Titanium-aluminum composite material with high interfacial bonding force and high strength, and preparation method and application thereof

Abstract

The application discloses a titanium-aluminum composite material with high interfacial bonding strength and high strength, and a preparation method and application thereof, and belongs to the technical field of titanium-aluminum composite materials. The titanium-aluminum composite material comprises aluminum layers and titanium layers which are alternately and laminatedly arranged. An intermetallic compound layer with a thickness of not more than 1 micrometer is arranged at the interface of the aluminum layers and the titanium layers. The tensile strength of the titanium-aluminum composite material is not less than 295 MPa, the elongation rate is not less than 15%, and the interfacial shear strength of the titanium layers and the aluminum layers in the titanium-aluminum composite material is not less than 130 MPa. The titanium-aluminum composite material is free of harmful brittle phase TiAl3 with excessive growth between the titanium layers and the aluminum layers, has high interfacial bonding strength, and has high tensile strength and elongation rate. The preparation method is simple in operation and can accurately control the thickness of each layer after compounding.

Description

Technical Field

[0001] This disclosure relates to the field of titanium-aluminum composite materials technology, and more specifically, to a titanium-aluminum composite material with high interfacial bonding strength and high strength, its preparation method and application. Background Technology

[0002] Titanium and its alloys possess high strength, low density, excellent corrosion resistance, and biocompatibility, but their high cost limits their widespread application in certain fields. Aluminum and its alloys, on the other hand, have even lower density, lower cost, and good electrical and thermal conductivity, but their strength, wear resistance, and corrosion resistance are relatively poor. By using composite technology to create layered composite materials from titanium and aluminum, the advantages of both can be combined.

[0003] However, current methods for preparing titanium-aluminum composites often suffer from insufficient interfacial bonding and difficulty in coordinating overall performance. An unreasonable thickness ratio design can lead to a "weak link" effect in the performance of titanium-aluminum composites, either resulting in reduced overall strength due to weak layers or insufficient plasticity and toughness. Furthermore, existing methods for preparing titanium-aluminum composites do not offer precise control over the layer thickness ratio of the final product, resulting in poor process controllability.

[0004] In view of this, this disclosure is hereby made.

[0005] Public content

[0006] The purpose of this disclosure is to provide a titanium-aluminum composite material with high interfacial bonding strength and high strength, as well as its preparation method and application, in order to solve or improve the above-mentioned technical problems.

[0007] This disclosure can be implemented as follows:

[0008] In a first aspect, this disclosure provides a titanium-aluminum composite material with high interfacial bonding strength and high strength, the titanium-aluminum composite material comprising alternating aluminum layers and titanium layers; the interface between the aluminum layer and the titanium layer has an intermetallic compound layer with a thickness not exceeding 1 μm;

[0009] The tensile strength of the titanium-aluminum composite material is not less than 295 MPa, the elongation is not less than 15%, and the interfacial shear strength between the titanium layer and the aluminum layer in the titanium-aluminum composite material is not less than 130 MPa.

[0010] In an optional embodiment, the titanium material used for the titanium layer includes at least one of pure titanium and titanium alloys.

[0011] In an optional embodiment, pure titanium includes at least one of TA1 pure titanium, TA2 pure titanium, and TA4 pure titanium.

[0012] In an optional embodiment, the titanium alloy includes at least one of TC4 titanium alloy and TA18 titanium alloy.

[0013] In an optional embodiment, the titanium layer also has at least one of the following characteristics:

[0014] Feature 1: The titanium layer has a uniform equiaxed α-grain structure;

[0015] Feature 2: The average grain size of the titanium layer is ≤8μm;

[0016] Feature 3: The aspect ratio of the grain size in the titanium layer is ≤2;

[0017] Feature 4: The volume percentage of the α phase in the titanium layer is ≥85%.

[0018] In an optional embodiment, the aluminum material used for the aluminum layer includes at least one of pure aluminum and aluminum alloys.

[0019] In an optional embodiment, the pure aluminum includes at least one of 1060 pure aluminum and 1100 pure aluminum.

[0020] In an optional embodiment, the aluminum alloy includes at least one of 5-series rust-resistant aluminum, 6-series forged aluminum, and 7-series super-durable aluminum.

[0021] In an optional embodiment, the aluminum layer also has at least one of the following characteristics:

[0022] Feature 5: The aluminum layer has an equiaxed crystal structure;

[0023] Feature 6: The average grain size of the aluminum layer is ≤100μm;

[0024] Feature 7: The aspect ratio of the grain size in the aluminum layer is ≤3.

[0025] In an optional embodiment, the metal layers in the titanium-aluminum composite material are arranged symmetrically.

[0026] Secondly, this disclosure provides a method for preparing a titanium-aluminum composite material as described in any of the foregoing embodiments, wherein a billet formed by alternating layers of titanium and aluminum is subjected to large deformation asynchronous rolling, followed by stress-relief annealing.

[0027] In an optional implementation, the large deformation asynchronous rolling process includes at least one of the following conditions:

[0028] Condition 1: Rolling temperature is 300℃~500℃;

[0029] Condition 2: The amount of compression deformation is ≥50%;

[0030] Condition 3: The roll speed ratio is 1.1:1 to 1.5:1.

[0031] In an optional embodiment, the stress-relief annealing temperature is 200°C to 300°C.

[0032] In an optional implementation, the thickness h of the i-th metal layer in the target titanium-aluminum composite material is used as the reference. i And the length L of the i-th metal layer in the titanium-aluminum composite material. i The length L of the i-th layer of metal material in the billet i0 The ratio λ is used to determine the thickness h of the i-th layer of metal material in the billet. i0 h i0 ≈h i ×λ.

[0033] In an optional implementation, the titanium and aluminum materials are laser-cleaned and laser-textured respectively before being stacked.

[0034] Thirdly, this disclosure provides an application of the titanium-aluminum composite material as described in any of the foregoing embodiments, for example, using the titanium-aluminum composite material to manufacture aerospace equipment, automobiles, electronic communication equipment, or battery casings.

[0035] The beneficial effects of this disclosure include:

[0036] In the titanium-aluminum composite material disclosed herein, an intermetallic compound layer with a thickness not exceeding 1 μm is present at the interface between the aluminum and titanium layers. This means there is no excessively grown harmful brittle phase (TiAl3) between the titanium and aluminum layers, thus ensuring high interfacial bonding strength and excellent adhesion between the aluminum and titanium layers. The titanium-aluminum composite material exhibits a tensile strength of not less than 295 MPa and an elongation of not less than 15%, demonstrating both superior tensile strength and elongation.

[0037] Furthermore, this disclosure creatively achieves precise prediction and control of the thickness ratio of each layer after composite based on the principle of constant volume before and after composite. Through reasonable material selection and structural design, combined with specific material pretreatment, large deformation asynchronous rolling process and annealing conditions, a titanium-aluminum layered composite material with excellent mechanical properties and functional characteristics is finally obtained. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 Here is a SEM image of the titanium-aluminum composite material prepared in Example 1;

[0040] Figure 2 Metallographic image of the aluminum layer in the titanium-aluminum composite material prepared in Example 1;

[0041] Figure 3 The image shows the metallographic structure of the titanium layer in the titanium-aluminum composite material prepared in Example 1.

[0042] Figure 4 Metallographic image of the interface between the aluminum and titanium layers of the titanium-aluminum composite material prepared in Example 1;

[0043] Figure 5 The image shows a SEM image of the titanium-aluminum composite material prepared in Example 3. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions in the embodiments of this disclosure will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0045] The following is a detailed description of the titanium-aluminum composite material with high interfacial bonding strength and high strength, its preparation method, and its application provided in this disclosure.

[0046] This disclosure provides a titanium-aluminum composite material with high interfacial bonding strength and high strength, which includes alternating aluminum layers and titanium layers; the interface between the aluminum layer and the titanium layer has an intermetallic compound layer with a thickness not exceeding 1 μm.

[0047] The titanium-aluminum composite material has a tensile strength of not less than 295 MPa, an elongation of not less than 15%, and an interfacial shear strength of not less than 130 MPa between the titanium layer and the aluminum layer.

[0048] In some optional embodiments, the titanium-aluminum composite material includes only an aluminum layer and a titanium layer; in other optional embodiments, in addition to the aluminum layer and the titanium layer, the titanium-aluminum composite material may also have other functional layers as needed.

[0049] In some alternative embodiments, the total number of aluminum and titanium layers can be two, three, four, or more. For example, when the total number of aluminum and titanium layers is two, the titanium-aluminum composite material is obtained by stacking one titanium layer and one aluminum layer. When the total number of aluminum and titanium layers is three, the titanium-aluminum composite material can be in the form of aluminum layer-titanium layer-aluminum layer, or titanium layer-aluminum layer-titanium layer, or it can also be in the form of aluminum layer-titanium layer-other functional layer, or titanium layer-aluminum layer-other functional layer.

[0050] Preferably, the metal layers in the titanium-aluminum composite material are symmetrically arranged. The symmetrical structure avoids the warping problem caused by asymmetrical composites, and the multilayer structure can further optimize stress distribution and functional integration.

[0051] In the titanium-aluminum composite material disclosed herein, the titanium layer is mainly used to provide high strength, high wear resistance, and corrosion resistance; the aluminum layer is mainly used to provide plasticity, toughness, thermal and electrical conductivity, and to reduce costs.

[0052] In some alternative embodiments, the titanium material used for the titanium layer may include at least one of pure titanium and titanium alloys. Pure titanium may, exemplarily, include at least one of TA1 pure titanium, TA2 pure titanium, and TA4 pure titanium. Titanium alloys may, exemplarily, include at least one of TC4 titanium alloy and TA18 titanium alloy.

[0053] In some alternative embodiments, the titanium layer has a uniform equiaxed α-grain structure.

[0054] In some alternative implementations, the average grain size of the titanium layer is ≤8 μm.

[0055] In some alternative implementations, the grain size aspect ratio in the titanium layer is ≤2.

[0056] In some alternative implementations, the α phase volume fraction in the titanium layer is ≥85%.

[0057] In some alternative embodiments, the aluminum material used for the aluminum layer may include at least one of pure aluminum and aluminum alloys. The pure aluminum may, exemplarily, include at least one of 1060 pure aluminum and 1100 pure aluminum. The aluminum alloy may, exemplarily, include at least one of 5-series rust-resistant aluminum, 6-series forged aluminum, and 7-series super-duralumin.

[0058] In some alternative embodiments, the aluminum layer has an equiaxed crystal structure.

[0059] In some alternative implementations, the average grain size of the aluminum layer is ≤100μm.

[0060] In some alternative implementations, the grain size aspect ratio in the aluminum layer is ≤3.

[0061] In this disclosure, the interface between the aluminum layer and the titanium layer has an intermetallic compound layer with a thickness not exceeding 1 μm, that is, there is no excessively grown harmful brittle phase (TiAl3) between the titanium layer and the aluminum layer, thereby ensuring that the interface between the aluminum layer and the titanium layer has high interfacial bonding strength (i.e., interfacial shear strength not less than 130 MPa) and excellent bonding force.

[0062] In this disclosure, the tensile strength of the titanium-aluminum composite material is not less than 295 MPa and the elongation is not less than 15%, that is, the titanium-aluminum composite material of this disclosure has both superior tensile strength and elongation.

[0063] Accordingly, this disclosure also provides a method for preparing the above-mentioned titanium-aluminum composite material, wherein a billet formed by alternating layers of titanium and aluminum is subjected to large deformation asynchronous rolling, followed by stress-relief annealing.

[0064] In some optional embodiments, before the stacking, the titanium and aluminum materials are subjected to laser cleaning and laser texturing treatments, respectively. Laser cleaning removes the oxide layer from the surfaces of the titanium and aluminum materials, while laser texturing creates a certain roughness on the surfaces of the titanium and aluminum materials to facilitate interfacial bonding.

[0065] Laser cleaning can be performed as follows: Laser cleaning uses a pulsed laser with a wavelength of 1064nm or 355nm. By adjusting the laser power, frequency, and scanning speed, selective removal of the oxide layer and contaminants on the surface of titanium and aluminum materials is achieved under inert gas protection, with minimal damage to the substrate (no blackening or remelting of the surface). For titanium, a higher power (120W–200W), an extremely high scanning speed (8000–9000mm / s), and a higher pulse frequency (180kHz–220kHz) are preferred. For aluminum, a relatively lower power (140W–165W), a medium scanning speed (600mm / s–3000mm / s), and a lower pulse frequency (29kHz–60kHz) are used.

[0066] Laser texturing can be performed as follows: Laser texturing uses a pulsed laser to scan the material surface, forming disordered or regular microstructures. Preferably, the surface roughness Ra after treatment is controlled between 2.0 μm and 8.0 μm, more preferably between 4.0 μm and 6.0 μm. In the above laser texturing treatment, for aluminum, a nanosecond pulsed fiber laser is preferably used, and the surface roughness Ra is controlled within the range of 2.0 μm to 4.0 μm by adjusting parameters such as power and scanning speed; for titanium, a picosecond or femtosecond pulsed laser is preferably used, and the surface roughness Ra is controlled within the range of 4.0 μm to 8.0 μm. Through the above differentiated treatment, the surfaces of the two materials can form microstructures most suitable for their own characteristics. Within this roughness range, the effective bonding area can be significantly increased, while avoiding interface defects caused by excessive roughness, thereby synergistically obtaining the optimal interface bonding strength.

[0067] After the above laser cleaning and laser texturing treatment, the interface is guaranteed to be dry and clean, without any dirt or residue, effectively improving the interface adhesion.

[0068] In some optional embodiments, the thickness scheme of each layer of metal material in the billet is determined by the following method: the performance of the titanium-aluminum composite material under different preset conditions is calculated using the ROM mixing method, a target titanium-aluminum composite material that meets the required performance is selected, and the number of composite layers n, the total thickness H of the composite material, and the thickness h of the i-th layer are obtained. i 1. Elongation coefficient λ; Based on the principle that the volume of each layer of metal material remains unchanged before and after rolling, according to the formula h i0 ×L i0 ×W i0 =h i ×L i ×W i and W i0 ≈W i L i / L i0 ≈λ, thus obtaining h i0 ≈h i ×λ; where h i0 h is the thickness of the i-th layer of metal material in the billet. i L represents the thickness of the i-th metal layer in the titanium-aluminum composite material. i0 and W i0 L represents the length and width of the i-th layer of metal material in the billet, respectively. i and W i and represent the length and width of the i-th metal layer in the titanium-aluminum composite material, respectively.

[0069] The aforementioned ROM mixing method is the Rule of Mixture in materials science. It is a core and fundamental method for predicting the properties and proportions of components in composite materials. It can be used to estimate key properties of composite materials such as tensile elastic modulus, tensile strength, and thermal conductivity. For specific operations, please refer to relevant existing technologies. We will not elaborate further or limit the specifics here.

[0070] Specifically, the target performance indicators (such as density, elastic modulus, target strength, bending performance, conductivity, cost control, etc.) of titanium-aluminum composite materials are determined according to the application scenario (such as load-bearing structure, corrosion-resistant components, lightweight components, etc.). Based on the above target performance indicators, material selection and combination design are carried out, that is, selecting titanium and aluminum materials and determining the layered structure of titanium-aluminum composite materials, which can solve the problem of blind trial and error.

[0071] In some alternative implementations, the thickness h of the i-th metal layer in the target titanium-aluminum composite material is used as the reference. i And the length L of the i-th metal layer in the titanium-aluminum composite material. i The length L of the i-th layer of metal material in the billet i0 The ratio λ is used to determine the thickness h of the i-th layer of metal material in the billet. i0 h i0 ≈h i×λ.

[0072] Specifically, based on the principle that the volume of each metal layer remains unchanged before and after composite bonding, the thickness of the original blank is precisely calculated and preset in order to achieve precise control over the thickness ratio of each layer in the finished composite product.

[0073] The specific design method is as follows: Assume that an n-layer titanium-aluminum composite material is prepared, and the original thickness of the i-th metal layer is h. i0 The thickness of the composite metal layer is h. i According to the principle of constant volume during plastic deformation, the following relationship holds: h i0 ×L i0 ×W i0 =h i ×L i ×W i ; among which, L i0 and W i0 L represents the length and width of the i-th layer of metal material in the composite preform, respectively. i and W i These represent the length and width of the i-th metal layer in the composite titanium-aluminum material, respectively. In composite processes such as rolling, where thickness reduction is the primary process, the change in the width direction is typically very small (W). i0 ≈W i Furthermore, the elongation rate of each layer in the length direction is basically the same (L). i / L i0 ≈λ, where λ is the total extension coefficient). Therefore, the above equation can be simplified to: h i0 ≈h i ×λ. For the entire titanium-aluminum composite material, the total thickness of the finished titanium-aluminum composite material H = Σh. i (i = 1 to n), the total thickness H0 of the pre-composite blank is Σh i0 ≈λ×Σh i =λ×H. Then the thickness ratio (thickness proportion) of the i-th layer after composite bonding is k. i For: k i =h i / H=(h i0 / λ) / (H0 / λ)=h i0 / H0. That is: the thickness ratio k of each layer after composite bonding. i It is approximately equal to the thickness ratio of the corresponding layer of blank before composite bonding. Based on the above principle, the thickness ratio (h) of the original blank can be set during the design stage. 10 :h 20 :...:h n0 This allows for direct and precise control of the thickness ratio (h1:h2:...:h) of each layer in the final product. n This avoids the waste of resources caused by traditional trial and error methods and realizes the integration of design, prediction and control of thickness ratio.

[0074] In conclusion, the layer thickness ratio design and control method provided in this disclosure has at least the following advantages:

[0075] First, by combining the ROM mixing principle to predict material density, elastic modulus, specific heat capacity, strength, elongation, and other indicators in advance, this approach breaks away from the traditional passive thickness ratio control mode of "trial and error-detection-adjustment." For the first time, it proactively applies the "volume invariance principle" of plastic processing to the layer thickness design stage of titanium-aluminum composite materials. This is achieved by establishing k... i =h i0 The simple yet precise mathematical model / H0 enables accurate prediction and control of the final product's layer thickness ratio during the design phase, allowing for customized performance and forming a new, predictable, and controllable integrated "design-manufacturing" solution.

[0076] Secondly, by systematically coupling the structural design of the thickness ratio with the process control (low temperature, large deformation, asynchronous rolling) to suppress brittle phases, high interfacial bonding is ensured through specific processes, so that composite products that meet specific "thickness ratio" and "interfacial bonding" can have good material properties.

[0077] Furthermore, the selection of materials, number of layers (symmetric / asymmetric), thickness ratio, and functional requirements of the application scenario (such as strength, corrosion resistance, conductivity, and cost) are systematically matched. The design concept of the material structure is derived from the performance requirements, thereby realizing the integration of structure and function.

[0078] Based on the principle of constant volume before and after composite, the method provided in this disclosure achieves accurate prediction and control of the thickness ratio of each layer after composite. Through reasonable material selection and structural design, combined with specific preparation process, a titanium-aluminum layered composite material with excellent mechanical properties and functional characteristics is finally obtained.

[0079] Furthermore, in this disclosure, the use of a large deformation asynchronous rolling process can solve the problem of inconsistent elongation of the two-layer heterogeneous metals. In addition, by combining the specific conditions of large deformation asynchronous rolling, the excessive formation of brittle intermetallic compounds can be suppressed during the composite process, thereby enabling the titanium-aluminum composite material to obtain high interfacial bonding strength.

[0080] Layered metal composite materials are produced by roll-rolling composite production. The roll-rolling composite uses a four-roll composite mill unit, which includes main equipment such as upper, middle and lower three or even multiple layers of uncoilers, leveling equipment, induction heating uniform temperature furnace (which can achieve rapid heating), four-roll composite mill, coiler, etc. Tension is established between the uncoiler, mill and coiler for rolling.

[0081] Asynchronous rolling is mainly achieved by having the upper and lower work rolls of a four-high mill have independent speed control functions, allowing for individual adjustment of the speed of the upper and lower work rolls. When the composite material is double-layered, the speed of the upper and lower rolls can be adjusted according to the difference in elongation of the materials for asynchronous rolling. The roll speed is faster on the side with greater elongation and slower on the side with less elongation. When the composite material is a multi-layered or three-layered symmetrical structure (such as titanium-aluminum-titanium symmetry), asynchronous rolling can apply a shear force to the bonding surface of the composite material, which is beneficial to the bonding. At the same time, asynchronous rolling can appropriately reduce the rolling force (compared to conventional synchronous rolling mills).

[0082] The aforementioned rolling mill for composite rolling adopts a four-high composite rolling mill with a rolling force exceeding 2000 tons (composite rolling requires a large single-pass deformation to increase the bonding strength of the composite plate. However, the rolling force will increase significantly, thus placing high demands on the rolling mill equipment). The mill's work rolls adopt a positive convexity (convexity value 0-0.3mm). The roll surface of the mill's work rolls can be heated to ensure that the roll surface temperature is not lower than 200℃ during composite rolling (the roll heating method is not limited to hot rolls, rolls with built-in heating functions, etc.). The purpose of roll surface heating is to take into account the influence of environmental factors and heat exchange, to avoid the material temperature dropping too quickly, and to further improve the bonding strength and reduce the rolling force.

[0083] Titanium and aluminum raw materials are heated using a medium-frequency electromagnetic induction heating furnace (which can heat rapidly and ensure thorough heating of the material). During heating, the entire raw material is thoroughly heated. The heating atmosphere is protected by argon gas, and the vacuum degree is less than 50ppm to avoid oxidation, nitriding, hydrogen absorption, etc. of the composite interface and titanium material during heating.

[0084] In some optional embodiments, the rolling temperature in the large deformation asynchronous rolling process can be 300℃ to 500℃, such as 300℃, 350℃, 400℃, 450℃, or 500℃, or other values ​​within the range of 300℃ to 500℃. Rolling temperature has a significant impact on the plasticity and deformation resistance of metallic materials. The rolling temperature set in this disclosure is lower than the recrystallization temperature of aluminum and much lower than the recrystallization temperature of titanium. By setting the rolling temperature to 300℃ to 500℃, excessive diffusion of Ti and Al atoms can be effectively suppressed, avoiding the formation of continuous, thick, brittle intermetallic compound layers; and combined with rapid rolling, the high-temperature dwell time can be shortened, deformation resistance reduced, and cracking avoided.

[0085] In some optional implementations, the reduction deformation in the large deformation asynchronous rolling process is ≥50%, such as 50%, 55%, 60%, 65%, 70%, 75%, or 80%, or other values ​​within the range of ≥50%. The reduction deformation directly affects the degree of deformation. By setting the reduction deformation to ≥50%, a huge deformation energy can be provided, promoting the interdiffusion of titanium and aluminum atoms at the interface and forming metallurgical bonding, while simultaneously breaking up the already formed micro-regions of brittle phase.

[0086] In some optional implementations, the roll speed ratio in the large deformation asynchronous rolling process can be from 1.1:1 to 1.5:1, such as 1.1:1, 1.2:1, 1.3:1, 1.4:1, or 1.5:1, or other values ​​within the range of 1.1:1 to 1.5:1. With the above roll speed ratio, strong shear deformation can be generated at the interface, effectively breaking down the surface oxide film, activating the interface, and promoting direct bonding between pure metals. If the roll speed ratio is too small, the shearing effect is not obvious; if the roll speed ratio is too large, it can easily lead to problems such as workpiece deviation, slippage, or surface scratches.

[0087] Building upon the above, by employing the large deformation asynchronous rolling process, the internal grains and second-phase particles of the metal can be effectively broken down to form an ultrafine grain structure, thereby improving the tensile strength and yield strength of the material while maintaining good plasticity. Compared to synchronous rolling, large deformation asynchronous rolling can reduce rolling force and the deformation resistance of the metal; furthermore, large deformation asynchronous rolling can effectively improve the formability and surface quality of the sheet metal. The internal stress distribution of asynchronously rolled composite materials is more uniform, and defects such as warping and wavy edges are less likely to occur; at the same time, a reasonable speed ratio can reduce the relative slippage between the rolls and the workpiece, reducing the risk of surface scratches.

[0088] Further, stress-relief annealing is performed to eliminate processing stress.

[0089] In some alternative embodiments, the stress-relief annealing temperature can be between 200°C and 300°C, such as 200°C, 250°C, or 300°C, or other values ​​within the range of 200°C to 300°C. It should be noted that this disclosure does not employ high-temperature diffusion annealing, which can effectively prevent the growth of brittle phases.

[0090] In addition, this disclosure also provides an application of the above-mentioned titanium-aluminum composite material, such as using the titanium-aluminum composite material to manufacture aerospace equipment, automobiles, electronic communication equipment or battery casings, etc.

[0091] The features and performance of this disclosure will be further described in detail below with reference to embodiments.

[0092] Example 1

[0093] This embodiment provides a titanium-aluminum composite material, which is obtained by combining one titanium layer and one aluminum layer. The preparation method of the titanium-aluminum composite material includes:

[0094] S1: Material selection and design.

[0095] The objective is to prepare a high-strength, high-toughness titanium-aluminum composite material for lightweight structural components. Based on the above performance requirements, the ROM mixing method was used to determine that TC4 titanium alloy is used as the titanium material and 6013 aluminum alloy is used as the aluminum material. The layered structure of the titanium-aluminum composite material was determined to be a two-layer structure with a target thickness ratio of 1:3 (titanium layer: aluminum layer).

[0096] S2: Calculation of billet thickness ratio.

[0097] The total thickness H of the pre-designed titanium-aluminum composite material is assumed to be 4mm. Based on the principle that the volume of each metal layer remains constant before and after lamination, the desired result is that the thickness k of the finished product... 钛层 :k 铝层 If the ratio is 1:3, then the thickness ratio of titanium to aluminum in the billet must also be set to 1:3. Based on the ROM mixing method, the preset total elongation coefficient λ is 2, therefore the total billet thickness H0 = λ × H = 2 × 4 mm = 8 mm. Thus, the billet thickness h of the titanium material... 钛材 =k 钛层 ×H0=1 / 4×8mm=2mm, aluminum billet thickness h 铝材 =k 铝层 ×H0=3 / 4×8mm=6mm.

[0098] S3: Process the blank.

[0099] S3-1: Perform laser cleaning and laser texturing on TC4 boards with a thickness of 2mm and 6013 boards with a thickness of 6mm, respectively.

[0100] The laser cleaning process is as follows: Under the protection of inert gas, a pulsed laser with a wavelength of 1064nm is used. For titanium materials, a power of 180W, a scanning speed of 8500mm / s, and a pulse frequency of 200kHz are used for cleaning; for aluminum materials, a low power of 150W, a scanning speed of 2000mm / s, and a pulse frequency of 50kHz are used for cleaning.

[0101] In laser texturing, for aluminum, a nanosecond pulsed fiber laser is used to control the surface roughness Ra within the range of 2.0 μm to 4.0 μm; for titanium, a picosecond pulsed laser is used to control the surface roughness Ra within the range of 4.0 μm to 8.0 μm.

[0102] S3-2: The laser-textured TC4 plate and 6013 plate are stacked together and then subjected to large deformation asynchronous rolling.

[0103] Large deformation asynchronous rolling is carried out in one pass using a four-high mill at 450°C with a 50% reduction deformation rate and a roll speed ratio of 1.2:1 between the aluminum and titanium sides, to obtain a titanium-aluminum composite plate with a total thickness of about 4 mm.

[0104] S3-3: The titanium-aluminum composite plate was stress-relieved annealed at 250℃ for 1 hour to obtain the titanium-aluminum composite material.

[0105] The SEM image of the titanium-aluminum composite material prepared in this embodiment is shown below. Figure 1 As shown, Figure 1 The thickness marked in the figure represents the thickness of the intermetallic compound layer. The thicknesses of the intermetallic compound at three randomly measured points were 130.3 nm, 111.6 nm, and 104.2 nm, falling within the range of 100 nm to 135 nm. The metallographic image of the aluminum layer in this titanium-aluminum composite material is shown below. Figure 2 As shown, the aluminum layer exhibits uniform grain size and an equiaxed grain structure, with an average grain size ≤100μm and an aspect ratio ≤3. The metallographic image of the titanium layer is shown below. Figure 3 As shown, the titanium layer exhibits a uniform equiaxed α-grain structure with an average grain size ≤8μm, an aspect ratio ≤2, and an α-phase volume fraction ≥85%. The metallographic diagram of the interface between the aluminum and titanium layers is shown below. Figure 4 As shown, the aluminum and titanium layers are uniformly and smoothly bonded together with good interfacial adhesion.

[0106] Testing revealed that the titanium-aluminum composite material has a layer thickness ratio of approximately 1:3.1 between the titanium and aluminum layers, which closely matches the design target. The interfacial shear strength of this composite material reaches 165 MPa. In the tensile test, fracture occurred in the aluminum layer, indicating that the interfacial bonding strength is higher than that of the aluminum matrix. The composite material exhibits a tensile strength of 520 MPa and an elongation of 15%, demonstrating excellent overall performance.

[0107] Example 2

[0108] This embodiment provides a titanium-aluminum composite material, which is obtained by combining two titanium layers and one aluminum layer. The preparation method of the titanium-aluminum composite material includes:

[0109] S1: Material selection and design.

[0110] The objective is to prepare a sandwich-structured composite material that combines the corrosion resistance of a titanium exterior with the low density of an aluminum core. Based on the aforementioned performance requirements, the ROM mixing method was used to determine that commercially pure titanium TA2 is the titanium material and rust-resistant aluminum 5052 is the aluminum material. The layered structure of the titanium-aluminum composite material was determined to be a three-layer structure (first titanium layer - aluminum layer - second titanium layer), with a target thickness ratio of 1:3:1 (first titanium layer: aluminum layer: second titanium layer).

[0111] S2: Calculation of billet thickness ratio.

[0112] The total thickness H of the finished titanium-aluminum composite material is assumed to be 5mm. Based on the principle that the volume of each metal layer remains constant before and after lamination, the desired result is that the finished product's thickness k... 第一钛层 :k铝层 :k 第二钛层 If the ratio is 1:3:1, then the thickness ratio of the first titanium material, aluminum material, and second titanium material in the billet must also be set to 1:3:1. Based on the ROM mixing method, the preset total elongation coefficient λ is 2.5, therefore the total billet thickness H0 = λ × H = 2.5 × 5 mm = 12.5 mm. Thus, the billet thickness h of the first titanium material... 第一钛材 =k 第一钛层 ×H0=1 / 5×12.5mm=2.5mm, the thickness h of the aluminum billet. 铝材 =k 铝层 ×H0=3 / 5×12.5mm=7.5mm, the blank thickness h of the second titanium material 第二钛材 =k 第二钛层 ×H0=1 / 5×12.5mm=2.5mm.

[0113] S3: Process the blank.

[0114] S3-1: Laser cleaning and laser texturing treatments were performed on a 2.5mm thick commercial pure titanium TA2 plate and a 7.5mm thick rust-proof aluminum 5052 plate, respectively.

[0115] The laser cleaning process is as follows:

[0116] Under inert gas protection, a pulsed laser with a wavelength of 355nm is used for cleaning. For titanium, the power is 120W, the scanning speed is 8000mm / s, and the pulse frequency is 180kHz. For aluminum, a low power of 140W, a scanning speed of 6000mm / s, and a pulse frequency of 29kHz are used for cleaning.

[0117] In laser texturing, for aluminum, a nanosecond pulsed fiber laser is used to control the surface roughness Ra within the range of 2.0 μm to 4.0 μm; for titanium, a femtosecond pulsed laser is used to control the surface roughness Ra within the range of 4.0 μm to 8.0 μm.

[0118] S3-2: The commercial pure titanium TA2 plate and the rust-proof aluminum 5052 plate after laser texturing are stacked in the order of first titanium plate - aluminum plate and second titanium plate, and then subjected to large deformation asynchronous rolling.

[0119] Large deformation asynchronous rolling is carried out in one pass using a four-high mill at 450°C with a 50% reduction deformation rate and a roll speed ratio of 1.2:1 between the aluminum and titanium sides, to obtain a titanium-aluminum composite plate with a total thickness of about 5 mm.

[0120] S3-3: The titanium-aluminum composite plate was stress-relieved annealed at 250℃ for 1 hour to obtain the titanium-aluminum composite material.

[0121] Testing revealed that the thickness ratio of the first titanium layer, aluminum layer, and second titanium layer in this titanium-aluminum composite material is approximately 1:2.98:1, which highly matches the design target. The interfacial shear strength of this titanium-aluminum composite material reaches 140 MPa, and the thickness of the intermetallic compound layer at the interface between the aluminum and titanium layers is 300 nm to 400 nm. In the tensile test, the fracture of this titanium-aluminum composite material occurred in the aluminum layer, indicating that the interfacial bonding strength is higher than the strength of the aluminum matrix. The tensile strength of this titanium-aluminum composite material reaches approximately 295 MPa, and the elongation reaches approximately 24%, demonstrating excellent overall performance.

[0122] Example 3

[0123] The difference between this embodiment and Embodiment 2 is as follows: In S3-2, large deformation asynchronous rolling is performed at 300°C with a reduction deformation rate of 60% and a roll speed ratio of 1.1:1 between the aluminum and titanium sides in one pass. In S3-3, stress-relief annealing is performed at 200°C for 2 hours.

[0124] The SEM image of the titanium-aluminum composite material prepared in this embodiment is shown below. Figure 5 As shown. Figure 5 The thickness marked in the figure represents the thickness of the intermetallic compound layer. The thicknesses of the intermetallic compound at three randomly measured points were 160.0 nm, 115.4 nm, and 156.3 nm, respectively, falling within the range of 100 nm to 180 nm.

[0125] Example 4

[0126] The difference between this embodiment and Embodiment 1 is as follows: In S3-2, large deformation asynchronous rolling is performed at 500°C with a reduction deformation rate of 55% and a roll speed ratio of 1.5:1 between the aluminum and titanium sides in one pass. In S3-3, stress-relief annealing is performed at 300°C for 1 hour.

[0127] Comparative Example 1

[0128] The difference between this comparative example and Example 1 is that in S3-2, the rolling temperature is 550°C, and the rolling method is synchronous rolling. 钛层 :k 铝层 =1:3, the aluminum layer deforms a lot during the rolling process, and the layer thickness ratio cannot be precisely controlled.

[0129] Metallographic observation revealed the formation of a continuous TiAl3 brittle layer exceeding 3 μm in thickness at the interface. The interfacial shear strength was only 65 MPa, and early interfacial peeling fracture occurred during tensile testing.

[0130] Comparative Example 2

[0131] The difference between this comparative example and Example 1 is that in S3-2, the rolling temperature for large deformation asynchronous rolling is 250°C. Severe edge cracking of the titanium layer prevented composite bonding.

[0132] Comparative Example 3

[0133] The difference between this comparative example and Example 1 is that in S3-2, the rolling temperature for large deformation asynchronous rolling is 550°C.

[0134] Comparative Example 4

[0135] The difference between this comparative example and Example 1 is that in S3-2, the speed ratio of the aluminum side and titanium side rolls in the large deformation asynchronous rolling is 0.5:1.

[0136] Comparative Example 5

[0137] The difference between this comparative example and Example 1 is that in S3-2, the speed ratio of the aluminum side and titanium side rolls in the large deformation asynchronous rolling is 1.8:1.

[0138] Comparative Example 6

[0139] The difference between this comparative example and Example 1 is that in S3-2, the speed ratio of the aluminum side and the titanium side rolls is 1:1, which means synchronous rolling.

[0140] Comparative Example 7

[0141] The difference between this comparative example and Example 1 is that in S3-2, the reduction deformation of the large deformation asynchronous rolling is 45%.

[0142] Comparative Example 8

[0143] The difference between this comparative example and Example 1 is that in S3-1, no laser texturing treatment was performed.

[0144] Test case

[0145] The performance of the titanium-aluminum composite materials prepared in Examples 1-4 and Comparative Examples 1-8 was compared, and the results are shown in Table 1.

[0146] Tensile strength and elongation were tested according to GB / T 228.1-2021; layer thickness ratio was tested using an OMM (Optical Method Instrument); interfacial bonding effect was obtained by observing the metallographic structure; and the thickness of the intermetallic compound layer was analyzed by SEM (Semiconductor Electron Microscopy). Interfacial fracture was observed through shear or tensile tests. An example of a shear test sample was provided, tested using a microcomputer-controlled servo electronic universal testing machine according to the room temperature tensile testing standard GB / T 228.1-2021.

[0147] Table 1 Performance Comparison Results

[0148]

[0149] As can be seen from Table 1, in the titanium-aluminum composite materials prepared in Examples 1 to 4 of this disclosure, the actual layer thickness ratios of the titanium layer and the aluminum layer are highly consistent with the design target, indicating that the method provided in this disclosure can accurately predict and control the layer thickness ratios after composite, and can obtain titanium-aluminum layered composite materials with both excellent mechanical properties and functional characteristics.

[0150] As can be seen from the comparison between Comparative Example 1 and Example 1, when the rolling method is changed to synchronous rolling and the rolling temperature is increased, a thicker intermetallic compound is formed at the interface between the titanium layer and the aluminum layer, resulting in a lower interfacial bonding strength.

[0151] As can be seen from the comparison between Comparative Examples 2 and 3 and Example 1, when the temperature of large deformation asynchronous rolling is too low or too high, the poor ductility of titanium material processing due to low temperature leads to serious edge cracking or rolling failure; the excessively high temperature results in excessively thick IMC layer and serious grain growth of aluminum material, affecting the bonding strength and mechanical properties of the final product.

[0152] As can be seen from the comparison between Comparative Examples 4 and 5 and Example 1, when the roll speed ratio of large deformation asynchronous rolling is too low or too high, the difference in roll speed is too large, the rolling process cannot be carried out stably, and the difference in rolling elongation between the upper and lower layers of material is too large.

[0153] As can be seen from the comparison between Comparative Example 6 and Example 1, when the large deformation asynchronous rolling is changed to synchronous rolling, the rolling force of the rolling mill is too high, which poses an overload risk; at the same time, the layer thickness ratio cannot be accurately controlled.

[0154] As can be seen from the comparison between Comparative Example 7 and Example 1, when the reduction deformation of large deformation asynchronous rolling is too small, some areas are delaminated, that is, composite is not achieved, and even in composite areas, there is a problem of low bonding strength (false bonding).

[0155] As can be seen from the comparison between Comparative Example 8 and Example 1, if the titanium and aluminum materials are not laser-textured before composite, the bonding strength is relatively low.

[0156] In summary, the solution provided in this disclosure has at least the following advantages over the prior art:

[0157] (1) High interfacial bonding strength of titanium-aluminum composite material: By adopting specific asynchronous rolling process and conditions, metallurgical bonding is achieved while the excessive growth of harmful brittle phase TiAl3 is effectively suppressed, thus obtaining high-strength interfacial bonding.

[0158] (2) Strong performance designability: Based on the principle of constant volume, the layer thickness ratio design method establishes a precise and quantifiable mathematical design method from the layer thickness ratio of the billet to the layer thickness ratio of the finished product. This enables the final comprehensive performance of composite materials (such as strength, stiffness, and toughness ratio) to be customized and controlled through design, truly realizing the integrated design of structure and function.

[0159] (3) Good process controllability: This method changes the layer thickness control from a post-test result detection to a pre-process design, which greatly improves production efficiency and product consistency, and reduces R&D costs and scrap rate.

[0160] (4) Flexible application: By selecting different titanium / aluminum grades and designing different layered structures (two or more layers), the performance of composite materials can be flexibly adjusted to meet the specific needs of various application scenarios.

[0161] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

[0162] Industrial applicability

[0163] This invention creatively achieves precise prediction and control of the thickness ratio of each layer after composite based on the principle of constant volume before and after composite. Through reasonable material selection and structural design, combined with specific material pretreatment, large deformation asynchronous rolling process and annealing conditions, a titanium-aluminum layered composite material with excellent mechanical properties and functional characteristics is obtained, providing guidance for industrial production.

Claims

1. A titanium-aluminum composite material with high interfacial bonding strength and high strength, characterized in that, The titanium-aluminum composite material comprises alternating layers of aluminum and titanium; the interface between the aluminum and titanium layers has an intermetallic compound layer with a thickness not exceeding 1 μm. The titanium-aluminum composite material has a tensile strength of not less than 295 MPa, an elongation of not less than 15%, and an interfacial shear strength of not less than 130 MPa between the titanium layer and the aluminum layer.

2. The titanium-aluminum composite material according to claim 1, characterized in that, The titanium material used for the titanium layer includes at least one of pure titanium and titanium alloys; Preferably, the pure titanium includes at least one of TA1 pure titanium, TA2 pure titanium, and TA4 pure titanium; Preferably, the titanium alloy includes at least one of TC4 titanium alloy and TA18 titanium alloy; Preferably, the titanium layer further has at least one of the following characteristics: Feature 1: The titanium layer has a uniform equiaxed α-grain structure; Feature 2: The average grain size of the titanium layer is ≤8μm; Feature 3: The aspect ratio of the grain size in the titanium layer is ≤2; Feature 4: The α phase volume percentage in the titanium layer is ≥85%.

3. The titanium-aluminum composite material according to claim 1, characterized in that, The aluminum material used in the aluminum layer includes at least one of pure aluminum and aluminum alloys; Preferably, the pure aluminum includes at least one of 1060 pure aluminum and 1100 pure aluminum; Preferably, the aluminum alloy includes at least one of 5-series rust-resistant aluminum, 6-series forged aluminum, and 7-series super-durable aluminum; Preferably, the aluminum layer further has at least one of the following characteristics: Feature 5: The aluminum layer has an equiaxed crystal structure; Feature 6: The average grain size of the aluminum layer is ≤100μm; Feature 7: The aspect ratio of the grain size in the aluminum layer is ≤3.

4. The titanium-aluminum composite material according to claim 1, characterized in that, The metal layers in the titanium-aluminum composite material are arranged symmetrically.

5. A method for preparing a titanium-aluminum composite material as described in any one of claims 1 to 4, characterized in that, The billet, formed by alternating layers of titanium and aluminum, is subjected to large deformation asynchronous rolling, followed by stress-relief annealing.

6. The preparation method according to claim 5, characterized in that, Large deformation asynchronous rolling process includes at least one of the following conditions: Condition 1: Rolling temperature is 300℃~500℃; Condition 2: The amount of compression deformation is ≥50%; Condition 3: The roll speed ratio is 1.1:1 to 1.5:

1.

7. The preparation method according to claim 5, characterized in that, The stress-relief annealing temperature is 200℃~300℃.

8. The preparation method according to claim 5, characterized in that, Based on the thickness h of the i-th metal layer in the target titanium-aluminum composite material i And the length L of the i-th metal layer in the titanium-aluminum composite material. i The length L of the i-th layer of metal material in the billet i0 The ratio λ is used to determine the thickness h of the i-th layer of metal material in the billet. i0 h i0 ≈h i ×λ.

9. The preparation method according to claim 5, characterized in that, Before the stacking process, the titanium material and the aluminum material are subjected to laser cleaning and laser texturing treatment, respectively.

10. An application of the titanium-aluminum composite material as described in any one of claims 1 to 4, characterized in that, The titanium-aluminum composite material is used to manufacture aerospace equipment, automobiles, electronic communication equipment, or battery casings.

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