A method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate

Abstract

This invention belongs to the field of composite material technology, specifically relating to a method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate. The steps of this invention include: first, preparing aluminum and titanium plates as raw materials; then, after surface treatment of the raw materials, combining and fixing them; after heat preservation, rolling the fixed plates; and finally, performing solution aging treatment to obtain a multilayer titanium-aluminum composite plate. Through alternating layer design, a three-layer (aluminum-titanium-aluminum), three-layer (titanium-aluminum-titanium), or five-layer (titanium-aluminum-titanium-aluminum-titanium) composite structure is constructed. With a simple preparation process, this invention achieves a significant improvement in plasticity and toughness. This invention provides a low-cost, simple, and mass-producible high-performance composite plate preparation scheme, offering a new material option for lightweight design in aerospace, transportation, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology and relates to a method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate. Background Technology

[0002] Titanium / aluminum composite plates combine the high strength of titanium alloys with the lightweight and low-cost advantages of aluminum alloys, making them an ideal lightweight material for aerospace, transportation, and other fields. Due to their ability to integrate the high strength of titanium alloys with the lightweight and low-cost advantages of aluminum alloys, titanium / aluminum composite plates have attracted much attention in the field of lightweight structures. In existing technologies, various preparation methods have been proposed. For example, publication number CN116809680A provides a technique combining aluminum powder self-ignition heating and multi-pass asynchronous rolling. This method utilizes the reaction heat of aluminum powder to achieve local fusion and atomic diffusion, but the reaction process is violent and difficult to control precisely, potentially leading to uneven interfacial bonding. Although subsequent multi-pass rolling gradually reduces the reduction, the process flow is still long and highly dependent on the initial bonding quality. Publication number CN120421509A innovatively employs gradient pressing and pore interlocking structures through powder metallurgy to enhance interfacial bonding, significantly improving the penetration depth of aluminum. However, this method involves multiple pressing and sintering processes, resulting in complex procedures and high costs. Furthermore, the use of powder raw materials increases the requirements for the production environment, which is not conducive to the low-cost manufacturing of large-scale plates. Another technology, CN120325688A, improves the bonding by laser-texturing the surface of titanium plates combined with a special hot rolling path. However, laser surface treatment increases process costs, and subsequent straightening of the arched plates may introduce new residual stresses. CN119704799A uses a process of casting molten aluminum between solid titanium sheets and then rolling it. Although it can produce ultra-thin composite plates, the contact between liquid aluminum and solid titanium easily promotes the continuous formation of brittle intermetallic compounds (such as TiAl3). Even after subsequent heat treatment and rolling, it is difficult to completely eliminate its adverse effects on interfacial toughness, limiting further improvement in the material's plasticity and toughness.

[0003] In summary, existing Ti / Al composite plate preparation technologies generally suffer from problems such as complex processes, high equipment requirements, low production efficiency, and difficulty in controlling brittle phases at the interface. This leads to high production costs, making it difficult to achieve stable, large-scale production, and also restricts the synergistic improvement of the composite material's strength, plasticity, and toughness to varying degrees. Therefore, developing a simple preparation method for multilayer titanium-aluminum composite plates that uses readily available raw materials, is low in cost, and can achieve a perfect combination of high strength, high plasticity, and high toughness has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate. The method involves selecting one of medium-high strength aluminum alloy and α, β, or α+β titanium alloy as the raw material, performing surface treatment, combining and fixing the raw material, feeding it into a rolling mill, and rolling it through multiple passes. Finally, the material undergoes solution treatment and aging to obtain a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate.

[0005] A method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate includes the following steps: first, prepare aluminum plates and titanium plates as blanks; then, after surface treatment of the blanks, combine and fix them; after heat preservation, roll the fixed plates; and finally, perform solution aging treatment to obtain a multilayer titanium-aluminum composite plate.

[0006] Furthermore, the surface treatment of the blank is as follows: first, the oil stains on the surface of the blank are washed away with acetone and ethanol solution, then the surface to be composited is polished with an automatic steel brush machine, and after polishing, it is cleaned with alcohol and dried.

[0007] Furthermore, the aluminum plate is a medium-high strength aluminum alloy, and the titanium plate is one of α, β, or α+β titanium alloys.

[0008] Furthermore, the assembly and fixing are as follows: the surface-treated blanks are stacked and aligned alternately with aluminum plates and titanium plates, fixed with fixing clamps, and then fixed with rivets after drilling holes at the four corners to obtain A3 plates or A5 plates. The layer thickness ratio of A3 plates or A5 plates is Ti:Al = 1:1~1:5.

[0009] Furthermore, the diameter of the hole is 5mm-10mm, and the rivet is an aluminum rivet.

[0010] Furthermore, the A3 plate is made by stacking aluminum plates and titanium plates in an aluminum-titanium-aluminum or titanium-aluminum-titanium manner; the A5 plate is made by stacking aluminum plates and titanium plates in a titanium-aluminum-titanium-aluminum-titanium manner.

[0011] Furthermore, the fixed plate is kept at a temperature of 400℃-550℃ for 0.5h-2h, and then fed into a rolling mill for 2-6 passes. The rolling reduction is 30%-60% in the first pass and 10%-30% in the other passes to achieve the initial bonding of the composite plate. Intermediate annealing is carried out during different rolling passes. The intermediate annealing process is to keep the plate at 300℃-550℃ for 15min-120min.

[0012] Furthermore, the solution aging treatment is performed at a temperature of 450℃-550℃, with water cooling for 0.5h-2h, followed by air cooling at 100℃-150℃ for 12h-48h.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] 1. This invention constructs a composite structure of three or five layers, namely "aluminum-titanium-aluminum" or "titanium-aluminum-titanium", through an alternating layered design. In the three-layer structure, when the hard and brittle aluminum alloy generates crack initiation due to stress concentration, the titanium layers on both sides can effectively constrain crack propagation, causing it to branch in multiple directions to form multiple crack initiation points, thereby uniformly dispersing the load and delaying overall failure. In the five-layer structure, the middle titanium layer acts as a "reinforcing rib", making the entire aluminum layer exist as a barrier layer in tensile behavior, Charpy impact behavior, and quasi-static compression behavior. That is, when subjected to external load, the high-strength, high-ductility, and high-toughness structural combination of titanium, aluminum, and titanium on one side can constrain the failure of the other side. During deformation, the high toughness and high work hardening rate of the middle titanium layer cause its cracks to deflect along the middle layer, which also hinders crack propagation to a certain extent, further improving the overall strength.

[0015] 2. With a simple preparation process, this invention achieves a leapfrog improvement in plasticity and toughness: the elongation is increased from 7.7% of the base aluminum alloy to 11.6% (three layers) and 13.9% (five layers), respectively; the Charpy impact energy is significantly increased from 8.3J to 55.7J (three layers) and 71.9J (five layers); the quasi-static compressive true strain is increased from 20% to 31% (three layers) and 41.8% (five layers). The above data show that, at the cost of only a 50MPa decrease in strength, the plasticity and toughness of the material are improved several times.

[0016] 3. This invention selects one of medium-high strength aluminum alloy and α, β, or α+β titanium alloy as the raw material. Through optimized surface treatment, riveting, multi-pass rolling, and solution aging treatment, it avoids the complex powder metallurgy, molten casting, or precision laser treatment in the prior art. A strong interface bond can be achieved through simple mechanical fixing and rolling processes. The large reduction in the first pass during rolling plus intermediate annealing ensures deformation coordination, effectively controls the interface reaction, and avoids excessive growth of brittle phases.

[0017] 4. This invention provides a low-cost, simple process for preparing high-performance composite panels suitable for mass production, offering a new material option for lightweight design in aerospace, transportation and other fields. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating a method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the stacking of aluminum and titanium plates in Embodiment 1 of the present invention, wherein (a) is a schematic diagram of the stacking of A3 plates and (b) is a schematic diagram of the stacking of A5 plates.

[0020] Figure 3Metallographic images of a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate prepared in Example 1 of the present invention are shown, wherein (a) is the metallographic image of plate A3 and (b) is the metallographic image of plate A5.

[0021] Figure 4 The room temperature tensile stress-strain curves of the A3 and A5 plates prepared in Example 1 of this invention are shown.

[0022] Figure 5 Charpy impact performance curves of the A3 and A5 plates prepared in Example 1.

[0023] Figure 6 The true stress-strain curves of quasi-static compression at room temperature are shown for plates A3 and A5 prepared in Example 1. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments based on the embodiments of the present invention, obtained by those skilled in the art without creative effort, are within the scope of protection of the present invention.

[0025] The significance of this invention lies in providing a new research direction for existing lightweight high-strength alloy laminates, namely, using titanium alloy as the plasticizing or reinforcing phase, and offering a simple preparation method with readily available raw materials, suitable for mass production. This invention overcomes the toughness constraints of high-strength and medium-strength aluminum alloys and the price limitations of titanium alloys, producing a low-cost, simple-process, high-strength, high-plasticity, and high-toughness titanium-aluminum composite plate.

[0026] Example 1

[0027] A method for preparing a high-strength, high-plasticity, and high-toughness titanium-aluminum composite plate, such as... Figure 1 As shown, it includes the following steps:

[0028] (1) Billet preparation: The titanium plate is TA2, and its composition by weight percentage is: Fe≤0.3%, C≤0.1%, N≤0.05%, H≤0.15%, O≤0.25%, with the balance being Ti; the aluminum alloy is 7A62, and its composition by weight percentage is: Si≤0.12%, Fe≤0.15%, 0.05%≤Cu≤0.5%, 0.2%≤Mn≤0.6%, 2.5%≤Mg≤3.2%, 0.1%≤Cr≤0.2%, 6.7%≤Zn≤7.4%, 0.03%≤Ti≤0.1%, 0.05%≤Zr≤0.15%, 0.0001%≤Be≤0.003%, with the balance being Al; the titanium-aluminum layer thickness ratio is 1:3;

[0029] (2) Surface treatment: First, use acetone and ethanol solution to wash away the oil stains on the surface of the blank in step (1), use an automatic steel brush machine to polish the surface to be composited, and then clean and dry it with alcohol.

[0030] (3) Assembly and Fixing: The surface-treated blanks are stacked and aligned alternately with aluminum and titanium plates. The configuration used is as follows: A3 plate consists of two layers of titanium sandwiching one layer of aluminum, such as... Figure 2 As shown in (a); the A5 plate is made of three layers of titanium sandwiched with two layers of aluminum, as... Figure 2 As shown in (b); after fixing with a fixing clamp, drill holes at the four corners, and then fix with aluminum rivets by hammering;

[0031] (4) Preparation of composite plate: The two plates A3 and A5 with fixed different arrangement are sent into the heat treatment furnace for heat treatment and heat preservation. The heat preservation time before rolling is 1 hour and the temperature is 470℃. Then they are sent into the rolling mill and rolled in three passes. The first pass has a reduction of 35%, the second pass has a reduction of 10%, and the third pass has a reduction of 10%, to achieve the initial bonding of the composite plate. Intermediate annealing is carried out during the rolling process of different passes. The intermediate annealing process is to keep the plate at 470℃ for 15 minutes.

[0032] (5) Heat treatment of composite plate: solution aging treatment is carried out in heat treatment furnace at 470℃ for 60 min, followed by quenching and aging process at 120℃ for 24 h, so as to achieve good bonding performance.

[0033] Figure 4 Table 1 shows the engineering stress-strain curves of the A3 and A5 plates prepared in this embodiment, and Table 1 shows the room temperature tensile properties of the A3 and A5 plates prepared in this embodiment. Figure 5 Table 2 shows the Charpy impact force and displacement curves of the A3 and A5 plates prepared in this embodiment, and Table 2 shows the Charpy impact performance of the A3 and A5 plates prepared in this embodiment. Figure 6 Table 3 shows the true stress-strain diagrams of the A3 and A5 plates prepared in this embodiment, and Table 3 shows the quasi-static compressive properties of the A3 and A5 plates prepared in this embodiment.

[0034] Table 1;

[0035] Brand A3 board A5 board Yield strength (MPa) 535 514 Tensile strength (MPa) 597 605 elongation 11.6% 13.9% Uniform elongation 6.5% 7.2%

[0036] Table 2;

[0037] Brand A3 board A5 board Maximum load (N) 5398 7334 Sprouting Function (J) 8.5 4.7 Absorbed work (J) 55.7 71.9 <![CDATA[Impact toughness (J / cm 2 )]]> 104.4 134.8

[0038] Table 3;

[0039] Brand A3 board A5 board True stress (MPa) 685.3 735.6 True response 31.0% 48.1%

[0040] like Figure 3As shown, for (a) the three-layer titanium-aluminum composite plate, even if crack initiation occurs due to local stress concentration caused by the hard and brittle aluminum phase during the tensile deformation process, the crack propagation will be delayed due to the constraint of the high-toughness titanium. In tensile and Charpy impact processes and static compression, the three-layer plate exhibits multi-crack initiation failure behavior, meaning that multiple crack points can fail simultaneously within the loaded area. This ensures that the load distribution within the matrix remains uniform during loading. During this process, the titanium layer undergoes work hardening due to intense plastic deformation, which partially increases its strength. This further reduces the strength difference between the titanium and aluminum layers, allowing uniform deformation to continue. In summary, this is the principle of achieving a leapfrog increase in plasticity and toughness while ensuring a slight decrease in strength. In contrast, (b) the five-layer titanium-aluminum composite plate, based on the three-layer plate, has a middle titanium layer acting as a reinforcing rib. This allows the entire aluminum layer to act as a barrier layer during tensile, Charpy impact, and quasi-static compression behaviors. That is, when subjected to external loads, the high-strength, high-plasticity, and high-toughness structural combination of titanium, aluminum, and titanium on one side can constrain the failure of the other side. During deformation, the high toughness and high work hardening rate of the middle titanium layer cause cracks to deflect along the middle layer, which also hinders crack propagation to a certain extent.

[0041] Compared to 7A62 aluminum alloy, the three-layer and five-layer titanium-aluminum composite plates prepared in this embodiment, at room temperature, showed an increase in elongation from 7.7% to 11.6% and 13.9% respectively, despite a 50 MPa decrease in tensile strength. Charpy impact performance, such as absorbed energy, increased from 8.3 J to 55.7 J and 71.9 J. Quasi-static compressive properties (compression rate of 0.1 mm / s), with a 50 MPa decrease in true stress, showed an increase in true strain from 20% to 31% and 41.8%. In summary, with a simple preparation method, a significant increase in plasticity and toughness was achieved by sacrificing a small amount of strength. The main principle of plasticization and toughening is to ensure uniform deformation of both the titanium alloy and aluminum alloy (usually the hard and brittle phase, such as 7A62) before failure. This allows the hard and brittle phase to be constrained by the plastic phase, limiting crack propagation even in cases of stress concentration leading to local crack initiation, thereby greatly improving the overall plasticity and toughness of the material.

[0042] Example 2

[0043] A method for preparing a high-strength, high-plasticity, and high-toughness titanium-aluminum composite plate includes the following steps:

[0044] (1) Billet preparation: The titanium plate is TA2 and the aluminum alloy is 2024. The weight percentage of its composition is: Cu: 3.8%-4.9%; Mn: 0.30%-1.0%; Mg: 1.2%-1.8%; Cr: 0.10%; Si: 0.50%; Zn: 0.25%; Al: balance; the titanium-aluminum layer thickness ratio is 1:5;

[0045] (2) Surface treatment: First, use acetone and ethanol solution to wash away the oil stains on the surface of the blank in step (1), use an automatic steel brush machine to polish the surface to be composited, and then clean and dry it with alcohol.

[0046] (3) Assembly and fixing: The surface-treated blanks are stacked and aligned alternately with aluminum plates and titanium plates. The configuration is two layers of aluminum sandwiched with one layer of titanium. After fixing with a fixing clamp, holes are drilled at the four corners, and then rivets are used to fix them.

[0047] (4) Preparation of composite plate: The two plates with different fixed arrangements are sent to the heat treatment furnace for heat treatment and heat preservation. The heat preservation time before rolling is 1 hour and the temperature is 500℃. Then, they are sent to the rolling mill and rolled in four passes to achieve the initial bonding of the composite plate. Intermediate annealing is carried out during different rolling passes. The intermediate annealing process is to keep the plate at 500℃ for 15 minutes.

[0048] (5) Heat treatment of composite plate: Solution aging treatment is carried out in heat treatment furnace. The solution temperature is 500℃ and the holding time is 35min. Then, quenching is performed and the aging process is 190℃ and the holding time is 12h, so as to achieve good bonding performance.

[0049] The titanium-aluminum composite plate prepared in this embodiment has an elongation rate that increases from 10% to 13% at room temperature while the tensile strength is still around 480 MPa. The impact performance and quasi-static compression performance are also significantly improved.

[0050] Example 3

[0051] A method for preparing a high-strength, high-plasticity, and high-toughness titanium-aluminum composite plate includes the following steps:

[0052] (1) Billet preparation: The titanium plate is TC4, and its composition by weight percentage is: Al: 5.5%-6.75%; V: 3.5-4.5%; Fe: ≤0.30%; O≤0.20%; C≤0.10%; N≤0.05%; H≤0.015%; The aluminum alloy is 6061, and its composition by weight percentage is: Mg: 0.8%-1.2%; Si: 0.4%-0.8%; Cu: 0.15%-0.4%; Mn: 0.15%-0.4%; Cr: 0.04%-0.35%; Al: balance; The titanium-aluminum layer thickness ratio is 1:4;

[0053] (2) Surface treatment: First, use acetone and ethanol solution to wash away the oil stains on the surface of the blank in step (1), then use an automatic steel brush machine to polish the surface to be composited, and after polishing, wash with alcohol and blow dry.

[0054] (3) Assembly and fixing: The surface-treated blanks are stacked and aligned alternately with aluminum plates and titanium plates. The configuration is two layers of aluminum sandwiched with one layer of titanium. After fixing with a fixing clamp, holes are drilled at the four corners, and then rivets are used to fix them.

[0055] (4) Preparation of composite plate: The two plates with different fixed arrangements are sent to the heat treatment furnace for heat treatment and heat preservation. The heat preservation time before rolling is 1 hour and the temperature is 530℃. Then, they are sent to the rolling mill and rolled in four passes to achieve the initial bonding of the composite plate. Intermediate annealing is carried out during different rolling processes. The intermediate annealing process is to keep the plate at 530℃ for 15 minutes.

[0056] (5) Heat treatment of composite plate: Solution aging treatment is carried out in heat treatment furnace at a temperature of 530℃ for 30 min, followed by quenching and aging process at 190℃ for 12 h, so as to achieve good bonding performance.

[0057] The titanium-aluminum composite plate prepared in this embodiment has a tensile strength of 430 MPa at room temperature compared to 6061, and an elongation of 14% compared to 10%.

[0058] Comparative Example 1

[0059] Similar to steps (2)-(5) of Example 1, step (1) uses single-layer titanium-aluminum asymmetric rolling, which will cause uneven deformation on both sides of the metal, causing severe interlayer internal stress in the composite plate when subjected to tensile and other experimental tests, resulting in premature failure of the interface between the two metals.

[0060] Comparative Example 2

[0061] Similar to (1)-(4) of Example 1, changing the solution aging temperature and time will cause a decrease in the strength of the laminate or a decrease in the interlayer bonding performance or the appearance of intermetallic compounds, resulting in a decrease in the performance of the laminate or a decrease in the bonding performance. For TA2 and 6061 in the aluminum-titanium-aluminum configuration, for the same aging time (190℃×12h), no intermetallic compounds appeared within 15min-30min of solution aging at 530℃, and the tensile strength and elongation were 340MPa and 25%, respectively. However, when the solution aging time was greater than 1h, obvious intermetallic compounds appeared, and the tensile strength and elongation were 319MPa and 20%, respectively. This result indicates that under more intense element diffusion, the appearance of intermetallic compounds is not conducive to improving the compatibility performance of the composite plate.

[0062] Comparative Example 3

[0063] Aluminum alloys can be accelerated and toughened by using aluminum alloys, such as the mature 7A52 and 7A62 composite. In the 7A62-7A52-7A62 configuration, the room temperature tensile strength and elongation are 626 MPa and 8.4%, respectively. Its plasticity and toughness are improved to a certain extent, and the tensile elongation can reach 9%. However, the constraints of the aluminum alloy material itself make it impossible for the plasticity and toughness of the laminate to be significantly improved as in this experimental example, and the plasticity and toughness enhancement ability is poor.

[0064] Composite plates prepared by other methods, such as solid-liquid composite or hot-press composite, suffer from the drawbacks of high temperatures or long holding times. This leads to excessively intense diffusion between the two metals, resulting in the localized formation of a hard and brittle TiAl3 phase at the interface. Consequently, under external loads, the composite plate experiences premature stress concentration between the layers, leading to cracking failure. Furthermore, rolling is the easiest and lowest-cost preparation method in this process.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate, characterized in that, The process includes the following steps: first, prepare aluminum and titanium plates as blanks; then, after surface treatment of the blanks, combine and fix them; after heat preservation, roll the fixed plates; and finally, perform solution treatment and aging to obtain multi-layer titanium-aluminum composite plates. The fixed plate is kept at a temperature of 400℃-550℃ for 0.5h-2h before being fed into a rolling mill. It undergoes 2-6 rolling passes with a reduction of 30%-60% in the first pass and 10%-30% in the other passes to achieve initial bonding of the composite plate. Intermediate annealing is performed during different rolling passes. The intermediate annealing process involves holding the plate at 300℃-550℃ for 15min-120min. The solution aging treatment is performed at a temperature of 450℃-550℃ for 0.5h-2h, followed by quenching and air cooling at 100℃-150℃ for 12h-48h.

2. The method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate according to claim 1, characterized in that, The surface treatment of the blank is as follows: first, the oil stains on the surface of the blank are washed away with acetone and ethanol solution, then the surface to be composited is polished with an automatic steel brush machine, and after polishing, it is cleaned with alcohol and dried.

3. The method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate according to claim 1, characterized in that, The aluminum plate is a medium-high strength aluminum alloy, and the titanium plate is one of α, β, or α+β titanium alloys.

4. The method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate according to claim 1, characterized in that, The assembly and fixing are as follows: the surface-treated blanks are stacked and aligned alternately with aluminum plates and titanium plates, fixed with fixing clamps, and then fixed with rivets after drilling holes at the four corners to obtain A3 plates or A5 plates. The layer thickness ratio of A3 plates or A5 plates is Ti:Al = 1:1~1:

5. The A3 plate is made by stacking aluminum and titanium plates in an aluminum-titanium-aluminum or titanium-aluminum-titanium manner; the A5 plate is made by stacking aluminum and titanium plates in a titanium-aluminum-titanium-aluminum-titanium manner.

5. The method for preparing a high-strength, high-plasticity, and high-toughness multilayer titanium-aluminum composite plate according to claim 4, characterized in that, The diameter of the hole is 5mm-10mm, and the rivet is an aluminum rivet.

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