Clad 2XXX Series Aerospace Products

Abstract

Provided herein is a rolled composite aerospace product comprising a 2XXX series core layer and an Al-Cu alloy clad layer bonded to at least one surface of the 2XXX series core layer, the Al-Cu alloy clad layer being an aluminum alloy containing about 0.06% to 2.8% Cu, preferably about 0.10% to 1.8% Cu. The rolled composite aerospace product is ideally suited for aerospace structural components. Also described herein is a method for making the rolled composite aerospace product.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit and priority of European Patent Application No. 20172082.2, filed on April 29, 2020, the content of which is hereby incorporated by reference in its entirety.

[0002] Disclosed herein is a rolled composite aerospace product comprising a core layer of the 2XXX series and an aluminum alloy layer connected to at least one surface of the core layer of the 2XXX series. The rolled composite aerospace product is preferably suitable for aerospace structural parts. The present disclosure further relates to a method of manufacturing the rolled composite aerospace product.

Background Art

[0003] In the aerospace industry, AA2024 series aluminum alloys and their improved versions are widely used mainly in the T3 condition or its improved versions as high - damage - tolerance aluminum alloys. Products made of these aluminum alloys have relatively high strength with respect to weight ratio, exhibit good fracture toughness, good fatigue properties, and appropriate corrosion resistance.

[0004] To improve corrosion resistance, alloy products of the AA2024 series may be provided as composite products having a relatively thin clad layer on one or both surfaces. The clad layer is usually of higher purity and protects the AA2024 core alloy from corrosion. The clad essentially contains non - alloyed aluminum. In many cases, generally 1XXX series aluminum alloys are referred to, which include sub - classes of type 1000, 1100, 1200, and 1300. However, in practice, the 1XXX series aluminum alloys used for the clad layer are quite extremely pure, having a composition of Si + Fe < 0.7%, Cu < 0.10%, Mn < 0.05%, Mg < 0.05%, Zn < 0.10%, Ti < 0.03%, and the balance being aluminum.

[0005] AA2024 series aluminum alloy cladding with 1XXX series alloys may also be anodized. Anodizing increases resistance to corrosion and wear and provides better adhesion to paint primers and adhesives than bare metal. Anodized articles are applied in structural adhesive metal bonding, such as wings, horizontal stabilizers, vertical stabilizers, or fuselage outer panels. Further known applications include sandwich structures in which one or more (glass) fiber reinforced layers are placed between aluminum panels or sheets using adhesive bonding, resulting in so-called fiber-metal laminates.

[0006] A drawback of 1XXX series alloys as cladding layers is that these alloys are extremely soft and susceptible to surface damage during product handling. During molding operations, this can, for example, lead to mold sticking. [Overview of the project]

[0007] The embodiments included in this invention are defined by the claims, not by this summary. This summary is a higher-level overview of the various aspects of the invention and introduces some of the concepts that will be further described in the sections on embodiments for carrying out the invention below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by referring to the entire specification, some or all of the drawings, and the appropriate parts of each claim.

[0008] This specification describes rolled composite aerospace products comprising a 2XXX series core layer and an Al-Cu alloy cladding layer bonded to at least one surface of the 2XXX series core layer, wherein the Al-Cu alloy cladding layer is an aluminum alloy containing 0.06% to 2.8% Cu. Optionally, the Al-Cu alloy cladding layer is an aluminum alloy containing 0.10% to 1.8% Cu. Optionally, the Al-Cu alloy cladding layer is an aluminum alloy containing 0.10% to 1.8% Cu. Cu: 0.06% to 2.8%, preferably 0.10% to 1.8%. Mg: Maximum 1.5%, preferably 0.10% to 1.2%. Mn: Maximum 0.5%, preferably 0.10% to 0.5%. Si: up to 0.5%, preferably up to 0.3%, Fe: up to 0.4%, Cr: Maximum 0.25%, V: Maximum 0.25%, Zr: up to 0.2%, Ag: up to 0.80%, Zn: up to 0.3%, Ti: up to 0.2%, and The remainder consists of unavoidable impurities and aluminum alloys, which have an aluminum composition.

[0009] Optionally, the Cu content is in the range of 0.2% to 1.5%, preferably 0.5% to 1.6%. Optionally, the Mg content is in the range of 0.20% to 1.2%, preferably 0.20% to 0.9%.

[0010] The Al-Cu aluminum alloy cladding layer may optionally have a corrosion potential of -710mV or less. Optionally, the Al-Cu alloy cladding layer is bonded to at least one surface of the 2XXX series core layers by rolling bonding. The Al-Cu alloy cladding layer may have a thickness in the range of 1% to 20%, preferably 1% to 10%, of the total thickness of the rolled composite aerospace product.

[0011] Optionally, the rolled composite aerospace products described herein consist of a 2XXX series core layer and an Al-Cu alloy cladding layer bonded to one or both surfaces of the 2XXX series core layer. An intermediate liner may be placed between the 2XXX series core layer and the Al-Cu alloy cladding layer, and optionally, the intermediate liner is made of a different aluminum alloy than the Al-Cu alloy cladding layer. In some examples, the intermediate liner is made of a 1XXX series aluminum alloy.

[0012] In some cases, the 2XXX series alloy of the core layer (20) is as follows in weight %: Cu: 1.9% to 7.0%, preferably 3.0% to 6.8%, more preferably 3.2% to 4.95%. Mg: 0.30% to 1.8%, preferably 0.35% to 1.8%. Mn: Maximum 1.2%, preferably 0.2% to 1.2%. Si: up to 0.40%, Fe: up to 0.40%, Cr: up to 0.35%, Zn: up to 1.0%, Ti: up to 0.15%, Zr: up to 0.25%, V: Maximum 0.25%, Li: up to 2.0%, Ag: up to 0.80%, Ni: up to 2.5%, and The remaining components consist of aluminum and impurities.

[0013] In some cases, the core layer (20) of the 2XXX series is derived from the alloy of the 2X24 series. Optionally, at least the core layer (20) of the 2XXX series is tempered to T3, T351, T39, T42, T8, or T851. The rolled composite aerospace product (10) can have a total thickness of 0.8 mm to 50.8 mm, preferably 0.8 mm to 25.4 mm.

[0014] Optionally, rolled composite aerospace products are aerospace structural components, preferably fuselages or fuselage components.

[0015] Also described herein are steps of providing an ingot of 2XXX series aluminum alloy for forming a core layer of a composite aerospace product; a step of homogenizing the 2XXX series aluminum alloy ingot at a temperature in the range of 400°C to 510°C for at least 2 hours; a step of providing an ingot of Al-Cu aluminum alloy or a rolled clad liner for forming an outer clad layer on the 2XXX series core aluminum alloy; and optionally, a step of homogenizing the ingot of Al-Cu aluminum clad alloy for forming the outer clad layer, preferably in the range of at least 400°C, preferably in the range of 400°C to 510°C. A method for producing a rolled composite aerospace product as described herein, comprising the steps of: homogenizing or preheating at a temperature for at least 0.5 hours; rolling and bonding an Al-Cu aluminum alloy clad layer to a 2XXX series core alloy, preferably by hot rolling, and optionally by cold rolling, to form a rolled bonded product; solution heat treating the rolled bonded product at a temperature in the range of 450°C to 510°C; cooling the solution heat treated rolled bonded product to less than 100°C, preferably to ambient temperature; optionally stretching the solution heat treated and cooled rolled bonded product; and aging the cooled rolled bonded product.

[0016] Optionally, the method further includes forming the solution-heat-treated, cold-rolled and joined, and optionally stretched products into products of a predetermined shape having uniaxial or biaxial curvature in a forming process. In some cases, the forming process may be performed after the aging process. Optionally, the forming process and the aging process are combined in the forming process at a high temperature, preferably in the range of 140°C to 200°C, and preferably for a period of 1 to 50 hours.

[0017] Other objects and advantages of the present invention will become apparent from the following detailed description of non-limiting embodiments and drawings. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic diagram of a rolled composite aerospace product as described herein. [Figure 2] Schematic view of a rolled composite aerospace product having five distinct layers as described herein. [Figure 3] Schematic flow schedule of some embodiments of a process for manufacturing a rolled composite aerospace product.

MODE FOR CARRYING OUT THE INVENTION

[0019] As will become apparent in the following specification, unless otherwise indicated, aluminum alloys and temper designations refer to the Aluminum Association designations as published by the Aluminum Association in 2018 and as frequently updated in Aluminum Standards and Data and the Registration Records, and are well known to those skilled in the art. The temper designations are also defined in European Standard EN515.

[0020] For any description of alloy composition or preferred alloy composition, all references to percentages are by weight percent, unless otherwise indicated.

[0021] When used herein, the terms "up to" and "up to about" clearly include, but are not limited to, the possibility of zero weight percent of the particular alloying component to which they refer. For example, up to 0.3% Zn may include aluminum alloys that do not contain Zn.

[0022] As used herein, the meanings of "a", "an", or "the" include references to both the singular and the plural, unless the context clearly dictates otherwise.

[0023] All ranges disclosed herein are intended to encompass any and all subranges contained therein. For example, the indicated range "1 to 10" should be considered to include any and all subranges (including 1 and 10) between a minimum value of 1 and a maximum value of 10, that is, all subranges begin with a minimum value of 1 or greater (e.g., 1 to 6.1) and end with a maximum value of 10 or less (e.g., 5.5 to 10).

[0024] For the purposes of this specification, a sheet product or sheet material should be understood as a rolled product having a thickness of 1.3 mm (0.05 inches) or more and 6.3 mm (0.25 inches) or less. For example, sheets can be 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.0 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm They may have thicknesses of 3.9 mm, 4.0 mm, 4.1 mm, 4.2 mm, 4.3 mm, 4.4 mm, 4.5 mm, 4.6 mm, 4.7 mm, 4.8 mm, 4.9 mm, 5.0 mm, 5.1 mm, 5.2 mm, 5.3 mm, 5.4 mm, 5.5 mm, 5.6 mm, 5.7 mm, 5.8 mm, 5.9 mm, 6.0 mm, 6.1 mm, 6.2 mm, or 6.3 mm. See Aluminium Standard and Data, the Aluminium Association, Chapter 5 Terminology, 1997.

[0025] For the purposes of this specification, plate material or plate product should be understood as a rolled product having a thickness greater than 6.3 mm (0.25 inches). For example, plate material or plate product may have a thickness greater than 6.3, 6.4 mm, 6.5 mm, 6.6 mm, 6.7 mm, 6.8 mm, 6.9 mm, 7.0 mm, 7.1 mm, 7.2 mm, 7.3 mm, 7.4 mm, 7.5 mm, 7.8 mm, 7.9 mm, 8.0 mm, 10.0 mm, 15.0 mm, 20.0 mm, 25.0 mm, 30.0 mm, 35.0 mm, 40.0 mm, 45.0 mm, 50.0 mm, or 100.0 mm. See Aluminium Standard and Data, the Aluminium Association, Chapter 5 Terminology, 1997.

[0026] Provided herein are rolled aerospace products based on 2XXX series alloys that offer an improved balance of corrosion resistance and formability, and further advantages. Specifically, described herein are rolled composite aerospace products including a 2XXX series core layer, the core layer having two faces, an Al-Cu alloy cladding layer bonded to at least one surface of the 2XXX series core layer, and the Al-Cu alloy cladding layer being made of an aluminum alloy containing 0.06% to 2.8% Cu, preferably 0.10% to 2.8%, and more preferably 0.10% to 1.8% Cu as the main alloying component.

[0027] Compared to the 1XXX series alloys, the Al-Cu alloys described herein offer several advantages. The aluminum alloy becomes even more cathode-oriented with Al-Cu alloys having up to 2.8%, preferably up to 1.8%, of Cu. Having at least 0.06%, preferably at least 0.10%, and more preferably at least 0.20%, the cladding layer has a sufficient potential difference with the 2XXX series core alloy, providing extremely good corrosion resistance, and especially good intergranular corrosion resistance, to rolled composite aerospace products.

[0028] Al-Cu alloys may possess extremely good formability, allowing rolled composite aerospace products to be formed in forming operations requiring high degrees of deformation. Formability is comparable to that of some aluminum alloys used in automotive seats. Mold adhesion of the cladding layer to the forming die is significantly reduced, or even avoided, due to the higher hardness of the Al-Cu alloy cladding layer compared to 1XXX series cladding layers. The absence of surface cracks prevents trapping of forming lubricants on the surface. The absence of surface cracks also significantly improves the fatigue performance of composite aerospace products. Furthermore, since fatigue is generally caused by pitting corrosion initiation sites, extremely good resistance to pitting corrosion also improves fatigue performance. Al-Cu alloys have significantly higher strength than 1XXX series alloys, resulting in a harder surface and reduced corresponding surface damage such as abrasions during product handling. Optionally, Al-Cu alloy cladding layers in T3 state have a yield strength (Rp) exceeding 100 MPa.

[0029] Al-Cu alloys are readily anodized and exhibit suitable properties during anodizing, ensuring that there are no problems with subsequent applications after the adhesive bonding layer and / or primer layer.

[0030] Al-Cu alloys are significantly stronger than 1XXX series alloys, resulting in increased overall strength in composite aerospace products compared to 1XXX series alloys with the same cladding thickness. This strength profile also allows for thinner cladding while reducing weight, enabling the design of composite aerospace products with the required good corrosion resistance and improved formability, or conversely, achieving high overall strength while maintaining the same thickness.

[0031] Furthermore, the industrial-scale recycling of waste from rolled composite aerospace products does not pose any major problems, as the 2XXX series alloys may have intentional additions of Cu, Mn, and Mg. The rolled and bonded products can be remelted without first separating the cladding layer(s) from the core layer and processed into new 2XXX series aluminum alloy products.

[0032] Optionally, the Al-Cu aluminum alloy cladding layer is joined to the 2XXX series core layer by rolling, preferably by hot rolling, to achieve the required metallurgical bond between the layers. Such a rolling joining process is extremely economical and yields a highly effective composite product exhibiting the desired properties. When such a rolling joining process is carried out to produce a rolled composite product as described in the present invention, it is preferable that both the core layer and the Al-Cu aluminum alloy cladding layer(s) are subjected to thickness reduction during rolling joining. Typically, before rolling, particularly before hot rolling, the rolled surfaces of both the core layer and the cladding layer(s) ingots are stripped to remove segregation regions near the as-cast surface of the rolled ingot and to improve the flatness of the product.

[0033] Preferably, the cast ingot or slab of the 2XXX alloy core layer may be homogenized and / or preheated before hot rolling and then hot-rolled immediately thereafter. Homogenization and / or preheating of the 2XXX series alloy before hot rolling is usually carried out in one or more steps at temperatures in the range of about 400°C to 505°C. In either case, segregation of alloying elements in the as-cast material is reduced and soluble elements are dissolved. If the treatment is carried out below about 400°C, the resulting homogenization effect is insufficient. If the temperature exceeds about 505°C, melting of the phase may occur, resulting in undesirable porosity formation. The preferred time for this heat treatment is between 2 and 30 hours. Longer times are usually detrimental. Homogenization is usually carried out at temperatures above about 480°C. Typical preheating temperatures are in the range of about 430°C to 460°C with immersion times ranging from a maximum of about 15 hours.

[0034] Al-Cu aluminum clad alloys can be supplied as ingots or slabs for processing into rolling raw materials, preferably having an ingot thickness of about 300 mm or more, for example, in the range of 500 mm or 600 mm, using semi-continuous casting techniques for cast products, such as direct chill casting (DC casting), electromagnetic casting (EMC casting), or electromagnetic stir casting (EMS casting). Optionally, even thinner standard slabs resulting from continuous casting, for example, using belt casters or roll casters, may be used to supply the raw material for Al-Cu aluminum alloy clad liners. Such even thinner standard slabs can have a maximum thickness of about 40 mm.

[0035] In some cases, cast ingots or slabs forming an Al-Cu aluminum alloy cladding layer are preheated or homogenized to a temperature of at least 400°C, preferably at least about 450°C, before being hot-rolled to thinner standards that form a rolled cladding liner in one or more rolling steps. To avoid melting of the phases that would result in the formation of undesirable pores within the ingot, the temperature should not be too high, typically not exceeding 510°C, preferably not exceeding 505°C. The time at the temperature for large commercial-sized ingots should be at least about 0.5 hours, and may be about 1 to 30 hours. Longer periods, for example, more than 48 hours, do not immediately adversely affect the desired properties, but are not economically attractive. Homogenization or preheating results in a more homogeneous microstructure where the phases are melted and the elemental segregation profiles are reduced, thereby improving the formability of the alloy for the hot-rolling process.

[0036] The rolled composite aerospace product is reduced to final specifications by hot rolling, and optionally by subsequent cold rolling. After the rolled composite product is rolled to final specifications, it is subjected to solution heat treatment at a temperature in the range of approximately 450°C to 510°C for a sufficient time for the solution effect to approach equilibrium, with a typical immersion time in the range of approximately 5 to 120 minutes. Preferably, the solution heat treatment is performed at a temperature in the range of approximately 475°C to 510°C, for example, approximately 495°C. Solution heat treatment (SHT) is typically carried out in a batch furnace or a continuous heating furnace. The preferred immersion time at the indicated temperatures is in the range of approximately 5 to 35 minutes. However, in clad products, excessively long immersion times should be avoided, as too much copper, particularly from the 2XXX core layer, may diffuse into the aluminum alloy clad layer(s), which can have a detrimental effect on the corrosion protection obtained by the layer(s). Continuous SHT operation reduces the formation of so-called tensile strain patterns compared to batch annealing. Continuous SHT requires rapid heating of moving rolled and joined products, with an average heating rate exceeding 5°C / second, preferably exceeding 10°C / second.

[0037] After solution heat treatment, it is important to cool the composite product to a temperature of 175°C or lower, preferably about 100°C or lower, and more preferably to ambient temperature, sufficiently quickly to prevent or minimize uncontrolled precipitation of secondary phases, such as Al2CuMg and Al2Cu. On the other hand, the cooling rate should not be excessively high in order to allow sufficient flatness and low levels of residual stress in the composite product. A suitable cooling rate can be achieved by using water, for example, by water immersion or water jet. Solution heat treatment and subsequent rapid cooling in this temperature range result in microstructure formation due to supersaturation. The composite product may further be cold-worked by stretching, for example, to a range of about 0.5 to 8% of its original length, in order to eliminate residual stress therein and to improve the flatness of the product. Preferably, the stretch is in the range of about 0.5 to 6%, more preferably about 0.5 to 4%, and most preferably about 0.5 to 3%.

[0038] After cooling, rolled composite aerospace products are typically naturally aged at ambient temperature. Alternatively, composite aerospace products can also be artificially aged. This artificial aging during the process can be particularly useful for products meeting higher standards.

[0039] In one embodiment, the composition of the Al-Cu aluminum alloy cladding layer is adjusted to provide optimal corrosion protection for the 2XXX series core alloy with an open-circuit potential corrosion value (relative to a reference molecular mercury electrode (SCE), also called the "corrosion potential") of -710 mV or less (e.g., -750 mV), measured by a material that has been solution-heat-treated with a 0.1 N molecular mercury electrode in a solution of 53 g / L NaCl + 3 g / L H2O2 at 25°C and rapidly cooled. In a preferred embodiment, the corrosion potential of the Al-Cu aluminum alloy cladding layer is in the range of -730 mV to -800 mV when measured after SHT and rapid cooling, and therefore when the important alloying elements are generally in solid solution.

[0040] In one embodiment, the corrosion potential difference between the 2XXX core layer and the Al-Cu aluminum alloy cladding layer, i.e., the corrosion potential difference in the final tempering stage, is in the range of 30mV to 100mV to provide sufficient corrosion protection from the anode cladding layer to the core layer.

[0041] The Al-Cu aluminum alloy cladding layer is typically much thinner than the core, with each Al-Cu aluminum alloy layer accounting for 1% to 20% of the total thickness of the composite. More preferably, the Al-Cu alloy cladding layer accounts for approximately 1% to 10% of the total thickness of the composite.

[0042] In one embodiment, the Al-Cu aluminum alloy cladding layer is bonded to one surface or one face of the 2XXX series core layer.

[0043] In one embodiment, an Al-Cu aluminum alloy cladding layer is bonded to both surfaces or both faces of a 2XXX series core layer that forms the outer surface of a rolled composite aerospace product.

[0044] In one embodiment, an intermediate liner or intermediate layer is positioned between a 2XXX series core layer and an Al-Cu aluminum alloy cladding layer, and the intermediate liner is made from a different aluminum alloy than the Al-Cu aluminum layer. In some cases, such an aluminum alloy for the intermediate liner may be a 1XXX series alloy. This intermediate liner acts as a further diffusion barrier for Cu from the core alloy to the outer surface layer formed by the Al-Cu aluminum alloy. It allows for the creation of differences in Cu content between the various layers and the creation of a Cu gradient, thereby providing increased cathodic protection to the 2XXX series core alloy and improving the resistance of the 2XXX series core alloy to pitting and intergranular corrosion by preferential corrosion of the intermediate liner, while maintaining the hardness and surface properties provided by the Al-Cu aluminum alloy outer layer. The intermediate liner is preferably also roll-bonded to the core alloy. Each intermediate liner constitutes 1% to 20% of the total thickness of the composite aerospace product, preferably about 1% to 10% of the total thickness of the composite aerospace product.

[0045] In one embodiment, the rolled composite aerospace product has a total thickness of at least 0.8 mm.

[0046] In one embodiment, the rolled composite aerospace product has a total thickness of at most 50.8 mm (2 inches), preferably at most 25.4 mm (1 inch), and most preferably at most 12 mm.

[0047] Optionally, rolled composite aerospace products are plate products.

[0048] Optionally, rolled composite aerospace products are sheet products.

[0049] The Al-Cu aluminum alloy cladding layer has a Cu content in the range of 0.06% to 2.8%. In one embodiment, the upper limit of the Cu content is about 1.8%, preferably about 1.6%. In one embodiment, the lower limit of the Cu content is preferably 0.10%, more preferably 0.20%, and most preferably 0.50%, providing optimal corrosion protection for the core alloy. The Cu content provides strength to the aluminum alloy cladding layer, allowing the corrosion potential to be adjusted to a target range and enabling control of intergranular corrosion resistance to an acceptable level for use in aerospace components.

[0050] Optionally, the Cu content in the cladding layer can be approximately 0.06% to 2.8% (0.1% to 2.5%, 0.1% to 1.8%, 0.5% to 2.0%, 0.5% to 1.6%, or 1.0% to 1.9%). Optionally, the Cu content in the cladding layer can be approximately 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0. It can be 6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 25%, 2.6%, 2.7%, or 2.8%.

[0051] In one embodiment, the Al-Cu aluminum alloy cladding layer is in weight % Cu: 0.06% to 2.8%, preferably 0.10% to 1.8%, more preferably 0.50% to 1.6%. Mg: Maximum 1.5%, preferably 0.10% to 1.2%, more preferably 0.2% to 0.9%. Mn: Maximum 0.5%, preferably 0.10% to 0.5%. Si: up to 0.5%, preferably up to 0.3%, Fe: up to 0.4%, preferably up to 0.3%, Cr: Maximum 0.25%, V: Maximum 0.25%, Zr: up to 0.2%, Ag: Maximum 0.80%, preferably maximum 0.40%, more preferably maximum 0.10%, Zn: up to 0.3%, preferably up to 0.15%, Ti: up to 0.2%, and The remainder comes from an aluminum alloy having a composition containing unavoidable impurities and aluminum. Preferably, each unavoidable impurity is at most 0.05%, and the total is at most 0.15%.

[0052] Mg can be added to the Al-Cu aluminum alloy clad layer in a range of up to about 1.5%, preferably up to about 1.2%, to provide additional strength to the clad layer through the precipitation of Al2CuMg precipitates and / or solid solution hardening. In one embodiment, the upper limit of the Mg content is about 0.9%, more preferably about 0.80%. The preferred lower limit of Mg addition is about 0.10%, more preferably about 0.20%, and most preferably about 0.35%.

[0053] Optionally, the Mg content in the cladding layer can be up to 1.5% (e.g., 0.10% to 1.2% or 0.2% to 0.9%). Optionally, the Mg content in the cladding layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%. It can be 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, or 1.5%.

[0054] In one embodiment, the Mg content is lower than the Cu content in the Al-Cu alloy, so that Cu remains the major alloying element.

[0055] Mn can be added to the Al-Cu aluminum alloy cladding layer in a range of up to 0.5%, preferably up to 0.4%, to control the granular structure through the formation of dispersed particles during homogenization and / or preheating before hot rolling, and which dispersed particles immobilize the grain boundaries. A preferred lower limit for this purpose is about 0.10%, more preferably about 0.15%. Mn contributes to maintaining a small grain size in the cladding layer(s), providing a better surface appearance and fewer surface cracks after subsequent forming operations. The presence of Mn promotes the conversion from the β-AlFeSi phase (Al5FeSi) to α-AlFeSi (Al8Fe2Si) and stabilizes the α-AlFeSi phase, thereby improving the quality of anodizing on the outer surface of the Al-Cu aluminum alloy cladding layer. The presence of Mn also favorably increases the corrosion potential of Al-Cu aluminum alloys, and by adjusting the amount of Mn added, the difference in corrosion potential between the 2XXX series core alloy and the outer cladding layer(s) can be optimized according to the application, thereby enhancing the corrosion resistance of rolled composite aerospace products.

[0056] Optionally, the Mn content in the cladding layer is at most 0.5% (e.g., 0.10% to 0.5% or 0.2% to 0.4%). Optionally, the Mn content in the cladding layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5%.

[0057] In another embodiment, the Mn content is at most 0.2%, preferably at most 0.15%, and more preferably at most 0.10%, so it is not intentionally added and, in combination with the presence of Fe, limits the formation of harmful coarse intermetallic compounds.

[0058] Iron is a common impurity and can be present in concentrations up to approximately 0.4%. When the Fe content exceeds 0.4%, large Fe-containing intermetallic compounds may form, which may cause veining patterns or clouding of the anodic oxide layer. In one embodiment, the Fe content is maintained at a maximum of approximately 0.3%. In another embodiment, the Fe content is at least 0.10%.

[0059] Optionally, the Fe content in the cladding layer is up to 0.4% (e.g., up to 0.3% or 0.06-0.35%). Optionally, the Fe content in the cladding layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, or 0.4%.

[0060] Silicon (Si) is a common impurity and can be present in a range of up to about 0.5%, preferably kept at a maximum of about 0.3%. A more preferable Si level is in the range of up to about 0.20%. In one embodiment, the Si level is at least about 0.05%, preferably at least about 0.07%, to obtain color intensity and stability after anodizing.

[0061] Optionally, the Si content in the cladding layer is at most 0.5% (e.g., 0.10% to 0.5% or 0.15% to 0.3%). Optionally, the Si content in the cladding layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5%.

[0062] To increase the strength of the aluminum alloy and to control the grain structure, Cr may be added up to a maximum of 0.25%. Preferably, it is present up to a maximum of 0.20%, and more preferably up to 0.15%. In one embodiment, Cr is among the unavoidable impurities.

[0063] In some cases, the Cr content in the cladding layer can be as high as 0.25% (e.g., up to 0.20%, up to 0.09%, up to 0.04%, 0.05%–0.25%, 0.1%–0.25%, or 0.15%–0.2%). Optionally, the Cr content can be 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, or 0.25%.

[0064] To increase the strength of the aluminum alloy and to control the grain structure, V may be added up to a maximum of 0.25%. Preferably, it is present at a maximum of 0.20%, and more preferably at a maximum of 0.15%. In one embodiment, V is among the unavoidable impurities, preferably at a maximum of only 0.02%, and more preferably at a maximum of only 0.01%.

[0065] In some cases, the V content in the cladding layer can be as high as 0.25% (e.g., up to 0.20%, up to 0.09%, up to 0.04%, 0.05% to 0.25%, 0.1% to 0.25%, or 0.15% to 0.2%). Optionally, the V content can be 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, or 0.25%.

[0066] Ag can be present in the cladding layer in amounts up to 0.80% (for example, up to 0.40% or up to 0.15%). In some cases, the Ag content in the cladding layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, or 0.8%.

[0067] Zn can be present in an amount of up to 0.3%, preferably up to 0.15%, without departing from the advantages described herein. Zn can further anodicate the aluminum alloy, and can be used to adjust the corrosion potential to an even lower value. In one embodiment, the aluminum alloy contains at least 0.05% Zn. In one embodiment, Zn is among the unavoidable impurities.

[0068] In some examples, the Zn content in the cladding layer can be up to 0.3% (e.g., up to 0.25%, up to 0.20%, up to 0.15%, up to 0.09%, up to 0.04%, 0.05%–0.3%, 0.1%–0.25%, or 0.15%–0.2%). Optionally, the Zn content can be 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, or 0.3%.

[0069] To control the grain structure without departing from the advantages described herein, Zr may be added in amounts up to 0.2%, preferably up to 0.1%. In preferred embodiments, Zr is among the unavoidable impurities, preferably up to only 0.02%, and more preferably up to only 0.01%. At high levels, it may form harmful intermetallic compound particles in the aluminum alloy.

[0070] In some cases, the Zr content in the cladding layer can be as high as 0.2% (e.g., up to 0.15%, up to 0.1%, 0.05%–0.2%, or 0.05%–0.15%). Optionally, the Zr content can be 0.01%, 0.05%, 0.1%, 0.15%, or 0.2%.

[0071] Ti is a grain refiner during solidification of both ingots and welded joints. The Ti level should not exceed about 0.2%, preferably up to 0.10%, and a more preferred range of Ti is about 0.005% to 0.07%. Ti can be added as a sole element or with either boron or carbon, as is known in the art, such as TiB2, Ti-C, etc., and serves as a casting aid for grain size control.

[0072] In some cases, the Ti content in the cladding layer can be as high as 0.2% (e.g., up to 0.15%, up to 0.1%, 0.05% to 0.2%, or 0.05% to 0.15%). Optionally, the Ti content can be 0.01%, 0.05%, 0.1%, 0.15%, or 0.2%.

[0073] In one embodiment, the Al-Cu aluminum alloy cladding layer is made of an aluminum alloy having a composition of 0.06% to 2.8%, preferably 0.10% to 1.8% by weight of Cu, up to 1.5% of Mg, up to 0.5% of Mn, up to 0.5% of Si, up to 0.4% of Fe, up to 0.25% of Cr, up to 0.25% of V, up to 0.2% of Zr, up to 0.3% of Zn, up to 0.2% of Ti, with the remainder being aluminum and impurities. A more preferred and narrower composition range is described herein and claimed.

[0074] In one embodiment, the core layer of the 2XXX series is in weight %. Cu: 1.9% to 7.0%, preferably 3.0% to 6.8%, more preferably 3.2% to 4.95%. Mg: 0.30% to 1.8%, preferably 0.35% to 1.8%, more preferably 0.6% to 1.8%. Mn: Maximum 1.2%, preferably 0.2% to 1.2%, more preferably 0.25% to 0.9%. Si: up to 0.40%, preferably up to 0.25%, Fe: up to 0.40%, preferably up to 0.25%, Cr: Maximum 0.35%, preferably maximum 0.10% Zn: up to 1.0%, preferably up to 0.25%, Ti: Maximum 0.15%, preferably 0.01% to 0.10%. Zr: Maximum 0.25, preferably maximum 0.12% V: Maximum 0.25%, Li: up to 2.0%, Ag: up to 0.80%, Ni: up to 2.5%, and The remainder comes from aluminum alloys with a composition containing aluminum and impurities. Typically, such impurities are present in amounts of less than 0.05% each, totaling less than 0.15%.

[0075] Optionally, the core layer of the 2XXX series is expressed in weight %. Cu: 1.9% to 7.0%, preferably 3.0% to 6.8%, more preferably 3.2% to 4.95%. Mg: 0.30% to 1.8%, preferably 0.6% to 1.8%, more preferably 0.8% to 1.8%. Mn: Maximum 1.2%, preferably 0.2% to 1.2%, more preferably 0.25% to 0.9%. Si: up to 0.40%, preferably up to 0.25%, Fe: up to 0.40%, preferably up to 0.25%, Cr: Maximum 0.35%, preferably maximum 0.10% Zn: up to 0.4%, preferably up to 0.25%, Ti: Maximum 0.15%, preferably 0.01% to 0.10%. Zr: Maximum 0.25, preferably maximum 0.12% V: up to 0.25%, preferably up to 0.05%, and The remainder is derived from an aluminum alloy having a composition containing aluminum and impurities, preferably a composition consisting of these. Typically, such impurities are present in amounts of less than 0.05% each, and totaling less than 0.15%.

[0076] The Cu content in the core layer can be 1.9% to 7.0% (for example, 2.0% to 7.0%, 3.0% to 6.8%, 3.0% to 6.0%, or 3.2% to 4.95%). Optionally, the Cu content in the core layer can be approximately 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4. It can be 4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, or 7.0%.

[0077] The Mg content in the core layer can be 0.30% to 1.8% (e.g., 0.35% to 1.8% or 0.6% to 1.8%). Optionally, the Mg content in the core layer can be approximately 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, or 1.8%.

[0078] The Mn content in the core layer can be up to 1.5% (for example, 0.2% to 1.2% or 0.25% to 0.9%). Optionally, the Mn content in the core layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.1%, or 1.2%.

[0079] The Si content in the core layer can be up to 0.4% (for example, up to 0.3%, up to 0.25%, or 0.06-0.35%). Optionally, the Si content in the core layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, or 0.4%.

[0080] Optionally, the Fe content in the core layer is up to 0.4% (e.g., up to 0.3%, up to 0.25%, or 0.06–0.35%). Optionally, the Fe content in the core layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, or 0.4%.

[0081] The Cr content in the core layer can be up to 0.35% (e.g., up to 0.20%, up to 0.10%, up to 0.09%, up to 0.04%, 0.05% to 0.25%, 0.1% to 0.25%, or 0.15% to 0.2%). Optionally, the Cr content can be 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, or 0.35%.

[0082] The Zn content in the core layer can be up to 1.0% (for example, up to 0.25%, 0.10% to 1.2%, or 0.2% to 0.9%). Optionally, the Zn content in the core layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, or 1.0%.

[0083] The Ti content in the core layer can be up to 0.15% (e.g., up to 0.10%, up to 0.01%, 0.05% to 0.2%, or 0.05% to 0.15%). Optionally, the Ti content can be 0.01%, 0.05%, 0.1%, or 0.15%.

[0084] The Zr content in the core layer can be up to 0.25% (e.g., up to 0.15%, up to 0.12%, up to 0.1%, 0.05% to 0.2%, or 0.05% to 0.15%). Optionally, the Zr content can be 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, or 0.25%.

[0085] The V content in the core layer can be up to 0.25% (e.g., up to 0.20%, up to 0.09%, up to 0.04%, 0.05% to 0.25%, 0.1% to 0.25%, or 0.15% to 0.2%). Optionally, the V content can be 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, or 0.25%.

[0086] The Li content in the core layer can be up to 2.0% (e.g., up to 1.5%, 0.10% to 1.2%, or 0.2% to 0.9%). Optionally, the Li content in the core layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0. It can be 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2.0%.

[0087] Ag can be present in the cladding layer in amounts up to 0.80% (for example, up to 0.40% or up to 0.15%). In some cases, the Ag content in the cladding layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, or 0.8%.

[0088] The Ni content in the core layer can be up to 2.5% (for example, up to 2.0%, up to 1.5%, 0.10% to 2.5%, or 0.2% to 2.0%). Optionally, the Ni content in the core layer can be approximately 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0. It can be 4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, or 2.5%.

[0089] In preferred embodiments, the core layers of the 2XXX series are derived from the AA2X24 series aluminum alloy in which X is equal to 0, 1, 2, 3, 4, 5, 6, 7, or 8. Particularly preferred aluminum alloys are those within the composition ranges of AA2024, AA2524, and AA2624.

[0090] In one embodiment, the 2XXX series core layer, which is metal-coated on one or both sides with an Al-Cu alloy cladding layer, is provided in the form of T3, T351, T39, T42, T8, or T851.

[0091] The 2XXX series core layers, which are metal-clad on one or both sides with an Al-Cu alloy cladding layer, are supplied to the user in an un-solution heat-treated state, e.g., "F" temper or annealed "O" temper, and can then be molded, solution heat-treated, and aged to the desired temper, e.g., T3, T351, T39, T42, T8, or T851.

[0092] Also provided is a method for manufacturing a rolled composite aerospace product as described herein, which is (a) A process of providing ingots or rolled raw materials of 2XXX series aluminum alloy for forming the core layer of a composite aerospace product, (b) A step of homogenizing the ingot of the 2XXX series aluminum alloy at a temperature in the range of 400°C to 510°C for at least 2 hours, (c) A step of providing an ingot or rolled clad liner of Al-Cu aluminum alloy for forming an outer clad layer on a 2XXX series core aluminum alloy, optionally a step of providing two ingots or two rolled clad liners of Al-Cu aluminum alloy for forming a clad layer on each face of a 2XXX series core aluminum alloy, (d) Optionally, homogenizing or preheating an ingot(s) of Al-Cu aluminum alloy at a temperature in the range of at least about 400°C, preferably in the range of about 400°C to 510°C, for at least 0.5 hours; (e) A step of forming a rolled and bonded product by rolling and bonding an Al-Cu aluminum alloy layer (or more) to a 2XXX series core alloy layer, preferably by hot rolling and optionally by subsequent cold rolling, (f) A process of performing solution heat treatment on rolled and joined products at a temperature in the range of approximately 450°C to 510°C, either in a batch or continuous operation, (g) A step of cooling the solution heat-treated rolled and joined product to less than approximately 100°C, preferably to ambient temperature, (h) Optionally, a step of cold stretching the solution heat-treated rolled jointed product, preferably in the range of about 0.5% to 8% of its original length, preferably in the range of about 0.5% to 6%, more preferably in the range of about 0.5% to 4%, and most preferably in the range of about 0.5% to 3%. (i) Cooled rolled and joined products nature The process includes aging by natural aging and / or artificial aging. In a preferred embodiment, aging tempers the 2XXX series core layer to T3, T351, T39, T42, T8, or T851. Aging tempers the Al-Cu alloy cladding layer to the same temper as the 2XXX series core layer.

[0093] In one embodiment of the method described herein, the rolled composite aerospace product is formed in the following processing step (j) into a molded product having at least one of uniaxial curvature or biaxial curvature by a molding process at ambient temperature or a high temperature.

[0094] In an alternative embodiment of the method, in step (e), an Al-Cu aluminum alloy(s) is roll-bonded to a 2XXX series core alloy, preferably by hot rolling and optionally by subsequent cold rolling, to form a roll-bonded product. The roll-bonded product is then formed in a forming process at ambient temperature or high temperature into a formed product having at least one of uniaxial curvature or biaxial curvature, followed by solution heat treatment and then aging to final temper.

[0095] The forming process may be by forming operations selected from the group consisting of bending, rolling, stretching, aging creep forming, deep drawing, and high-energy hydroforming, particularly by explosive forming or electrical discharge forming.

[0096] In one embodiment, the high-temperature forming process or operation is carried out at a temperature in the range of approximately 140°C to 200°C, and preferably the rolled composite aerospace product is held at the forming temperature for a time in the range of approximately 1 to 50 hours. In a preferred embodiment, the high-temperature forming is performed by an aging creep forming operation. Aging creep forming is a process or operation that constrains a part to a specific shape during aging heat treatment, allowing the part to release stress and creep to occur with respect to the contour, e.g., a fuselage skin with a single or double curve.

[0097] In one embodiment, as disclosed in Patent Document US-2014 / 036699-A1 incorporated herein by reference, a rolled composite aerospace product described herein, after solution heat treatment (SHT) and before being formed into a predetermined shape, undergoes a post-SHT cold working step that induces at least 25% cold working in the rolled composite aerospace product, and the cold working includes cold rolling to the final specification of the rolled aerospace product, which is excluded from this disclosure.

[0098] One aspect described herein relates to the use of the Al-Cu aluminum alloy described herein and claimed as a cladding layer on one or both surfaces of a 2XXX series aluminum alloy for forming rolled aerospace cladding products.

[0099] In a further embodiment, provided herein is a welded structure comprising a rolled composite aerospace product as described herein and at least one aluminum alloy reinforcing element joined to the rolled composite aerospace product by riveting or welding.

[0100] This disclosure also relates to a welded structural member of an aircraft, comprising a rolled composite aerospace product as described herein and at least one aluminum alloy reinforcing element, preferably a longitudinal member, joined to the rolled composite aerospace product by riveting or welding, for example, by laser beam welding or friction stir welding.

[0101] It also relates to welded fuselage structures in which fuselage panels are joined to one another by laser beam welding ("LBW") or friction stir welding ("FSW"), for example, by butt welding.

[0102] The products described herein also include aircraft or spacecraft in which the fuselage is constructed from the rolled composite aerospace products described herein, which may be incorporated, in whole or in part, into various structural parts of the aircraft. For example, various disclosed embodiments may be used to form structural parts in the assembly of the main wing and / or structural parts in the assembly of the tail (tail section). Aircraft generally represent commercial passenger aircraft or cargo aircraft. In alternative embodiments, the products described herein may also be incorporated into other types of aircraft. Examples of such aircraft include manned or unmanned military aircraft, rotary-wing aircraft, or even ballistic aircraft.

[0103] The rolled composite aerospace products described herein can be formed into components for aircraft, such as fuselage components or fuselage panels, or, for example, wing components or wing panels, and aircraft can take advantage of the benefits of the products described. The formings referred to may include bending, stretching, machining, and other forming operations known in the art for forming panels or other components for aircraft, aerospace, or other vehicles. Forming involving bending or other plastic deformation may be carried out at room temperature or at high temperatures. [Examples]

[0104] Figure 1 illustrates a rolled composite aerospace product 10, as shown and claimed herein, comprising a three-layer structure of a 2XXX series core alloy layer 20 having an Al-Cu aluminum alloy clad layer 30 on each side. In another embodiment, the 2XXX series core alloy is metal-coated on one or both sides by an Al-Cu aluminum alloy clad liner.

[0105] Figure 2 illustrates a rolled composite aerospace product 10 having a five-layer structure consisting of a 2XXX series core alloy layer 20 having an Al-Cu aluminum alloy clad layer 30 on each surface, with an intermediate liner or clad layer 40 of a different aluminum alloy placed between the core alloy layer 20 and the Al-Cu aluminum alloy clad layer 30 so that the Al-Cu aluminum alloy clad layer 30 forms the outer layer of the rolled composite aerospace product 10. In one embodiment, the intermediate liner or clad layer 40 is made of an aluminum alloy derived from a 1XXX series aluminum alloy.

[0106] Figure 3 shows a schematic flow schedule of several embodiments of the processes described herein for manufacturing rolled composite aerospace products. In process step 1, the ingot is a casting of a 2XXX series alloy that forms the core alloy of the composite aerospace product, which can optionally be stripped in step 2 to remove segregation areas near the as-cast surface of the rolled ingot and improve the flatness of the product. In process step 3, the rolled ingot is homogenized. In parallel in process step 4, the ingot is a casting of an Al-Cu aluminum alloy that forms at least one cladding layer on the surface of the core alloy of the composite aerospace product and optionally on both sides of the core alloy. This ingot can also optionally be stripped in step 5. In process step 6, the Al-Cu alloy is preheated to the hot-rolling start temperature, and then, since the cladding layer is usually much thinner than the core, it is hot-rolled in process step 7 to form the liner plate(s). In process step 8, the 2XXX core alloy and the Al-Cu aluminum alloy liner plate on one or both faces of the core alloy are preferably roll-joined by hot rolling. Depending on the desired final specification, the rolled-joined product can be cold-rolled in process step 9 to the final specification, for example, a sheet product or a thin-spec plate product. In process step 10, the rolled aerospace product is solution-heat treated, then cooled in process step 11, and preferably stretched in process step 12.

[0107] In one embodiment, the cooled product is formed in molding process 13, and in process step 14, it is aged to the final temper, for example, T3 or T8, i.e., nature The statute of limitations, either by prescription or through artificial prescription, will be applied.

[0108] In one embodiment, the molding process 13 and the aging process step 14 can be combined. For example, the molding operation is carried out at a temperature in the range of approximately 140°C to 200°C for a time range of approximately 1 to 50 hours, so as to induce artificial aging of both the 2XXX series core and the Al-Cu alloy cladding layer(s).

[0109] In one embodiment, the cooled product is aged in process step 14 until it reaches the desired temper, i.e., nature The material is subjected to aging or artificial aging, and then molded into a product of a predetermined shape in molding process 13.

[0110] In an alternative embodiment, after rolling and joining the 2XXX series core and Al-Cu aluminum alloy cladding layer(s) to the final specification, the rolled product is formed into a predetermined shape in forming process 13, solution heat treatment is performed in process step 15, cooling is performed in process step 11, and then aging is performed in process step 14 to the final temper, for example, to temper T3 or T8, i.e., nature The statute of limitations, either by prescription or through artificial prescription, will be applied.

[0111] Examples Example 1 is a rolled composite aerospace product comprising a 2XXX series core layer and an Al-Cu alloy cladding layer bonded to at least one surface of the 2XXX series core layer, wherein the Al-Cu alloy cladding layer is made of an aluminum alloy containing 0.06% to 2.8% Cu.

[0112] Example 2 is a rolled composite aerospace product described in any of the preceding or succeeding examples, wherein the Al-Cu alloy cladding layer is made of an aluminum alloy containing 0.10% to 1.8% Cu.

[0113] Example 3 shows that the Al-Cu alloy cladding layer is in weight % Cu: 0.06%~2.8% Mg: up to 1.5%, Mn: Maximum 0.5%, Si: up to 0.5%, Fe: up to 0.4%, Cr: Maximum 0.25%, V: Maximum 0.25%, Zr: up to 0.2%, Ag: up to 0.80%, Zn: up to 0.3%, Ti: up to 0.2%, The remainder is an aluminum alloy having a composition with unavoidable impurities and aluminum, which is a rolled composite aerospace product as described in any preceding or succeeding example.

[0114] Example 4 is a rolled composite aerospace product described in any of the preceding or succeeding examples, wherein the Cu content is in the range of 0.2% to 1.5%.

[0115] Example 5 is a rolled composite aerospace product described in any of the preceding or subsequent examples, wherein the Mg content is in the range of 0.20% to 1.2%.

[0116] Example 6 is a rolled composite aerospace product according to any of the preceding or following examples, wherein the Al-Cu aluminum alloy cladding layer has a corrosion potential of -710 mV or less.

[0117] Example 7 is a rolled composite aerospace product according to any preceding or subsequent example, wherein the Al-Cu alloy cladding layer is bonded to at least one surface of the 2XXX series core layer by rolling bonding.

[0118] Example 8 is a rolled composite aerospace product according to any of the preceding or succeeding examples, wherein the Al-Cu alloy cladding layer has a thickness in the range of 1% to 20% of the total thickness of the rolled composite aerospace product.

[0119] Example 9 is a rolled composite aerospace product according to any of the preceding or succeeding examples, comprising a 2XXX series core layer and an Al-Cu alloy cladding layer bonded to one or both surfaces of the 2XXX series core layer.

[0120] Example 10 is a rolled composite aerospace product according to any preceding or succeeding example, wherein an intermediate liner is positioned between the 2XXX series core layer and the Al-Cu alloy cladding layer, and the intermediate liner is made of a different aluminum alloy than the Al-Cu alloy cladding layer.

[0121] Example 11 is a rolled composite aerospace product described in any of the preceding or succeeding examples, wherein the intermediate liner is made of an aluminum alloy of the 1XXX series.

[0122] Example 12 shows that the 2XXX series alloy of the core layer is by weight % Cu: 1.9%~7.0% Mg: 0.30%~1.8% Mn: Maximum 1.2%, Si: up to 0.40%, Fe: up to 0.40%, Cr: up to 0.35%, Zn: up to 1.0%, Ti: up to 0.15%, Zr: Maximum 0.25, V: Maximum 0.25%, Li: up to 2.0%, Ag: up to 0.80%, Ni: up to 2.5%, and The remainder is a rolled composite aerospace product as described in any preceding or subsequent example, having a composition of aluminum and impurities.

[0123] Example 13 is a rolled composite aerospace product described in any preceding or subsequent example, wherein the core layer of the 2XXX series is derived from the 2X24 series alloy.

[0124] Example 14 is a rolled composite aerospace product according to any preceding or succeeding example, wherein at least the core layer of the 2XXX series is tempered to T3, T351, T39, T42, T8, or T851.

[0125] Example 15 is a rolled composite aerospace product described in any of the preceding or succeeding examples, wherein the rolled composite aerospace product has a total thickness of 0.8 mm to 50.8 mm.

[0126] Example 16 is a rolled composite aerospace product described in any of the preceding or succeeding examples, wherein the rolled composite aerospace product is an aerospace structural component.

[0127] Example 17 is a method for manufacturing a rolled composite aerospace product described in any preceding or subsequent example, comprising the following steps: A step of providing an ingot of 2XXX series aluminum alloy for forming the core layer of the composite aerospace product, A step of homogenizing the ingot of the 2XXX series aluminum alloy at a temperature in the range of 400°C to 510°C for at least 2 hours, A step of providing an Al-Cu aluminum alloy ingot or rolled clad liner for forming an outer clad layer on the 2XXX series core aluminum alloy, Optionally, the process involves homogenizing or preheating the ingot of the Al-Cu aluminum alloy that forms the outer cladding layer at a temperature in the range of at least 400°C for at least 0.5 hours. The Al-Cu aluminum alloy cladding layer is roll-bonded to the 2XXX series core alloy to form a roll-bonded product, and optionally cold rolling follows this process. The process involves a step of performing a solution heat treatment on the rolled and joined product at a temperature in the range of 450°C to 510°C, A step of cooling the rolled and joined product that has undergone solution heat treatment to below 100°C, Optionally, the process includes stretching the solution heat-treated and cooled rolled-jointed product, and aging the cooled rolled-jointed product. The method includes the above.

[0128] Example 18 is a method of any preceding or subsequent example, wherein the method further comprises forming the rolled jointed product, which has been solution-heat-treated, cooled, and optionally stretched, into a product of a predetermined shape having uniaxial or biaxial curvature in a forming process.

[0129] Example 19 is a method of any preceding or subsequent example in which the molding process is performed after the aging process.

[0130] Example 20 is a method according to any preceding or subsequent example, wherein the molding process and the aging process are combined in the molding process for a period of time ranging from 1 to 50 hours at a high temperature.

[0131] All patents, publications, and abstracts cited above are incorporated herein by reference in their entirety. Various embodiments of the present invention have been described in the course of achieving various objectives of the present invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention as defined in the following claims. This disclosure includes the following embodiments of the invention: <Aspect 1> A rolled composite aerospace product comprising a 2XXX series core layer and an Al-Cu alloy cladding layer bonded to at least one surface of the 2XXX series core layer, wherein the Al-Cu alloy cladding layer is made of an aluminum alloy containing 0.06% to 2.8% Cu. <Aspect 2> The rolled composite aerospace product according to embodiment 1, wherein the Al-Cu alloy cladding layer is made of an aluminum alloy containing 0.10% to 1.8% Cu. <Aspect 3> The Al-Cu alloy cladding layer is in weight % Cu: 0.06%~2.8% Mg: up to 1.5%, Mn: Maximum 0.5%, Si: up to 0.5%, Fe: up to 0.4%, Cr: Maximum 0.25%, V: Maximum 0.25%, Zr: up to 0.2%, Ag: up to 0.80%, Zn: up to 0.3%, Ti: up to 0.2%, and The rolled composite aerospace product according to embodiment 1 or 2, wherein the remainder is an aluminum alloy having a composition in which the remainder is unavoidable impurities and aluminum. <Aspect 4> The rolled composite aerospace product according to embodiment 3, wherein the Cu content is in the range of 0.2% to 1.5%. <Aspect 5> The rolled composite aerospace product according to embodiment 3 or 4, wherein the Mg content is in the range of 0.20% to 1.2%. <Aspect 6> The rolled composite aerospace product according to any one of embodiments 1 to 5, wherein the Al-Cu aluminum alloy cladding layer has a corrosion potential of -710 mV or less. <Aspect 7> The rolled composite aerospace product according to any one of embodiments 1 to 6, wherein the Al-Cu alloy cladding layer is bonded to at least one surface of the 2XXX series core layer by rolling bonding. <Aspect 8> The rolled composite aerospace product according to any one of embodiments 1 to 7, wherein the Al-Cu alloy cladding layer has a thickness in the range of 1% to 20% of the total thickness of the rolled composite aerospace product. <Pattern 9> A rolled composite aerospace product according to any one of embodiments 1 to 8, comprising a core layer of the 2XXX series and an Al-Cu alloy cladding layer connected to one or both surfaces of the core layer of the 2XXX series. <Aspect 10> A rolled composite aerospace product according to any one of embodiments 1 to 9, wherein an intermediate liner is disposed between the core layer of the 2XXX series and the Al-Cu alloy cladding layer, and the intermediate liner is made of an aluminum alloy different from the Al-Cu alloy cladding layer. <Aspect 11> The rolled composite aerospace product according to embodiment 10, wherein the intermediate liner is made of an aluminum alloy of the 1XXX series. <Aspect 12> The 2XXX series alloy of the core layer is, by weight %, Cu: 1.9%~7.0% Mg: 0.30%~1.8% Mn: Maximum 1.2%, Si: up to 0.40%, Fe: up to 0.40%, Cr: up to 0.35%, Zn: up to 1.0%, Ti: up to 0.15%, Zr: Maximum 0.25, V: Maximum 0.25%, Li: up to 2.0%, Ag: up to 0.80%, Ni: up to 2.5%, and A rolled composite aerospace product according to any one of embodiments 1 to 11, having a composition in which the remainder is aluminum and impurities. <Aspect 13> A rolled composite aerospace product according to any one of embodiments 1 to 12, wherein the core layer of the 2XXX series is derived from the alloy of the 2X24 series. <Aspect 14> A rolled composite aerospace product according to any one of embodiments 1 to 13, wherein at least the core layer of the 2XXX series is tempered to T3, T351, T39, T42, T8, or T851. <Aspect 15> The rolled composite aerospace product according to any one of embodiments 1 to 14, wherein the rolled composite aerospace product has a total thickness of 0.8 mm to 50.8 mm. <Aspect 16> The rolled composite aerospace product according to any one of embodiments 1 to 15, wherein the rolled composite aerospace product is an aerospace structural component. <Aspect 17> A method for manufacturing a rolled composite aerospace product according to any one of the embodiments 1 to 16, A step of providing an ingot of 2XXX series aluminum alloy for forming the core layer of the composite aerospace product, A step of homogenizing the ingot of the 2XXX series aluminum alloy at a temperature in the range of 400°C to 510°C for at least 2 hours, A step of providing an Al-Cu aluminum alloy ingot or rolled clad liner for forming an outer clad layer on the 2XXX series core aluminum alloy, Optionally, the process involves homogenizing or preheating the ingot of the Al-Cu aluminum clad alloy that forms the outer clad layer at a temperature in the range of at least 400°C for at least 0.5 hours. The Al-Cu aluminum alloy cladding layer is roll-bonded to the 2XXX series core alloy to form a roll-bonded product, and optionally cold rolling follows this process. The process involves a step of performing a solution heat treatment on the rolled and joined product at a temperature in the range of 450°C to 510°C, A step of cooling the rolled and joined product that has undergone solution heat treatment to below 100°C, The method optionally includes the steps of stretching the solution-heat-treated and cooled rolled-jointed product and aging the cooled rolled-jointed product. <Aspect 18> The method according to embodiment 17, wherein the method further comprises forming the rolled and joined product, which has been solution-heat-treated, cooled, and optionally further stretched, into a product of a predetermined shape having a uniaxial or biaxial curvature in a forming process. <Aspect 19> The method according to embodiment 17 or 18, wherein a molding step is performed after the aging step. <Aspect 20> The method according to embodiment 19, wherein the molding process and the aging process are combined in the molding process at a high temperature for a period of time ranging from 1 to 50 hours.

Claims

1. A rolled composite aerospace product comprising a 2XXX series core layer and an Al-Cu alloy cladding layer bonded to at least one surface of the 2XXX series core layer, wherein the Al-Cu alloy cladding layer is in weight % Cu: 2.8% or less, Mg: 0.20% to 1.2%, Mn: Maximum 0.5%, Si: up to 0.5%, Fe: up to 0.4%, Cr: up to 0.25%, V: Maximum 0.25%, Zr: up to 0.2%, Ag: up to 0.80%, Zn: up to 0.3%, Ti: up to 0.2%, and The remainder consists of aluminum alloys with unavoidable impurities and aluminum in their composition. However, the Mg content in the Al-Cu alloy cladding layer is less than the Cu content. When measured in the aforementioned rolled composite aerospace product that has undergone natural or artificial aging to its final tempering stage, the corrosion potential difference between the 2XXX series core layer and the Al-Cu alloy cladding layer is in the range of 30 mV to 100 mV. The aforementioned rolled composite aerospace product.

2. The rolled composite aerospace product according to claim 1, wherein the Al-Cu alloy cladding layer is made of an aluminum alloy containing more than 0.20% to 1.8% Cu.

3. The rolled composite aerospace product according to claim 1, wherein the Cu content is in the range of more than 0.2% to 1.5%.

4. The rolled composite aerospace product according to any one of claims 1 to 3, wherein the Al-Cu aluminum alloy cladding layer has a corrosion potential of -710 mV or less.

5. The rolled composite aerospace product according to any one of claims 1 to 4, wherein the Al-Cu alloy cladding layer is bonded to at least one surface of the 2XXX series core layer by rolling bonding.

6. The rolled composite aerospace product according to any one of claims 1 to 5, wherein the Al-Cu alloy cladding layer has a thickness in the range of 1% to 20% of the total thickness of the rolled composite aerospace product.

7. A rolled composite aerospace product according to any one of claims 1 to 6, comprising a 2XXX series core layer and an Al-Cu alloy cladding layer connected to one or both surfaces of the 2XXX series core layer.

8. The rolled composite aerospace product according to any one of claims 1 to 7, wherein an intermediate liner is disposed between the core layer of the 2XXX series and the Al-Cu alloy cladding layer, and the intermediate liner is made of an aluminum alloy different from the Al-Cu alloy cladding layer.

9. The rolled composite aerospace product according to claim 8, wherein the intermediate liner is made of an aluminum alloy of the 1XXX series.

10. The 2XXX series alloy of the core layer is, by weight %, Cu: 1.9% to 7.0%, Mg: 0.30% to 1.8%, Mn: Maximum 1.2%, Si: up to 0.40%, Fe: up to 0.40%, Cr: up to 0.35%, Zn: up to 1.0%, Ti: up to 0.15%, Zr: Maximum 0.25, V: Maximum 0.25%, Li: up to 2.0%, Ag: up to 0.80%, Ni: up to 2.5%, and A rolled composite aerospace product according to any one of claims 1 to 9, having a composition in which the remainder is aluminum and impurities.

11. The rolled composite aerospace product according to any one of claims 1 to 10, wherein the core layer of the 2XXX series is made of an alloy of the 2X24 series.

12. The rolled composite aerospace product according to any one of claims 1 to 11, wherein at least the core layer of the 2XXX series is tempered to T3, T351, T39, T42, T8, or T851.

13. The rolled composite aerospace product according to any one of claims 1 to 12, wherein the rolled composite aerospace product has a total thickness of 0.8 mm to 50.8 mm.

14. The rolled composite aerospace product according to any one of claims 1 to 13, wherein the rolled composite aerospace product is an aerospace structural component.

15. A method for manufacturing a rolled composite aerospace product according to any one of claims 1 to 14, A step of providing an ingot of 2XXX series aluminum alloy for forming the core layer of the composite aerospace product, A step of homogenizing the ingot of the 2XXX series aluminum alloy at a temperature in the range of 400°C to 510°C for at least 2 hours, A step of providing an Al-Cu aluminum alloy ingot or rolled clad liner for forming an outer clad layer on the 2XXX series core aluminum alloy, Optionally, the process involves homogenizing or preheating the ingot of the Al-Cu aluminum clad alloy that forms the outer clad layer at a temperature in the range of at least 400°C for at least 0.5 hours. The Al-Cu aluminum alloy cladding layer is roll-bonded to the 2XXX series core alloy to form a roll-bonded product, and optionally cold rolling follows this process. The process involves a step of performing a solution heat treatment on the rolled and joined product at a temperature in the range of 450°C to 510°C, A step of cooling the rolled and joined product that has undergone solution heat treatment to below 100°C, The method optionally includes the steps of stretching the solution-heat-treated and cooled rolled-jointed product and aging the cooled rolled-jointed product.

16. The method according to claim 15, further comprising forming the rolled and joined product, which has been solution-heat-treated, cooled, and optionally further stretched, into a product of a predetermined shape having a uniaxial or biaxial curvature in a forming process.

17. The method according to claim 15 or 16, wherein a molding step is performed after the aging step.

18. The method according to claim 17, wherein the molding step and the aging step are combined in the molding step at a high temperature in the range of 140°C to 200°C for a period of 1 to 50 hours.

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