Rotating aluminum target and method of making the same
By employing steps such as cold forging, stress-relief annealing, piercing extrusion, and recrystallization annealing, a rotating aluminum target with an average grain size of <100μm and uniform microstructure was prepared. This solved the problems of coarse grain size and long delivery cycle of domestic rotating aluminum targets, and achieved localization and efficient production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XINJIANG JOINWORLD CO LTD
- Filing Date
- 2023-07-10
- Publication Date
- 2026-07-10
AI Technical Summary
Existing technologies make it difficult to produce rotating aluminum targets that meet the high requirements of LCD panels. Domestically produced rotating aluminum targets have coarse grains, which cannot meet customer needs, and reliance on imports leads to long delivery cycles.
Rotary aluminum targets with an average grain size of <100μm and uniform microstructure are prepared by using steps such as cold forging, stress-relief annealing, piercing extrusion and recrystallization annealing, and by controlling the temperature and deformation amount.
This technology achieves a dense and uniform internal structure in rotating aluminum targets, meeting the requirements of electronic devices such as LCD panels, reducing reliance on imports and shortening delivery cycles.
Smart Images
Figure CN116904941B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of sputtering target technology, and in particular to a rotating aluminum target and its preparation method. Background Technology
[0002] Ultra-high purity metals and sputtering targets are important components of electronic materials. The sputtering target industry chain mainly includes metal purification, target manufacturing, sputtering coating, and end-use applications. Among these, target manufacturing is the most critical link in the entire sputtering target industry chain. High-purity aluminum has become the most widely used ultra-pure metal material in sputtering target manufacturing due to its excellent characteristics such as low resistivity, ease of deposition, and good etching performance.
[0003] Sputtering targets can be categorized into planar targets and rotating targets based on their shape. Planar targets are simple in structure and highly versatile, making them the preferred choice for most magnetron sputtering coating manufacturers. However, their utilization rate is only 30%, and their sputtering efficiency is low. Rotating targets, also known as tube targets, have a compact structure and high sputtering efficiency, with a utilization rate reaching 70%, more than twice that of planar targets. Therefore, considering both utilization rate and sputtering efficiency, sputtering equipment tends to favor rotating targets.
[0004] Currently, rotating aluminum sputtering targets are mainly used in LCD panels and semiconductors. For LCD panels, these targets require aluminum purity of 99.999% or higher, an average grain size of <200μm, and good microstructure uniformity. With the continuous increase in LCD panel size, even higher requirements are being placed on aluminum sputtering targets: in 8.5-generation lines and later, the average grain size of the rotating aluminum sputtering target must be <100μm.
[0005] Rotary aluminum sputtering targets are primarily produced by extruding 5N high-purity aluminum ingots. Due to the high purity requirements, refining agents cannot be added during the casting process. The absence of heterogeneous nucleation sites during solidification makes grain growth highly likely, resulting in extremely coarse microstructures in the high-purity aluminum ingots. This poses significant challenges to microstructure refinement during subsequent processing. Currently, domestically used rotary aluminum sputtering targets are mainly sourced from abroad, or obtained by plastically processing large-sized 5N high-purity aluminum round ingots imported from overseas. Because both the ingots and finished products are imported, delivery cycles are lengthy. Furthermore, domestically produced large-sized high-purity aluminum ingots have an average grain size exceeding 3mm, resulting in rotary aluminum sputtering targets with coarse microstructures that fail to meet customer requirements. Summary of the Invention
[0006] Based on this, the present invention provides a rotating aluminum target with an average grain size of <100μm and a dense and uniform internal structure, and a method for preparing the same.
[0007] The specific technical solution is as follows:
[0008] According to one aspect of the present invention, a method for preparing a rotating aluminum target is provided, comprising the following steps:
[0009] Provide high-purity aluminum ingots;
[0010] The high-purity aluminum ingot is subjected to cold forging to obtain the first forging billet;
[0011] The first forging billet is turned to obtain the second forging billet. ；
[0012] The second forging billet is subjected to stress-relief annealing at 50℃~60℃ for 1h~2h;
[0013] The second forging billet after stress-relief annealing is subjected to piercing extrusion to obtain the first aluminum tube billet; wherein the temperature of the piercing needle is 350℃~450℃, the temperature of the extrusion cylinder is 350℃~450℃, and the extrusion speed is 0.5m / s~1.5m / s.
[0014] The first aluminum tube blank is subjected to recrystallization annealing at 280℃~320℃ for 3h~6h to obtain a rotating aluminum target.
[0015] In one embodiment, the average grain size of the high-purity aluminum ingot is ≤3.5mm.
[0016] In one embodiment, the high-purity aluminum ingot has an aluminum mass fraction of 99.999% or higher.
[0017] In one embodiment, the cold forging process includes: free forging the high-purity aluminum ingot, followed by at least three upsetting and drawing processes; the deformation amount of each upsetting and drawing process is ≥50%.
[0018] In one embodiment, the turning process includes the step of turning the first forging billet into a regular cylindrical forging.
[0019] In one embodiment, prior to the recrystallization annealing treatment, the preparation method further includes a step of straightening the first aluminum tube blank.
[0020] In one embodiment, the straightness of the first aluminum tube blank after the straightening treatment is ≤1mm / m.
[0021] In one embodiment, after the recrystallization annealing treatment, the preparation method further includes a step of sawing the rotating aluminum target.
[0022] A rotating aluminum target is prepared using the above-described method for preparing rotating aluminum targets.
[0023] In one embodiment, the average grain size of the rotating aluminum target is <100 μm.
[0024] Compared with traditional technologies, the present invention has the following beneficial effects:
[0025] The method for preparing the rotating aluminum target of this invention adds a forging process before extrusion to refine the ingot microstructure, which is beneficial for deformation during subsequent extrusion and for refining the internal microstructure of the target. Stress-relief annealing at 50℃~60℃ for 1h~2h softens the ingot, facilitating extrusion. A recrystallization annealing step at 280℃~320℃ ensures complete recrystallization of the final rotating aluminum target microstructure, resulting in a uniform and fine internal structure. This method has lower requirements for the grain size of the high-purity aluminum ingot; it can use high-purity aluminum ingots with larger grain sizes to prepare rotating aluminum targets with no internal defects, dense microstructure, good uniformity, and an average grain size <100μm, meeting customer requirements and suitable for industrial mass production. Attached Figure Description
[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0027] Figure 1 This is a process flow diagram of a method for preparing a rotating aluminum target according to an embodiment of the present invention;
[0028] Figure 2 This is a diagram showing the internal microstructure of the rotating aluminum target prepared in Example 1;
[0029] Figure 3 The internal microstructure of the rotating aluminum target prepared in Comparative Example 1 is shown in the diagram.
[0030] Figure 4 This is a diagram showing the internal microstructure of the rotating aluminum target prepared in Comparative Example 2.
[0031] Figure 5 This is a diagram showing the internal microstructure of the rotating aluminum target prepared in Comparative Example 3.
[0032] Figure 6 This is a diagram of the internal microstructure of the rotating aluminum target prepared in Comparative Example 4. Detailed Implementation
[0033] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Unless otherwise specifically stated, all raw materials, reagents, instruments, and equipment used in this invention are commercially available or can be prepared by existing methods.
[0035] the term
[0036] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:
[0037] In this invention, terms such as "multiple", "various", "multiple times", and "multi-source" are used, and unless otherwise specified, they refer to a quantity greater than or equal to 2. For example, "one or more" means one or more types.
[0038] In this document, terms such as “preferred,” “better,” “more suitable,” and “ideal” are merely used to describe implementation methods or examples that yield better results, and should be understood not to limit the scope of protection of this invention.
[0039] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.
[0040] In this invention, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.
[0041] Unless otherwise specified, the temperature parameters in this invention can be either constant temperature treatment or variations within a certain temperature range. It should be understood that the constant temperature treatment allows temperature fluctuations within the precision range controlled by the instrument. Fluctuations are permitted within ranges such as ±5℃, ±4℃, ±3℃, ±2℃, and ±1℃.
[0042] Some embodiments of the present invention provide a method for preparing a rotating aluminum target.
[0043] exist Figure 1 In the example shown, the above-mentioned method for preparing the rotating aluminum target includes steps S10 to S20 and S40 to S60.
[0044] S10: Provides high-purity aluminum ingots;
[0045] S20: The above-mentioned high-purity aluminum ingot is subjected to cold forging to obtain the first forging billet;
[0046] S30: The first forging billet is machined to obtain the second forging billet;
[0047] S40: The second forging billet is subjected to stress-relief annealing at 50℃~60℃ for 1h~2h;
[0048] S50: The second forging billet after stress-relief annealing is subjected to piercing extrusion to obtain the first aluminum tube billet; wherein, the temperature of the piercing needle is 350℃~450℃, the temperature of the extrusion cylinder is 350℃~450℃, and the extrusion speed is 0.5m / s~1.5m / s.
[0049] S60: The first aluminum tube blank is subjected to recrystallization annealing at 280℃~320℃ for 3h~6h to obtain a rotating aluminum target.
[0050] In the above preparation method, the synergistic effect of various steps and parameters, such as cold forging, stress-relief annealing, piercing extrusion, and recrystallization annealing, results in a rotating aluminum sputtering material with an average grain size of <100μm, good microstructure uniformity, and no internal defects. Its performance is essentially on par with imported rotating aluminum sputtering materials. Therefore, using the method of this invention to prepare rotating aluminum sputtering materials can reduce dependence on imports and significantly shorten the delivery cycle.
[0051] In some embodiments, in step S10, the high-purity aluminum ingot satisfies an average grain size of ≤3.5mm.
[0052] In some embodiments, in step S10, the diameter of the high-purity aluminum ingot is 400mm to 460mm.
[0053] In some specific examples, in step S10, the high-purity aluminum ingot is preferably a high-purity aluminum round ingot.
[0054] In some specific examples, in step S10, the aluminum mass fraction in the high-purity aluminum ingot reaches 99.999% or more, and there are no defects on the surface or inside.
[0055] In some embodiments, step S20, the cold forging process includes: free forging the raw material and performing at least three upsetting and drawing processes; wherein the deformation amount of each upsetting and each drawing is ≥50%.
[0056] In some specific examples, in step S20, the free forging method is to perform reversible free forging at room temperature.
[0057] Understandably, "at least three upsetting and drawing processes" means that high-purity aluminum ingots must undergo at least three upsetting and three drawing processes, and the deformation amount of each upsetting and drawing process is ≥50%.
[0058] Reducing the grain size of rotating aluminum sputtering targets mainly involves two approaches: one is to refine the microstructure of large-sized high-purity aluminum ingots and then process them to obtain rotating aluminum sputtering targets with fine grain sizes; the other is to increase the amount of plastic deformation of high-purity aluminum ingots, thereby reducing the grain size of rotating aluminum sputtering targets. However, it is difficult to refine the microstructure of high-purity aluminum ingots to below 1 mm in the short term; therefore, increasing the amount of deformation is an effective method to achieve a grain size of <100 μm for rotating aluminum sputtering targets.
[0059] Cold forging of high-purity aluminum ingots allows for sufficient deformation and complete grain breakage, which is beneficial for subsequent extrusion deformation and microstructure refinement of the aluminum target material. Furthermore, using an ultra-large deformation amount of ≥50% ensures complete deformation of the ingot structure and thorough grain breakage.
[0060] In some specific examples, in step S30, the circular surface of the first forging blank is machined by 4mm to 10mm, and the two ends of the first forging blank are machined flat to obtain a regular cylindrical forging.
[0061] Understandably, the forging billet is machined before extrusion to ensure that the forging material enters the extrusion cylinder smoothly during extrusion without damaging the extrusion cylinder.
[0062] In some embodiments, in step S40, the stress-relieving annealing treatment is carried out at a temperature of 50°C to 60°C for 1 hour to 2 hours.
[0063] At this temperature, the internal stress of the forging can be removed, and the softening of the forging makes the subsequent extrusion process easier. This temperature is 20°C to 30°C lower than the minimum recrystallization temperature of high-purity aluminum, so recrystallization will not occur in the internal structure of the forging; it also softens the forging, extends the deformation to the extrusion process, increases the deformation of the bar extrusion, and is beneficial to recrystallization after extrusion, resulting in a fine and uniform microstructure of the final aluminum target material.
[0064] In some embodiments, in step S40, the temperature of the piercing needle is 350°C to 450°C, the temperature of the extrusion cylinder is 350°C to 450°C, and the extrusion speed is 0.5m / s to 1.5m / s.
[0065] In some embodiments, in step S40, the diameter of the perforation is 120mm to 140mm.
[0066] Under this piercing extrusion process, the grains inside the forging are further broken down, resulting in a fully deformed internal structure without recrystallization, ensuring the total deformation of the final aluminum target and accumulating a large amount of deformation energy. Simultaneously, the aluminum tube obtained using this extrusion process has a smooth inner wall, requiring no secondary processing.
[0067] In some embodiments, in step S50, the straightness of the second aluminum tube blank is ≤1mm / m.
[0068] In some specific examples, in step S50, after the first aluminum tube blank is cooled to room temperature after being extruded, it is straightened on a straightening machine to obtain a second aluminum tube blank; wherein, the straightness of the second aluminum tube blank after straightening is ≤1mm / m.
[0069] In some specific examples, in step S50, the total length of the second aluminum tube blank is 2.5m to 3.5m.
[0070] In some embodiments, in step S60, the recrystallization annealing temperature is 280°C to 320°C, and the annealing time is 3h to 6h.
[0071] The straightened second aluminum tube blank is subjected to recrystallization annealing to transform the deformed microstructure into a fully equiaxed crystal structure. Furthermore, controlling the recrystallization annealing temperature to 280℃~320℃ and the annealing time to 3h~6h can ensure complete recrystallization of the aluminum tube target microstructure, prevent microstructure growth, and ensure good microstructure uniformity.
[0072] In some embodiments, after step S60, the above-mentioned method for preparing the rotating aluminum target further includes step S70: sawing the rotating aluminum target.
[0073] After the second aluminum tube blank has been annealed and cooled to room temperature, a rotating aluminum target is prepared. This rotating aluminum target is then sawn to the size required by the customer to obtain the finished rotating aluminum target. The finished product is then packaged and shipped. The length of the finished aluminum tube is 2m to 3.5m.
[0074] Some embodiments of the present invention also provide a rotating aluminum target prepared by the method for preparing rotating aluminum targets according to any of the above embodiments.
[0075] In some embodiments, the average grain size of the aforementioned rotating aluminum target is <100 μm.
[0076] The aforementioned rotating aluminum sputtering target has at least the following advantages: average grain size <100μm, good microstructure uniformity, and no internal defects. The performance of this rotating sputtering target fully meets the requirements of LCD panels, semiconductor electronic devices, etc., and is therefore suitable for mass production and widespread application.
[0077] The present invention will be further described below with reference to specific embodiments and comparative examples, but these should not be construed as limiting the scope of protection of the present invention.
[0078] Example 1:
[0079] (1) Raw material selection: High-purity aluminum round ingots with a diameter of φ460mm*1200mm were selected as the raw material. The aluminum content in the high-purity aluminum round ingots reached 99.999% or more, the average grain size of the ingot cross section was ≤3.5mm, and there were no defects on the surface and inside.
[0080] (2) Cold forging process: Select a 10,000-ton press with a special flat anvil. The flat anvil does not require heating. The free forging method of three-stage forging and three-stage drawing is used to forge directly. The ingot does not require heating. The final forging diameter is 460±10mm. The specific operation is as follows: First, the round ingot is upturned to a height of 400mm. Then, the ingot is squared, axially drawn, and rolled to φ450±10mm. The operation is repeated three times. The deformation amount of each upturn and each drawing is 66%. Finally, the ingot is rolled and trimmed into the first forging billet of (φ460+10)*(900+10)mm.
[0081] (3) Turning process: The raised surface of the first forging billet is turned off by about 5mm, and the two ends are turned into flat surfaces to obtain the second forging billet with a size of φ450*900mm.
[0082] (4) Stress-relief annealing: The second forging billet is moved into an industrial frequency heating furnace and rapidly heated to 55°C and held for 1.5 hours.
[0083] (5) Perforation and extrusion: A 55MN reverse extrusion press was selected for extrusion. The inner diameter of the extrusion cylinder was 460mm and the extrusion needle was φ171mm. Before extrusion, the perforation needle, extrusion cylinder and die were preheated to 380℃. The second forging billet after stress relief annealing was fed into the extrusion press and the second forging billet was extruded at an extrusion speed of 1m / s. After all the material was extruded, the extruded aluminum tube was quickly sent into the prepared water tank for cooling. After cooling to room temperature, it was taken out to obtain the first aluminum tube billet with an inner diameter of 125mm, an outer diameter of 171mm, a wall thickness of 46mm and a length of 13m.
[0084] (6) Straightening treatment: The first aluminum tube blank is straightened using a straightening machine to obtain a second aluminum tube blank with a straightness of ≤1mm / m.
[0085] (7) Recrystallization annealing: The straightened second aluminum tube blank is subjected to recrystallization annealing at a temperature of 290℃ and a holding time of 4h. After annealing, it is cooled to room temperature with air.
[0086] (8) Sample cutting and metallographic analysis: Small samples were cut from the cooled rotating aluminum target at 500mm from both the head and tail. Metallographic analysis was performed on the samples, and the results are as follows: Figure 2 As shown: the microstructure is completely recrystallized, with an average grain size of <100μm and good microstructure uniformity.
[0087] (9) Finished product sawing, packaging and shipping: Cut the finished rotating aluminum target material into 2940mm lengths, arrange personnel to package the finished aluminum target material and ship it to the client.
[0088] Comparative Example 1:
[0089] (1) Raw material selection: High-purity aluminum round ingots with diameters of φ460mm*850mm were selected as the raw material. The aluminum content in the pure aluminum round ingots reached 99.999% or more, the average grain size of the ingot cross section was ≤3.5mm, and there were no defects on the surface and inside.
[0090] (2) Turning treatment: The raised surface of the round surface of the high-purity aluminum round ingot is turned off by 4mm to obtain an ingot blank with a size of 452mm*850mm and a smooth surface.
[0091] (3) Heat treatment: Move the ingot billet to a medium-frequency heating furnace, heat it rapidly to 105°C, and hold it for 1.5 hours.
[0092] (4) Perforation and extrusion: A 55MN reverse extrusion press was selected for extrusion. The inner diameter of the extrusion cylinder was 460mm and the extrusion needle was φ171mm. Before extrusion, the perforation needle, extrusion cylinder and mold were preheated to 380℃. The heated ingot billet was fed into the extrusion press and the ingot billet was extruded at an extrusion speed of 1m / s. After all the material was extruded, the extruded aluminum tube was quickly sent into the prepared water tank for cooling. After cooling to room temperature, it was taken out to obtain the first aluminum tube billet with an inner diameter of 125mm, an outer diameter of 171mm, a wall thickness of 46mm and a length of 12m.
[0093] (5) Straightening treatment: The first aluminum tube blank is straightened using a straightening machine to obtain a second aluminum tube blank with a straightness of ≤1mm / m.
[0094] (6) Recrystallization annealing: The straightened second aluminum tube blank is subjected to recrystallization annealing at a temperature of 290℃ and a holding time of 4h. After annealing, it is cooled to room temperature with air.
[0095] (7) Sample sawing and metallographic analysis: Small samples were sawed from the cooled rotating aluminum target at a distance of 500 mm from both ends. Metallographic analysis was performed on the small samples, and the results are as follows: Figure 3 As shown: the tissue is in a regressive state, the structure is uneven, and it does not meet the usage requirements.
[0096] Comparative Example 2:
[0097] (1) Raw material selection: High-purity aluminum round ingots with a diameter of φ460mm*1200mm were selected as the raw material. The aluminum content in the high-purity aluminum round ingots reached 99.999% or more, the average grain size of the ingot cross section was ≤3.5mm, and there were no defects on the surface and inside.
[0098] (2) Cold forging process: Select a special flat anvil for a 10,000-ton press. The flat anvil does not require heating. The free forging method of three-stage forging and three-stage drawing is used to forge directly. The ingot does not require heating. The final forging diameter is 460±10mm. The specific operation is as follows: First, the round ingot is upturned to a height of 400mm. Then, the ingot is squared, axially drawn, and rolled to φ450+10mm. The operation is repeated three times. The deformation amount of each upturning and each drawing is 66%. Finally, the ingot is rolled and trimmed to the first forging blank of (φ460+10)*(900+10)mm.
[0099] (3) Turning process: The raised surface of the first forging billet is turned off by about 5mm, and the two ends are turned into flat surfaces to obtain the second forging billet with a size of φ450*900mm.
[0100] (4) Perforation and extrusion: A 55MN reverse extrusion press was selected for extrusion. The inner diameter of the extrusion cylinder was 460mm and the extrusion needle was φ171mm. Before extrusion, the perforation needle, extrusion cylinder and die were preheated to 380℃. The second forging billet after stress relief annealing was moved into the industrial frequency heating furnace and rapidly heated to 55℃ and held for 1.5h. The heated second forging billet was sent into the extrusion press and the ingot was extruded at an extrusion speed of 1.5m / s. After all the material was extruded, the extruded aluminum tube was quickly sent into the prepared water tank for cooling. After cooling to room temperature, it was taken out to obtain the first aluminum tube billet with an inner diameter of 125mm, an outer diameter of 171mm, a wall thickness of 46mm and a length of 13m.
[0101] (5) Straightening treatment: The first aluminum tube blank is straightened using a straightening machine to obtain a rotating aluminum target with a flatness of ≤1mm / m.
[0102] (6) Sample sawing and metallographic analysis: Small samples were sawed from the cooled rotating aluminum target at a distance of 500 mm from both ends. Metallographic analysis was performed on the small samples, and the results are as follows: Figure 4 As shown: the tissue has partially recrystallized, resulting in an uneven structure that does not meet the requirements for use.
[0103] Comparative Example 3:
[0104] (1) Raw material selection: High-purity aluminum round ingots with a diameter of φ460mm*1200mm are selected as the target material with a purity of 99.999% or higher, an average grain size of ≤3.5mm in the cross section of the ingot, and no defects on the surface and inside.
[0105] (2) Cold forging process: Select a 10,000-ton press with a special flat anvil. The flat anvil does not require heating. The forging is directly forged using a three-stage forging method with reversing direction. The ingot does not require heating. The final forging diameter is 460±10mm. The specific operation is as follows: First, the round ingot is upturned to a height of 800mm. Then, the ingot is squared, axially elongated, and rolled to φ450±10mm. The operation is repeated three times. The deformation amount of each upturning and elongation is 33%. Finally, the ingot is rolled and trimmed into a first forging billet of (φ460+10)*(900+10)mm.
[0106] (3) Turning process: The raised surface of the first forging billet is turned off by about 5mm, and the two ends are turned into flat surfaces to obtain the second forging billet with a size of φ450*900mm.
[0107] (4) Stress-relief annealing: The second forging billet is moved into an industrial frequency heating furnace and rapidly heated to 55°C and held for 1.5 hours.
[0108] (5) Perforation and extrusion: A 55MN reverse extrusion press was selected for extrusion. The inner diameter of the extrusion cylinder was 460mm and the extrusion needle was φ171mm. Before extrusion, the perforation needle, extrusion cylinder and die were preheated to 380℃. The second forging billet after stress relief annealing was fed into the extrusion press and the extrusion speed was 1m / s. After all the material was extruded, the extruded aluminum tube was quickly sent into the prepared water tank for cooling. After cooling to room temperature, it was taken out to obtain the first aluminum tube billet with an inner diameter of 125mm, an outer diameter of 171mm, a wall thickness of 46mm and a length of 13m.
[0109] (5) Straightening treatment: The first aluminum tube blank is straightened using a straightening machine to make its straightness ≤1mm / m.
[0110] (6) Recrystallization annealing: The straightened aluminum tube is subjected to recrystallization annealing at a temperature of 290℃ and a holding time of 4h. After annealing, it is cooled to room temperature with air.
[0111] (7) Sample cutting and metallographic analysis: Small samples were cut from the cooled aluminum tube at 500mm from both ends. Metallographic analysis was performed on the samples, and the results are as follows: Figure 5 As shown, the average grain size is 231 μm, the microstructure is uneven, and it does not meet the requirements for use.
[0112] Comparative Example 4:
[0113] (1) Raw material selection: High-purity aluminum round ingots with a diameter of φ460mm*1200mm are selected as the target material with a purity of 99.999% or higher, an average grain size of ≤3.5mm in the cross section of the ingot, and no defects on the surface and inside.
[0114] (2) Cold forging process: Select a 10,000-ton press with a special flat anvil. The flat anvil does not require heating. The forging is directly forged using a three-stage forging method with reversing direction. The ingot does not require heating. The final forging diameter is 460±10mm. The specific operation is as follows: First, the round ingot is upturned to a height of 400mm. Then, the ingot is squared, axially elongated, and rolled to φ450±10mm. The operation is repeated three times. The deformation amount of each upturn and elongation is 66%. Finally, the ingot is rolled and trimmed into a first forging billet of (φ460+10)*(900+10)mm.
[0115] (3) Turning process: The raised surface of the first forging billet is turned off by about 5mm, and the two ends are turned into flat surfaces to obtain the second forging billet with a size of φ450*900mm.
[0116] (4) Stress-relief annealing: The machined ingot billet is transferred into an industrial frequency heating furnace and rapidly heated to 55°C and held for 1.5 hours.
[0117] (5) Perforation and extrusion: A 55MN reverse extrusion press was selected for extrusion. The inner diameter of the extrusion cylinder was 460mm and the extrusion needle was φ171mm. Before extrusion, the perforation needle, extrusion cylinder and die were preheated to 380℃. The second forging billet after stress relief annealing was fed into the extrusion press and the extrusion speed was 1m / s. After all the material was extruded, the extruded aluminum tube was quickly sent into the prepared water tank for cooling. After cooling to room temperature, it was taken out to obtain the first aluminum tube billet with an inner diameter of 125mm, an outer diameter of 171mm, a wall thickness of 46mm and a length of 13m.
[0118] (5) Straightening treatment: The first aluminum tube blank is straightened using a straightening machine to make its straightness ≤1mm / m.
[0119] (6) Recrystallization annealing: The straightened aluminum tube is subjected to recrystallization annealing at a temperature of 250°C and a holding time of 4 hours. After annealing, it is cooled to room temperature with air.
[0120] (7) Sample cutting and metallographic analysis: Small samples were cut from the cooled aluminum tube at 500mm from both ends. Metallographic analysis was performed on the samples, and the results are as follows: Figure 6 As shown, the microstructure of the rotating aluminum target is not fully recrystallized, which does not meet the requirements for use.
[0121] Compared with Example 1, the preparation method of Comparative Example 1 did not involve cold forging before the perforation extrusion process, and the temperature of the stress-relief annealing step was higher than the minimum recrystallization temperature of high-purity aluminum; the internal structure of the prepared rotating aluminum target was in a restored state, which could not meet the requirements for use.
[0122] In the preparation method of Comparative Example 2, the first aluminum tube blank obtained by piercing extrusion was not subjected to recrystallization annealing treatment and was directly straightened; the internal structure of the prepared rotating aluminum target was only partially recrystallized and the structure was uneven.
[0123] The preparation method of Comparative Example 3 differs from that of Example 1 only in that the deformation amount of each upsetting and each drawing is 33%; the average grain size of the prepared rotating aluminum target is 231 μm, the structure is uneven and does not meet the requirements for use.
[0124] The preparation method of Comparative Example 4 differs from that of Example 1 only in that the recrystallization annealing temperature is reduced to 250°C; and the recrystallization of the prepared rotating aluminum target is incomplete.
[0125] The rotating aluminum target prepared by the method of the present invention has no internal defects, dense structure, good uniformity, average grain size <100μm, and no deformation texture, which can meet the performance requirements of downstream products.
[0126] The above results indicate that only by controlling the parameters of cold forging, stress-relief annealing, piercing extrusion, and recrystallization annealing within a specific range, and by making each step work synergistically, can a rotating aluminum target with a grain size of <100μm and a uniform microstructure be prepared.
[0127] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0128] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A method for preparing a rotating aluminum target, characterized in that, Includes the following steps: Provide high-purity aluminum ingots; the average grain size of the high-purity aluminum ingots is ≤3.5mm; The high-purity aluminum ingot is subjected to cold forging to obtain a first forging billet; the cold forging process includes: free forging of the high-purity aluminum ingot, undergoing at least three upsetting and drawing processes; the deformation amount of each upsetting and drawing process is ≥50%; The first forging billet is turned to obtain the second forging billet; The second forging billet is subjected to stress-relief annealing at 50℃~60℃ for 1h~2h; The second forging billet after stress-relief annealing is subjected to piercing extrusion to obtain the first aluminum tube billet; wherein the temperature of the piercing needle is 350℃~450℃, the temperature of the extrusion cylinder is 350℃~450℃, and the extrusion speed is 0.5m / s~1.5m / s. The first aluminum tube blank is subjected to recrystallization annealing at 280℃~320℃ for 3h~6h to obtain a rotating aluminum target.
2. The method for preparing the rotating aluminum target according to claim 1, characterized in that, The high-purity aluminum ingot contains an aluminum mass fraction of 99.999% or higher.
3. The method for preparing the rotating aluminum target according to claim 1, characterized in that, The diameter of the high-purity aluminum ingot is 400mm~460mm.
4. The method for preparing the rotating aluminum target according to claim 1, characterized in that, The turning process includes the step of turning the first forging billet into a regular cylindrical forging.
5. The method for preparing the rotating aluminum target according to claim 1, characterized in that, Prior to the recrystallization annealing treatment, the preparation method further includes a step of straightening the first aluminum tube blank.
6. The method for preparing the rotating aluminum target according to claim 5, characterized in that, The straightness of the first aluminum tube blank after the straightening treatment is ≤1mm / m.
7. The method for preparing the rotating aluminum target according to any one of claims 1 to 6, characterized in that, After the recrystallization annealing treatment, the preparation method further includes a step of sawing the rotating aluminum target.
8. A rotating aluminum target, characterized in that, It is prepared by the method for preparing the rotating aluminum target according to any one of claims 1 to 7.
9. The rotating aluminum target according to claim 8, characterized in that, The average grain size of the rotating aluminum target is <100μm.