Multilayer composite structure of dissimilar titanium alloy

Abstract

The invention discloses a dissimilar titanium alloy multilayer composite structure. Modularized corrugated units are adopted as basic constituent elements, a complex hollow interlayer structure is constructed through single corrugations, multi-layer corrugations and composite variants of the single corrugations, the multi-layer corrugations and the composite variants of the single corrugations, the design flexibility and the bearing efficiency of the structure are remarkably improved, the pneumatic and mechanical property requirements are met, meanwhile, the weight of the structure is greatly reduced, and the cost is reduced. And an effective technical path is provided for light weight of aerospace equipment. The structure can be expanded to more levels from three layers, four layers and other basic levels, and is suitable for various hollow components including the tail edge of an aero-engine. All the layers are integrally manufactured by adopting a superplastic forming and diffusion bonding combined process, so that the interface bonding quality is ensured, and meanwhile, the structural function and lightweight requirements are considered. According to the gradient corrugated angle design, precast block integration and the like, the function integration and the working condition adaptability of the structure are further enhanced, and important engineering application value and popularization prospects are achieved.

Description

Technical Field

[0001] This invention relates to the technical field of superplastic forming, and in particular to a multilayer composite structure of dissimilar titanium alloys. Background Technology

[0002] With the increasing demand for lightweight structures in aerospace equipment, hollow structures have become one of the mainstream technologies for reducing structural weight. Superplastic forming, as an advanced metal structure forming process, plays an increasingly important role in the manufacturing of complex aerospace components. However, while traditional titanium alloys such as TC4 have relatively mature processes for superplastic forming and diffusion bonding, Ti2AlNb-based dissimilar titanium alloys are difficult to directly adopt using traditional titanium alloy hollow sandwich structure manufacturing methods due to significant differences in their superplastic deformation capacity and diffusion bonding performance. These materials exhibit poor fluidity at high temperatures, a narrow forming window, and are prone to problems such as inhomogeneous microstructure and insufficient bonding strength at the diffusion bonding interface, limiting their application in complex hollow components. Therefore, there is an urgent need to develop a novel hollow composite structure and its forming process suitable for Ti2AlNb dissimilar titanium alloys. Summary of the Invention

[0003] This invention provides a multi-layer composite structure of dissimilar titanium alloys. Specifically addressing the technological challenges faced by Ti2AlNb-based alloys in the forming of hollow sandwich structures, it proposes a combined structure based on single corrugations or multi-layer corrugations. This effectively solves the technical bottlenecks of poor structural integrity, insufficient connection strength, and difficulty in shape control during the superplastic forming process of this type of material, enabling the reliable manufacturing of high-performance, lightweight hollow components.

[0004] In a first aspect, a multilayer composite structure of dissimilar titanium alloys is provided, comprising a first shell layer, a second shell layer, and N corrugated layers stacked together, wherein the N corrugated layers are located between the first shell layer and the second shell layer, and N≥1; wherein, among the N corrugated layers, there is a target corrugated layer, and the area in contact between the target corrugated layer and the adjacent layer includes a diffusion connection region; furthermore, in the edge region of the multilayer composite structure, the area in contact between the target corrugated layer and the adjacent layer is a pressing edge region; two adjacent diffusion connection regions are respectively in contact with and connected to the upper and lower layers of the target corrugated layer, and the area in the target corrugated layer connected between the two adjacent diffusion connection regions forms a corrugated angle with the upper or lower layer.

[0005] In conjunction with the first aspect, in some implementations of the first aspect, the corrugated angle is taken as 30° to 75°.

[0006] In conjunction with the first aspect, in some implementations of the first aspect, the target corrugated layer forms multiple corrugated angles with the upper or lower layer at the same angle.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, the target corrugated layer forms multiple corrugated angles with the upper or lower layer at different angles.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, at least two of the following angles are selected from multiple corrugated angles of different angles: 30°, 45°, 60°, and 75°.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the corrugated angle formed by the target corrugated layer in the central region is smaller than the corrugated angle formed by the target corrugated layer in the edge region.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the first shell forms a cavity, and the depth of the cavity decreases from the first side to the second side, and the corrugated angle of the target corrugated layer gradually decreases from the first side to the second side.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, when N is an even number, the multi-layer composite structure is symmetrically set.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, when N=1, the first shell forms a cavity, a single corrugated layer is housed in the cavity of the first shell, and the second shell is a flat cover for sealing the cavity formed by the first shell.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the width of the diffusion connection region is 18–22 mm.

[0014] Compared with the prior art, the solution provided by the present invention has at least the following beneficial technical effects:

[0015] This invention proposes a superplastic forming / diffusion bonding multilayer composite structure suitable for dissimilar titanium alloys such as Ti2AlNb, breaking through the process limitations of traditional hollow sandwich structure manufacturing for this type of material, and providing a new structural paradigm for high-performance complex hollow components. By introducing single-corrugated, multi-corrugated, and composite configurations, the design flexibility and load-bearing efficiency of the structure are significantly improved. While meeting aerodynamic and mechanical performance requirements, the structure achieves substantial weight reduction, providing an effective technical path for lightweighting aerospace equipment.

[0016] The gradient corrugated corner design and prefabricated block integration methods proposed in this invention further enhance the functional integration and adaptability of the structure to different working conditions, and have significant engineering application value and promotion prospects. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the SPF / DB forming process for a Ti2AlNb three-layer composite structure.

[0018] Figure 2 This is a schematic diagram of the SPF / DB forming process for a four-layer Ti2AlNb composite structure.

[0019] Figure 3 A schematic diagram of the SPF / DB forming of the trailing edge structure of Ti2AlNb with preformed blocks. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0021] This invention provides a multilayer composite structure of dissimilar titanium alloys, comprising a first shell layer, a second shell layer, and N corrugated layers stacked together, wherein the N corrugated layers are located between the first and second shell layers, and N ≥ 1. Among the N corrugated layers, there is a target corrugated layer, and the region where the target corrugated layer contacts the adjacent layers includes a diffusion connection region (corresponding to...). Figure 1 and Figure 2 The diffusion layer). Additionally, in the edge region of the multilayer composite structure, the area where the target corrugated layer and the adjacent layer contact is the pressure edge region (corresponding to...). Figure 1 and Figure 2 (The pressing edge). Two adjacent diffusion connection regions are respectively in contact with the upper and lower layers of the target corrugated layer, and the region in the target corrugated layer connected between the two adjacent diffusion connection regions forms a corrugated angle with the upper or lower layer.

[0022] In some embodiments, the corrugated angle can be 30° to 75°.

[0023] In some embodiments, the target corrugated layer forms multiple corrugated angles with the upper or lower layer at the same angle.

[0024] In some embodiments, the target corrugated layer forms multiple corrugated angles with the upper or lower layer at different angles.

[0025] In some embodiments, the corrugated angles of different angles are selected from at least two of the following angles: 30°, 45°, 60°, and 75°.

[0026] In some embodiments, the corrugated angle formed by the target corrugated layer in the central region is smaller than the corrugated angle formed by the target corrugated layer in the edge region.

[0027] In some embodiments, the first shell forms a cavity, and the depth of the cavity decreases from the first side to the second side, and the corrugation angle of the target corrugated layer gradually decreases from the first side to the second side.

[0028] In some embodiments, when N is an even number, the multilayer composite structure is symmetrically arranged. For example, when N = 2, the first shell and the second shell are symmetrically arranged, and the two corrugated layers are symmetrically arranged.

[0029] In some embodiments, when N=1, the first housing forms a cavity, a single corrugated layer is housed in the cavity of the first housing, and the second housing is a flat cover for sealing the cavity formed by the first housing.

[0030] In some embodiments, the width of the diffusion connection region is 18–22 mm.

[0031] In summary, this invention provides a superplastic forming multilayer composite structure of dissimilar titanium alloys, particularly suitable for Ti2AlNb. Modular corrugated units are used as the basic building blocks, and complex hollow sandwich configurations are constructed through single-corrugated, multi-corrugated, and composite variants. Starting from basic three- or four-layer levels, this structure can be expanded to more layers, making it suitable for various hollow components, including the trailing edge of aero-engines. The layers are manufactured as a single unit using a combination of superplastic forming and diffusion bonding processes, ensuring interface bonding quality while balancing structural functionality and lightweight requirements.

[0032] Example 1

[0033] like Figure 1 As shown, this embodiment relates to a three-layer Ti2AlNb dissimilar titanium alloy composite structure, employing a single-corrugated basic configuration. In this embodiment, the Ti2AlNb three-layer composite structure includes a first shell layer, a second shell layer, and one corrugated layer. Except for the pressing area, the area of ​​the corrugated layer in contact with the first and second shell layers is a diffusion connection area. The diffusion connection areas on the corrugated layer alternately connect with the first and second shell layers. Two adjacent diffusion connection areas contact and connect with the first and second shell layers respectively, thereby forming a corrugated angle. In this structure, basic composite units are constructed by setting different corrugated angles (such as 30°, 45°, 60°, and 75°), and multiple combinations of corrugated angles can be used in the same structural unit to meet local load-bearing and aerodynamic shape requirements. The two sides of the structure are pressed according to the mold, with a draft angle set to 75° and a forming height of 75mm, meaning the cavity height formed by the first shell layer is approximately 75mm. The plates are bonded using diffusion bonding technology, with the diffusion layer width set at 20mm to ensure sufficient connection strength and structural integrity between the Ti2AlNb layers.

[0034] Example 2

[0035] like Figure 2As shown, this embodiment provides a four-layer Ti2AlNb dissimilar titanium alloy composite structure, employing a butt-jointed double-corrugated configuration. In this embodiment, the four-layer composite structure includes a first shell layer, a second shell layer, and two corrugated layers. The four-layer composite structure is symmetrically arranged vertically, that is, the first shell layer and the second shell layer are symmetrically arranged, and the two corrugated layers are symmetrically arranged. The corrugated layer closer to the first shell layer is corrugated layer 1, and the corrugated layer closer to the second shell layer is corrugated layer 2. Taking corrugated layer 1 as an example, corrugated layer 1 is connected to the first shell layer and corrugated layer 2 vertically, respectively. Except for the edge pressing area, the area of ​​corrugated layer 1 that contacts the first shell layer and corrugated layer 2 is the diffusion connection area of ​​corrugated layer 1. The diffusion connection area on corrugated layer 1 alternately connects with the first shell layer and corrugated layer 2. Two adjacent diffusion connection areas on corrugated layer 1 are respectively in contact with and connected to the first shell layer and corrugated layer 2, thereby forming a corrugated corner.

[0036] The structure is formed on both sides, each with a height of 75mm. It can also utilize various corrugated angle combinations (30°, 45°, 60°, 75°) and supports gradient angle designs within the same component to achieve superior mechanical performance and spatial adaptability. The inter-plate connections employ a diffusion bonding process, with the diffusion layer width also controlled at 20mm to ensure the quality of the multi-layer interface bonding and overall load-bearing capacity.

[0037] Example 3

[0038] like Figure 3 As shown, this embodiment provides a four-layer composite structure with a prefabricated Ti2AlNb tail edge. In this embodiment, the four-layer composite structure includes a first shell, a second shell, and two corrugated layers. The four-layer composite structure is symmetrically arranged vertically, that is, the first shell and the second shell are symmetrically arranged, and the two corrugated layers are symmetrically arranged. The corrugated layer closer to the first shell is corrugated layer 1, and the corrugated layer closer to the second shell is corrugated layer 2. Taking corrugated layer 1 as an example, corrugated layer 1 is connected to the first shell and corrugated layer 2 vertically. Except for the edge pressing area, the area of ​​corrugated layer 1 that contacts the first shell and corrugated layer 2 is the diffusion connection area of ​​corrugated layer 1. The diffusion connection area on corrugated layer 1 is alternately connected to the first shell and corrugated layer 2. Two adjacent diffusion connection areas on corrugated layer 1 are respectively connected to the first shell and corrugated layer 2, thereby forming a corrugated corner. In addition, the first shell forms a cavity, and the depth of the cavity decreases from the first side to the second side, and the corrugated angle formed by the corrugated layer 1 gradually decreases from the first side to the second side.

[0039] This four-layer composite tail-edge structure adopts a butt-jointed double-corrugated form and incorporates a progressive corrugation angle design concept. Specifically, the corrugation angle gradually changes continuously or segmentally from the small end to the large end of the tail-edge to achieve a smooth transition between the aerodynamic shape and internal support. This design not only improves the overall stiffness and fatigue performance of the tail-edge structure, but also ensures the uniformity of material flow and shape stability during superplastic forming.

[0040] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. A heterogeneous titanium alloy multilayer composite structure, characterized by, The multilayer composite structure comprises a first shell layer, a second shell layer and N corrugated layers arranged in a stack, the N corrugated layers being located between the first shell layer and the second shell layer, and N≥1; wherein, one of the N corrugated layers is a target corrugated layer, and a region where the target corrugated layer contacts with an adjacent layer comprises a diffusion connection region; in addition, in an edge region of the multilayer composite structure, the region where the target corrugated layer contacts with the adjacent layer is a press edge region; The two adjacent diffusion connection regions are in contact with an upper layer and a lower layer of the target corrugated layer, respectively, and a region of the target corrugated layer connected between the two adjacent diffusion connection regions forms a corrugated angle with the upper layer or the lower layer.

2. The structure of claim 1, wherein The corrugated angle is 30°-75°.

3. The structure of claim 1, wherein The target corrugated layer forms a plurality of corrugated angles with the upper layer or the lower layer, and the corrugated angles have the same angle.

4. The structure of claim 1, wherein The target corrugated layer forms a plurality of corrugated angles with the upper layer or the lower layer, and the corrugated angles have different angles.

5. The structure of claim 4, wherein The plurality of corrugated angles with different angles are selected from at least two of the following angles: 30°, 45°, 60° and 75°.

6. The structure of claim 4, wherein The corrugated angle formed by the target corrugated layer in a central region is smaller than the corrugated angle formed by the target corrugated layer in an edge region.

7. The structure of claim 4, wherein The first shell layer forms a cavity, and the depth of the cavity decreases from a first side to a second side, and the corrugated angle formed by the target corrugated layer gradually decreases from the first side to the second side.

8. The structure of claim 1, wherein When N is even, the multilayer composite structure is symmetrically arranged.

9. The structure of claim 1, wherein When N=1, the first shell forms a cavity, the single corrugated layer is accommodated in the cavity of the first shell, and the second shell is a flat cover body for covering the cavity formed by the first shell.

10. The structure of claim 1, wherein The width of the diffusion connection region is 18-22 mm.

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