A method for producing a beryllium-aluminum alloy foil

Abstract

The application provides a preparation method of a beryllium-aluminum alloy foil and belongs to the technical field of beryllium-aluminum alloy materials. The preparation method comprises the following steps: step S1, cutting a beryllium-aluminum alloy plate into multiple small beryllium-aluminum alloy plates with the same size and then stacking the small beryllium-aluminum alloy plates; step S2, placing the stacked small beryllium-aluminum alloy plates into a tungsten-molybdenum sheath, heating the small beryllium-aluminum alloy plates to 660-680 DEG C, keeping the temperature for 35-50 minutes, and then performing multi-pass stack rolling to obtain a beryllium-aluminum alloy sheet; and step S3, performing multi-pass lubricating cold rolling on the beryllium-aluminum alloy sheet to obtain a beryllium-aluminum alloy foil. The beryllium-aluminum alloy foil prepared by the method has a thickness of 0.02-0.08 mm and good mechanical properties.

Description

Technical Field

[0001] This invention belongs to the technical field of beryllium aluminum alloy materials, and particularly relates to a method for preparing beryllium aluminum alloy foil. Background Technology

[0002] Beryllium-aluminum alloys possess numerous advantages, including light weight, high specific strength, high specific stiffness, good thermal stability, high damping, high toughness, and corrosion resistance. Combining the low density and high elastic modulus of metallic beryllium with the high toughness and machinability of metallic aluminum, beryllium-aluminum alloys are an important structural and novel material, considered a crucial material for the 21st century from laboratory to engineering applications, and possessing broad application prospects in the defense and aerospace fields.

[0003] Currently, the rolling processes for beryllium plates, foils, beryllium copper plates, and strips in China are relatively mature and stable. However, the melting points of beryllium and aluminum differ significantly (beryllium is 1289℃, while aluminum is 661℃). The inherent properties of beryllium-aluminum make it difficult to cast. The very limited solubility between beryllium and aluminum causes these two materials to separate during solidification. Ingots produced using traditional ingot-making processes do not form any intermetallic compounds between beryllium and aluminum, do not exhibit true alloying, and have extremely low mutual solid solution ability, failing to form a solid solution. In essence, they are metal-based composite materials of pure beryllium and pure aluminum. The extremely low plastic deformation capacity of beryllium aluminum alloy during rolling makes the sheet very easy to crack. At the same time, the ductility varies greatly at different points and parts of the sheet. This large difference in ductility causes additional stress at different points and parts of the sheet, which seriously restricts the subsequent rolling of the sheet. This brings great difficulties to the subsequent foil preparation, making it difficult to prepare beryllium aluminum alloy foil with a thickness of less than 0.1 mm and good performance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing beryllium aluminum alloy foil, which can produce beryllium aluminum alloy foil with a thickness of 0.02 to 0.08 mm and good performance.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for preparing beryllium aluminum alloy foil, the method comprising the following steps:

[0007] Step S1: Cut the beryllium aluminum alloy sheet into multiple small beryllium aluminum alloy sheets of the same size and stack them.

[0008] Step S2: After stacking multiple small beryllium aluminum alloy plates, put them into a tungsten-molybdenum cladding and heat them to 660-680°C, hold them at that temperature for 35-50 minutes, and then perform multiple rolling passes to obtain beryllium aluminum alloy thin plates.

[0009] Step S3: Perform multiple passes of lubricated cold rolling on the beryllium aluminum alloy sheet to obtain beryllium aluminum alloy foil.

[0010] Furthermore, in step S1, the preparation process of the beryllium aluminum alloy sheet includes:

[0011] Step S11: Under vacuum conditions, mix beryllium powder and aluminum powder in a mass ratio of 5-7:3-5, then place the mixture in a beryllium oxide crucible, and then heat it at a pressure of 1.6-2.4 x 10⁻⁶ mm. -3 Under a vacuum and inert gas protective atmosphere of Pa, beryllium aluminum alloy melt was obtained by suspension melting at 1360–1460℃ for 28–33 minutes and then held at that temperature.

[0012] Step S12: Under magnetic levitation stirring, the beryllium aluminum alloy melt in the beryllium oxide crucible is injected into the graphite cavity coated with alumina at a speed of 50-150 ml / s within 10-15 s. Then, the graphite cavity is preheated to 360-480°C and cast at 1160-1190°C for 10-15 s under vacuum and inert gas protective atmosphere to obtain beryllium aluminum plate ingot.

[0013] Step S13: The beryllium aluminum plate ingot is machined and milled, then clad and fitted, and then the machined and milled beryllium aluminum plate ingot is placed into the cladding and subjected to high-rate hot rolling, stress-relieving heat treatment and 20 to 22 passes of cold rolling in sequence.

[0014] The process conditions for high-processing-rate hot rolling are as follows: temperature is 330-620℃, number of passes is 12-15, total processing rate is 78-80%, first pass is held for 25-30 minutes, and the remaining passes are held for 15-20 minutes.

[0015] The process conditions for the stress-relief heat treatment are as follows: temperature is 475℃~546℃, holding time is 94~116 minutes, heating time is 60~120 minutes, and cooling method is power-off cooling with furnace.

[0016] The process conditions for each cold rolling pass are as follows: at room temperature, rolling is performed with a rolling force of 20-50KN at a speed of 0.2-0.5m / s, followed by work hardening heat treatment at 420℃-480℃ for 66-114 minutes; the heating time is 60-90 minutes; and the cooling method is to cool the furnace with the power off.

[0017] Furthermore, in step S13, the cold rolling pass processing rate for each cold rolling pass is 10.6-11%, and the maximum total cold rolling deformation is 90%.

[0018] Furthermore, in step S2, the thickness of the beryllium aluminum alloy sheet is 0.08 to 0.12 mm.

[0019] Furthermore, in step S2, the number of passes in the multi-pass rolling is 16 to 20.

[0020] Furthermore, in step S3, the number of passes in the lubricated cold rolling process is 1160 to 2496.

[0021] Furthermore, in step S3, the number of reduction distributions between the two heat treatments in the multi-pass lubricated cold rolling is 3 to 5 times; the number of rolling passes under the same reduction distribution is 52 to 58.

[0022] Furthermore, the process conditions for each heat treatment are as follows: temperature 400–500℃, time 60–120 min, heating time 62–87 min, and cooling method is power-off cooling along with the furnace.

[0023] Furthermore, the thickness of the beryllium aluminum alloy foil is 0.02 to 0.08 mm.

[0024] In summary, the technical solution of the present invention has the following technical effects:

[0025] This invention prepares 0.08–0.12 mm thick beryllium-aluminum alloy sheets through multi-pass rolling of beryllium-aluminum alloy plates. These sheets exhibit high mechanical properties, with tensile strength, yield strength, and elongation at room temperature meeting the plasticity requirements for normal rolling of beryllium-aluminum alloy foil. The addition of a tungsten-molybdenum cladding facilitates thinning of the beryllium-aluminum alloy, altering the stress state and microstructure orientation during the rolling deformation process, improving the microstructure, reducing anisotropy, and enhancing rolling plasticity, thus facilitating the subsequent preparation of beryllium-aluminum alloy foil. Through multi-pass lubricated cold rolling, the 0.08–0.12 mm thick beryllium-aluminum alloy sheets are cold-rolled into 0.02–0.08 mm thick beryllium-aluminum alloy foils with tensile strength of 352–373 MPa, yield strength of 318–332 MPa, and elongation of 4.5–5.2%. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This embodiment provides a method for preparing beryllium aluminum alloy foil, which includes the following steps:

[0028] Step S1: Cut the beryllium aluminum alloy sheet into multiple small beryllium aluminum alloy sheets of the same size and then stack them.

[0029] In this embodiment, 5 to 8 small beryllium aluminum alloy plates are horizontally stacked together after being horizontally cut into the same size from a beryllium aluminum alloy plate.

[0030] This embodiment can use existing beryllium aluminum alloy plates, or it can use beryllium aluminum alloy plates prepared by the following method, the specific preparation process of which includes:

[0031] Step S11: Under vacuum conditions, mix beryllium powder and aluminum powder in a mass ratio of 5-7:3-5, then place the mixture in a beryllium oxide crucible, and then heat it at a pressure of 1.6-2.4 x 10⁻⁶ mm. -3 Under a vacuum and inert gas protective atmosphere, beryllium aluminum alloy melt is obtained by suspension melting at 1360–1460°C for 28–33 minutes followed by holding at that temperature.

[0032] This embodiment employs a vacuum suspension melting furnace, where suspension melting is carried out under a vacuum and inert gas protective atmosphere. The crucible utilizes conformal cooling and precise slit cutting, and employs excellent electromagnetic fields and optimal electromagnetic field distribution. After all raw materials have melted, the furnace charge is held at this temperature for 28–33 minutes to promote thorough and uniform melting of the charge.

[0033] Step S12: Under magnetic levitation stirring, the beryllium-aluminum alloy melt in the beryllium oxide crucible is injected into the graphite cavity coated with alumina at a speed of 50-150 ml / s within 10-15 s. Then, the graphite cavity is preheated to 360-480°C and cast at 1160-1190°C for 10-15 s under a vacuum and inert gas protective atmosphere to obtain beryllium-aluminum plate ingots.

[0034] This embodiment employs magnetic levitation stirring, reducing major defects such as porosity, segregation, shrinkage cavities, and looseness during the casting process. The crucible is tilted towards the mold (i.e., a casting mold with a graphite cavity coated with alumina). The crucible tilting can be driven by a motor, with controllable speed and adjustable angle. This allows the beryllium-aluminum alloy fusion in the crucible to be injected into the square mold at a controllable speed and adjustable angle, casting the beryllium-aluminum alloy fusion into a relatively thin beryllium-aluminum plate ingot with a thickness of 6.0 mm. The tilting speed is 15–20° / s, and the tilting angle is -10–110°.

[0035] Compared to traditional cast cylindrical ingots, magnetically levitated beryllium aluminum plate ingots exhibit superior performance due to the more thorough and uniform melting of the furnace charge during the magnetic levitation casting process. The magnetically levitated stirring also reduces the occurrence of major defects during the casting process.

[0036] The beryllium-aluminum alloy fusion body is injected into a square mold at a controllable speed and adjustable angle. In addition, the beryllium-aluminum plate ingot is relatively thin. Therefore, the nucleation and crystallization rate of the beryllium-aluminum alloy plate ingot is faster during the magnetic levitation casting process. The grains will be refined to a certain extent, reducing the occurrence of major defects such as segregation, shrinkage cavities, and porosity, improving the uniformity of microstructure distribution, and improving the rolling plastic deformation capability of beryllium-aluminum alloy ingot.

[0037] Step S13: The beryllium aluminum plate ingot is machined and milled, then clad and fitted. After the machined and milled beryllium aluminum plate ingot is placed into the cladding, it is then subjected to high-rate hot rolling, stress-relief heat treatment and 20-22 passes of cold rolling.

[0038] In this embodiment, a 5.0 mm thick beryllium aluminum plate ingot is obtained by machining and milling. The upper and lower surfaces of the machined beryllium aluminum plate ingot are smooth and flat. The cladding configuration facilitates thinning of the beryllium aluminum alloy, alters the stress state and microstructure orientation during the rolling deformation process of the beryllium aluminum alloy plate ingot, improves the microstructure, weakens anisotropy, and facilitates subsequent rolling plastic deformation. High-rate hot rolling breaks up coarse columnar dendrites, refines grains, homogenizes the microstructure, reduces anisotropy, and improves subsequent rolling plastic deformation capacity and plate mechanical properties. This avoids coarse grains, uneven microstructure, severe anisotropy, and poor plastic deformation capacity, resulting in beryllium aluminum plates with a thickness of 0.1–1.0 mm.

[0039] The process conditions for high-processing-rate hot rolling in this embodiment are: temperature 330-620℃, 12-15 passes, total processing rate 78-80%, first pass holding time 25-30 minutes, and the remaining passes holding time 15-20 minutes.

[0040] The beryllium-aluminum sheet obtained by high-ratio hot rolling is placed in a high-vacuum furnace for stress-relief heat treatment to eliminate the internal stress generated during the hot rolling process due to the high ratio. The process conditions for stress-relief heat treatment are: temperature 475℃~546℃, holding time 94~116 minutes; heating time 60~120 minutes; cooling method: power off and furnace cooling.

[0041] The process conditions for each cold rolling pass are as follows: rolling at room temperature with a rolling force of 20–50 kN and a speed of 0.2–0.5 m / s, followed by work-hardening heat treatment at 420℃–480℃ for 66–114 minutes; the heating time is 60–90 minutes; and the cooling method is furnace cooling with the power off. The cold rolling pass yield is 10.6–11%, and the maximum total deformation is 90%.

[0042] The beryllium-aluminum alloy sheet, after stress-relief heat treatment, is cold-rolled. The cold rolling pass rate is controlled to the limit of the maximum allowable pass rate for rolling plastic deformation (generally 10.6-11%, preferably 10.8%), so that the rolled sheet undergoes normal elongation deformation while generating a moderate number of process-controllable microcracks on both sides of the edges. The microcracks are 1-1.5 mm long and 20-25 mm apart. The additional stress is released through the microcracks. After the additional stress is released, the beryllium-aluminum alloy sheet undergoes work-hardening heat treatment and edge finishing before the next cold rolling pass. In this embodiment, the number of cold rolling passes is 1-18, preferably 8-14.

[0043] By employing single-pass cold rolling with a near-limit processing rate, a certain amount of plastic deformation can be achieved in the beryllium aluminum alloy sheet, initially reducing its thickness. Simultaneously, it ensures the formation of controllable microcracks on both sides of the beryllium aluminum alloy sheet, effectively releasing additional stress. Releasing additional stress through these microcracks facilitates subsequent rolling processes. Subsequent multi-pass cold rolling gradually reduces the sheet thickness, resulting in a beryllium aluminum alloy sheet with the required thickness and mechanical properties. In this embodiment, the beryllium aluminum alloy sheet has a thickness of 0.1–0.1 mm.

[0044] To ensure the smooth operation of the next cold rolling process, this embodiment employs edge trimming. The edges of the beryllium aluminum alloy sheet are sheared with microcracks of 1–1.5 mm in length to release additional stress, while the edges are repaired and smoothed.

[0045] Step S2: After stacking multiple small beryllium aluminum alloy plates, place them into a tungsten-molybdenum cladding and heat them to 660-680°C. Hold the temperature for 35-50 minutes and then perform multiple rolling passes to obtain beryllium aluminum alloy thin plates.

[0046] In this embodiment, stacked beryllium-aluminum alloy sheets are placed inside a prepared tungsten-molybdenum cladding, which is then welded shut. The welded tungsten-molybdenum cladding (including horizontally stacked beryllium-aluminum alloy sheets of the same size) is heated and held at a constant temperature before undergoing multiple rolling passes. This embodiment uses 16 to 20 rolling passes to obtain beryllium-aluminum alloy sheets with a thickness of 0.08 to 0.12 mm.

[0047] The cladding material is selected from tungsten-molybdenum plates, which have the closest ductility and heat dissipation properties to beryllium-aluminum alloys. The cladding configuration facilitates the thinning of beryllium-aluminum alloys, alters the stress state and microstructure orientation during the rolling deformation process of the beryllium-aluminum alloy plates, improves the microstructure, weakens anisotropy, enhances rolling plasticity, and facilitates the subsequent preparation of beryllium-aluminum alloy foils.

[0048] As the thickness of rolled beryllium aluminum alloy sheets gradually decreases and becomes thinner, the internal microstructure gradually improves with the increase in plastic deformation and rolling cycles. As the internal microstructure gradually improves, the density and mechanical properties of the beryllium aluminum alloy sheets continuously increase, and the plastic deformation capacity during the rolling process gradually improves, achieving the plasticity conditions required for normal rolling of beryllium aluminum alloy foil.

[0049] Step S3: Perform multiple passes of lubricated cold rolling on the beryllium aluminum alloy sheet to obtain beryllium aluminum alloy foil.

[0050] In this embodiment, the cold rolling is lubricated cold rolling, with 1160–2496 passes and 3–18 heat treatments. Multiple rolling passes are performed for each reduction, meaning multiple rolling passes are performed within the same reduction allocation. Several reduction allocations are performed between two heat treatments, and multiple lubricated rolling passes are performed under the same reduction allocation to prepare beryllium-aluminum alloy foil of the required thickness. Specifically, the number of reduction allocations is 3–5; the number of rolling passes under the same reduction allocation is 52–58.

[0051] After multiple rounds of lubrication rolling and heat treatment, as the thickness of the rolled foil gradually decreases and the number of rolling and heat treatment cycles increases, the microstructure of the foil gradually becomes denser, the morphological distribution gradually becomes more uniform, and internal defects gradually decrease and weaken.

[0052] The work-hardening elimination heat treatment is performed during the cold rolling process. The purpose of work-hardening elimination annealing is to eliminate the work hardening caused by cold rolling deformation in beryllium aluminum alloy foil, so as to facilitate the smooth progress of subsequent cold rolling. The process conditions for each heat treatment (work-hardening elimination heat treatment) are as follows: temperature 400-500℃, time 60-120min, heating time 62-87min, and cooling method is furnace cooling with power off.

[0053] The thickness of the beryllium aluminum alloy foil in this embodiment is 0.02 to 0.08 mm.

[0054] Example 1:

[0055] 1. Mix beryllium powder and aluminum powder evenly under vacuum at a mass ratio of 6:4 to obtain raw materials.

[0056] 2. Using a vacuum suspension melting furnace, the prepared raw materials are placed in a beryllium oxide crucible for melting at a temperature of 2.0*10. -3 Under a vacuum of Pa, at a melting temperature of 1410℃, the material was melted for 30 minutes. After all the raw materials were melted, the temperature was maintained for 32 minutes to promote full and uniform melting of the furnace charge, thus obtaining beryllium aluminum alloy melt.

[0057] 3. Under magnetic levitation stirring, using a motor-driven mode, the beryllium oxide crucible is tilted 50° at a speed of 18° / s into the graphite cavity coated with alumina. The beryllium-aluminum alloy melt in the beryllium oxide crucible is injected into the graphite cavity coated with alumina at a speed of 100ml / s within 12s. Then, the graphite cavity is preheated to 390℃, and under a vacuum and inert gas protective atmosphere, it is cast at a temperature of 1175℃ for 13s to obtain a 6.0mm thick beryllium-aluminum plate ingot. Argon gas is then purged after casting is completed.

[0058] 4. The beryllium aluminum alloy plate ingot is machined and milled to remove oxide scale. The thickness after milling is 5.0 mm. After machining, the upper and lower surfaces of the beryllium aluminum alloy plate ingot are smooth and flat.

[0059] 5. After the beryllium aluminum plate ingot with the machined and milled surface is placed into the prepared sleeve, it is hot rolled with a high processing rate.

[0060] The process conditions for high-processing-rate hot rolling are: temperature of 470℃, 14 passes, total processing rate of 79%, holding time of 28 minutes for the first pass, and holding time of 18 minutes for the remaining passes.

[0061] 6. The sheet metal obtained by hot rolling with a large processing rate is placed in a high vacuum furnace for stress relief heat treatment to eliminate the internal stress generated during the hot rolling process due to the large processing rate.

[0062] The process conditions for stress-relieving heat treatment are: temperature 494℃, holding time 105 minutes; heating time 80 minutes; cooling method is power-off cooling with the furnace.

[0063] 7. The beryllium aluminum alloy sheet after stress relief heat treatment is subjected to 6 passes of cold rolling.

[0064] The process conditions for single-pass cold rolling are as follows: rolling at room temperature with a rolling force of 30 kN at a speed of 0.3 m / s, followed by work-hardening heat treatment at 450°C for 90 minutes; the heating time is 75 minutes; and the cooling method is furnace cooling with the power off. The cold rolling yield per pass is 10.8%, and the maximum total deformation is 90%.

[0065] 8. The edges of the single-pass cold-rolled beryllium aluminum alloy sheet are trimmed to obtain a 0.5mm thick beryllium aluminum alloy sheet. The tensile strength σ of the beryllium aluminum alloy sheet at room temperature... b The yield strength is 323 MPa, and the yield strength σ is 323 MPa. 0.2 The strength is 281 MPa, and the elongation δ is 3.8%.

[0066] 9. After horizontally cutting the 0.5mm thick beryllium aluminum alloy plate into 6 small beryllium aluminum alloy plates of the same size, stack them, put them into a tungsten-molybdenum cladding, heat them to 670℃, hold them for 40 minutes, and then perform 18 passes of rolling to obtain a 0.1mm thick beryllium aluminum alloy sheet.

[0067] 10. A 0.1 mm thick beryllium-aluminum alloy sheet was subjected to 1728 passes of lubricated cold rolling to obtain a 0.05 mm thick beryllium-aluminum alloy foil. The number of reduction distributions between two heat treatments was 4, and the number of rolling passes under the same reduction distribution was 54. The process conditions for each heat treatment were: temperature 450℃, time 90 min, heating time 70 min, and cooling method: power off and furnace cooling.

[0068] The beryllium aluminum alloy sheet in this embodiment has a tensile strength of 356 MPa, a yield strength of 325 MPa, and an elongation of 4.6% at room temperature.

[0069] Example 2:

[0070] 1. Mix beryllium powder and aluminum powder evenly under vacuum at a mass ratio of 5:5 to obtain raw materials.

[0071] 2. Using a vacuum suspension melting furnace, the prepared raw materials are placed in a beryllium oxide crucible for melting at a temperature of 2.2*10. -3 Under a vacuum of Pa, at a melting temperature of 1390℃, the material was melted for 29 minutes. After all the raw materials were melted, the temperature was maintained for 28 minutes to promote full and uniform melting of the furnace charge, thus obtaining beryllium aluminum alloy melt.

[0072] 3. Under magnetic levitation stirring, using a motor-driven mode, the beryllium oxide crucible is tilted 110° at a speed of 20° / s into the graphite cavity coated with alumina. The beryllium-aluminum alloy melt in the beryllium oxide crucible is injected into the graphite cavity coated with alumina at a speed of 150ml / s within 15s. Then, the graphite cavity is preheated to 440℃, and under a vacuum and inert gas protective atmosphere, it is cast at a temperature of 1180℃ for 15s to obtain a 6.0mm thick beryllium-aluminum plate ingot. Argon gas is then purged after casting is completed.

[0073] 4. The beryllium aluminum alloy plate ingot is machined and milled to remove oxide scale. The thickness after milling is 5.0 mm. After machining, the upper and lower surfaces of the beryllium aluminum alloy plate ingot are smooth and flat.

[0074] 5. After the beryllium aluminum plate ingot has been machined and milled, it is placed into the prepared sleeve and then hot rolled at a high processing rate.

[0075] The process conditions for high-processing-rate hot rolling are: temperature of 450℃, 15 passes, total processing rate of 80%, holding time of 30 minutes for the first pass, and holding time of 20 minutes for the remaining passes.

[0076] 6. The sheet metal obtained by hot rolling with a large processing rate is placed in a high vacuum furnace for stress relief heat treatment to eliminate the internal stress generated during the hot rolling process due to the large processing rate.

[0077] The process conditions for stress-relieving heat treatment are: temperature 534℃, holding time 116 minutes; heating time 120 minutes; cooling method is power-off cooling with the furnace.

[0078] 7. The beryllium aluminum alloy sheet after stress relief heat treatment is subjected to 12 cold rolling passes.

[0079] The process conditions for single-pass cold rolling are as follows: rolling at room temperature with a rolling force of 50 kN at a speed of 0.5 m / s, followed by work-hardening heat treatment at 480℃ for 114 minutes; the heating time is 90 minutes; and the cooling method is furnace cooling with the power off. The cold rolling pass yield is 11%, and the maximum total deformation is 90%.

[0080] 8. The edges of the single-pass cold-rolled beryllium aluminum alloy sheet are trimmed to obtain a 0.25mm thick beryllium aluminum alloy sheet. Tensile strength σ at room temperature. b The yield strength is 333 MPa, and the yield strength σ is 333 MPa. 0.2 It has a strength of 297 MPa and an elongation δ of 4.2%.

[0081] 9. After horizontally cutting the 0.25mm thick beryllium aluminum alloy plate into 5 small beryllium aluminum alloy plates of the same size, stack them, put them into a tungsten molybdenum cladding, heat them to 660℃, hold them for 35 minutes, and then perform 16 passes of rolling to obtain a 0.08mm thick beryllium aluminum alloy sheet.

[0082] 10. A 0.08mm thick beryllium-aluminum alloy sheet was subjected to 2496 passes of lubricated cold rolling to obtain a 0.02mm beryllium-aluminum alloy foil. The number of reduction passes between two heat treatments was 3, and the number of rolling passes under the same reduction pass was 52. The process conditions for each heat treatment were: temperature 400℃, time 60min, heating time 62min, and cooling method was power-off furnace cooling.

[0083] The beryllium aluminum alloy sheet in this embodiment has a tensile strength of 373 MPa, a yield strength of 332 MPa, and an elongation of 5.2% at room temperature.

[0084] Example 3:

[0085] 1. Mix beryllium powder and aluminum powder evenly under vacuum at a mass ratio of 7:3 to obtain raw materials.

[0086] 2. A vacuum suspension melting furnace is used. The prepared raw materials are placed in a beryllium oxide crucible and melted at a temperature of 1.6*10. -3 Under a vacuum of Pa, at a melting temperature of 1360℃, the material was melted for 28 minutes. After all the raw materials were melted, the temperature was maintained for 33 minutes to promote full and uniform melting of the furnace charge, thus obtaining beryllium aluminum alloy melt.

[0087] 3. Under magnetic levitation stirring, using a motor-driven mode, the beryllium oxide crucible is tilted -10° at a speed of 15° / s into the graphite cavity coated with alumina. The beryllium-aluminum alloy melt in the beryllium oxide crucible is injected into the graphite cavity coated with alumina at a speed of 50ml / s within 10s. Then, the graphite cavity is preheated to 360℃, and under a vacuum and inert gas protective atmosphere, it is cast at a temperature of 1160℃ for 10s to obtain a 6.0mm thick beryllium-aluminum plate ingot. Argon gas is then purged after casting is completed.

[0088] 4. The beryllium aluminum alloy plate ingot is machined and milled to remove oxide scale. The thickness after milling is 5.0 mm. After machining, the upper and lower surfaces of the beryllium aluminum alloy plate ingot are smooth and flat.

[0089] 5. After the beryllium aluminum plate ingot has been machined and milled, it is placed into the prepared sleeve and then hot rolled at a high processing rate.

[0090] The process conditions for high-processing-rate hot rolling are: temperature of 330℃, 12 passes, total processing rate of 78%, holding time of 25 minutes for the first pass, and holding time of 15 minutes for the remaining passes.

[0091] 6. The sheet metal obtained by hot rolling with a large processing rate is placed in a high vacuum furnace for stress relief heat treatment to eliminate the internal stress generated during the hot rolling process due to the large processing rate.

[0092] The process conditions for stress-relieving heat treatment are: temperature 475℃, holding time 94 minutes; heating time 60 minutes; cooling method is power-off cooling with the furnace.

[0093] 7. The beryllium aluminum alloy sheet after stress relief heat treatment is subjected to one cold rolling pass.

[0094] The process conditions for single-pass cold rolling are as follows: rolling at room temperature with a rolling force of 20 kN at a speed of 0.2 m / s, followed by work-hardening heat treatment at 420°C for 66 minutes; the heating time is 60 minutes; and the cooling method is furnace cooling with the power off. The cold rolling yield per pass is 10.6%, and the maximum total deformation is 90%.

[0095] 8. The edges of the single-pass cold-rolled beryllium aluminum alloy sheet are trimmed to obtain a 1.0 mm thick beryllium aluminum alloy sheet. The tensile strength σ at room temperature is... b The yield strength is 283 MPa, and the yield strength σ is 283 MPa. 0.2 It has a strength of 257 MPa and an elongation δ of 3.5%.

[0096] 9. After horizontally cutting a 1.0mm thick beryllium aluminum alloy plate into 8 smaller beryllium aluminum alloy plates of the same size, stacking them, placing them in a tungsten-molybdenum cladding, heating to 680℃, holding for 50 minutes, and then performing 20 passes of rolling to obtain a 0.12mm thick beryllium aluminum alloy sheet.

[0097] 10. A 0.12mm thick beryllium-aluminum alloy sheet was subjected to 1160 passes of lubricated cold rolling to obtain a 0.08mm beryllium-aluminum alloy foil. The number of reduction passes between two heat treatments was 5, and the number of rolling passes under the same reduction pass was 58. The process conditions for each heat treatment were: temperature 500℃, time 120min, heating time 87min, and cooling method: power off and furnace cooling.

[0098] The beryllium aluminum alloy sheet in this embodiment has a tensile strength of 352 MPa, a yield strength of 318 MPa, and an elongation of 4.5% at room temperature.

[0099] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing beryllium aluminum alloy foil, characterized in that, The preparation method includes the following steps: Step S1: Cut the beryllium aluminum alloy sheet into multiple small beryllium aluminum alloy sheets of the same size and stack them. In step S1, the preparation process of the beryllium aluminum alloy sheet includes: Step S11: Under vacuum conditions, mix beryllium powder and aluminum powder in a mass ratio of 5~7:3~5, place the mixture in a beryllium oxide crucible, and then... Under the conditions of vacuum and inert gas protective atmosphere, beryllium aluminum alloy melt is obtained by suspension melting at 1360~1460℃ for 28~33 minutes and then holding at the temperature. Step S12: Under magnetic levitation stirring, the beryllium aluminum alloy melt in the beryllium oxide crucible is injected into the graphite cavity coated with alumina at a speed of 50~150ml / s within 10~15s. Then, the graphite cavity is preheated to 360~480℃ and cast at 1160~1190℃ for 10~15s under vacuum and inert gas protective atmosphere to obtain beryllium aluminum plate ingot. Step S13: The beryllium aluminum plate ingot is machined and milled, then clad and fitted, and then the machined and milled beryllium aluminum plate ingot is placed into the cladding and subjected to high-rate hot rolling, stress-relief heat treatment and 20-22 passes of cold rolling in sequence. The process conditions for high-processing-rate hot rolling are as follows: temperature is 330~620℃, number of passes is 12~15, total processing rate is 78~80%, first pass is held for 25~30 minutes, and the remaining passes are held for 15~20 minutes. The process conditions for the stress-relief heat treatment are as follows: temperature is 475℃~546℃, holding time is 94~116 minutes, heating time is 60~120 minutes, and cooling method is power-off cooling with furnace. The process conditions for each cold rolling pass are as follows: at room temperature, rolling is performed with a rolling force of 20~50KN at a speed of 0.2~0.5m / s, followed by work hardening heat treatment at 420℃~480℃ for 66~114 minutes; the heating time is 60~90 minutes; the cooling method is to cool the furnace with the power off. Step S2: After stacking multiple small beryllium aluminum alloy plates, put them into a tungsten-molybdenum cladding and heat them to 660~680℃, hold for 35~50 minutes, and then perform multiple rolling passes to obtain beryllium aluminum alloy thin plates. Step S3: Perform multiple passes of lubrication cold rolling and heat treatment on the beryllium aluminum alloy sheet to obtain beryllium aluminum alloy foil.

2. The preparation method according to claim 1, characterized in that, In step S13, the cold rolling pass processing rate for each cold rolling pass is 10.6~11%, and the maximum total deformation of cold rolling is 90%.

3. The preparation method according to claim 2, characterized in that, In step S2, the thickness of the beryllium aluminum alloy sheet is 0.08~0.12mm.

4. The preparation method according to claim 3, characterized in that, In step S2, the number of passes in the multi-pass rolling process is 16 to 20.

5. The preparation method according to claim 4, characterized in that, In step S3, the number of passes in the lubricated cold rolling process is 1160 to 2496.

6. The preparation method according to claim 5, characterized in that, In step S3, the number of reduction distributions between the two heat treatments in the multi-pass lubricated cold rolling is 3 to 5 times; the number of rolling passes under the same reduction distribution is 52 to 58.

7. The preparation method according to claim 6, characterized in that, The process conditions for each heat treatment are as follows: temperature 400~500℃, time 60~120min, heating time 62~87min, and cooling method is power off and furnace cooling.

8. The preparation method according to claim 7, characterized in that, The thickness of the beryllium aluminum alloy foil is 0.02~0.08mm.