A tungsten alloy wire multi-layer cold insert die and a cross-section sample preparation method

Abstract

The application belongs to the technical field of material detection and analysis, and particularly relates to a tungsten alloy wire multilayer cold-embedding mold and a cross-section sample preparation method. The tungsten alloy wire multilayer cold-embedding mold comprises a bottom cover plate, a lower layer barrel body, a middle cover plate, an upper layer barrel body and a through hole arranged at the geometric center of the middle cover plate, and the cold-embedding mold is symmetrical about the vertical line of the geometric center of the middle cover plate. The tungsten alloy wire is fixed by cold embedding with embedding material comprising epoxy resin, aluminum oxide powder and curing agent in the lower layer of the mold, the cold-embedding mold is hung by passing through the through hole at the other end, the tungsten alloy wire is cold-embedded and cured in the upper layer of the mold, and finally, the embedding sample is polished to obtain a tungsten alloy wire cross-section sample. The technical scheme can effectively prevent cracks from occurring in the wire material due to being too thin, the tungsten alloy wire is kept vertical by using the weight of the lower layer of the mold, which is accurate and time-saving, the tungsten alloy wire continuous cross-section sample is obtained by multilayer cold embedding, which is convenient for determining the microstructure uniformity, and has important significance for production practice and experimental detection.

Description

Technical Field

[0001] This application belongs to the field of materials testing and analysis technology, specifically a multi-layer cold-mounting mold for tungsten alloy wire and a method for preparing cross-section samples. Background Technology

[0002] Driven by the dual technologies of thinning photovoltaic silicon wafers and improving the precision of diamond wire cutting, the diameter of tungsten alloy wires has undergone a revolutionary reduction, leaping from the traditional 100-200 μm range to the 30-50 μm level, and continuing to develop towards even finer diameters. This change makes accurate characterization of its microstructure and grain boundary features a key aspect of ensuring material performance, but currently there is no specific embedding method for tungsten alloy wires. However, current tungsten alloy wires are much thinner than previous sample diameters. The traditional hot embedding method involves folding the tungsten alloy wire and directly hot embedding it in phenolic resin. This method cannot accurately fix the position of the tungsten alloy wire, making it difficult to produce good tungsten alloy wire cross-section samples. The cold embedding method not only needs to solve the aforementioned problem of positioning the tungsten alloy wire cross-section, but also the problem of the low hardness of the cold embedding resin; otherwise, the low resin strength can easily lead to cracking and deformation of the tungsten alloy wire during polishing. Simultaneously, to detect the uniformity of the grain structure of the tungsten alloy wire over a certain length, frequent sampling is required within that section of the tungsten alloy wire, and the spacing cannot be too short, otherwise sample preparation will be difficult. Summary of the Invention

[0003] To address the aforementioned issues, this application presents a multi-layer cold-mounting mold for tungsten alloy wire and a method for preparing cross-section samples. In use, the various components of the mold are simply assembled together, and then the tungsten alloy wire is inlaid. The first inlay fixes the tungsten alloy wire, acting as a counterweight. A second mold assembly and sample inlay are then performed to obtain a properly aligned tungsten alloy wire cross-section sample. If necessary, mold assembly and sample inlay can be continued on this basis to obtain cross-section samples at multiple locations within a short distance of the same wire.

[0004] According to a first aspect of this application, this application provides a multi-layer cold-insertion mold for tungsten alloy wire, including a bottom cover plate, a lower cylinder, a middle cover plate and an upper cylinder, wherein the lower cylinder and the upper cylinder are respectively detachably disposed on two opposite surfaces of the middle cover plate, and one end of the lower cylinder away from the middle cover plate is detachably disposed on the bottom cover plate.

[0005] The cold-fitting mold is symmetrical about the vertical line of the geometric center of the central cover plate, and the central cover plate has through holes on its two opposite surfaces through its geometric center.

[0006] Furthermore, the cold-setting mold includes N sets of middle cover plates and upper cylinder bodies, so that the cold-setting mold forms an N+1 layer structure along the vertical line, where N is an integer greater than or equal to 2.

[0007] Furthermore, the end of the upper cylinder away from the middle cover plate is detachably mounted on another middle cover plate.

[0008] Furthermore, the bottom cover plate, the lower cylinder body, the middle cover plate, and the upper cylinder body are all coaxially arranged.

[0009] Furthermore, both the bottom cover plate and the middle cover plate are centrally symmetrical shapes;

[0010] Both the lower and upper cylindrical bodies are cylindrical.

[0011] Furthermore, the diameter of the through hole is 40~60μm.

[0012] According to a second aspect of this application, this application provides a method for preparing a tungsten alloy wire cross-section sample, which uses the aforementioned multi-layer cold-mounting mold for tungsten alloy wire preparation, and includes the following steps:

[0013] S1. Assemble and fix the bottom cover plate to the lower cylinder body, put the first end of the tungsten alloy wire into the lower cylinder body, and then add inlay material to perform the first cold inlay and the first curing of the tungsten alloy wire. The inlay material includes epoxy resin, alumina powder and curing agent.

[0014] S2. Pass the second end of the tungsten alloy wire through the through hole, and assemble the lower cylinder and the upper cylinder onto the middle cover plate respectively. Use the second end of the tungsten alloy wire to suspend and fix the cold-mounting mold.

[0015] S3. Add the inlay material into the upper cylinder to perform a second cold inlay on the tungsten alloy wire and perform a second curing to obtain an inlay sample;

[0016] S4. Grind and polish the inlay to obtain a tungsten alloy wire cross-section sample.

[0017] In the above technical solution, after simply splicing the bottom cover plate and the lower cylinder body in step S1, tungsten alloy wires are cold-mounted using inlay material. During static curing, the mass of the inlay material is evenly distributed under the action of gravity. The purpose of this step is to fix the tungsten alloy wires, so there is no need to specifically position the tungsten alloy wires. Adding alumina powder to the epoxy resin can ensure that the inlay material has sufficient hardness and strength, effectively preventing cracks in the tungsten alloy wires during polishing. In step S2, the tungsten alloy wires are passed through the through hole. Since the through hole is located at the geometric center of the middle cover plate, and the vertical line of the cold-mounting mold is symmetrical about the geometric center of the middle cover plate, after suspending the cold-mounting mold, it can be stably and balanced by gravity, making the tungsten alloy wires perpendicular to the middle cover plate of the mold. Then, in step S3, the upper tungsten alloy wires are cold-mounted. After solidification, a well-formed tungsten alloy wire cross-section inlay sample is obtained. In addition, due to the existence of the through hole, if the inlay material leaks, it will only flow into the lower layer through the through hole, thus not affecting the upper inlay sample. After the sample is polished in step S4, a tungsten alloy wire cross-section sample that is easy to observe can be obtained.

[0018] Furthermore, after step S3, the method further includes: repeating step S2 and step S3 n times, and then executing step S4, where n is an integer greater than or equal to 1.

[0019] To obtain cross-sectional samples of the same tungsten alloy wire at different locations, simply splice together multiple sets of middle cover plates and upper cylinders, then cold-mount the tungsten alloy wires passing through the through holes one by one, and finally grind and polish them.

[0020] Furthermore, the diameter of the tungsten alloy wire is 30~50μm.

[0021] Furthermore, in the inlay material, the mass ratio of the alumina powder to the epoxy resin is 0.3:1 to 0.4:1, and the mass ratio of the epoxy resin to the curing agent is 2:1 to 3:1.

[0022] Furthermore, the curing agent includes polyamide 651.

[0023] Furthermore, the first curing time is 20-40 minutes, and the second curing time is 20-40 minutes.

[0024] Furthermore, the grinding and polishing process includes: grinding the mounting sample with 54μm and 23μm grinding discs successively, and then polishing the mounting sample with 3μm and 1μm diamond suspensions respectively.

[0025] Furthermore, the pressure during grinding and polishing is 0.5~1MPa, the rotation speed of the grinding disc is 500~700rpm, the grinding time is 2~4min, and the polishing time is 30~90s.

[0026] This application proposes a multi-layer cold-mounting mold for tungsten alloy wire and a method for preparing cross-section samples, which produces the following beneficial effects: the mounting material with added alumina powder has sufficient hardness and strength, effectively preventing cracks from occurring due to excessively thin wire; the use of counterweights in the lower layer of the mold to keep the tungsten alloy wire vertical is both accurate and time-saving; multi-layer cold mounting can quickly obtain continuous cross-section samples of the same tungsten alloy wire over a short distance, which is convenient for determining the microstructure uniformity of the tungsten alloy wire and is of great significance for production practice and experimental testing. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the tungsten alloy wire multilayer cold inlay device of this application.

[0029] Figure 2 This is a front view (side view) of the tungsten alloy wire multilayer cold-setting device of this application.

[0030] Figure 3 This is a top view of the tungsten alloy wire multilayer cold-setting device of this application.

[0031] Figure 4 This is a cross-sectional view of the tungsten alloy wire multilayer cold-mounting device of this application.

[0032] Figure 5 This is a metallographic micrograph of Example 1.

[0033] Figure 6 This is a metallographic micrograph of Comparative Example 3.

[0034] Wherein: 1-bottom cover plate, 2-lower cylinder body, 3-middle cover plate, 31-through hole, 4-upper cylinder body.

[0035] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0037] According to the first aspect of this application, Figures 1-4 As shown, this application provides a multi-layer cold-insertion mold for tungsten alloy wire, including a bottom cover plate 1, a lower cylinder 2, a middle cover plate 3, and an upper cylinder 4. The lower cylinder 2 and the upper cylinder 4 are respectively detachably disposed on two opposite surfaces of the middle cover plate 3, and the end of the lower cylinder 2 away from the middle cover plate 3 is detachably disposed on the bottom cover plate 1.

[0038] The cold-fitting mold is symmetrical about the vertical line of the geometric center of the middle cover plate 3, and the middle cover plate 3 has through holes 31 on its two opposite surfaces through its geometric center.

[0039] Preferably, the cold-setting mold includes N sets of middle cover plates 3 and upper cylinder body 4, so that the cold-setting mold forms an N+1 layer structure along the vertical line, where N is an integer greater than or equal to 2.

[0040] Preferably, the end of the upper cylinder 4 away from the middle cover plate 3 is detachably mounted on another middle cover plate.

[0041] Preferably, the bottom cover plate 1, the lower cylinder body 2, the middle cover plate 3, and the upper cylinder body 4 are all coaxially arranged.

[0042] Preferably, both the bottom cover plate 1 and the middle cover plate 3 are centrally symmetrical figures;

[0043] Both the lower cylindrical body 2 and the upper cylindrical body 4 are cylindrical.

[0044] Preferably, the diameter of the through hole is 40~60μm.

[0045] According to a second aspect of this application, this application provides a method for preparing a tungsten alloy wire cross-section sample, which uses the aforementioned multi-layer cold-mounting mold for tungsten alloy wire preparation, and includes the following steps:

[0046] S1. Assemble and fix the bottom cover plate 1 to the lower cylinder 2, put the first end of the tungsten alloy wire into the lower cylinder 2, and then add inlay material to perform the first cold inlay and the first curing of the tungsten alloy wire. The inlay material includes epoxy resin, alumina powder and curing agent.

[0047] S2. Pass the second end of the tungsten alloy wire through the through hole 31, and assemble the lower cylinder 2 and the upper cylinder 4 onto the middle cover plate 3 respectively. Use the second end of the tungsten alloy wire to suspend and fix the cold-mounting mold.

[0048] S3. Add the inlay material into the upper cylinder 4 to perform a second cold inlay of the tungsten alloy wire and a second curing to obtain an inlay sample;

[0049] S4. Grind and polish the inlay to obtain a tungsten alloy wire cross-section sample.

[0050] Preferably, after step S3, the method further includes: repeating step S2 and step S3 n times, and then executing step S4, where n is an integer greater than or equal to 1.

[0051] Preferably, the diameter of the tungsten alloy wire is 30~50μm; specifically, the diameter of the tungsten alloy wire can be any one of 30μm, 35μm, 40μm, 45μm, 50μm or any range between two of them.

[0052] Preferably, in the inlay material, the mass ratio of alumina powder to epoxy resin is 0.3:1 to 0.4:1, and the mass ratio of epoxy resin to curing agent is 2:1 to 3:1. Specifically, the mass ratio of alumina powder to epoxy resin can be any one or a range between any two of 0.3:1, 0.33:1, 0.35:1, 0.38:1, and 0.4:1, and the mass ratio of epoxy resin to curing agent can be any one or a range between any two of 2:1, 2.3:1, 2.5:1, 2.8:1, and 3:1.

[0053] Preferably, the first curing time is 20-40 min, and the second curing time is 20-40 min; specifically, the first curing time can be any one or any two of 20 min, 25 min, 30 min, 35 min, and 40 min, and the second curing time can be any one or any two of 20 min, 25 min, 30 min, 35 min, and 40 min.

[0054] Preferably, the grinding and polishing includes: grinding the mounting sample with 54μm and 23μm grinding discs successively, and then polishing the mounting sample with 3μm and 1μm diamond suspensions respectively.

[0055] More preferably, the pressure during grinding and polishing is 0.5~1MPa, the rotation speed of the grinding disc is 500~700rpm, the grinding time is 2~4min, and the polishing time is 30~90s; specifically, the pressure during grinding and polishing can be any one or any two of 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa, the rotation speed of the grinding disc can be any one or any two of 500rpm, 550rpm, 600rpm, 650rpm, 700rpm, the grinding time can be any one or any two of 2min, 2.5min, 3min, 3.5min, 4min, and the polishing time can be any one or any two of 30s, 45s, 60s, 75s, 90s.

[0056] The technical solution of this application will be further described below with reference to specific embodiments.

[0057] Example 1

[0058] A method for preparing a tungsten alloy wire cross-section sample includes the following steps:

[0059] S1. Assemble and fix the bottom cover plate 1 to the lower cylinder 2. Place the first end of the 30μm diameter tungsten alloy wire into the lower cylinder 2, then add the inlay material to cold inlay the tungsten alloy wire and wait 20 minutes for curing. The inlay material is epoxy resin, alumina powder and curing agent with a mass ratio of 90:27:30.

[0060] S2. Pass the second end of the tungsten alloy wire through the through hole 31, and assemble the lower cylinder 2 and the upper cylinder 4 onto the middle cover plate 3 respectively. Use the second end of the tungsten alloy wire to suspend and fix the cold-mounting mold.

[0061] S3. Add inlay material to the upper cylinder 4 to cold inlay the tungsten alloy wire and wait 20 minutes for curing to obtain the inlay sample;

[0062] S4. Polish the mounting sample to obtain a tungsten alloy wire cross-section sample. The polishing process includes: polishing the mounting sample with 54μm and 23μm grinding discs for 2 minutes, and then polishing the mounting sample with 9μm, 3μm and 1μm diamond suspensions for 30 seconds each. The pressure during polishing is 0.5MPa and the rotation speed of the grinding disc is 500rpm.

[0063] Metallographic micrograph of the tungsten alloy wire cross-section sample prepared in this embodiment is shown below. Figure 5 As shown, its cross-section is close to a perfect circle, which can better expose the grain structure of the tungsten wire.

[0064] Example 2

[0065] S1. Assemble and fix the bottom cover plate 1 and the lower cylinder 2. Place the first end of the 40μm diameter tungsten alloy wire into the lower cylinder 2, then add the inlay material to cold inlay the tungsten alloy wire and wait 30 minutes for curing. The inlay material is epoxy resin, alumina powder and curing agent with a mass ratio of 80:28:30.

[0066] S2. Pass the second end of the tungsten alloy wire through the through hole 31, and assemble the lower cylinder 2 and the upper cylinder 4 onto the middle cover plate 3 respectively. Use the second end of the tungsten alloy wire to suspend and fix the cold-mounting mold.

[0067] S3. Add inlay material to the upper cylinder 4 to cold inlay the tungsten alloy wire and wait 30 minutes for curing to obtain the inlay sample;

[0068] S4. Polish the mounting sample to obtain a tungsten alloy wire cross-section sample. The polishing process includes: polishing the mounting sample with 54μm and 23μm grinding discs for 3 minutes, and then polishing the mounting sample with 9μm, 3μm and 1μm diamond suspensions for 60 seconds. The pressure during polishing is 0.8MPa and the rotation speed of the grinding disc is 600rpm.

[0069] Example 3

[0070] S1. Assemble and fix the bottom cover plate 1 to the lower cylinder 2. Place the first end of the 50μm diameter tungsten alloy wire into the lower cylinder 2, then add the inlay material to cold inlay the tungsten alloy wire and wait 40 minutes for curing. The inlay material is epoxy resin, alumina powder and curing agent with a mass ratio of 80:32:40.

[0071] S2. Pass the second end of the tungsten alloy wire through the through hole 31, and assemble the lower cylinder 2 and the upper cylinder 4 onto the middle cover plate 3 respectively. Use the second end of the tungsten alloy wire to suspend and fix the cold-mounting mold.

[0072] S3. Add inlay material to the upper cylinder 4 to cold inlay the tungsten alloy wire and wait 40 minutes for curing to obtain the inlay sample;

[0073] S4. Polish the mounting sample to obtain a tungsten alloy wire cross-section sample. The polishing process includes: polishing the mounting sample with 54μm and 23μm grinding discs for 4 minutes, and then polishing the mounting sample with 9μm, 3μm and 1μm diamond suspensions for 90 seconds. The pressure during polishing is 1MPa and the rotation speed of the grinding disc is 700rpm.

[0074] Example 4

[0075] Steps S1 to S3 in this embodiment are the same as in embodiment 1. Then, after step S3, steps S2 and S3 are repeated twice. Finally, the sample preparation is completed according to step S4 in embodiment 1, resulting in three tungsten alloy wire cross-section samples within a short distance.

[0076] Comparative Example 1

[0077] The comparative example steps S1~S3 adopt the conventional cold-setting sample preparation method: the tungsten alloy wire is cut into small segments and then vertically placed into the inlay material to be solidified in the cold-setting mold; step S4 is the same as in Example 1.

[0078] Because the resin cooling time is too long, the tungsten alloy wire, which is not fixed, is prone to falling over and shifting, resulting in the tungsten alloy wire having an inclined cross-section, which is elliptical.

[0079] Comparative Example 2

[0080] In step S2 of this comparative example, the mold is placed on the table, and the tungsten alloy wire is straightened with a clamp without leaving the ground. It is visually aligned as perpendicular as possible to the plane of the middle cover plate. Other steps are the same as in Example 1.

[0081] Because the position of the tungsten alloy wire is adjusted manually, which takes time and there are cases where it is not completely perpendicular, the cross-section of the tungsten alloy wire is slightly deformed.

[0082] Comparative Example 3

[0083] The inlay material used in this comparative example was epoxy resin and curing agent in a mass ratio of 90:30; otherwise, it was the same as in Example 1.

[0084] The lack of alumina powder in the inlay material resulted in insufficient hardness, failing to protect the tungsten alloy wire during polishing and causing it to tear. A metallographic micrograph of the tungsten alloy wire cross-section sample is shown below. Figure 6 As shown, its cross-section cracked, and the sample preparation failed.

[0085] This application proposes a multi-layer cold-mounting mold for tungsten alloy wire and a method for preparing cross-section samples, which produces the following beneficial effects: the mounting material with added alumina powder has sufficient hardness and strength, effectively preventing cracks from occurring due to excessively thin wire; the use of counterweights in the lower layer of the mold to keep the tungsten alloy wire vertical is both accurate and time-saving; multi-layer cold mounting can quickly obtain continuous cross-section samples of the same tungsten alloy wire over a short distance, which is convenient for determining the microstructure uniformity of the tungsten alloy wire and is of great significance for production practice and experimental testing.

[0086] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A multi-layer cold-fitting mold for tungsten alloy wire, comprising a bottom cover plate, a lower cylindrical body, a middle cover plate, and an upper cylindrical body, characterized in that, The lower cylinder and the upper cylinder are detachably mounted on two opposite surfaces of the middle cover plate, and the end of the lower cylinder away from the middle cover plate is detachably mounted on the bottom cover plate. The cold-fitting mold is symmetrical about the vertical line of the geometric center of the middle cover plate, and the middle cover plate has through holes on its two opposite surfaces through its geometric center. When using the cold-setting mold for sample preparation, the bottom cover plate is assembled and fixed with the lower cylinder body, the first end of the tungsten alloy wire is placed into the lower cylinder body, and then the inlay material is added to perform the first cold-setting of the tungsten alloy wire and the first curing. The second end of the tungsten alloy wire is passed through the through hole, and the lower cylinder and the upper cylinder are respectively assembled on the middle cover plate. The cold-set mold is suspended and fixed using the second end of the tungsten alloy wire.

2. The tungsten alloy wire multi-layer cold-setting mold according to claim 1, characterized in that, The cold-setting mold also includes N sets of middle cover plates and upper cylinder bodies, so that the cold-setting mold forms an N+1 layer structure along the vertical line, where N is an integer greater than or equal to 2.

3. The tungsten alloy wire multilayer cold-setting mold according to claim 2, characterized in that, The upper cylinder body is detachably mounted on another middle cover plate at one end away from the middle cover plate.

4. A method for preparing a tungsten alloy wire cross-section sample, characterized in that, The sample preparation using the tungsten alloy wire multilayer cold-mounting mold according to any one of claims 1 to 3 includes the following steps: S1. Assemble and fix the bottom cover plate to the lower cylinder body, put the first end of the tungsten alloy wire into the lower cylinder body, and then add inlay material to perform the first cold inlay and the first curing of the tungsten alloy wire. The inlay material includes epoxy resin, alumina powder and curing agent. S2. Pass the second end of the tungsten alloy wire through the through hole, and assemble the lower cylinder and the upper cylinder onto the middle cover plate respectively. Use the second end of the tungsten alloy wire to suspend and fix the cold-mounting mold. S3. Add the inlay material into the upper cylinder to perform a second cold inlay on the tungsten alloy wire and perform a second curing to obtain an inlay sample; S4. Grind and polish the inlay to obtain a tungsten alloy wire cross-section sample.

5. The method for preparing a tungsten alloy wire cross-section sample according to claim 4, characterized in that, The procedure following step S3 further includes: repeating steps S2 and S3 n times, and then executing step S4, where n is an integer greater than or equal to 1.

6. The method for preparing a tungsten alloy wire cross-section sample according to claim 4, characterized in that, The diameter of the tungsten alloy wire is 30~50μm.

7. The method for preparing a tungsten alloy wire cross-section sample according to claim 4, characterized in that, In the inlay material, the mass ratio of the alumina powder to the epoxy resin is 0.3:1 to 0.4:1, and the mass ratio of the epoxy resin to the curing agent is 2:1 to 3:

1.

8. The method for preparing a tungsten alloy wire cross-section sample according to claim 4, characterized in that, The first curing time is 20-40 minutes, and the second curing time is 20-40 minutes.

9. The method for preparing a tungsten alloy wire cross-section sample according to claim 4, characterized in that, The grinding and polishing process includes: grinding the mounting sample with 54μm and 23μm grinding discs successively, and then polishing the mounting sample with 3μm and 1μm diamond suspensions respectively.

10. The method for preparing a tungsten alloy wire cross-section sample according to claim 9, characterized in that, The pressure during grinding and polishing is 0.5~1MPa, the rotation speed of the grinding disc is 500~700rpm, the grinding time is 2~4min, and the polishing time is 30~90s.

Images