A high-strength titanium alloy / aluminum alloy layered composite plate and its preparation method

Abstract

This invention discloses a high-strength titanium alloy / aluminum alloy layered composite sheet, prepared by explosive bonding, heat treatment strengthening and stress-relief annealing, heat treatment microstructure regulation, and machining of titanium alloy and aluminum alloy. The preparation method includes: 1. Selecting the sheet material; 2. Full annealing heat treatment; 3. Leveling, grinding and polishing, followed by cleaning and air drying; 4. Preparing the composite blank; 5. Explosive bonding to obtain the layered composite blank. The composite sheet of this invention achieves initial bonding and interface sealing through explosive bonding, followed by heat treatment strengthening and stress-relief annealing to improve interface bonding strength and eliminate some stress. Further heat treatment microstructure regulation further improves bonding strength and eliminates stress. The composite sheet undergoes initial leveling and aluminum alloy microstructure restoration, followed by fine leveling and machining to improve surface quality, resulting in a layered composite sheet with large area, good formability, high flatness, high bonding strength, and good surface quality, suitable for electronics, aerospace, shipbuilding, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a high-strength titanium alloy / aluminum alloy layered composite plate and its preparation method. Background Technology

[0002] Titanium (alloy) / aluminum (alloy) layered composite sheets, as a typical type of layered metal composite material, have broad application prospects in electronics, aerospace, and shipbuilding. Literature review shows that titanium / aluminum layered composite sheets using pure titanium and pure aluminum as raw materials are currently the most theoretically researched and have the most mature preparation technology; however, the strength, impact resistance, high-temperature resistance, and corrosion resistance of this type of titanium / aluminum layered composite material are relatively low, making it difficult to meet current product requirements. Correspondingly, titanium alloy / aluminum alloy layered metal composite materials using titanium alloys and aluminum alloys as raw materials exhibit superior comprehensive performance, thus creating a more urgent application demand.

[0003] Currently, the main methods for preparing titanium alloy / aluminum alloy layered composite sheets include hot-pressing composite, rolling composite, and explosive composite. From a composite technology perspective, hot-pressing composite preparation of titanium alloy / aluminum alloy layered composite materials faces challenges such as limited composite sheet size specifications, compound formation at the interface, and low interfacial bonding strength. Rolling composite technology faces problems such as severe incompatibility in deformation between titanium and aluminum alloys, high rolling composite difficulty, and low interfacial bonding strength. In contrast, explosive composite technology is a composite method integrating pressure welding, diffusion welding, and fusion welding. This method utilizes the chemical energy released by explosives to convert into energy during the composite process of the base and cladding plates. It leverages the intense plastic deformation and jet formation at the interface during the collision of the base and cladding plates to achieve a solid-state connection of the composite materials through metallurgical bonding. It offers advantages such as high bonding strength, no change to the properties of the base and cladding plates, no need for specialized equipment, high production efficiency, and the ability to produce large-format composite sheets. Therefore, explosive composite technology is often chosen as the preparation technology for titanium alloy / aluminum alloy composite sheets.

[0004] However, due to the poor compatibility between titanium alloys and aluminum alloys, their deformation capacity is significantly reduced compared to pure titanium and pure aluminum, and the differences in their physicochemical properties are further widened. This leads to three main challenges in the current use of single explosive bonding technology to prepare titanium alloy / aluminum alloy layered composite sheets: first, low bonding strength; second, poor formability, making it difficult to prepare large-format composite sheets; and third, the difficulty in achieving a balance between bonding strength and composite sheet size. Furthermore, for thinner titanium alloy / aluminum alloy composite sheets, leveling is difficult after explosive bonding hardening, resulting in poor surface quality and flatness – another urgent problem to be solved. Summary of the Invention

[0005] The technical problem this invention aims to solve is to address the shortcomings of the prior art by providing a high-strength titanium alloy / aluminum alloy layered composite sheet. This composite sheet is formed by explosive bonding of titanium alloy and aluminum alloy to achieve initial bonding and interface sealing. It is then strengthened through heat treatment and stress-relief annealing to improve interface bonding strength and eliminate some stress. Further heat treatment and microstructure regulation further enhance bonding strength and eliminate stress. The composite sheet undergoes initial leveling and aluminum alloy microstructure restoration, followed by fine leveling and machining to improve surface quality. This results in a titanium alloy / aluminum alloy layered composite sheet with a large surface area, good formability, high flatness, high bonding strength, and excellent surface quality. This solves the problem of achieving synergistic bonding strength and surface area coordination in titanium alloy / aluminum alloy layered composite sheets, as well as the difficulty in leveling them.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a high-strength titanium alloy / aluminum alloy layered composite plate, characterized in that it is prepared by a combination of explosive bonding, heat treatment strengthening and stress-relieving annealing, heat treatment microstructure control and machining of titanium alloy and aluminum alloy; the dimensional specifications of the titanium alloy / aluminum alloy layered composite plate meet the following requirements: length ≥ 800mm, width ≥ 800mm, and surface area 0.64m. 2 The thickness of the titanium alloy layer is 1mm to 5mm, and the thickness of the aluminum alloy layer is 2mm to 12mm; the bonding performance meets the following requirements: interlayer bonding strength is above 140MPa; the tensile properties meet the following requirements: yield strength Rp 0.2 ≥430MPa, tensile strength Rm≥550MPa, elongation after fracture A≥10%; surface quality meets the following requirements: flatness ≤0.2mm / 100mm, roughness Ra≤2μm.

[0007] Explosive bonding can achieve one-time molding of the substrate and cladding materials without significantly altering their microstructure and properties. This, combined with subsequent low-temperature heat treatment and stress-relief annealing, yields a composite plate with high interfacial bonding strength. However, due to the poor deformability of titanium and aluminum alloys, obtaining titanium-aluminum alloy layered composite plates with high interfacial bonding strength requires higher explosive energy. Higher explosive energy leads to the titanium and aluminum alloys being more prone to cracking, resulting in poorer formability and limiting the size of the composite plate. Furthermore, the flatness and surface quality are also poor. In other words, achieving a balance between bonding strength and size in the composite plate is difficult, creating an unresolved contradiction in the preparation of titanium / aluminum alloy layered composite plates. Additionally, thin titanium / aluminum alloy composite plates are difficult to level after explosive bonding hardening.

[0008] Compared to titanium and aluminum materials, titanium alloys and aluminum alloys have higher strength and lower ductility and toughness, which increases the difference between the two. Direct explosive bonding faces the challenge of high explosive bonding energy, high bonding strength, poor formability of composite plate, and small composite plate size, as well as low explosive bonding energy, low bonding strength, better formability of composite plate, and large composite plate size. To address the aforementioned problems, this invention first employs a relatively small explosive energy for explosive bonding, achieving the welding of titanium alloy and aluminum alloy with low bonding strength but large surface area, resulting in a pre-bonded titanium alloy / aluminum alloy composite slab and achieving interface sealing. Then, heat treatment is used for strengthening. Due to the difference in interatomic diffusion capabilities between titanium alloy and aluminum alloy, and the good solid solubility of aluminum in titanium, heat treatment effectively improves the interfacial bonding strength while simultaneously achieving stress-relief annealing. Next, heat treatment is used to regulate the microstructure, further enhancing the interfacial bonding strength and relieving stress, thus achieving composite plate leveling and restoring the microstructure of the raw aluminum alloy damaged by explosive bonding and heat treatment. Finally, machining improves the surface quality, ultimately yielding a titanium alloy / aluminum alloy layered composite slab with a large surface area, good formability, high flatness, high bonding strength, and excellent surface quality.

[0009] The aforementioned high-strength titanium alloy / aluminum alloy layered composite plate is characterized in that the titanium alloy is derived from α-type or near-α-type titanium alloys of the TA series (TA5-TA10 grades), α+β-type dual-phase titanium alloys of the TC series (TC1-TC4 grades), and β-type or near-β-type titanium alloys of the TB series (TB2, TB5 grades); the titanium alloy has an elongation at break (A) ≥ 12% and a thickness of 2mm-6mm, and serves as a cladding layer in the titanium alloy / aluminum alloy layered composite plate. The preparation method of this invention is applicable to a wide range of titanium alloys, thus expanding the application scope of the method.

[0010] The aforementioned high-strength titanium alloy / aluminum alloy layered composite sheet is characterized in that the aluminum alloy is derived from 2-series 2Al2Al and 2014Al, 6-series 6061Al and 6013Al, and 7-series 7050Al and 7055Al; the aluminum alloy is in a solution-treated or annealed state, with an elongation after fracture A ≥ 12% and a thickness of 4mm to 14mm, and serves as the base layer in the titanium alloy / aluminum alloy layered composite sheet.

[0011] This invention ensures the deformability of aluminum alloys and titanium alloys by limiting their elongation after fracture and thickness, thereby ensuring the smooth progress of explosive bonding.

[0012] Meanwhile, this invention also discloses a method for preparing the high-strength titanium alloy / aluminum alloy layered composite plate as described above, characterized in that the method includes the following steps:

[0013] Step 1: Select the corresponding size of titanium alloy sheet and aluminum alloy sheet according to the size specifications of the target product, titanium alloy / aluminum alloy layered composite sheet.

[0014] Step 2: Perform a full annealing heat treatment on the titanium alloy sheet selected in Step 1. The heat treatment regime is to hold at 650℃~870℃ for 10min~120min. Perform a full annealing heat treatment on the aluminum alloy sheet selected in Step 1. The heat treatment regime is to hold at 320℃~415℃ for 1h~3h.

[0015] Step 3: Level, grind and polish the titanium alloy and aluminum alloy plates that have undergone full annealing heat treatment in Step 2 until the roughness Ra≤10μm, then clean the surface with ethanol and air dry.

[0016] Step 4: Using the air-dried titanium alloy sheet from Step 3 as the cladding plate and the air-dried aluminum alloy as the substrate, a rigid metal support is placed in the gap between the cladding plate and the substrate, and then fixed to obtain a titanium alloy / aluminum alloy composite blank; the gap between the cladding plate and the substrate is 4mm to 18mm.

[0017] Step 5: In the titanium alloy / aluminum alloy composite slab obtained in Step 4, the surface of the titanium alloy cladding is coated with a grease protective layer, and gypsum board is laid under the aluminum alloy substrate. Then, an explosive composite is carried out using an emulsion explosive or ammonium nitrate explosive with powder as the main component. The explosive height is 30mm to 40mm, and the detonation velocity is 1600m / s to 2400m / s, to obtain a titanium alloy / aluminum alloy layered composite slab.

[0018] The above-described preparation method is characterized in that, in step four, an intermediate layer is added between the substrate and the cladding plate. This intermediate layer is TA1 titanium or TA2 titanium, with a thickness of 1mm to 2mm. The intermediate layer is first leveled, surface-ground, and polished until the roughness Ra ≤ 10μm. Then, the surface is cleaned with ethanol and air-dried. The air-dried intermediate layer is then bonded to the cladding plate titanium alloy sheet using an explosive bonding method. Finally, it is bonded to the substrate aluminum alloy sheet in step five to prepare a titanium alloy / aluminum alloy layered composite slab. This invention adds a titanium intermediate layer between the substrate and the cladding plate before explosive bonding to prepare the titanium alloy / aluminum alloy composite slab. The intermediate layer is first bonded to the titanium alloy sheet via explosive bonding. The introduction of the titanium intermediate layer, on the one hand, coordinates the deformation of the titanium alloy sheet during the explosive bonding process, protecting the cladding titanium alloy sheet; on the other hand, it blocks the interdiffusion of titanium and aluminum alloy elements, reducing the content of interfacial compounds and the influence of alloy elements on the interfacial detonation shock wave.

[0019] The above-described preparation method is characterized in that the bonding strength between the substrate and the cladding in the titanium alloy / aluminum alloy layered composite slab in step five is above 80 MPa. By limiting the bonding strength between the substrate and the cladding in the titanium alloy / aluminum alloy composite slab, it is ensured that delamination will not occur at the interface during subsequent heat treatment, thus guaranteeing the successful achievement of heat treatment strengthening.

[0020] The above-described preparation method is characterized in that, after spraying an anti-oxidation coating with Al2O3 as the main component onto the surface and sides of the titanium alloy / aluminum alloy layered composite slab obtained in step five, it is placed in an air heat treatment furnace and held at 250℃~450℃ for 5h~20h for heat treatment strengthening and stress-relieving annealing. By coating the surface and sides (i.e., all six surfaces) of the titanium alloy / aluminum alloy layered composite slab with an anti-oxidation coating, surface and interface oxidation of the titanium alloy / aluminum alloy layered composite slab during heat treatment is avoided.

[0021] The above-described preparation method is characterized by subjecting the heat-treated and stress-relief annealed titanium alloy / aluminum alloy layered composite slab to solution heat treatment. The solution heat treatment regime is to hold at 460℃~540℃ for 20min~80min, followed by cooling with warm water at 60℃~100℃. By performing solution treatment on the titanium alloy / aluminum alloy layered composite slab, the aluminum alloy microstructure is softened, facilitating subsequent leveling processes.

[0022] The above-mentioned preparation method is characterized in that the titanium alloy / aluminum alloy layered composite slab blank after solution heat treatment is leveled using a straightening machine until the flatness does not exceed 0.2mm / 100mm, and then the surface is mechanically polished.

[0023] The above-described preparation method is characterized by subjecting the titanium alloy / aluminum alloy layered composite slab, after surface mechanical polishing, to aging heat treatment at 140℃~230℃ for 3h~25h. Then, it is leveled using a straightening machine until the straightness does not exceed 0.2mm / 100mm, followed by surface finishing to a roughness Ra≤2μm, thus obtaining the titanium alloy / aluminum alloy layered composite sheet. By subjecting the titanium alloy / aluminum alloy layered composite slab to aging heat treatment, the microstructure of the aluminum alloy damaged by explosive bonding, heat treatment strengthening, and stress-relief annealing is restored.

[0024] In this invention, the selected raw materials, titanium alloy plates and aluminum alloy plates, are subjected to full annealing heat treatment to reduce the hardness of the raw materials and further improve their deformation capacity. Combined with solution heat treatment and aging heat treatment after explosive bonding, the plasticity and toughness of the titanium alloy plates and aluminum alloy plates are further improved, enhancing the deformation capacity of the raw materials and ensuring the forming capacity of explosive bonding.

[0025] This invention eliminates the large deformation that occurs after explosive bonding by leveling the titanium alloy / aluminum alloy layered composite slab after solution heat treatment, and eliminates the minor deformation of the composite slab during the aging heat treatment process by leveling the titanium alloy / aluminum alloy layered composite slab after aging heat treatment, thus ensuring the flatness of the titanium alloy / aluminum alloy layered composite sheet product.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. This invention uses titanium alloy and aluminum alloy as raw materials and combines multiple methods such as explosive bonding, heat treatment strengthening and stress relief annealing, heat treatment microstructure control and machining to prepare titanium alloy / aluminum alloy layered composite plates. The titanium alloy / aluminum alloy layered composite plates have high interfacial bonding strength, excellent tensile properties, good surface quality, high flatness and large size, and are suitable for electronics, aerospace, shipbuilding and other fields.

[0028] 2. This invention employs explosive bonding combined with subsequent heat treatment and machining, which not only improves the deformation bonding ability of titanium alloy and aluminum alloy, realizing the composite of titanium alloy / aluminum alloy layered composite plates, but also enables the control of the microstructure, bonding strength, residual stress surface quality, and flatness of the titanium alloy / aluminum alloy layered composite plates. The preparation process is controllable, simple, and flexible.

[0029] 3. This invention uses explosive bonding to prepare titanium alloy / aluminum alloy layered composite slabs, which does not require special equipment, has low cost, and can realize the preparation of large-format composite slabs with high bonding strength.

[0030] 4. This invention uses explosive bonding combined with subsequent heat treatment and machining to overcome the technical difficulties of titanium alloy / aluminum alloy layered composite plates, such as difficulty in bonding, low bonding strength, large residual stress, and difficulty in leveling.

[0031] 5. Through the ingenious design of the heat treatment process, this invention not only achieves interface strengthening and stress-relieving annealing, but also realizes the leveling of the composite plate, solving the problem of difficulty in leveling thin titanium alloy / aluminum alloy composite plates after explosive composite hardening.

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the titanium alloy / aluminum alloy layered composite plate of the present invention without the addition of an intermediate layer.

[0034] Figure 2 This is a schematic diagram of the structure of the titanium alloy / aluminum alloy layered composite plate of the present invention with an intermediate layer added.

[0035] Figure 3 This is a physical image of the TC4 titanium alloy / 6061Al alloy layered composite slab prepared in Example 1 of the present invention.

[0036] Figure 4 This is a low-magnification image of the interfacial metallographic structure of the TC4 titanium alloy / 6061Al alloy layered composite plate prepared in Example 1 of the present invention.

[0037] Figure 5 This is a high-magnification image of the interfacial metallographic structure of the TC4 titanium alloy / 6061Al alloy layered composite plate prepared in Example 1 of the present invention.

[0038] Figure 6 This is a low-magnification image of the interfacial metallographic structure of the TC4 titanium alloy / 6061Al alloy layered composite slab after heat treatment prepared in Example 1 of the present invention.

[0039] Figure 7 This is a high-magnification image of the interfacial metallographic structure of the TC4 titanium alloy / 6061Al alloy layered composite slab after heat treatment prepared in Example 1 of the present invention.

[0040] Figure 8 The image shows the interfacial metallographic structure of the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite plate prepared in Example 2 of this invention.

[0041] Figure 9 for Figure 8 Enlarged view of the metallographic structure within the square frame in the middle interface.

[0042] Figure 10 for Figure 8 Enlarged view of the metallographic structure within the square frame in the middle interface.

[0043] Figure 11 The TC4 titanium alloy / TA1 titanium alloy prepared in Example 2 of this invention after heat treatment

[0044] High magnification image of the interfacial metallographic structure of a 6061Al alloy layered composite slab.

[0045] Figure 12 The TC4 titanium alloy / TA1 titanium alloy prepared in Example 2 of this invention after heat treatment

[0046] Low magnification image of the interfacial metallographic structure of a 6061Al alloy layered composite slab. Detailed Implementation

[0047] like Figure 1 As shown, the titanium alloy / aluminum alloy layered composite plate of the present invention is composed of titanium alloy and aluminum alloy; as Figure 2 As shown, the titanium alloy / aluminum alloy layered composite plate of the present invention is composed of titanium alloy, aluminum alloy and a titanium intermediate layer located between the two.

[0048] Example 1

[0049] The titanium alloy / aluminum alloy layered composite plate of this embodiment is prepared by a combination of explosive bonding, heat treatment strengthening and stress-relieving annealing, heat treatment microstructure control and machining of titanium alloy and aluminum alloy; the method includes the following steps:

[0050] Step 1: Based on the size specifications of the target product, titanium alloy / aluminum alloy layered composite plate, select TC4 titanium alloy plate with a length × width × thickness of 1000mm × 1000mm × 2mm and 6061Al alloy plate with a length × width × thickness of 1000mm × 1000mm × 4mm as raw materials.

[0051] Step 2: Perform a full annealing heat treatment on the TC4 titanium alloy plate selected in Step 1 by holding it at 720℃ for 20 minutes, and perform a full annealing heat treatment on the 6061Al alloy plate selected in Step 1 by holding it at 380℃ for 120 minutes.

[0052] Step 3: Using machining, the titanium alloy sheet and aluminum alloy sheet that have undergone full annealing heat treatment in Step 2 are leveled, the surface oxide layer is removed by grinding and polished to a roughness Ra = 10μm. Then, the surface oil stains are cleaned with acetone and ethanol and air-dried.

[0053] Step 4: Using the TC4 titanium alloy sheet that has been air-dried in Step 3 as the cladding plate and the 6061Al alloy that has been air-dried as the substrate, a hard metal support is placed in the gap between the cladding plate and the substrate, and then fixed to obtain a TC4 titanium alloy / 6061Al alloy composite slab blank; the gap between the cladding plate and the substrate is 10mm.

[0054] Step 5: In the TC4 titanium alloy / 6061Al alloy composite slab obtained in Step 4, the surface of the cladding titanium alloy plate is coated with a grease protective layer, and gypsum board is laid under the base aluminum alloy plate. Then, the composite is detonated using an emulsion explosive with powder as the main component. The explosive height is 35mm and the detonation velocity is 1800m / s, resulting in the TC4 titanium alloy / 6061Al alloy layered composite slab.

[0055] Step 6: After cleaning the TC4 titanium alloy / 6061Al alloy layered composite slab obtained in Step 5, spray an anti-oxidation coating with Al2O3 as the main component on the surface and sides, and place it in an air heat treatment furnace. Heat treatment and stress relief annealing are carried out at a temperature of 370℃ for 10 hours.

[0056] Step 7: The TC4 titanium alloy / 6061Al alloy layered composite slab that has undergone heat treatment strengthening and stress relief annealing in Step 6 is subjected to solution heat treatment at 530℃ for 40 minutes, then cooled with warm water at 60℃~100℃, and then the TC4 titanium alloy / 6061Al alloy layered composite slab after solution heat treatment is leveled using a straightening machine until the flatness is below 0.15mm / 100mm, and then the surface is mechanically polished.

[0057] Step 8: The TC4 titanium alloy / 6061Al alloy layered composite slab, after surface mechanical polishing in Step 7, undergoes aging heat treatment at 160℃ for 17 hours. Then, it is leveled using a straightening machine until the flatness is below 0.15mm / 100mm. Finally, it is surface-finished using a grinding machine until the roughness Ra ≤ 1.5μm, yielding the TC4 titanium alloy / 6061Al alloy layered composite sheet. A schematic diagram of the structure is shown below. Figure 1 As shown.

[0058] Figure 3 Here is a physical image of the TC4 titanium alloy / 6061Al alloy layered composite slab prepared in this embodiment. Figure 3 It can be seen that the TC4 titanium alloy / 6061Al alloy layered composite slab has a length greater than 900 mm, a width greater than 800 mm, and a total surface area exceeding 0.72 m. 2 .

[0059] Figure 4 and Figure 5 These are low-magnification and high-magnification images of the interfacial metallographic structure of the TC4 titanium alloy / 6061Al alloy layered composite plate prepared in this embodiment. Figure 4 and Figure 5 It can be seen that the interface of the TC4 titanium alloy / 6061Al alloy layered composite plate forms a certain wave-like bond, but the wave formation is not obvious, the interface bonding is good, and no obvious defects are observed.

[0060] The interfacial tensile and shear strength of the TC4 titanium alloy / 6061Al alloy layered composite slab prepared in this embodiment was tested, and the results are shown in Table 1 below.

[0061] Table 1

[0062]

[0063] As can be seen from Table 1, the average interfacial bonding strength of the TC4 titanium alloy / 6061Al alloy layered composite slab is 127 MPa.

[0064] Figure 6 and Figure 7The images shown are low-magnification and high-magnification images of the interfacial metallographic structure of the TC4 titanium alloy / 6061Al alloy layered composite slab after heat treatment (step eight) prepared in this embodiment. Figure 6 and Figure 7 It can be seen that the interface of the heat-treated TC4 titanium alloy / 6061Al alloy layered composite slab does not have obvious defects such as compounds or pores, and the interface bonding is good.

[0065] The interfacial tensile shear strength, tensile properties, roughness and straightness of the TC4 titanium alloy / 6061Al alloy layered composite plate prepared in this embodiment after heat treatment were tested, and the results are shown in Tables 2 to 4 below.

[0066] Table 2

[0067]

[0068] As can be seen from Table 2, the average interfacial bonding strength of the TC4 titanium alloy / 6061Al alloy layered composite plate is 172 MPa. Compared with Table 1, it can be seen that the interfacial bonding strength of the TC4 titanium alloy / 6061Al alloy layered composite billet is significantly enhanced after heat treatment.

[0069] Table 3

[0070]

[0071] As can be seen from Table 3, the TC4 titanium alloy / 6061Al alloy layered composite plate has excellent tensile properties, with a tensile strength of 562 MPa, a yield strength of 539 MPa, and an elongation after fracture of 14%.

[0072] Table 4

[0073]

[0074] As can be seen from Table 4, the roughness and flatness of the TC4 titanium alloy / 6061Al alloy layered composite plate meet the requirements after final heat treatment and machining.

[0075] Testing revealed that the tensile properties of the TC4 titanium alloy / 6061Al alloy layered composite plate prepared in this embodiment meet the following requirements: yield strength Rp 0.2 ≥430MPa, tensile strength Rm≥550MPa, elongation after fracture A≥10%; surface quality meets the following requirements: flatness ≤0.2mm / 100mm, roughness Ra≤2μm.

[0076] In this embodiment, the TC4 titanium alloy sheet can also be replaced with α-type or near-α-type titanium alloys of grades TA5 to TA10 from the TA series, α+β-type duplex titanium alloys of grades TC1 to TC4 from the TC series other than TC4 titanium alloy, and β-type or near-β-type titanium alloys of grades TB2 and TB5 from the TB series; the elongation after fracture of the titanium alloy is ≥12%, and the thickness is 2mm to 6mm; the 6061Al alloy sheet in this embodiment can also be replaced with 2Al2Al and 2014Al from the 2 series, 6013Al from the 6 series, and 7050Al and 7055Al from the 7 series; the aluminum alloy is in the solution-treated or annealed state, with an elongation after fracture of ≥12% and a thickness of 3mm to 12mm.

[0077] Example 2

[0078] The difference between this embodiment and Embodiment 1 is as follows: In step four, a 2mm thick TA1 titanium interlayer is added between the substrate and the cladding. The TA1 titanium interlayer is first leveled, surface-ground, and polished until the roughness Ra ≤ 10μm. Then, the surface is cleaned with ethanol and air-dried. The TA1 titanium interlayer is then bonded to the air-dried TC4 titanium alloy sheet using an explosive bonding method. Finally, a hard metal support is installed and the air-dried 6061Al alloy is used to fix it, resulting in a TC4 titanium alloy / TA1 titanium / 6061Al alloy composite blank. In step five, an explosive bonding process is used to obtain a TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite blank. Steps six through eight are then performed to obtain the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite sheet, as shown in the schematic diagram below. Figure 2 As shown.

[0079] Figure 8 The image shows the interfacial metallographic structure of the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite plate prepared in this embodiment. Figure 8 It can be seen that the interface of the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite plate is well bonded, and no defects such as pores or cracks are found.

[0080] Figure 9 for Figure 8 Enlarged view of the metallographic structure within the square frame in the middle interface. Figure 10 for Figure 8 The magnified metallographic structure of the square frame in the middle interface, from Figure 9 and Figure 10 It can be seen that in the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite plate, both the TC4 / TA1 and TA1 / 6061Al interfaces form a wave-like bond, but the wave formation is more obvious at the TC4 / TA1 interface.

[0081] The interfacial tensile and shear strength of the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite slab prepared in this embodiment was tested, and the results are shown in Table 5 below.

[0082] Table 5

[0083]

[0084] As can be seen from Table 5, the average bonding strengths of the TC4 / TA1 and TA1 / 6061Al interfaces are 157 MPa and 134 MPa, respectively, indicating that the TA1 / 6061Al interface in the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite slab is a weak interface with a lower bonding strength than the TC4 / TA1 side.

[0085] Figure 11 and Figure 12 The images show the low-magnification and high-magnification microstructure of the interface metallographic structure of the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite slab prepared by the present invention after heat treatment (step eight). Figure 11 and Figure 12 It can be seen that the interface of the heat-treated TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite slab does not show obvious defects such as compounds or pores.

[0086] The interfacial tensile shear strength of the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite plate prepared in this embodiment after heat treatment was tested, and the results are shown in Table 6 below.

[0087] Table 6

[0088]

[0089] As can be seen from Table 6, the average bonding strength of the TC4 / TA1 and TA1 / 6061Al interfaces is 230MPa and 164MPa, respectively. Compared with Table 5, it can be seen that the bonding strength of the TC4 / TA1 and TA1 / 6061Al interfaces in the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite plate is significantly improved after heat treatment.

[0090] Testing revealed that the tensile properties of the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite plate prepared in this embodiment meet the following requirements: yield strength Rp 0.2 ≥430MPa, tensile strength Rm≥550MPa, elongation after fracture A≥10%; surface quality meets the following requirements: flatness ≤0.2mm / 100mm, roughness Ra≤2μm.

[0091] Example 3

[0092] The difference between this embodiment and embodiment 1 is that: in step five, sand is laid under the aluminum alloy plate of the substrate, and then ammonium nitrate oil explosive is used for detonation and compounding. The explosive height is 30mm and the detonation velocity is 1700m / s.

[0093] Testing showed that the bonding performance of the TC4 titanium alloy / 6061Al alloy layered composite plate prepared in this embodiment met the following requirements: interlayer bonding strength was above 140 MPa; tensile properties met the following requirements: yield strength Rp 0.2 ≥430MPa, tensile strength Rm≥550MPa, elongation after fracture A≥10%; surface quality meets the following requirements: flatness ≤0.2mm / 100mm, roughness Ra≤2μm.

[0094] Example 4

[0095] The difference between this embodiment and Embodiment 1 is that in step six, after cleaning the TC4 titanium alloy / 6061Al alloy layered composite slab, it is directly subjected to heat treatment strengthening and stress relief annealing in a vacuum heat treatment furnace, instead of spraying an anti-oxidation coating with Al2O3 as the main component on its surface and sides.

[0096] Testing showed that the bonding performance of the TC4 titanium alloy / 6061Al alloy layered composite plate prepared in this embodiment met the following requirements: interlayer bonding strength was above 140 MPa; tensile properties met the following requirements: yield strength Rp 0.2 ≥430MPa, tensile strength Rm≥550MPa, elongation after fracture A≥10%; surface quality meets the following requirements: flatness ≤0.2mm / 100mm, roughness Ra≤2μm.

[0097] Example 5

[0098] The differences between this embodiment and Embodiment 1 are as follows: the 6061Al alloy plate in step one is replaced with a 2A12 alloy plate with a thickness of 4mm; the temperature for the complete annealing heat treatment of the 2A12 alloy plate in step two is 360℃, and the holding time is 120min; the temperature for the solution heat treatment in step seven is 495℃, and the holding time is 50min; and the temperature for the aging heat treatment in step eight is 190℃, and the holding time is 10h.

[0099] Testing showed that the bonding performance of the TC4 titanium alloy / 6061Al alloy layered composite plate prepared in this embodiment met the following requirements: interlayer bonding strength was above 140 MPa; tensile properties met the following requirements: yield strength Rp 0.2 ≥430MPa, tensile strength Rm≥550MPa, elongation after fracture A≥10%; surface quality meets the following requirements: flatness ≤0.2mm / 100mm, roughness Ra≤2μm.

[0100] Example 6

[0101] The difference between this embodiment and embodiment 2 is that in step four, a 1mm thick TA1 titanium layer is added between the substrate and the cladding as an intermediate layer.

[0102] Testing revealed that the tensile properties of the TC4 titanium alloy / TA1 titanium / 6061Al alloy layered composite plate prepared in this embodiment meet the following requirements: yield strength Rp 0.2 ≥430MPa, tensile strength Rm≥550MPa, elongation after fracture A≥10%; surface quality meets the following requirements: flatness ≤0.2mm / 100mm, roughness Ra≤2μm.

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A high-strength titanium alloy / aluminum alloy layered composite sheet material, characterized by comprising: The titanium alloy / aluminum alloy layered composite plate is prepared by the method of explosion compounding of titanium alloy and aluminum alloy, heat treatment strengthening and stress relief annealing, heat treatment organization regulation and mechanical processing, and the size specification of the titanium alloy / aluminum alloy layered composite plate meets: length of 800 mm or more, width of 800 mm or more, and surface width of 0.64 m 2 The titanium alloy layer has a thickness of 1 mm to 5 mm, and the aluminum alloy layer has a thickness of 2 mm to 12 mm; the bonding performance meets: interlayer bonding strength of 140 MPa or more; the tensile performance meets: yield strength Rp 0.2 ≥430 MPa, tensile strength Rm≥550 MPa, and elongation A≥10%; the surface quality meets: flatness of 0.2 mm / 100 mm or less, and roughness Ra≤2 μm; The preparation method of the titanium alloy / aluminum alloy layered composite plate comprises the following steps: Step one, according to the size specification of the target product titanium alloy / aluminum alloy layered composite plate, select the corresponding size of titanium alloy plate and aluminum alloy plate; Step two, the titanium alloy plate selected in step one is subjected to complete annealing heat treatment, and the heat treatment system is 10 min~120 min at 650℃~870℃, and the aluminum alloy plate selected in step one is subjected to complete annealing heat treatment, and the heat treatment system is 1h~3h at 320℃~415℃; Step three, the titanium alloy plate and the aluminum alloy plate after complete annealing heat treatment in step two are leveled, surface polished and polished to a roughness Ra≤10μm, then the surface is cleaned with ethanol and air dried; Step four, the titanium alloy plate after air drying in step three is used as a cover plate, the aluminum alloy plate after air drying is used as a base plate, and a hard metal support is arranged in the gap between the cover plate and the base plate, then fixed, to obtain a titanium alloy / aluminum alloy composite plate blank; the gap distance between the cover plate and the base plate is 4mm~18mm; Step five, the titanium alloy plate surface of the titanium alloy / aluminum alloy composite plate blank obtained in step four is coated with a butter protection layer, and a gypsum board is laid under the aluminum alloy plate, then ammonium oil explosive is used for explosive compounding, the explosive height is 30mm~40mm, and the detonation rate is 1600m / s~2400m / s, to obtain a titanium alloy / aluminum alloy layered composite plate blank; The surface and side of the titanium alloy / aluminum alloy layered composite plate blank are sprayed with an oxidation-resistant coating with Al2O3 as the main component, and then placed in an air heat treatment furnace for heat treatment strengthening and stress relief annealing at a temperature of 250℃~450℃ for 5h~20h; The titanium alloy / aluminum alloy layered composite plate blank after heat treatment strengthening and stress relief annealing is subjected to solid solution heat treatment at 460℃~540℃ for 20min~80min, and then cooled with water at 60℃~100℃; The titanium alloy / aluminum alloy layered composite plate blank after solid solution heat treatment is leveled by a straightening machine to a flatness of not more than 0.2mm / 100mm, and then subjected to surface mechanical polishing treatment; The titanium alloy / aluminum alloy layered composite plate blank after surface mechanical polishing treatment is subjected to aging heat treatment at 140℃~230℃ for 3h~25h, then leveled by a straightening machine to a flatness of not more than 0.2mm / 100mm, and then subjected to surface finishing to a roughness Ra≤2μm, to obtain a titanium alloy / aluminum alloy layered composite plate.

2. The high-strength titanium alloy / aluminum alloy layered composite sheet according to claim 1, characterized in that, The titanium alloy is derived from TA series TA5~TA10 brand alpha or near alpha titanium alloy, TC series TC1~TC4 brand alpha+beta two-phase titanium alloy, and TB series TB2, TB5 brand beta or near beta titanium alloy; the elongation A of the titanium alloy in step one is ≥12%, and the thickness is 2mm~6mm.

3. The high-strength titanium alloy / aluminum alloy layered composite sheet according to claim 1, characterized in that, The aluminum alloy is 2A12Al, 2014Al of 2 series, 6061Al, 6013Al of 6 series, and 7050Al, 7055Al of 7 series; the aluminum alloy plate in step one is in a solid solution state or an annealing state, and the elongation A after breaking is greater than or equal to 12%, and the thickness is 4mm-14mm.

4. The high-strength titanium alloy / aluminum alloy layered composite sheet according to claim 1, characterized in that, In step four, an intermediate layer is added between the base plate and the cover plate, the intermediate layer is TA1 titanium or TA2 titanium, the thickness is 1mm-2mm, the intermediate layer is first leveled, surface polished and polished to a roughness Ra of less than or equal to 10um, then the surface is cleaned with ethanol and air dried, the air dried intermediate layer is combined on the cover plate titanium alloy plate by explosion compounding, and then the base plate aluminum alloy plate is explosion compounded in step five to prepare a titanium alloy / aluminum alloy layered composite plate blank.

5. The high-strength titanium alloy / aluminum alloy layered composite sheet according to claim 1, characterized in that, In step five, the bonding strength of the base plate and the cover plate in the titanium alloy / aluminum alloy layered composite plate blank is greater than or equal to 80MPa.

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