In-situ SEM tensile sample double-sided grinding and polishing method for marine corrosion-resistant titanium alloy

Abstract

The invention relates to the technical field of metal material sample preparation, in particular to an in-situ SEM tensile sample double-sided grinding and polishing method for marine corrosion-resistant titanium alloy, which comprises the following specific steps: S1, sampling; s2, embedding the surface A; s3, grinding and polishing the surface A; s4, embedding the surface B; s5, grinding and polishing the surface B; and S6, taking out the sample, namely taking out the sample subjected to double-sided grinding and polishing from the cold inlaying material in a heating and melting manner, so as to obtain the prepared in-situ SEM tensile sample. By preparing the solid / liquid blended low-melting-point cold inlaying liquid, the in-situ SEM tensile sample can be conveniently taken out; compared with a conventional cold inlaying liquid, the cold inlaying liquid can effectively avoid the situation that the sample is deformed in the knocking and taking-out process, the flatness of the sample is influenced, and the subsequent stretching process of the in-situ SEM stretching sample is influenced; and the defect that the sample is difficult to take out in a cold embedding method is effectively overcome.

Description

Technical Field

[0001] The invention relates to the technical field of metal material sample preparation, and in particular to a double-sided grinding and polishing method for an in-situ SEM tensile sample for marine corrosion-resistant titanium alloy. Background Art

[0002] Titanium alloys have the characteristics of low density, high specific strength, and non-magnetic properties. Especially in chloride-rich marine environments, they have excellent corrosion resistance and have become the preferred material for many marine equipment. In order to further expand the application scenarios of titanium alloys in the field of marine engineering, it is necessary to further clarify the micromechanical behavior of titanium alloys in complex external environments, and to explain the evolution of titanium alloy organizational characteristics in marine corrosion environments, so as to guide the performance regulation and application evaluation of titanium alloys. Therefore, it is urgent to carry out in-situ SEM tests on marine corrosion-resistant titanium alloys, analyze the evolution of microstructures under external forces, and deeply understand the correlation between the mechanical properties of materials and microstructures, so as to provide basic technical support for the application of corrosion-resistant titanium alloys.

[0003] In-situ SEM is to carry out the tensile stage in the scanning electron microscope (SEM), and observe the microstructure morphology while mechanically loading the sample, that is, the in-situ SEM technology. In-situ SEM tensile test uses a load loading device to apply tensile load to the sample, so as to obtain the mechanical property curve during the material test, and use SEM to observe the necking area and fracture area that appear during the tensile process, and obtain the dynamic evolution process of the microstructure of the material at different deformation stages, so as to establish the intrinsic connection between the mechanical properties of the material and the deformation of the microstructure. In the in-situ SEM test, the sample must be prepared by metallographic sampling and double-sided grinding and polishing to remove the wire cutting cladding layer and the surface damage layer and ensure the flatness of the sample, so as to ensure the SEM observation effect of the test and the accuracy of the mechanical test results. The common sample preparation procedure for double-sided sample preparation mainly consists of sampling, single-sided grinding and polishing, and other side grinding and polishing.

[0004] Limited by the chamber of the scanning electron microscope, the maximum load (generally ≤5000 N) and movable stroke (generally ≤30 cm) of the tensile stage carried by the SEM are also relatively small. Therefore, the samples of the in-situ SEM tensile test are smaller in size and usually less than 2 mm thick than those of conventional tensile testing machines, and double-sided grinding and polishing are difficult to prepare. The biggest difficulty in the process of grinding and polishing the in-situ SEM tensile specimen is how to fix and maintain the flatness of the specimen. At present, the main methods for double-sided grinding and polishing of such thin specimens are manual preparation (pressing with hands / rubber support), gluing (gluing to a specific mold for easy holding), and inlaying (using cold mounting liquid to inlay into blocks). These three commonly used preparation methods have significant defects for in-situ SEM observations. Manual preparation, pressing with hands / rubber support, will cause the specimen to have shortcomings such as chamfers, uneven sizes, poor flatness, and low efficiency. The gluing method and the mounting method can effectively reduce the chamfer problem and improve the efficiency of single-sided grinding and polishing. However, during the gluing method, double-sided tape is used, and the weak bonding force will cause the sample to fly out due to high-speed grinding and polishing. The gluing method using strong glue such as 502 and the mounting method using cold mounting liquid will make it difficult to peel the sample from the mold and easily accompanied by solid residue, resulting in poor sample flatness and affecting the observation effect. It cannot meet the in-situ SEM test tensile mechanics and scanning test observation requirements.

[0005] Publication No.: CN115931488A A method for preparing a metallographic test sample of an axial cross section of an air film hole of an aircraft engine adopts a cold mounting technology to mount the metallographic sample, ensuring that the mounting liquid is filled into the air film hole and the metallographic sample is not compressed during mounting to avoid the metallographic sample from tilting. However, the cold mounting liquid prepared by the cold mounting resin and the curing agent is not easy to remove the sample after polishing, and solid residues are likely to remain on the surface of the sample.

[0006] Therefore, it is urgent to propose a new double-sided grinding and polishing method for tensile specimens to solve the problems of low flatness and preparation efficiency of specimens prepared by existing inlay technology and difficulty in peeling off residual cold inlay materials. Summary of the invention

[0007] In view of this, the present invention aims to propose a double-sided grinding and polishing method for in-situ SEM tensile specimens of marine corrosion-resistant titanium alloys to solve the problems of low flatness and preparation efficiency of specimens prepared by existing inlay technology and difficulty in stripping off residual cold inlay materials.

[0008] In view of the requirements of double-sided grinding and polishing and high flatness for the preparation of in-situ SEM tensile test specimens, the present invention optimizes the mounting method and creatively proposes a mounting method using a solid / liquid mixed low-melting-point cold mounting liquid, which not only retains the advantages of the cold mounting method such as easy holding after thickening, high grinding and polishing efficiency, and no chamfering, but also solves the problems of poor flatness caused by difficult peeling and cold mounting material residue affecting SEM observation effect. This cold mounting liquid can effectively optimize the double-sided grinding and polishing process, improve sample flatness and preparation efficiency, and can realize sample preparation of different materials, so as to solve the problem that the existing sample preparation method cannot meet the requirements of in-situ SEM tensile test specimens.

[0009] The technical solution of the present invention is achieved in this way:

[0010] The present invention discloses a double-sided grinding and polishing method of an in-situ SEM tensile specimen for marine corrosion-resistant titanium alloy, comprising the following specific steps:

[0011] S1: Sampling: Cut the in-situ SEM tensile specimen according to the specimen drawing requirements, and clean and dry the specimen surface as needed;

[0012] S2: A-side mounting: Place the sample with its A-side facing downwards in a mold, keep it flat, prepare a solid / liquid blended low-melting-point cold mounting solution, heat it until it melts, pour it into the mold to wrap the sample, and cool it to solidify;

[0013] S3: Grinding and polishing of surface A: Grind surface A until there are no obvious scratches on the surface, and then perform final polishing to ensure a smooth surface;

[0014] S4: Mounting of surface B: Take the processed surface A sample out of the cold mounting material by heating and melting, and repeat step S2 to mount the surface B in the same way;

[0015] S5: grinding and polishing of surface B: taking out the mounted sample, and repeating S3 to perform the same grinding and polishing operation on surface B;

[0016] S6: Removing the sample: removing the double-sided polished sample from the cold mounting material by heating and melting to obtain a prepared in-situ SEM tensile sample.

[0017] Furthermore, in step S1, the sample is prepared by wire electric discharge cutting technology.

[0018] Furthermore, in step S2, two weight blocks are placed at the clamping end of the sample to keep the A surface parallel.

[0019] Furthermore, in step S2, the mold is a silicone mold, and the container for preparing the cold mounting liquid is one of a high temperature resistant glass beaker, a stainless steel container, a ceramic container, and a quartz glass container.

[0020] Furthermore, in step S2, parts of paraffin wax and parts of absorbent cotton are placed alternately in a container and heated until they are completely melted to form a solid / liquid blend of low melting point cold mounting liquid.

[0021] Furthermore, in step S2, the ratio of paraffin wax to cotton wool is 20:1.

[0022] Furthermore, in step S2, the melted cold mounting liquid is poured into the mold to ensure that the sample is completely wrapped and at a suitable height for hand-held polishing. After cooling for 0.5-1 hour, the mounted sample is taken out from the mold.

[0023] Furthermore, in step S3, the specific steps are as follows:

[0024] S31: Use sandpaper to polish the A surface on a grinding and polishing machine until there are no obvious scratches on the surface. After polishing, clean the surface of the sample to remove residual particles;

[0025] S32: Repeat step S31, use sandpaper with different mesh sizes for multiple times, polish the A surface on a grinder and polisher, and clean the surface of the sample;

[0026] S33: Use silica polishing liquid plus hydrogen peroxide as the polishing medium and perform final polishing on a grinder and polisher until the surface of surface A is smooth and scratch-free.

[0027] Further, in step S3, the number of polishing is 7 times, and the mesh number of the sandpaper can be 80#, 240#, 400#, 600#, 800#, 1200#, 2000#, and they are used in sequence from coarse to fine.

[0028] Furthermore, in step S3, the sandpaper is water-based sandpaper.

[0029] Compared with the prior art, the in-situ SEM tensile specimen double-sided grinding and polishing method for marine corrosion-resistant titanium alloy of the present invention has the following advantages:

[0030] 1. The present invention prepares a solid / liquid blended low-melting-point cold mounting solution, which is convenient for taking out the in-situ SEM tensile specimen. Compared with the conventional cold mounting solution, it can effectively avoid deformation of the specimen during the knocking and taking-out process, which affects the flatness of the specimen and thus affects the subsequent stretching process of the in-situ SEM tensile specimen. At the same time, the preparation efficiency is high, which can effectively overcome the disadvantage that the specimen is not easy to take out in the cold mounting method.

[0031] 2. Compared with manual preparation, the cold mounting method of the present invention can use a high-speed rotating grinding and polishing machine to effectively improve the grinding and polishing efficiency and avoid chamfering. Compared with the gluing method, it can avoid the phenomenon of the sample flying out due to the centrifugal force of high-speed rotation, thereby avoiding the damage caused by the flying of the sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 It is an in-situ SEM tensile specimen after wire cutting;

[0034] Figure 2 This is the in-situ SEM photo of the A surface of the tensile specimen after grinding and polishing;

[0035] Figure 3 This is the in-situ SEM photo of the B surface of the tensile specimen after grinding and polishing;

[0036] Figure 4 This is an in-situ SEM tensile specimen after double-sided grinding and polishing;

[0037] Figure 5 Schematic diagram of the sample fixing structure during the mounting process.

[0038] Reference numerals:

[0039] 1. Mold; 2. Specimen; 3. Gravity block. DETAILED DESCRIPTION

[0040] In order to make the technical means, objectives and effects of the present invention easy to understand, the embodiments of the present invention are described in detail below with reference to specific drawings.

[0041] It should be noted that all the terms used in the present invention to indicate directionality and position, such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "inside", "outside", "top", "lower", "lateral", "longitudinal", "center", etc., are only used to explain the relative positional relationship and connection status between the components in a certain state, and are only for the convenience of describing the present invention, rather than requiring the present invention to be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features.

[0042] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0044] like Figure 1-5 As shown, the present invention discloses a double-sided grinding and polishing method for an in-situ SEM tensile specimen of marine corrosion-resistant titanium alloy, comprising the following specific steps:

[0045] S1: Sampling: Cut the in-situ SEM tensile specimen according to the drawing requirements of specimen 2, and clean and dry the surface of specimen 2 as needed;

[0046] According to the requirements of the design drawings, cut sample 2 suitable for in-situ SEM tensile test, and ensure that the size and shape of sample 2 meet the experimental requirements. If there is oil or impurities on the surface of sample 2, first clean the surface of sample 2 with anhydrous ethanol and deionized water alternately, and then use a hair dryer to blow dry sample 2 thoroughly. If the surface of sample 2 is clean and dry, you can go directly to the next step.

[0047] S2: A-side mounting: Place the sample with its A-side facing downwards in the mold 1, keep it flat, prepare a solid / liquid blended low-melting-point cold mounting solution, heat it until it melts, pour it into the mold 1 to wrap the sample 2, and cool it to solidify;

[0048] Select a suitable mold 1 according to the size of the sample 2, place one of the grinding surfaces of the sample, named surface A, in the mold 1 with surface A facing down, and keep surface A parallel, then pour the cold mounting liquid raw materials into the container according to the proportion, heat until completely melted to form a solid / liquid blended low melting point cold mounting liquid, pour the melted cold mounting liquid into the mold 1, ensure that the sample 2 is completely wrapped and the height is appropriate for hand-held grinding and polishing, and after cooling, take out the mounted sample 2 from the mold 1. In this step, the B surface is actually mounted with the cold mounting liquid, such as Figure 2 shown.

[0049] S3: Grinding and polishing of surface A: Grind surface A until there are no obvious scratches on the surface, and then perform final polishing to ensure a smooth surface;

[0050] Grind surface A on a grinder and polisher until there are no obvious scratches on the surface. After each step of grinding, clean the surface of sample 2 to remove residual particles, and perform final polishing on a grinder and polisher until the surface of surface A is smooth and scratch-free.

[0051] S4: Inlaying on the B side: Take out the processed A-side sample from the cold inlay material by heating and melting, and repeat Step S2 to perform the same inlaying on the B side;

[0052] Put the specimen 2 that has completed the A-side treatment into the container again to heat and melt it. Take out the specimen 2 and place its other side, named the B side, face down in the mold 1, and repeat the inlaying process in Step S2.

[0053] S5: Grinding and polishing on the B side: Take out the inlaid specimen 2 and repeat S3 to perform the same grinding and polishing operations on the B side;

[0054] Grind the B side on the grinding and polishing machine until there are no obvious scratches on the surface. After each step of grinding, clean the surface of the specimen 2 to remove the residual particles, and perform final polishing on the grinding and polishing machine until the surface of the A side is smooth and free of scratches.

[0055] S6: Taking out the specimen 2: Take out the specimen 2 that has completed double-sided grinding and polishing from the cold inlay material by heating and melting to obtain the prepared in-situ SEM tensile specimen 2;

[0056] For the specimen 2 that has completed double-sided grinding and polishing, put it into a high-temperature resistant glass beaker to heat and melt the cold inlay material, and take out the specimen 2 from the cold inlay material, then the prepared double-sided ground and polished in-situ SEM tensile specimen is obtained. By using the solid / liquid blended low-melting-point cold inlay liquid, it can be easily removed by simple heating when needed, without causing damage to the specimen 2, and at the same time reducing the influence of residues on SEM imaging.

[0057] This setting can reduce the observation errors caused by uneven sample surfaces or residues by optimizing the inlaying and grinding and polishing processes, thereby improving the accuracy of experimental data. Using the solid / liquid blended low-melting-point cold inlay liquid instead of traditional inlay materials improves the production efficiency of specimen 2 preparation and the hardness of the inlaid block, effectively avoiding the chamfering phenomenon that is likely to occur during grinding and polishing, facilitating the subsequent removal of the specimen 2, reducing the deformation risk that may be encountered in traditional methods, ensuring the flatness of the sample. In addition, the sample can be easily removed by heating and melting, avoiding the damage that may be caused by physical methods such as knocking.

[0058] Specifically, in Step S1, the specimen 2 is prepared by wire electrical discharge machining.

[0059] Wire electrical discharge machining can cut according to the precise dimensional requirements of the design drawing to ensure that the obtained specimen 2 meets the specific specifications required for the experiment. Compared with mechanical processing methods, wire electrical discharge machining will not cause significant heat-affected zones or deformation to the titanium alloy during the process, thus maintaining the original microstructure and mechanical properties of the material.

[0060] This setup enables very high cutting accuracy, helps control dimensional tolerances, and provides a high surface finish, reducing the need for subsequent grinding or other finishing operations.

[0061] Specifically, in step S2, two weight blocks 3 are placed at the clamping end of the sample 2 to keep the A surface parallel, such as Figure 5 shown.

[0062] In step S2, the gravity block 3 is pressed on the side of the sample 2 away from the mold 1, that is, the B side. After the cold embedding liquid is poured in, the gravity block 3 and the sample 2 are wrapped as a whole. By using the gravity block 3 to fix the sample 2, it can be ensured that during the process of pouring the cold embedding liquid into the mold 1 and solidifying, the A side of the sample 2 can remain horizontal and flat, avoiding the displacement or tilt of the lightweight sample 2 caused by the flow of liquid when the cold embedding liquid is poured into the mold 1, ensuring that the sample 2 prepared each time has a similar height and flatness, thereby improving the consistency and repeatability of the sample preparation process.

[0063] This setting ensures that the A surface is effectively protected and flattened during the entire mounting process, which helps to obtain a high-quality, high-precision sample surface.

[0064] Specifically, in step S2, the mold 1 can be one of a silicone mold 1, a metal mold 1, a polytetrafluoroethylene mold 1, a plastic mold 1, a ceramic mold 1, an epoxy resin mold 1 and a glass mold 1, and the container for preparing the cold mounting liquid can be one of a high temperature resistant glass beaker, a stainless steel container, a ceramic container, a quartz glass container, etc.

[0065] By using transparent materials such as glass or quartz glass, users can directly observe the changes in the state of the cold mounting liquid, such as whether it is completely melted, whether bubbles are generated, etc.

[0066] This setting ensures that no adverse reaction occurs with the cold mounting liquid during the heating process, while ensuring the safety and durability of the container itself, facilitating subsequent cleaning work, reducing the risk of cross contamination, and improving work efficiency.

[0067] Specifically, in step S2, (10-20 parts) of paraffin wax and (0.5-1) parts of absorbent cotton are alternately placed in a container and heated until completely melted to form a solid / liquid blended low melting point cold mounting solution.

[0068] By adding cotton wool to paraffin, the cotton wool fibers can provide additional support structures after the cold mounting liquid solidifies, increase the overall strength and toughness of the mounted block, reduce the risk of brittle fracture, and significantly improve the hardness of the final cold mounted block. It has been measured that the hardness of the block obtained by mounting with the solid / liquid blended cold mounting liquid is increased by about 25%, which helps to maintain the shape and dimensional stability of the sample 2 during subsequent processing. Moreover, compared with traditional pure paraffin, the cold mounting liquid with the addition of cotton wool is easier to flow when heated and melted, thereby simplifying the process of removing the sample 2 from the mold 1 and reducing the possibility of damage to the surface of the sample 2.

[0069] This setting can better maintain the surface flatness of the sample 2, fix the sample 2 more firmly, and avoid the safety hazard caused by the sample 2 flying out due to centrifugal force. The operation process is relatively simple, easy to master and implement, and effectively improves the quality and efficiency of sample preparation. It can also solve problems existing in traditional methods such as difficulty in peeling and poor flatness.

[0070] Preferably, the ratio of paraffin wax to absorbent cotton is 20:1.

[0071] Specifically, in step S2, the melted cold mounting liquid is poured into the mold 1 to ensure that the sample 2 is completely wrapped and at a moderate height for hand-held grinding and polishing. After cooling for 0.5-1 hour, the mounted sample 2 is taken out from the mold 1.

[0072] By ensuring that the cold mounting liquid completely wraps around the specimen 2, all-round physical protection can be provided for the specimen 2 to avoid accidental damage to the specimen 2 during subsequent processing, such as grinding and polishing. The appropriate height design makes the mounted specimen 2 easy to hold for grinding and polishing, which increases the convenience and safety of operation and reduces errors or accidents caused by unstable grip. Evenly filling the cold mounting liquid and controlling its height helps to maintain the flatness of the specimen 2 and reduce the risk of deformation during the cooling and solidification process, thereby ensuring that the required high precision requirements can be achieved during subsequent grinding and polishing.

[0073] The well-set inlay not only facilitates handheld operation, but also reduces additional processing steps or repeated work caused by improper fixation of the specimen 2, thereby improving overall work efficiency.

[0074] Specifically, in step S3, the specific steps are as follows:

[0075] S31: Use sandpaper to polish surface A on a grinding and polishing machine until there are no obvious scratches on the surface. After polishing, clean the surface of sample 2 to remove residual particles;

[0076] S32: Repeat step S31, use sandpaper with different mesh sizes for multiple times, polish surface A on a grinder and polisher, and clean the surface of sample 2;

[0077] S33: Use silica polishing liquid plus hydrogen peroxide as the polishing medium and perform final polishing on a grinder and polisher until the surface of surface A is smooth and scratch-free.

[0078] The initial grinding with coarse-grit sandpaper can effectively remove the cutting marks, burrs or other surface defects generated during the wire EDM process. The use of sandpaper with different meshes for multiple times for step-by-step grinding can gradually reduce surface scratches and make the surface of Sample 2 gradually smooth, meeting the requirements for SEM observation. The use of silica polishing liquid plus hydrogen peroxide as a polishing medium can achieve a mirror effect in the final stage, ensuring that there are no scratches or defects on the surface of Sample 2, meeting the requirements of high flatness and smoothness for in-situ SEM tensile testing.

[0079] This setting adopts a step-by-step grinding method using sandpaper from coarse to fine, which can gradually improve the surface quality of Sample 2, avoid surface damage or unevenness caused by one-time excessive grinding, and effectively reduce the residual stress on the surface of Sample 2 caused by rough machining, thereby reducing the risk of fracture of Sample 2 in subsequent experiments.

[0080] Specifically, in step S3, the number of polishing is 7 times, and the mesh size of the sandpaper can be 80#, 240#, 400#, 600#, 800#, 1200#, and 2000#, and they are used in sequence from coarse to fine.

[0081] Starting with coarser sandpaper such as 80#, large particles, cutting marks and other significant defects on the surface of Sample 2 can be quickly removed. As the number of sandpapers gradually increases, the surface can be gradually refined and finally a very smooth surface can be achieved. Through step-by-step grinding, each step provides a finer foundation for the next step, which ensures uniform treatment on the entire surface and avoids surface unevenness or damage caused by excessive grinding in a single step. Each level of grinding further refines the surface based on the previous level, reducing the demand and workload for higher-grit sandpaper and improving overall efficiency.

[0082] This setting uses sandpaper of different mesh sizes from coarse to fine to effectively remove scratches and surface irregularities of various sizes, ensuring that the surface of Sample 2 achieves extremely high smoothness and flatness, reducing the risk of material surface deterioration or deformation due to excessive heat generated by long-term friction, reducing the use of fine sandpaper, and being more economical and efficient.

[0083] Specifically, in step S3, the sandpaper is water-based sandpaper.

[0084] Water-based sandpaper, also known as wet sandpaper, is usually used with water during the grinding process to help cool the surface of the sample 2 to prevent overheating, while washing away metal powder and other particulate matter generated during the grinding process, reducing dust pollution in the air, and also preventing these particles from reattaching to the surface of the sample 2 to cause scratches or other damage.

[0085] This setting effectively prevents surface damage of Sample 2 caused by overheating, which is particularly important for temperature-sensitive materials such as titanium alloys. It ensures that the original microstructure of Sample 2 is not affected, reduces the wear rate of the sandpaper, and the water flow helps clean the residue on the sandpaper, maintaining the effective grinding ability of the sandpaper, thereby extending the service life of the sandpaper.

[0086] Specifically, the block obtained by embedding with the solid / liquid mixed low melting point cold embedding fluid was subjected to Shore hardness test, and the hardness of the block was increased by more than 25% compared with the paraffin block.

[0087] The increase in hardness means that the cold-mounted block has better mechanical strength and rigidity, which helps to better support sample 2 during the grinding and polishing process, and reduce the risk of deformation or damage to sample 2 due to the mounting material being too soft. The higher hardness makes the cold-mounted block more stable in subsequent processing such as grinding and polishing, and is less likely to deform or wear, thereby ensuring the consistency and accuracy of the sample surface treatment. Although the hardness is increased, sample 2 can still be easily removed from the cold-mounted block by heating and melting, and no excessive residue will be left to affect the surface quality of sample 2.

[0088] Example 1

[0089] S1 Sample 2 sampling: Use electric spark wire cutting to cut in-situ SEM tensile specimen 2 from TC4 plate according to the requirements of the sample 2 drawing. Use anhydrous ethanol and deionized water to alternately clean the sample 2, and use a hair dryer to blow dry the sample 2. The actual in-situ SEM tensile specimen 2 after machining is shown in Figure 2. Figure 1 shown.

[0090] S2 Inlay of surface A of sample 2: select a rectangular inlay silicone mold 1 with a length of 6 cm according to the size of sample 2, place any polished surface of the sample (this surface is named surface A, and the parallel surface to be polished is surface B) facing downward in the mold 1, and place two gravity blocks 3 at the clamping ends of sample 2 to ensure that surface A of sample 2 is parallel during the inlay process; alternately place 20 parts of paraffin wax and 1 part of absorbent cotton in a high-temperature resistant glass beaker, heat until melted to form a solid / liquid mixed cold inlay liquid, pour it into the mold 1 and add the cold inlay liquid in an amount that the sample 2 can be completely wrapped after inlaying and the height is suitable for hand-held grinding and polishing. After cooling for 0.5-1h, take the inlaid sample 2 out of the mold 1 to complete the inlay operation.

[0091] S3 Grinding and polishing of surface A of sample 2: Grind and polish the mounted sample 2 according to the conventional grinding and polishing steps; polish with 80#, 240#, 400#, 600#, 800#, 1200#, 2000# water-based sandpaper on the grinding and polishing machine in turn, and clean the surface of sample 2 after polishing; polish, use silica polishing liquid + hydrogen peroxide on the grinding and polishing machine, and polish until there are no obvious scratches on the surface of surface A of sample 2, such as Figure 2 shown.

[0092] S4 Inlaying of surface B of sample 2: Place the polished sample 2 in a high-temperature resistant glass beaker, heat and melt it, and then take out the sample 2. Place the sample with the ground surface B facing downward in the mold 1, and place two gravity blocks 3 at the clamping ends of the sample 2 to ensure that the surface B of the sample 2 is parallel during the inlay process; alternately place 20 parts of paraffin wax and 1 part of absorbent cotton in a high-temperature resistant glass beaker, heat until melted to form a solid / liquid mixed cold inlay liquid, pour it into the mold 1 and add the cold inlay liquid in an amount that the sample 2 can be completely wrapped after inlaying and the height is suitable for hand-held polishing. After cooling for 0.5-1 h, take out the inlaid sample 2 from the mold 1 to complete the inlay operation.

[0093] S5 Grinding and polishing of surface B of sample 2: Grind and polish the mounted sample 2 according to the conventional grinding and polishing steps; polish with 80#, 240#, 400#, 600#, 800#, 1200#, 2000# water-based sandpaper on the grinding and polishing machine in turn, and clean the surface of sample 2 after polishing; polish, use silica polishing liquid + hydrogen peroxide on the grinding and polishing machine, and polish until there are no obvious scratches on the surface of surface B of sample 2, such as Figure 3 shown.

[0094] S6 Take out the sample 2: Place the polished sample 2 in a high temperature resistant glass beaker, heat and melt it, and then take out the sample 2. The sample 2 is the prepared double-sided polished in-situ SEM tensile sample 2, such as Figure 4 shown.

[0095] The Shore hardness of pure paraffin-mounted blocks and blocks mounted with a solid / liquid mixed low-melting-point cold mounting solution used in this invention patent was measured with 20 parts of paraffin and 1 part of absorbent cotton. The Shore hardness tester is suitable for the hardness determination of general rubber, wax, and polyols. As shown in Table 1, the hardness of the blocks mounted with the solid / liquid mixed low-melting-point cold mounting solution of this invention patent is increased by 25%.

[0096] Table 1 Shore hardness of test blocks obtained using paraffin mounting and solid / liquid mixed low melting point cold mounting solution mounting

[0097]

[0098] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A double-sided grinding and polishing method for in-situ SEM tensile specimens of marine corrosion-resistant titanium alloys, characterized in that: The specific steps are as follows: S1: Sampling: Cut the in-situ SEM tensile specimen according to the drawing requirements of specimen (2), and clean and dry the specimen surface as needed; S2: A-surface mounting: Place the sample with its A-surface facing downward in the mold (1) and keep it flat. Prepare a solid / liquid blended low-melting-point cold mounting liquid, heat it until it melts, pour it into the mold (1) and wrap the sample (2), and cool it to solidify. S3: Grinding and polishing of surface A: Grind surface A until there are no obvious scratches on the surface, and then perform final polishing to ensure a smooth surface; S4: Mounting of surface B: Take the processed surface A sample out of the cold mounting material by heating and melting, and repeat step S2 to mount the surface B in the same way; S5: grinding and polishing of surface B: taking out the mounted sample (2), and repeating S3 to perform the same grinding and polishing operation on surface B; S6: Removing the sample (2): removing the sample (2) after double-sided grinding and polishing from the cold mounting material by heating and melting, thereby obtaining a prepared in-situ SEM tensile sample.

2. The in-situ SEM tensile specimen double-sided grinding and polishing method for marine corrosion-resistant titanium alloy according to claim 1, characterized in that: In step S1, a sample is prepared by wire electric discharge cutting technology.

3. The in-situ SEM tensile specimen double-sided grinding and polishing method for marine corrosion-resistant titanium alloy according to claim 1, characterized in that: In step S2, two weight blocks (3) are placed at the clamping end of the sample (2) to keep the A surface parallel.

4. The method for double-sided grinding and polishing of in-situ SEM tensile specimens for marine corrosion-resistant titanium alloy according to claim 1, characterized in that: In step S2, the mold (1) is a silicone mold (1), and the container for preparing the cold mounting liquid is one of a high temperature resistant glass beaker, a stainless steel container, a ceramic container, and a quartz glass container.

5. The in-situ SEM tensile specimen double-sided grinding and polishing method for marine corrosion-resistant titanium alloy according to claim 1, characterized in that: In step S2, (10-20) parts of paraffin wax and (0.5-1) parts of absorbent cotton are alternately placed in a container and heated until completely melted to form a solid / liquid blended low melting point cold mounting solution.

6. The method for double-sided grinding and polishing of in-situ SEM tensile specimens for marine corrosion-resistant titanium alloy according to claim 1, characterized in that: In step S2, the ratio of paraffin wax to cotton wool is 20:

1.

7. The method for double-sided grinding and polishing of in-situ SEM tensile specimens for marine corrosion-resistant titanium alloy according to claim 1, characterized in that: In step S2, the melted cold mounting liquid is poured into the mold (1) to ensure that the sample (2) is completely wrapped and at a suitable height for hand-held polishing. After cooling for 0.5-1 hour, the mounted sample (2) is removed from the mold (1).

8. The in-situ SEM tensile specimen double-sided grinding and polishing method for marine corrosion-resistant titanium alloy according to claim 1, characterized in that: In step S3, the specific steps are as follows: S31: using sandpaper, polishing the A surface on a grinding and polishing machine until there are no obvious scratches on the surface. After polishing, the surface of the sample (2) is cleaned to remove residual particles; S32: Repeat step S31, use sandpaper of different mesh sizes for multiple times, polish surface A on a grinder and polisher, and clean the surface of the sample (2); S33: Use silica polishing liquid plus hydrogen peroxide as the polishing medium and perform final polishing on a grinder and polisher until the surface of surface A is smooth and scratch-free.

9. The method for double-sided grinding and polishing of in-situ SEM tensile specimens for marine corrosion-resistant titanium alloy according to claim 8, characterized in that: In step S3, the number of polishing is 7 times, and the mesh of the sandpaper can be 80#, 240#, 400#, 600#, 800#, 1200#, 2000#, and they are used in order from coarse to fine.

10. The method for double-sided grinding and polishing of in-situ SEM tensile specimens for marine corrosion-resistant titanium alloy according to claim 1, characterized in that: In step S3, the sandpaper is water-based sandpaper.

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