.

[0060] 4. All collected samples underwent grain boundary morphology and microstructure analysis, and the results are as follows: Figure 4 , 5 As shown. Figure 4 The graph visually reveals the grain size and shape of the material. By further quantitatively analyzing and spatially analyzing the graph, information such as grain size, shape, distribution, and grain orientation can be obtained, which can then be correlated with the material properties. Figure 5 For this sample <100> , <110> , <111> Pole figures of crystal orientations provide a visual representation of the orientation density of different crystal orientations in a sample.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions 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 method for batch preparation of EBSD samples, characterized in that, Includes the following steps: S1. Sample cutting: Cut the raw material sample into round bars with a diameter of 8-10 mm, and then cut the round bars into round cakes with a thickness of 6-8 mm. S2, Sample clamping: Clamp the cut discs in the sample holder; S3. Sample polishing: The clamped sample, along with the sample holder, is placed in an automatic polishing fixture for mechanical polishing. After mechanical polishing, the sample, along with the sample holder, is ultrasonically cleaned in alcohol and dried. Then, the sample, along with the sample holder, is placed in a vibratory polishing device for vibratory polishing.

2. The method for batch preparation of EBSD samples according to claim 1, characterized in that, The raw material sample mentioned in step S1 is steel or a high-temperature alloy.

3. The method for batch preparation of EBSD samples according to claim 1, characterized in that, The raw material sample cutting in step S1 is performed using wire electrical discharge machining; and / or, the round bar cutting is performed using a metallographic cutting machine.

4. The method for batch preparation of EBSD samples according to claim 1, characterized in that, The sample holder in step S2 includes a base, a plurality of sample holes recessed downward along the axial direction of the base on one end face, bolt holes extending radially from the side wall of the base into the base and communicating with the sample holes, and calipers that mate with the bolt holes.

5. The method for batch preparation of EBSD samples according to claim 4, characterized in that, The base is made of stainless steel or copper and is a cylinder with a diameter of 38-42mm and a height of 20-25mm.

6. The method for batch preparation of EBSD samples according to claim 4, characterized in that, The sample holes are drilled on one end face of the base. The sample holes have a diameter of 10 mm and a depth of 4 mm. The sample holes are evenly distributed around the center of the base.

7. The method for batch preparation of EBSD samples according to claim 4, characterized in that, Bolt holes are machined at the corresponding locations of the sample holes, and the diameter of the bolt holes is 3-5 mm.

8. The method for batch preparation of EBSD samples according to claim 1, characterized in that, In step S3, the mechanical grinding and polishing includes five steps: rough grinding, fine grinding, rough polishing, fine polishing, and alumina polishing.

9. The method for batch preparation of EBSD samples according to claim 1, characterized in that, In step S3, the alcohol is analytical grade alcohol; the ultrasonic cleaning time in the alcohol is 5-10 minutes; and the ultrasonic power is 1500-2000W.

10. The method for batch preparation of EBSD samples according to claim 1, characterized in that, In step S3, the vibration frequency of the vibratory polishing is 90-110 Hz, and the polishing time is 1.5-2 hours.

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