An ultralight aluminum-lithium-based laminated composite material and a preparation method thereof

Abstract

The present application belongs to the technical field of design and hot processing of metal matrix composites, and relates to a kind of ultra-light aluminum-lithium-based laminated composite material and a preparation method thereof.The present application uses 5A90 aluminum-lithium alloy as the main structural material, and other aluminum alloys such as industrial pure aluminum, Al-Mn alloy and Al-Si alloy are arranged in the order of 5A90 aluminum-lithium alloy / industrial pure aluminum / Al-Mn alloy / Al-Si alloy to form an ultra-light aluminum-lithium-based laminated composite material.The thickness of the base plate of 5A90 aluminum-lithium alloy is 0.6-1.2 mm, the thickness of the base plate of industrial pure aluminum is 0.03-0.06 mm, the thickness of the base plate of Al-Mn alloy is 0.08-0.12 mm, and the thickness of the base plate of Al-Si alloy is 0.08-0.12 mm.Through the reasonable use of various technical means such as thin plate laminated hot rolling, efficient welding, vacuum treatment and metal surface treatment, an ultra-light aluminum-lithium-based laminated composite material with high interfacial bonding strength, good brazing property and excellent specific stiffness is prepared.The material is designed ingeniously, combines the advantages of different grades of aluminum alloys, has high technical feasibility, and is beneficial to popularization in the fields of aerospace and electronics.

Description

Technical Field

[0001] This invention belongs to the field of design and thermal processing technology of metal matrix composites, specifically relating to an ultralight aluminum-lithium based laminated composite material and its preparation method. Background Technology

[0002] The new generation of materials for aerospace and electronics have placed more stringent design requirements on their structural quality, material stiffness, and weldability. 5A90 aluminum-lithium alloy has been rapidly developed in aerospace materials to replace conventional high-strength aluminum alloys. However, the poor brazing ability of aluminum-lithium alloy limits the flexibility of its application.

[0003] Composite materials are prepared using multiple aluminum alloys, leveraging the performance advantages of each alloy component to compensate for the application limitations of single-grade aluminum alloys. This novel aluminum-based laminated composite material, developed using this design approach, will well meet the design requirements of next-generation aerospace materials. For several different grades of aluminum alloy thin sheets, hot rolling with metal laminations is a relatively mature technology for achieving reliable bonding between different aluminum sheets. However, because Mg and Li elements in 5A90 aluminum-lithium alloy are highly reactive and easily oxidize during heating, a loose and thick oxide layer forms on the surface of the aluminum-lithium sheet. Directly using traditional rolling processes to hot-roll the aluminum-lithium sheet into laminates will severely affect the bonding quality of the lamination interface and will be difficult to meet the design requirements of aerospace materials. Summary of the Invention

[0004] The purpose of this invention is to provide an ultralight aluminum-lithium-based laminated composite material and its preparation method. The composite material uses 5A90 aluminum-lithium alloy as the main structural material and is composed of aluminum alloys with good brazing properties, such as Al-Mn and Al-Si alloys, to achieve a low density (≤2.53 g / cm³). 3 High specific stiffness (≥29.3GPa / g / cm) 3 It possesses excellent comprehensive material properties, such as easy brazing (brazed joint strength ≥74MPa).

[0005] To solve this technical problem, the technical solution of the present invention is as follows:

[0006] An ultralight aluminum-lithium-based laminated composite material is provided, which is composed of four substrate thin plates: Al-Mg-Li aluminum-lithium alloy, industrial pure aluminum, Al-Mn aluminum alloy and Al-Si aluminum alloy; the ultralight aluminum-lithium-based laminated composite material is composed of Al-Mg-Li alloy / industrial pure aluminum / Al-Mn alloy / Al-Si alloy in the structural order of Al-Mg-Li alloy / industrial pure aluminum / Al-Mn alloy / Al-Si alloy.

[0007] The aluminum-lithium-based laminated composite material is composed of four substrate thin plates: Al-Mg-Li aluminum-lithium alloy, industrial pure aluminum, Al-Mn aluminum alloy and Al-Si aluminum alloy; it is an ultra-lightweight aluminum-lithium-based laminated composite material composed of Al-Mg-Li alloy / industrial pure aluminum / Al-Mn alloy / Al-Si alloy in structural order.

[0008] The substrate thickness of the Al-Mg-Li alloy is 0.6–1.2 mm, the substrate thickness of industrial pure aluminum is 0.03–0.06 mm, the substrate thickness of the Al-Mn alloy is 0.08–0.12 mm, and the substrate thickness of the Al-Si alloy is 0.08–0.12 mm.

[0009] Specifically, the Al-Mg-Li aluminum-lithium alloy is 5A90 aluminum-lithium alloy. The Al-Mn alloy is 3A21 aluminum alloy; the Al-Si alloy is 4004 aluminum alloy.

[0010] The aluminum-lithium-based laminated composite material is obtained by hot rolling, welding, vacuum treatment, and metal surface treatment after the substrates are stacked together. The density of the prepared aluminum-lithium-based laminated composite material is ≤2.53 g / cm³. 3 Specific stiffness ≥ 29.3 GPa / g / cm 3 The joint strength after brazing is ≥74MPa.

[0011] Preferably, the industrial pure aluminum is 1060 industrial pure aluminum.

[0012] On the other hand, a method for preparing an ultralight aluminum-lithium-based multilayer composite material is provided, comprising the following steps:

[0013] Step 1

[0014] Thin plates of industrial pure aluminum, Al-Mn alloy and Al-Si alloy substrates are stacked in the structural order of industrial pure aluminum / Al-Mn alloy / Al-Si alloy. After being fixed, they are heated to 400-450°C in a heating furnace. After the materials are fully heated, they are taken out of the furnace and hot rolled in multiple passes with a single-pass reduction of 10%-20% using a metal lamination hot rolling process until the predetermined thickness is reached, to obtain the laminated plate I.

[0015] Step Two

[0016] After the rolled plate I is trimmed and cleaned, its industrial pure aluminum side is stacked on top of the 5A90 aluminum-lithium alloy substrate. The stacked edges are circumferentially welded, and an opening of about 5-10 mm is left at the intersection of the circumferential weld seams for vacuuming.

[0017] Step 3

[0018] Vacuum is drawn into the gap between the 5A90 aluminum-lithium alloy substrate and the obtained rolled plate I through the opening. After the vacuum level reaches 100-1000 Pa and is relatively stable, the opening is welded while maintaining the vacuum, thereby forming a stable low vacuum environment in the cavity between the 5A90 aluminum-lithium alloy substrate and the rolled plate I.

[0019] Step Four

[0020] The whole part with the structural characteristics of 5A90 aluminum-lithium alloy / industrial pure aluminum / Al-Mn alloy / Al-Si alloy obtained after step three is heated to 400-450°C in an air furnace. After the material is fully heated, it is quickly transferred to a rolling mill for rolling. Hot rolling is carried out with a single pass reduction of 5%-20% until the required thickness is achieved.

[0021] Step 5

[0022] The 5A90 aluminum-lithium alloy / industrial pure aluminum / Al-Mn alloy / Al-Si alloy laminated rolled sheet, which was hot-rolled into one piece in step four, was stripped of unwelded flash, sliced ​​and finished, and then annealed at a low temperature of 280℃~350℃ for 20~40min to obtain an ultra-lightweight aluminum-lithium laminated composite material.

[0023] The preparation method involves milling the surfaces of the substrates before step one: the surfaces of the 5A90 aluminum-lithium alloy, industrial pure aluminum, Al-Mn aluminum alloy and Al-Si aluminum alloy substrates to be composited are milled to remove the oxide layer and keep the surface bright.

[0024] Preferably, in step one, the substrate sheet is fixed by mechanical means.

[0025] Preferably, in step two, fusion welding or friction stir welding is used to perform through-circumferential welding on the stacked edges.

[0026] This invention proposes an ultralight aluminum-lithium-based laminated composite material. The key challenge in its preparation lies in addressing surface oxidation during the hot rolling of 5A90 aluminum-lithium alloy and preventing alloying element reactions between the 5A90 and 3A21 aluminum alloys. The process utilizes industrially pure aluminum as a transition between the 5A90 and 3A21 alloys to avoid interference between alloying elements. Furthermore, the gap between the industrially pure aluminum and the 5A90 alloy is treated with a low-vacuum to reduce the damage caused by surface oxidation of the aluminum-lithium alloy during rolling. The aluminum-lithium-based laminated composite material prepared by this invention has a density ≤2.53 g / cm³. 3 Specific stiffness ≥ 29.3 GPa / g / cm 3 The joint strength after brazing is ≥74MPa.

[0027] The beneficial effects of this invention are:

[0028] This invention proposes a novel ultralight aluminum-lithium-based laminated composite material that combines the advantages of low density, high specific stiffness, and good brazing properties, making it particularly suitable as a novel material in the aerospace field. This invention uses 5A90 aluminum-lithium alloy as the main structural material, combined with 3A21 and 4004 aluminum alloys, which have excellent brazing properties. Industrially pure aluminum is used as a transition between the 5A90 aluminum-lithium alloy and the 3A21 aluminum alloy, avoiding interference from reactions between alloying elements. Furthermore, the density of the aluminum-lithium-based laminated composite material is controlled by designing the thickness ratio of each aluminum substrate layer. Through the rational application of various techniques such as thin-plate lamination rolling, high-efficiency welding, vacuum sealing, and metal surface treatment, the prepared ultralight aluminum-lithium-based laminated composite material exhibits stable performance and high interfacial bonding strength. Attached Figure Description

[0029] To more clearly illustrate the technical solutions implemented in this invention, the accompanying drawings used in the embodiments of this invention will be briefly explained below. Obviously, the drawings described below are merely some embodiments of this invention. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0030] Figure 1 This is a schematic diagram of the preparation method of the ultralight aluminum-lithium-based composite material of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The features of various aspects of the embodiments of the present invention will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can also be practiced without these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples. The invention is not limited to any specific setups and methods provided below, but covers all improvements, substitutions, etc., to product structures and methods without departing from the spirit of the invention.

[0033] In the various accompanying drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessarily obscuring the invention.

[0034] Example 1

[0035] 5A90 aluminum-lithium alloy, 1060 industrial pure aluminum, 3A21 aluminum alloy, and 4004 aluminum alloy were selected as substrates for the aluminum-lithium-based multilayer composite material. The aluminum-lithium-based multilayer composite material was prepared according to the following steps:

[0036] Step 1

[0037] First, the surfaces of substrates such as 5A90 aluminum-lithium alloy, 1060 industrial pure aluminum, 3A21 aluminum alloy and 4004 aluminum alloy to be laminated are milled to remove the oxide layer and keep the surface bright.

[0038] Step 2

[0039] After milling in step 1, aluminum alloys of different grades such as 1060, 3A21, and 4004 are stacked in the structural order of 1060 / 3A21 / 4004, bundled and fixed with steel straps, heated to 450℃ in a heating furnace and held for 60 minutes. The laminated plate is then hot rolled in three passes with a reduction of 20% to form a continuous whole, resulting in laminated plate I.

[0040] Step 3

[0041] After the 1060 / 3A21 / 4004 stacked plate I, which was hot-rolled into one piece in step 2, was trimmed and cleaned, its 1060 pure aluminum side was stacked with the 5A90 aluminum-lithium alloy plate. Laser welding was used to perform a through-ring weld on the stacked edge, and an opening of about 10mm was left at the intersection of the ring weld.

[0042] Step 4

[0043] Vacuum the gap between the 5A90 substrate and the 1060 / 3A21 / 4004 composite laminate using the opening left in step 3. When the vacuum in the inner cavity stabilizes at 100Pa, weld the opening together to form a stable low vacuum environment between the 5A90 substrate and the laminate I.

[0044] Step 5

[0045] The 5A90 / 1060 / 3A21 / 4004 structural piece obtained in step 4 was heated to 450°C in an air furnace and held for 60 minutes. Finally, it was rolled in 3 passes with a reduction of 20%.

[0046] Step 6

[0047] The 5A90 / 1060 / 3A21 / 4004 aluminum-lithium based laminated composite material, which was hot-rolled into one piece in step 5, was trimmed of unwelded flash, sliced ​​and finished, and then annealed at 350℃ for 20 minutes.

[0048] The aluminum-lithium based laminated composite material obtained in this embodiment has the following substrate thicknesses: 5A90 aluminum-lithium alloy substrate with a thickness of 0.8 mm, 1060 industrial pure aluminum substrate with a thickness of 0.03 mm, 3A21 aluminum alloy substrate with a thickness of 0.09 mm, and 4004 aluminum alloy substrate with a thickness of 0.09 mm. The density of the laminated composite plate is 2.52 g / cm³. 3 After overall tensile testing, its breaking strength reached 363 MPa, and its specific stiffness was 29.7 GPa / g / cm. 3 The results of the interface shear test showed that the interface strength was 104 MPa. The aluminum-lithium based laminated composite material was brazed in a vacuum brazing furnace. There were no obvious defects at the weld, and the joint strength was 77 MPa.

[0049] Example 2

[0050] 5A90 aluminum-lithium alloy, 1060 industrial pure aluminum, 3A21 aluminum alloy, and 4004 aluminum alloy were selected as substrates for the aluminum-lithium-based multilayer composite material. The aluminum-lithium-based multilayer composite material was prepared according to the following steps:

[0051] Step 1

[0052] First, the surfaces of substrates such as 5A90 aluminum-lithium alloy, 1060 industrial pure aluminum, 3A21 aluminum alloy and 4004 aluminum alloy to be laminated are milled to remove the oxide layer and keep the surface bright.

[0053] Step 2

[0054] After milling in step 1, aluminum alloys of different grades such as 1060, 3A21, and 4004 are stacked in the structural order of 1060 / 3A21 / 4004, bundled and fixed with steel straps, heated to 400℃ in a heating furnace and held for 60 minutes. The laminated plate is then hot rolled in 5 passes with a reduction of 10% to form a continuous whole, resulting in laminated plate I.

[0055] Step 3

[0056] After the 1060 / 3A21 / 4004 stacked plate I, which was hot-rolled into one piece in step 2, was trimmed and cleaned, its 1060 pure aluminum side was stacked with the 5A90 aluminum-lithium alloy plate. The stacked edge was circumferentially welded by friction stir welding, and an opening of about 5mm was left at the intersection of the circumferential weld seam.

[0057] Step 4

[0058] Vacuum the gap between the 5A90 substrate and the 1060 / 3A21 / 4004 composite laminate using the opening left in step 3. When the vacuum in the inner cavity stabilizes at 1000Pa, weld the opening together to form a stable low vacuum environment between the 5A90 substrate and the laminate I.

[0059] Step 5

[0060] The 5A90 / 1060 / 3A21 / 4004 structural piece obtained in step 4 is heated to 400℃ in an air furnace, held for 60 minutes, and finally rolled in 5 passes with a reduction of 10%.

[0061] Step 6

[0062] The 5A90 / 1060 / 3A21 / 4004 aluminum-lithium based laminated composite material, which was hot-rolled into one piece in step 5, was trimmed of unwelded flash, sliced ​​and finished, and then annealed at 280℃ for 40 min.

[0063] The aluminum-lithium based laminated composite material obtained in this embodiment has the following substrate thicknesses: 5A90 aluminum-lithium alloy substrate with a thickness of 1.0 mm, 1060 industrial pure aluminum substrate with a thickness of 0.06 mm, 3A21 aluminum alloy substrate with a thickness of 0.12 mm, and 4004 aluminum alloy substrate with a thickness of 0.12 mm. The density of the laminated composite plate is 2.53 g / cm³. 3 After overall tensile testing, its fracture strength reached 349 MPa, and its specific stiffness was 29.4 GPa / g / cm². 3 The results of the interface shear test showed that the interface strength was 96 MPa; the aluminum-lithium based laminated composite material was brazed in a vacuum brazing furnace, and there were no obvious defects at the weld, with a joint strength of 74 MPa.

[0064] Example 3

[0065] 5A90 aluminum-lithium alloy, 1060 industrial pure aluminum, 3A21 aluminum alloy, and 4004 aluminum alloy were selected as substrates for the aluminum-lithium-based multilayer composite material. The aluminum-lithium-based multilayer composite material was prepared according to the following steps:

[0066] Step 1

[0067] First, the surfaces of substrates such as 5A90 aluminum-lithium alloy, 1060 industrial pure aluminum, 3A21 aluminum alloy and 4004 aluminum alloy to be laminated are milled to remove the oxide layer and keep the surface bright.

[0068] Step 2

[0069] After milling in step 1, aluminum alloys of different grades such as 1060, 3A21, and 4004 are stacked in the structural order of 1060 / 3A21 / 4004, bundled and fixed with steel straps, heated to 430℃ in a heating furnace and held for 60 minutes. The laminated plate is then hot rolled in three passes with a reduction of 20% to form a continuous whole, resulting in laminated plate I.

[0070] Step 3

[0071] After the 1060 / 3A21 / 4004 stacked plate I, which was hot-rolled into one piece in step 2, was trimmed and cleaned, its 1060 pure aluminum side was stacked with the 5A90 aluminum-lithium alloy plate. Laser welding was used to perform a through-ring weld on the stacked edge, and an opening of about 8mm was left at the intersection of the ring weld seam.

[0072] Step 4

[0073] Vacuum the gap between the 5A90 substrate and the 1060 / 3A21 / 4004 composite laminate using the opening left in step 3. When the vacuum in the inner cavity stabilizes at 500Pa, weld the opening together to form a stable low vacuum environment between the 5A90 substrate and the laminate I.

[0074] Step 5

[0075] The 5A90 / 1060 / 3A21 / 4004 structural whole obtained in step 4 is heated to 430℃ in an air furnace, held for 60 minutes, and finally rolled in 3 passes with a reduction of 20%.

[0076] Step 6

[0077] The 5A90 / 1060 / 3A21 / 4004 aluminum-lithium based laminated composite material, which was hot-rolled into one piece in step 5, was trimmed of unwelded flash, sliced ​​and finished, and then annealed at 330℃ for 30 min.

[0078] The aluminum-lithium based laminated composite material obtained in this embodiment has the following substrate thicknesses: 5A90 aluminum-lithium alloy substrate with a thickness of 0.9 mm, 1060 industrial pure aluminum substrate with a thickness of 0.05 mm, 3A21 aluminum alloy substrate with a thickness of 0.11 mm, and 4004 aluminum alloy substrate with a thickness of 0.10 mm. The density of the laminated composite plate is 2.52 g / cm³. 3 After overall tensile testing, its fracture strength reached 355 MPa, and its specific stiffness was 29.7 GPa / g / cm². 3 The results of the interface shear test showed that the interface strength was 101 MPa. The aluminum-lithium based laminated composite material was brazed in a vacuum brazing furnace. There were no obvious defects at the weld, and the joint strength was 75 MPa.

[0079] This invention proposes an ingeniously designed ultralight aluminum-lithium-based laminated composite material that combines the advantages of different aluminum alloy grades, meeting the design requirements of next-generation aerospace materials for low density, high specific stiffness, and easy brazing. The proposed preparation method rationally utilizes techniques such as hot rolling of metal laminates, efficient welding, vacuum treatment, and metal surface treatment, fully considering the physicochemical properties of various aluminum alloy grades. This method is highly feasible, and the prepared samples are of reliable quality.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. An ultra-lightweight aluminum-lithium-based laminated composite material, characterized in that: the aluminum-lithium-based laminated composite material is composed of four-layer base plate sheets of Al-Mg-Li system aluminum-lithium alloy, industrial pure aluminum, Al-Mn system aluminum alloy and Al-Si system aluminum alloy; and the ultra-lightweight aluminum-lithium-based laminated composite material is composed of the Al-Mg-Li system alloy / industrial pure aluminum / Al-Mn system alloy / Al-Si system alloy in the order of structure; the base plate thickness of the Al-Mg-Li system alloy is 0.6-1.2 mm, the base plate thickness of the industrial pure aluminum is 0.03-0.06 mm, the base plate thickness of the Al-Mn system alloy is 0.08-0.12 mm, and the base plate thickness of the Al-Si system alloy is 0.08-0.12 mm; after the base plates are combined, the aluminum-lithium-based laminated composite material is obtained through hot rolling, welding, vacuum treatment and metal surface treatment, wherein the hot rolling, welding and vacuum treatment processes are as follows: Step one, hot rolling: the industrial pure aluminum, Al-Mn system alloy and Al-Si system alloy base plate sheets are stacked in the order of industrial pure aluminum / Al-Mn system alloy / Al-Si system alloy, and after being fixed, the temperature is raised to 400-450℃ in a heating furnace, and after the material is fully heat penetrated, the furnace is taken out, and the stacked plates are hot rolled in multiple passes with a single pass reduction of 10%-20% until the predetermined thickness is reached, to obtain a laminated plate I; Step two, welding: after the laminated plate I is edge cut and surface cleaned, the industrial pure aluminum side is stacked with the 5A90 aluminum-lithium alloy base plate, the edge part is penetrated and ring welded, and an opening of about 5-10 mm is reserved at the intersection of the ring weld; Step three, vacuum treatment: the gap between the 5A90 aluminum-lithium alloy base plate and the obtained laminated plate I is vacuumed through the opening, and after the vacuum degree reaches 100-1000 Pa and is relatively stable, the opening is welded while maintaining the vacuum, so as to form a stable low-vacuum environment in the cavity between the 5A90 aluminum-lithium alloy base plate and the laminated plate I; the Al-Mg-Li system aluminum-lithium alloy is 5A90 aluminum-lithium alloy; the Al-Mn system alloy is 3A21 aluminum alloy; the Al-Si system alloy is 4004 aluminum alloy; and the industrial pure aluminum is 1060 industrial pure aluminum.

3. The composite material according to claim 1, characterized in that: after the hot rolling, welding and vacuum treatment, the following processes are further performed: the whole piece obtained after the treatment and having the structure of 5A90 aluminum-lithium alloy / industrial pure aluminum / Al-Mn system alloy / Al-Si system alloy is heated to 400-450℃ in an air furnace, and after the material is fully heat penetrated, it is quickly transferred to a rolling mill for rolling, and hot rolling is performed with a single pass reduction of 5%-20% until the required thickness is reached; the 5A90 aluminum-lithium alloy / industrial pure aluminum / Al-Mn system alloy / Al-Si system alloy laminated plate rolled into one piece is cut to remove the un-welded flash, and after slicing and finishing, low-temperature annealing is performed at 280-350℃ for 20-40 min to obtain an ultra-lightweight aluminum-lithium laminated composite material. ​ 2. The composite material of claim 1, wherein: The density of the obtained aluminum-lithium based laminated composite is ≤ 2.53 g / cm 3 , the specific stiffness is ≥ 29.3 GPa / g / cm 3 , and the joint strength after brazing is ≥ 74 MPa. ​ ​ ​ ​ 4. The composite material of claim 1, wherein: Also included before step one is a milling operation for each substrate: the surface to be compounded of 5A90 aluminum lithium alloy, industrial pure aluminum, Al-Mn aluminum alloy and Al-Si aluminum alloy substrate is subjected to milling treatment, removing the oxide layer and keeping the surface bright.

5. The composite material of claim 1, wherein: In step one, the substrate sheet is fixed by mechanical method.

6. The composite material of claim 1, wherein: In step two, the penetration ring welding is performed on the stacked edge by fusion welding.

7. The composite material of claim 1, wherein: In step two, the penetration ring welding is performed on the stacked edge by friction stir welding.

8. An aerospace part housing characterized by: The shell is the ultra-lightweight aluminum lithium-based laminated composite material of claim 1.

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