Method for preparing composite board with the aid of hetero-energy field and composite board

Abstract

The application provides a composite plate, which is obtained by laminating and pressing a laminated base body, the laminated base body comprising Ti2AlNb plates and TA15 titanium alloy plates which are alternately laminated, and a diffusion layer is formed at the interface of the Ti2AlNb plates and the TA15 titanium alloy plates after pressing, and the grain morphology of the diffusion layer evolves from coarse grains to fine grains when observed from the TA15 side to the Ti2AlNb side, a gradient structure is formed at the interface, and the grains on the TA15 side and the Ti2AlNb side in the diffusion layer region are mainly α2 / O phases. The application also provides a method for preparing the composite plate by using a heterogeneous energy field. The method is beneficial to improving the tensile strength and the toughness. The method for preparing the composite plate is combined with a pretreatment step by using a heterogeneous energy field, so that the hot-pressing of the heterogeneous metal plates can be realized at a lower temperature, a lower pressure and a shorter time, thereby being beneficial to inhibiting the generation of brittle intermetallic compounds caused by 'high temperature-high pressure-long time', and promoting the formation of a diffusion layer mainly composed of α2 / O phases.

Description

Technical Field

[0001] This invention relates to the technical field of heterogeneous metal layered composite materials, specifically to a method for preparing composite plates with heterogeneous energy field assistance and the composite plates themselves. Background Technology

[0002] Ti2AlNb intermetallic compounds have become candidate materials for hot-end components of next-generation aerospace engines due to their excellent high-temperature strength, creep resistance, and low density. TA15 titanium alloy, on the other hand, is a near-α-type titanium alloy with excellent comprehensive properties, including good room-temperature plasticity, weldability, and thermal stability. Theoretically, combining these two materials to prepare layered composite plates can fully leverage the toughness of TA15 alloy and the high-temperature resistance of Ti2AlNb alloy, achieving gradient design and optimization of material properties to meet the requirements of complex high-temperature and high-load conditions.

[0003] However, due to the significant differences in physical properties (such as coefficient of thermal expansion and elastic modulus) and crystal structure between TA15 and Ti2AlNb, the composite plates produced by the commonly used rolling composite method and explosive composite method have poor high-temperature mechanical properties, which restricts their application in aerospace hot-end components. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a composite plate in which a diffusion layer is formed at the interface between heterogeneous metal layers, and a gradient diffusion layer mainly composed of α2 / O phase is formed, which is beneficial to improving the tensile strength and toughness of the composite plate.

[0005] This application also provides a method for preparing composite plates with the assistance of heterogeneous energy fields. Through the synergistic pretreatment steps of heterogeneous energy fields, hot pressing composite between heterogeneous metal plates can be achieved with lower temperature, pressure and less time. This helps to suppress the formation of brittle intermetallic compounds caused by "high temperature-high pressure-long time" and promotes the formation of a gradient diffusion layer dominated by α2 / O phase.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: A composite sheet is obtained by laminating a laminated matrix, wherein the laminated matrix comprises alternating layers of Ti2AlNb sheet and TA15 titanium alloy sheet. After lamination, a diffusion layer is formed at the interface between the Ti2AlNb sheet and the TA15 titanium alloy sheet. When viewed from the TA15 side to the Ti2AlNb side, the grain morphology of the diffusion layer evolves from coarse grains to fine grains, forming a gradient structure at the interface. The grains on both the TA15 side and the Ti2AlNb side in the diffusion layer region are dominated by the α2 / O phase.

[0007] In some possible implementations, the grain structure of the diffusion layer is equiaxed.

[0008] In some possible implementations, one of the TA15 titanium alloy plates is placed between two of the Ti2AlNb plates.

[0009] In some possible implementations, the thickness of the diffusion layer is 20-30 µm.

[0010] This application also provides a method for preparing composite panels with the assistance of a different energy field, the method comprising the following steps: The TA15 titanium alloy sheet was placed in a liquid nitrogen environment, and the sheet temperature was gradually brought up to the liquid nitrogen temperature. Then, the cryogenically treated TA15 titanium alloy sheet was left to stand at room temperature until the sheet temperature reached room temperature, thus completing the cryogenic energy field treatment of the TA15 titanium alloy sheet. The surface of the Ti2AlNb substrate to be composited is treated with a laser energy field. The TA15 titanium alloy plate treated with ultra-low temperature energy field and the Ti2AlNb plate treated with laser energy field are stacked together, so that the surface of the Ti2AlNb plate to be composited is attached to the surface of the TA15 titanium alloy plate, thus obtaining a pretreated body. The pretreated body was subjected to vacuum hot-press diffusion welding. After welding, the pressure was released, and the plate was cooled to room temperature in the furnace to obtain a composite plate. The parameters for vacuum hot-press diffusion welding included: welding temperature of 950-1050 ℃, pressure of 15-25 MPa, hot-pressing time of 40-60 min, and vacuum degree of not less than 5×10 - ³ Pa.

[0011] In some possible implementations, the TA15 titanium alloy sheet is cooled to liquid nitrogen temperature at a rate of 1-5 °C / min, and the cryogenic treatment time of the TA15 titanium alloy sheet is greater than or equal to 60 min.

[0012] In some possible implementations, the maximum temperature of the laser in the laser energy field is controlled at 900-1050 °C.

[0013] In some possible implementations, the laser energy field uses a pulsed laser with a laser scanning speed of 300-800 mm / s, a scanning line spacing of 30-100 μm, and a vertical distance of 20-30 mm between the laser head of the laser system and the outer surface of the Ti2AlNb substrate.

[0014] In some possible implementations, the laser energy field treatment causes the surface to be composited to form an array of micro-pits or micro-grooves, and the tilt angle between the laser head and the Ti2AlNb substrate is 0°.

[0015] In some possible implementations, the following steps are also included: Before the TA15 titanium alloy sheet undergoes ultra-low temperature energy field treatment, surface stains on the surface to be composited are removed by grinding, cleaning, and drying. Before the Ti2AlNb substrate is subjected to laser energy field treatment, surface stains on the surface to be composited are removed by grinding, cleaning and drying. Before lamination, the surfaces of the Ti2AlNb plate and the TA15 titanium alloy plate to be laminated are sequentially subjected to ultrasonic cleaning with acetone and wiping with anhydrous ethanol. Before hot pressing, a release agent is sprayed onto the top and bottom surfaces of the pretreated body along the stacking direction and then air-dried. After hot pressing, the release agent on the surface of the composite board is removed.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In this application, a diffusion layer is formed at the interface between the Ti2AlNb plate and the TA15 titanium alloy plate after lamination. When viewed from the TA15 side to the Ti2AlNb side, the grain structure of the diffusion layer evolves from coarse grains to fine grains, forming a gradient structure at the interface. This is beneficial for improving the tensile strength of the composite plate as well as its toughness.

[0017] In this application, the combined pretreatment steps of cryogenic treatment and laser energy field enable hot pressing composite between dissimilar metal plates to be achieved with lower temperature, pressure and less time. This helps to suppress the formation of brittle intermetallic compounds caused by "high temperature-high pressure-long time" and promotes the formation of a gradient diffusion layer dominated by α2 / O phase. This, in turn, can improve the tensile strength of the composite plate while also improving its toughness.

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 Metallographic image (a) and corresponding backscattered electron (BSE) image (b) of the interface microstructure of the composite plate provided in Embodiment 1 of this application.

[0020] Figure 2 This is a schematic diagram of the stacked structure of Ti2AlNb plate and TA15 titanium alloy plate in one embodiment.

[0021] Figure 3Stress-strain curves of the composite plates provided in Example 1 and Comparative Example 1.

[0022] Figure 4 Backscattered electron (BSE) image of the interface microstructure of the composite material provided in Example 2.

[0023] Figure 5 The stress-strain curve of the composite plate provided in Example 2.

[0024] Figure 6 Backscattered electron (BSE) pattern of the interface microstructure of the composite material provided in Example 3.

[0025] Figure 7 The stress-strain curve of the composite plate provided in Example 3.

[0026] Explanation of reference numerals in the attached figures: 10-Ti2AlNb plate; 20-TA15 titanium alloy plate; 30-diffusion layer. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0028] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are constructed to distinguish different objects, not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The accompanying drawings only depict the stacking relationship between different layers and do not limit their thickness relationships.

[0029] Reference Figure 1 and Figure 2This application provides a composite sheet material, which is obtained by laminating a laminated matrix. The laminated matrix includes alternating layers of Ti2AlNb sheet 10 and TA15 titanium alloy sheet 20. After lamination, a diffusion layer 30 is formed at the interface between the Ti2AlNb sheet 10 and the TA15 titanium alloy sheet 20. When viewed from the TA15 side to the Ti2AlNb side, the grain morphology of the diffusion layer 30 evolves from coarse grains to fine grains, forming a gradient structure at the interface. The grains on both the TA15 side and the Ti2AlNb side in the diffusion layer region are dominated by the α2 / O phase (the grain phase in the diffusion layer region in the specific embodiment can be seen from the provided interface microstructure image).

[0030] In this application, a diffusion layer 30 is formed at the interface between the Ti2AlNb plate 10 and the TA15 titanium alloy plate 20 after lamination. When viewed from the TA15 side to the Ti2AlNb side, the grain structure of the diffusion layer 30 evolves from coarse grains to fine grains, forming a gradient structure at the interface. This is beneficial for improving the tensile strength of the composite plate while also improving its toughness.

[0031] In some embodiments, the grain structure of the diffusion layer 30 is equiaxed. Equiaxed grains can reduce stress concentration caused by anisotropic structures, making the stress distribution at the interface more uniform. The equiaxed grain structure can coordinate the plastic deformation of the matrix on both sides of the interface, inhibit the initiation and propagation of cracks at the interface, improve the strength of the composite material, improve the interface toughness and plasticity matching, and avoid brittle interface failure.

[0032] In some embodiments, a TA15 titanium alloy plate 20 is placed between two Ti2AlNb plates 10.

[0033] In some embodiments, the thickness of the diffusion layer 30 is 20-30 µm. The appropriate thickness of the diffusion layer helps to achieve an optimal balance between atomic diffusion and interfacial properties. A moderate diffusion layer thickness ensures sufficient interdiffusion between the two components, forming a stable and reliable metallurgical bond and guaranteeing interfacial bonding strength; it also prevents softening of the interfacial region, grain coarsening, or excessive precipitation of brittle phases due to an excessively thick diffusion layer, thus preventing a decrease in interfacial toughness.

[0034] This application also provides a method for preparing composite plates using a different energy field. The method is used to prepare the aforementioned composite plates, specifically, by pressing alternately stacked Ti2AlNb plates 10 and TA15 titanium alloy plates 20 together, a diffusion layer 30 is formed at the interface. When viewed from the TA15 side towards the Ti2AlNb side, the grain morphology of the diffusion layer 30 evolves from coarse to fine grains, forming a gradient structure at the interface. The grains on both the TA15 side and the Ti2AlNb side within the diffusion layer 30 region are predominantly α2 / O phase. The method includes the following steps.

[0035] The TA15 titanium alloy sheet 20 is placed in a liquid nitrogen environment, gradually raising its temperature to the liquid nitrogen temperature. After cryogenic treatment, the TA15 titanium alloy sheet 20 is then left to stand at room temperature until it reaches room temperature, completing the cryogenic energy field treatment of the TA15 titanium alloy sheet 20. For example, the TA15 titanium alloy sheet 20 can be millimeter-thick or thicker. For example, if further adjustments to the dimensions of the TA15 titanium alloy sheet 20 are needed, it can be cut to a predetermined aspect ratio using wire cutting. For example, the liquid nitrogen temperature can include -196 °C.

[0036] In some embodiments, the TA15 titanium alloy sheet 20 is cooled to liquid nitrogen temperature at a rate of 1-5 °C / min, and the cryogenic treatment time of the TA15 titanium alloy sheet 20 is greater than or equal to 60 min. This treatment parameter can induce lattice distortion within the material, generating high-density dislocations and leading to dislocation pile-up, which helps to improve the alloy strength. It also allows TA15 to more effectively resist plastic deformation during hot pressing, resulting in tight physical contact at the interface and thus eliminating obvious pores at the interface.

[0037] In some embodiments, the method further includes the steps of: before the TA15 titanium alloy sheet 20 undergoes cryogenic energy field treatment, removing surface stains from the surface to be laminated by means of polishing (e.g., polishing with a wire brush until a metallic luster appears), cleaning (e.g., ultrasonic cleaning with acetone for 20 minutes or more, and further, rinsing with ethanol after ultrasonic cleaning), and drying (e.g., drying with hot air or drying in an oven). The cleaning steps are primarily to prevent oil stains from affecting the bonding strength of the laminate.

[0038] The surface of the Ti2AlNb plate 10 to be laminated is treated with a laser energy field. It is understood that the laser treatment of the Ti2AlNb plate and the cryogenic treatment of the TA15 titanium alloy plate 20 can be performed simultaneously or sequentially; that is, cryogenic treatment can be performed first followed by laser treatment, or vice versa. For example, the Ti2AlNb plate 10 can be selected with a thickness of millimeters or greater.

[0039] In some embodiments, the maximum temperature of the laser in the laser energy field is controlled at 900-1050 °C. Preferably, the laser energy field uses a pulsed laser with a laser scanning speed of 300-800 mm / s, a scanning line spacing of 30-100 μm, and a vertical distance of 20-30 mm between the laser head of the laser system and the outer surface of the Ti2AlNb substrate. These laser energy field parameters, on the one hand, form a clean, highly surface-active remelted layer through surface micro-melting; on the other hand, the rapid laser melting refines the surface structure and even forms an amorphous state, greatly increasing the surface activation energy of the material, providing more nucleation sites for atomic bonding, and thus improving the diffusion ability of atoms. Furthermore, these processing parameters can prevent the formation of macroscopic cracks.

[0040] In some embodiments, laser energy field treatment causes the surface to be composited to form an array of micro-pits or micro-grooves, and the tilt angle between the laser head and the Ti2AlNb substrate is 0°.

[0041] In some embodiments, the method may further include the steps of: before the Ti2AlNb plate 10 is treated with laser energy field, removing surface stains from the surface to be laminated by means of grinding (e.g., grinding with a wire brush until a metallic luster appears), cleaning (e.g., ultrasonic cleaning with acetone, the ultrasonic cleaning time can be 20 minutes or more, and further, rinsing with ethanol after ultrasonic cleaning), and drying (e.g., drying with hot air or drying in an oven).

[0042] A TA15 titanium alloy plate 20 treated with an ultra-low temperature energy field and a Ti2AlNb plate 10 treated with a laser energy field are stacked together, so that the surface of the Ti2AlNb plate 10 to be composited is attached to the surface of the TA15 titanium alloy plate 20, thus obtaining a pre-treated body. It can be understood that, according to the stacking settings, a TA15 titanium alloy plate 20 can be placed between two Ti2AlNb plates 10, so that the Ti2AlNb plate 10 forms the top and bottom layers of the pre-treated body in the stacking direction.

[0043] In some embodiments, the method further includes the steps of: before lamination, performing acetone ultrasonic cleaning and anhydrous ethanol wiping on the surfaces of the Ti2AlNb plate 10 and TA15 titanium alloy plate 20 to be laminated, thereby achieving secondary cleaning and ensuring that there are no contaminants interfering before lamination, which further helps to improve the lamination effect of the plates.

[0044] The pretreated body was subjected to vacuum hot-press diffusion welding. After welding, the pressure was released, and the plate was cooled to room temperature in the furnace to obtain the composite plate. The parameters for vacuum hot-press diffusion welding included: welding temperature of 950-1050 ℃, pressure of 15-25 MPa, hot-pressing time of 40-60 min, and vacuum degree of not less than 5×10⁻⁶. -³ Pa. This application achieves rapid composite between dissimilar metals through relatively gentle hot pressing parameters, thanks to the synergistic pretreatment steps of cryogenic treatment and laser energy field, which reduces thermal damage to the matrix properties and avoids the formation of brittle intermetallic compounds caused by high temperature and high pressure, thus reducing the toughness of the composite plate.

[0045] In some embodiments, the method further includes the steps of: spraying a release agent onto both the top and bottom surfaces of the pre-treated body along the lamination direction before hot pressing and air drying; and removing the release agent from the surface of the composite board after hot pressing. Exemplarily, the release agent can be removed by mechanical grinding or ultrasonic cleaning. Exemplarily, the release agent may include boron nitride, and its function is to facilitate the smooth demolding of the hot-pressed composite board.

[0046] In this application, the combined pretreatment steps of cryogenic treatment and laser energy field enable hot pressing composite between dissimilar metal plates to be achieved with lower temperature, pressure and less time. This helps to suppress the formation of brittle intermetallic compounds caused by "high temperature-high pressure-long time" and promotes the formation of a gradient diffusion layer dominated by α2 / O phase. This, in turn, can improve the tensile strength of the composite plate while also improving its toughness.

[0047] The following detailed examples illustrate this.

[0048] Example 1 Machining: TA15 titanium alloy sheet 20 (2 mm thick) and Ti2AlNb sheet 10 (2 mm thick) were selected and wire-cut into rectangles of 72 mm × 38 mm. The surfaces of the two sheets to be laminated were then subjected to the following steps: polishing with a wire brush until a metallic luster appeared, ultrasonic cleaning with acetone for 20 minutes, rinsing with ethanol, and drying. Wire cutting to the predetermined size was done for ease of laboratory operation.

[0049] Heterogeneous energy field processing: The TA15 titanium alloy sheet 20 was immersed in liquid nitrogen in a beaker (the sheet was placed in a liquid nitrogen environment) and cooled to -196 ℃ (liquid nitrogen temperature) at a rate of 5 ℃ / min, and held at this temperature for 60 min. The sheet was then removed and allowed to stand at room temperature until it reached room temperature. The Ti2AlNb sheet 10 was then subjected to laser treatment on the surface to be composited. The laser energy field parameters were: wavelength 1064 nm, pulse width in the nanosecond range, scanning speed 300-800 mm / s, scanning line spacing 30-100 μm, and average laser power of 20–100 W. The laser energy field treatment resulted in a micro-dimple array on the surface to be composited. The tilt angle between the laser head and the Ti2AlNb sheet 10 was 0°, and the vertical distance from the laser head to the outer surface of the Ti2AlNb sheet 10 was 30 mm.

[0050] After the two plates were treated, the composite surfaces were ultrasonically cleaned with acetone for 10 minutes and wiped with ethanol. The surfaces of the two plates to be composited were then quickly aligned and placed into a graphite mold coated with boron nitride release agent. This process was used to stack the TA15 titanium alloy plate 20 treated with ultra-low temperature energy field and the Ti2AlNb plate 10 treated with laser energy field, thus obtaining the pretreated body.

[0051] Hot pressing process: The mold containing the pre-treated body is placed in a vacuum hot press furnace and evacuated to a vacuum level of 5×10. - ³ Pa. The temperature was increased to 1000℃ (welding temperature) at a rate of 10℃ / min. The β-phase transformation point of TA15 is approximately 980℃, and the B2 phase ordering transformation temperature of Ti2AlNb is 1050℃. A pressure of 25 MPa was applied, and the temperature and pressure were maintained for 60 minutes. The pressure was immediately removed after the hot-pressing time was reached, and the plate was allowed to cool with the furnace until room temperature.

[0052] The prepared layered composite plate with a multilayered structure was removed, and the residual boron nitride coating on the surface of the plate was removed (specifically, by mechanical grinding and ultrasonic cleaning). The metallographic image of the interface microstructure of the composite plate obtained in Example 1 is shown below. Figure 1 As shown in (a), the interface is straight, and the grain structure exhibits a gradient change from the TA15 side to the Ti2AlNb side. There are no obvious micropores or continuous brittle oxides, and the crystal plane bonding quality is good. The corresponding diffusion layer thickness is 20-30 µm. The corresponding backscattered electron (BSE) image is shown below. Figure 1 As shown in (b), the grain structure is equiaxed crystal after hot pressing. The composite plate obtained in Example 1 has a tensile strength of 671.57 MPa and an elongation of 9.52%.

[0053] Comparative Example 1 The difference from Example 1 is that the TA15 titanium alloy plate 20 was not cryogenically treated, the Ti2AlNb plate 10 was not treated with a laser energy field, the hot pressing temperature was 1000 ℃, the pressure was 25 MPa, the holding time was 60 minutes, and the vacuum degree was 5×10⁻⁶. - The temperature was 3 Pa, and the heating rate was 10 °C / min. The tensile strength of the composite plate obtained in Comparative Example 1 was 549.03 MPa, and the elongation was 5.72%. The stress-strain curves of the composite plates of Example 1 and Comparative Example 1 are shown below. Figure 3 As shown. Comparing the experimental data of uniaxial tensile tests conducted at 650 °C with those of Example 1 and Comparative Example 1, it was found that the high-temperature comprehensive performance of the layered composite material treated with the energy field was significantly improved compared to the high-temperature performance of the untreated layered composite material.

[0054] Example 2 The difference from Example 1 lies in the holding and pressure times during the hot-pressing process. The diffusion layer thickness is 20-25µm. The holding and pressure time is set to 40 minutes, with only the holding and pressure times varied. Pressure is immediately removed after the hot-pressing time is reached, and the board is cooled with the furnace to room temperature. The backscattered electron (BSE) image of the interfacial microstructure of the composite board obtained in Example 2 is shown below. Figure 4 As shown. The composite plate obtained in Example 2 has a tensile strength of 657.01 MPa and an elongation of 8.54%. The stress-strain curves of the composite plate in Example 2 are shown below. Figure 5 As shown.

[0055] Example 3 The difference from Example 1 is that the vertical distance of the laser head is 20 mm. Only the vertical distance of the laser energy field treating the Ti2AlNb plate surface is changed; all other parameters remain the same as in Example 1. The backscattered electron (BSE) image of the interface microstructure of the composite plate obtained in Example 3 is shown below. Figure 6 As shown. The composite plate obtained in Example 3 has a tensile strength of 658.93 MPa and an elongation of 8.45%. The stress-strain curves of the composite plate in Example 3 are shown in the figure. Figure 7 As shown. The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A composite board, characterized in that, The composite plate is obtained by laminating a laminated matrix, which includes alternating layers of Ti2AlNb plate and TA15 titanium alloy plate. After lamination, a diffusion layer is formed at the interface between the Ti2AlNb plate and the TA15 titanium alloy plate. When viewed from the TA15 side to the Ti2AlNb side, the grain morphology of the diffusion layer evolves from coarse grains to fine grains, forming a gradient structure at the interface. The grains on both the TA15 side and the Ti2AlNb side in the diffusion layer region are dominated by the α2 / O phase.

2. The composite board as described in claim 1, characterized in that, The grain structure of the diffusion layer is equiaxed.

3. The composite board as described in claim 1, characterized in that, One of the TA15 titanium alloy plates is placed between two of the Ti2AlNb plates.

4. The composite board as described in claim 1, characterized in that, The thickness of the diffusion layer is 20-30 µm.

5. A method for preparing composite panels with the assistance of a heterogeneous energy field, characterized in that, The method is used to prepare the composite board according to any one of claims 1 to 4, and the method includes the following steps: The TA15 titanium alloy sheet was placed in a liquid nitrogen environment, and the sheet temperature was gradually brought up to the liquid nitrogen temperature. Then, the cryogenically treated TA15 titanium alloy sheet was left to stand at room temperature until the sheet temperature reached room temperature, thus completing the cryogenic energy field treatment of the TA15 titanium alloy sheet. The surface of the Ti2AlNb substrate to be composited is treated with a laser energy field. The TA15 titanium alloy plate treated with ultra-low temperature energy field and the Ti2AlNb plate treated with laser energy field are stacked together, so that the surface of the Ti2AlNb plate to be composited is attached to the surface of the TA15 titanium alloy plate, thus obtaining a pretreated body. The pretreated body was subjected to vacuum hot-press diffusion welding. After welding, the pressure was released, and the plate was cooled to room temperature in the furnace to obtain a composite plate. The parameters for vacuum hot-press diffusion welding included: welding temperature of 950-1050 ℃, pressure of 15-25 MPa, hot-pressing time of 40-60 min, and vacuum degree of not less than 5×10 - ³ Pa.

6. The method as described in claim 5, characterized in that, The TA15 titanium alloy sheet is cooled to liquid nitrogen temperature at a rate of 1-5 °C / min, and the cryogenic treatment time of the TA15 titanium alloy sheet is greater than or equal to 60 min.

7. The method as described in claim 6, characterized in that, The maximum temperature of the laser in the laser energy field is controlled at 900-1050 ℃.

8. The method as described in claim 7, characterized in that, The laser energy field uses a pulsed laser with a laser scanning speed of 300-800 mm / s, a scanning line spacing of 30-100 μm, and a vertical distance of 20-30 mm between the laser head of the laser system and the outer surface of the Ti2AlNb plate.

9. The method as described in claim 8, characterized in that... The laser energy field treatment causes the surface to be composited to form an array of micro-pits or micro-grooves, and the tilt angle between the laser head and the Ti2AlNb plate is 0°.

10. The method according to any one of claims 5 to 9, characterized in that... It also includes the following steps: Before the TA15 titanium alloy sheet undergoes ultra-low temperature energy field treatment, surface stains on the surface to be composited are removed by grinding, cleaning, and drying. Before the Ti2AlNb substrate is subjected to laser energy field treatment, surface stains on the surface to be composited are removed by grinding, cleaning and drying. Before lamination, the surfaces of the Ti2AlNb plate and the TA15 titanium alloy plate to be laminated are sequentially subjected to ultrasonic cleaning with acetone and wiping with anhydrous ethanol. Before hot pressing, a release agent is sprayed onto the top and bottom surfaces of the pretreated body along the stacking direction and then air-dried. After hot pressing, the release agent on the surface of the composite board is removed.

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