Manufacturing method for 2XXX series aluminum alloy products

Abstract

Described herein is an aging process for solution heat treated and quenched wrought 2XXX series aluminum alloys, which process includes (1) aging the product in a first aging step at one or more temperatures in the range of 90°C to 120°C for a cumulative time of at least 10 hours, followed by (2) aging the product in a second aging step at one or more temperatures in the range of 150°C to 205°C for a cumulative time of at least 4 hours. Wrought aluminum alloys can be processed into various product forms, such as, for example, sheet, thin plate, thick plate, extruded product, or wrought product.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit and priority of U.S. Provisional Patent Application No. 63 / 198,906, filed on November 20, 2020, the content of which is hereby incorporated by reference in its entirety.

[0002] The present invention relates to a method for manufacturing an extension material of a 2XXX series aluminum alloy, and particularly to an improved aging process. Products made from this alloy are very suitable for aerospace applications, but are not limited thereto. The aluminum alloy can be processed into various product forms such as, for example, sheets, thin plates, thick plates, extruded products, or forged products.

Background Art

[0003] In aerospace applications, generally a very special set of properties is required. Generally, high - strength alloys are desired, but depending on the intended use, other properties such as high fracture toughness, ductility, and excellent corrosion resistance are also required.

[0004] A key characteristic is the product's resistance to stress corrosion cracking ("SCC"), which is particularly pronounced when loaded in the thickness direction (ST). Historically, in higher-strength alloys (such as aircraft structures), most service failures, including SCC in aluminum alloys, have been attributed to assembly stresses or residual stresses acting in the thickness direction relative to the grain flow of the product. This is generally more problematic in parts machined from relatively thick portions of rolled plates, extruded parts, or forged parts of complex shapes, where the grain orientation in the thickness direction may be exposed. Within the high-strength alloy class, including 2XXX series aluminum alloys, broad generalizations regarding susceptibility to SCC and strength or fracture toughness appear impossible. Control of alloy processing and heat treatment is key to ensuring high resistance to SCC without significantly impairing mechanical properties. Thick-walled products of naturally aged T3 and T4 grade 2XXX series aluminum alloys have low ratings for resistance to SCC in the thickness direction. Ratings of such products in other directions are high, as are those of thin-walled products in all directions. These differences are related to the effect of the quenching rate (which is mainly determined by the thickness of the section) on the amount of precipitate generated during quenching.

[0005] Artificial aging of 2XXX series aluminum alloys according to the precipitation hardening T8 temper yields relatively high resistance to delamination and SCC, a slight increase in strength compared to naturally aged counterparts, and very good high-temperature properties. This temper requires cold working by stretching or other means after quenching from the solution heat treatment temperature and before artificial aging (for example, the 2XXX alloy is solution heat treated, quenched, and then cold worked or cold formed). Optionally, cold working may be applied in one or more cold working steps, after solution heat treatment and quenching, optionally after further natural aging, and either before final artificial aging or between two artificial aging steps.

[0006] The response to age hardening is enhanced by stretching strain hardening or cold working by other means prior to artificial aging (T8 grade), and the yield strength can increase very significantly compared to T6 grade. On the other hand, T6 grade relates to wrought materials that have undergone solution heat treatment, quenching, and artificial aging with little or no cold working, so that cold working is not considered to affect the limits of the mechanical properties. High-strength 2XXX series aluminum alloys with very high resistance to stress corrosion cracking are required. [Overview of the Initiative]

[0007] The embodiments included in the present invention are defined by the claims, not by this summary. This summary is a higher-level overview of the various aspects of the present invention and introduces some of the concepts further described in the sections on embodiments for carrying out the invention below. This summary is not intended to identify the main 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 of the present invention 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 an aging process for a solution-heat-treated and quenched wrought 2XXX series aluminum alloy, the process comprising: (1) a first aging step in which the product is aged for at least 10 cumulative hours at one or more temperatures in the range of 90°C to 120°C; and (2) a second aging step in which the product is aged for at least 4 cumulative hours at one or more temperatures in the range of 150°C to 205°C, preferably at least 8 cumulative hours at one or more temperatures in the range of 150°C to 195°C.

[0009] Furthermore, this specification describes a method for manufacturing a 2XXX series aluminum alloy wrought material, the method comprising the steps of (i) casting an ingot of the 2XXX series aluminum alloy described herein, (ii) preheating and / or homogenizing the ingot, (iii) hot working the ingot into a hot-worked wrought material by one or more methods selected from the group consisting of rolling, extrusion, and forging, (iv) optionally cold working the hot-worked wrought material, (v) solution heat treating the wrought material ("SHT"), (vi) quenching or quenching the SHT product, (vii) optionally cold working or cold forming the SHT and quenched product, and (viii) artificially aging the SHT, quenched and optionally cold-worked or cold-formed product by the method described herein.

[0010] This specification further describes wrought 2XXX series aluminum alloy products. In some examples, wrought 2XXX series aluminum alloy products having a leather layer on one or both sides, optionally having a cross-sectional thickness of 1.6 mm to 12 mm, preferably 1.6 mm to 8 mm, which are aged to achieve (1) a conventional tensile yield strength (MPa) above 400 MPa measured in the L direction, or (2) improved IGC resistance measured without the leather layer, mainly exhibiting pitting corrosion and minor IGC.

[0011] In some cases, wrought 2XXX series aluminum alloy products having a cross-sectional thickness of 12 mm to 250 mm, preferably 12 mm to 130 mm, are aged to achieve (1) a conventional tensile yield strength (MPa) exceeding 380 MPa + 0.57 (120-t) MPa measured in the L direction at one-quarter thickness (where t is the thickness of the product in mm), or (2) a minimum life without failure due to stress corrosion cracking for at least 20 days, preferably at least 25 days, at a plate thickness direction stress level of 250 MPa in accordance with ASTM G47.

[0012] Optionally, a wrought 2XXX series aluminum alloy product having a cross-sectional thickness of 12 mm to 250 mm, preferably 12 mm to 130 mm, is subjected to aging treatment to achieve (1) a conventional tensile yield strength (MPa) exceeding 380 MPa + 0.57 (120-t) MPa measured in the L direction at one-quarter thickness (where t is the thickness of the product in mm), or (2) improved IGC resistance measured without a skin that mainly exhibits pitting corrosion and minor IGC.

[0013] Other objects and advantages of the present invention will become apparent from the following non-limiting embodiments and detailed description of the drawings. [Modes for carrying out the invention]

[0014] As understood herein, unless otherwise specified, aluminum alloy designations and temper symbols refer to the designations used by the Aluminum Society in the Aluminum Standards and Data and the Registration Records published by the Aluminum Society in 2019, and are well known to those skilled in the art, such as "Teal Sheet." Temper symbols are defined in the European standard EN515.

[0015] In any description of alloy composition or preferred alloy composition, all references to proportions are in weight percentages unless otherwise specified.

[0016] As used herein, the term “about” means, when used to describe a compositional range or amount of alloying elements, that the actual amount of alloying elements may vary from the nominal intended amount due to factors such as variations in standard processing, as understood by those skilled in the art.

[0017] As used herein, the terms “up to” and “up to about” expressly include, but are not limited to, the possibility of zero weight percent of the particular alloy component they refer to. For example, up to 0.25% Cr may include alloys that do not contain Cr.

[0018] As used herein, the meanings of "a," "an," or "the" include both singular and plural forms unless otherwise clearly indicated by the context.

[0019] All ranges disclosed herein are intended to encompass any and all subranges contained therein. For example, a range described as "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 that 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).

[0020] For the purposes of this specification, a sheet product or sheet material (also referred to herein as “sheet”) 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, a sheet may 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.

[0021] For the purposes of this specification, a plate material or plate product (also referred to herein as “plate”) should be understood as a rolled product having a thickness greater than 6.3 mm (0.25 inches). For example, a plate material or plate product may have a thickness greater than 6.3 mm, 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.

[0022] As used herein, “ambient temperature” may include temperatures from about 15°C to the first aging process temperature described herein (e.g., about 15°C to about 90°C, about 15°C to about 120°C, about 20°C to about 90°C, about 20°C to about 120°C, about 22°C to about 90°C, about 22°C to about 120°C, about 20°C to about 100°C, about 20°C to about 110°C, about 15°C to about 100°C, or about 15°C to about 110°C). For example, "ambient temperature" is approximately 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, Approximately 41°C, approximately 42°C, approximately 43°C, approximately 44°C, approximately 45°C, approximately 46°C, approximately 47°C, approximately 48°C, approximately 49°C, approximately 50°C, approximately 51°C, approximately 52°C, approximately 53°C, approximately 54°C, approximately 55°C, approximately 56°C, approximately 57°C, approximately 58°C, approximately 59°C, approximately 60°C, approximately 61°C, approximately 62°C, approximately 63°C, approximately 64°C, approximately 65°C, approximately 66°C, approximately 67°C, approximately 68°C, approximately 69°C ℃, approx. 70℃, approx. 71℃, approx. 72℃, approx. 73℃, approx. 74℃, approx. 75℃, approx. 76℃, approx. 77℃, approx. 78℃, approx. 79℃, approx. 80℃, approx. 81℃, approx. 82℃, approx. 83℃, approx. 84℃, approx. 85℃, approx. 86℃, approx. 87℃, approx. 88℃, approx. 89℃, approx. 90℃, approx. 91℃, approx. 92℃, approx. 93℃, approx. 94℃, approx. 95℃, approx. 96℃, approx. 97℃, approx. 98°C, approximately 99°C, approximately 100°C, approximately 101°C, approximately 102°C, approximately 103°C, approximately 104°C, approximately 105°C, approximately 106°C, approximately 107°C, approximately 108°C, approximately 109°C, approximately 110°C, approximately 111°C, approximately 112°C, approximately 113°C, approximately 114°C, approximately 115°C, approximately 116°C, approximately 117°C, approximately 118°C, approximately 119°C, or approximately 120°C may be.

[0023] The object of this disclosure is to provide a method for manufacturing a 2XXX series aluminum alloy wrought material having improved properties, at least in the thickness direction (ST direction). As used herein, the wrought material is a cast aluminum alloy that has been solution-heat-treated, quenched, and subsequently cold-worked or cold-formed.

[0024] Another object of the present disclosure is to provide a method for manufacturing a 2XXX series aluminum alloy sheet having improved SCC resistance at least in the ST direction.

[0025] These and other objects and further advantages are met or exceeded by the present disclosure that provides an aging process for a solution heat-treated and quenched 2XXX series aluminum alloy sheet, the process including the steps in the following order. (1) In a first aging step, the product is aged at one or more temperatures within the range of 90°C to 120°C (for example, 95°C to 115°C, 90°C to 110°C, 100°C to 120°C, 99°C to 119°C, 91°C to 119°C, or 92°C to 117°C) for at least 10 hours in cumulative time, (2) Subsequently, in a second aging step, the product is aged at one or more temperatures within the range of 150°C to 205°C (for example, 155°C to 200°C, , 160°C to 205°C, 150°C to 204°C, 151°C to 199°C, or 159°C to 201°C), preferably within the range of 150°C to 195°C (for example, 150°C to 190°C, 155°C to 195°C, 151°C to 194°C, or 150°C to 194°C) for at least 4 hours in cumulative time, to increase the strength and corrosion resistance of the alloy product. In some cases, the second aging step is for at least 12 hours (for example, at least 13 hours, at least 15 hours, at least 20 hours, at least 24 hours, at least 36 hours, at least 48 hours, at least 60 hours, at least 72 hours, at least 84 hours, at least 96 hours, at least 108 hours, at least 120 hours, at least 132 hours, or up to 144 hours) in cumulative time.

[0026] In addition to the multi-step aging process described above, the aging process described herein may include any desired number of aging steps. For example, the aging process may include 2 steps, 3 steps, 4 steps, 5 steps, 6 steps, 7 steps, 8 steps, 9 steps, 10 steps, or more. The aging step may include heating the aluminum alloy extruded material to any desired temperature and holding the aluminum alloy extruded material at the desired temperature for any desired time. As described herein, all ranges describing processes, properties, compositions, characteristics, etc. include all endpoints and all sub-ranges included therein.

[0027] In the prior art, the solution heat treatment and the artificially aged 2XXX series aluminum alloy extruded material after quenching are aged in a single-step aging process at a relatively high temperature to obtain the T6 or T8 state. According to the disclosure herein, a first step, phase, or treatment at a relatively low temperature for at least 10 hours, preferably at least 24 hours, in terms of cumulative time, followed by a second step, phase, or treatment at a higher temperature above the temperature of the first step for at least 8 hours in terms of cumulative time. It has been found that after applying the aging process, improvement in properties can be achieved, particularly in the ST direction.

[0028] In some cases, the cooling (i.e., quenching) from the solution heat treatment of a 2XXX series aluminum alloy plate in the thickness range of 1.6 mm to 12 mm is measured during cooling when the temperature of the 2XXX series aluminum alloy is in the range of 150 °C to 400 °C, and is carried out at a cooling rate of 100 °C / min to 1000 °C / min (for example, 110 °C / min to 900 °C / min, 100 °C / min to 800 °C / min, 110 °C / min to 700 °C / min, or 120 °C / min to 600 °C / min), more preferably 200 °C / min to 600 °C / min (for example, 210 °C / min to 600 °C / min, 200 °C / min to 550 °C / min, or 250 °C / min to 500 °C / min). For example, the cooling rate is similar to the cooling rate using water cooling in a 2XXX series aluminum alloy plate with a thickness of 120 mm.

[0029] The aging process improves the metallurgical properties in the ST direction. In particular, 2XXX series aluminum alloy wrought materials are more resistant to ST stress corrosion cracking. The improvement in ST direction SCC resistance is especially pronounced in thicker gauge wrought materials. "ST stress corrosion cracking resistance" means that, in accordance with ASTM G47, after performing an alternating immersion test for 20 days at a net stress of 250 megapascals (MPa) in the ST direction using at least three test specimens required for the test, at least two of the three test specimens of the 2XXX series aluminum alloy product do not fail. In one embodiment, after performing an alternating immersion test for 20 days at a net stress of 250 MPa in the ST direction in accordance with ASTM G47, all three test specimens do not fail. In another embodiment, after performing an alternating immersion test for 25 days at a net stress of 250 MPa in the ST direction in accordance with ASTM G47, all three test specimens do not fail.

[0030] The aging process described herein improves SCC corrosion resistance and maintains the mechanical strength level at least at the level of a counterpart aged in a single-step aging process at 190°C for 12 hours, thereby achieving an improved balance of engineering properties for 2XXX series aluminum alloy wrought materials. The counterpart is a wrought material of the same thickness, similar alloy composition, and the same thermomechanical history, except for the final aging treatment.

[0031] In one embodiment of the aging process, the wrought material in the first aging step is aged at one or more temperatures in the range of 90°C to 120°C for a cumulative time of at least 10 hours, more preferably at least 24 hours. In a preferred embodiment of the first aging step, the wrought material is aged for a cumulative time of 144 hours or less, preferably 96 hours or less, more preferably 64 hours or less.

[0032] In one embodiment of the aging process, the wrought material in the second aging step is aged at one or more temperatures in the range of 150°C to 195°C for a cumulative time of at least 8 hours, preferably at least 12 hours. In a preferred embodiment of the second aging step, the wrought material is aged for a cumulative time of 144 hours or less, preferably 96 hours or less. In a preferred embodiment of the second aging step, the wrought material is aged at one or more temperatures in the range of about 160°C to 190°C.

[0033] In one embodiment of the aging process, for convenience, the aging of the wrought material may be carried out in a single programmable furnace, as is known in the art for other aging treatments of other heat-treatable aluminum alloys.

[0034] In another embodiment of the aging process, the wrought material is cooled to, for example, ambient temperature at the end of the first aging step and then reheated to a second aging step to complete the aging cycle described herein, thereby improving the metallurgical properties. This intermediate cooling to ambient temperature can be done for logistical reasons, however, if necessary, an intermediate cold working operation, particularly a stretching operation to stretch the material to about 0.5% to 11% of its original length, may be performed to increase the subsequent aging rate and strength level. Preferably, the stretching is in the range of about 0.5% to 6%, more preferably about 1% to 3% of the original length.

[0035] The aging process according to the present invention can be used for a wide range of 2XXX series aluminum alloy wrought materials.

[0036] In one embodiment, a 2XXX series wrought aluminum alloy contains, by weight %, at least the following main components: about 3.0–5.5% Cu, about 0.15–1.0% Mn, about 0.2–1.8% Mg, and up to about 0.7% Ag, up to 0.15% impurities, and aluminum, having a preferred composition range described herein and / or claimed. The term “comprising” in relation to aluminum alloys should be understood to mean that the alloy may contain further alloying elements, as illustrated below.

[0037] In another embodiment, the 2XXX series aluminum alloy wrought material has the following composition in weight percent: Cu approximately 3.0% to 5.5% Mn about 0.15%~1.0%, Mg about 0.2%~1.8%, Ag maximum approximately 0.7%, Zn maximum approximately 1.0%, Fe maximum approximately 0.3%, Si maximum approximately 0.2%, Ti: approximately 0.01% to 0.2% Optionally, the composition has one or more disperse-forming elements selected from the group consisting of approximately 0.05% to 0.25% Cr, approximately 0.05% to 0.25% Zr, approximately 0.05% to 0.25% V, approximately 0.05% to 0.4% Hf, and approximately 0.05% to 0.4% Sc, preferably 0.05% to 0.2% Cr, 0.05% to 0.15% Zr, 0.05% to 0.15% V, 0.05% to 0.25% Hf, and 0.05% to 0.25% Sc, up to 0.15% impurities, and aluminum, having a preferred narrower composition range as described herein and / or claimed. Typically, each impurity may be present at a maximum of 0.05%, with a total maximum of 0.15%.

[0038] Cu is the primary alloying element in 2XXX alloys and should be in the range of about 3.0% to 5.5% for the methods or processes described herein. The preferred lower limit of the Cu content is about 3.5%. The preferred upper limit of the Cu content is about 5.1%. In one embodiment, the Cu content is in the range of about 3.0% to 4.4%, preferably in the range of about 3.5% to 4.4% (e.g., 3.6% to 4.4%, 3.5% to 4.3%, 3.75% to 4.25%, or 3.6% to 4.3%). In another embodiment, the Cu content is in the range of about 4.4% to 5.5%, preferably in the range of about 4.4% to 5.1% (e.g., 4.4% to 5.4%, 4.5% to 5.5%, 4.5% to 5.4%, 4.7% to 5.2%, or 4.75% to 5.25%).

[0039] Mn is another important alloying element in 2XXX series aluminum alloys and should be present in a range of about 0.15% to 1.0%. In one embodiment, the Mn content is in the range of about 0.15% to 0.8%, preferably about 0.2% to about 0.8% (e.g., 0.25% to 0.75%, 0.3% to 0.8%, 0.2% to 0.5%, 0.2% to 0.6%, or 0.21% to 0.79%).

[0040] Mg is another important alloying element and should be present in the range of 0.2% to 1.8% (e.g., 0.25% to 1.75%, 0.3% to 1.8%, 0.2% to 1.5%, 0.2% to 1.6%, or 0.21% to 1.79%). The preferred lower limit for Mg content is about 0.4%. The preferred upper limit for Mg content is about 1.4%.

[0041] The strength after artificial aging can be further increased by adding Ag in the range of up to approximately 0.7%. The preferred lower limit for intentional Ag addition would be about 0.05%, more preferably about 0.2%. The preferred upper limit is about 0.7%. For example, Ag can be added in amounts of 0.05% to 0.7%, 0.1% to 0.7%, 0.2% to 0.7%, 0.15% to 0.69%, 0.05% to 0.65%, or 0.2% to 0.66%.

[0042] In one embodiment, Ag is an impurity element, which may be present in an amount of up to about 0.05%, preferably up to about 0.03%.

[0043] The aging strength can be further increased by intentionally adding Zn in a range of up to approximately 1% (e.g., 0.05% to 1%, 0.05% to 0.99%, 0.1% to 1%, 0.1% to 0.9%, or 0.09% to 0.99%), and when added, it may replace a portion of the desired Ag. The preferred lower limit for intentional Zn addition would be 0.2%, more preferably about 0.3%. The preferred upper limit would be about 0.5%.

[0044] In one embodiment, Zn is an impurity element, which may be present in an amount of up to about 0.25%, preferably up to about 0.15%.

[0045] Optionally, dispersed-phase forming elements can be added to aluminum alloys to control changes in particle structure or particle size during hot working operations such as hot rolling, extrusion, or forging. When added, one or more dispersed-phase forming elements may be approximately 0.05% to 0.25% Cr (e.g., 0.05% to 0.2%, 0.05% to 0.15%, or 0.09% to 0.24%), up to approximately 0.15% Zr or approximately 0.05% to 0.25% Zr (e.g., 0.05% to 0.25%, 0.05% to 0.15%, or 0.09% to 0.24%), and approximately 0.05% to 0.25% V (e.g., 0.05%). You can choose from the group consisting of %~0.2%, 0.05%~0.15%, or 0.09%~0.24%, approximately 0.05%~0.4% Hf (e.g., 0.05%~0.35%, 0.05%~0.25%, or 0.09%~0.39%), and / or approximately 0.05%~0.4% Sc (e.g., 0.05%~0.35%, 0.05%~0.25%, or 0.09%~0.39%).

[0046] During the casting of 2XXX series aluminum alloys, Ti can be added to the alloy product, particularly for the purpose of grain refinement. The addition of Ti should not exceed about 0.2%, preferably not exceeding 0.15% (e.g., 0.05%-0.2%, 0.05%-0.15%, 0.1%-0.15%, or 0.09%-0.15%). The lower limit of preferred Ti addition is about 0.01%. Ti can be added as a single element or together with either B (e.g., TiB2) or C (TiC) used as a casting aid to control grain size. Adding Ti above the upper limit of this range, i.e., about 0.08%, can also further improve the SCC resistance and strength of the product.

[0047] Fe is a common impurity in aluminum alloys and can be tolerated up to about 0.3% (e.g., 0.05%-0.3%, 0.05%-0.2%, 0.05%-0.1%, 0.1%-0.3%, 0.1%-0.2%, or 0.09%-0.29%). Preferably, it is maintained at a level of about 0.2%, more preferably about 0.1%.

[0048] Si is also a common impurity in aluminum alloys and can be tolerated up to about 0.2% (e.g., 0.05% to 0.2%, 0.1% to 0.2%, 0.05% to 0.15%, or 0.05% to 0.1%). Preferably, it is kept at a level of up to 0.15%, more preferably up to 0.1%.

[0049] The remainder consists of aluminum and normal and / or unavoidable impurities. Typically, impurities may be present in amounts of up to 0.05% each, and up to 0.15% in total. In one embodiment, impurities may be present in amounts of up to 0.03% each, and up to 0.1% in total. For the purposes of the present invention, unavoidable impurities include other elements that can be added during the casting operation, such as Be or Ca. These elements are generally called deoxidizers and are used to control or limit the oxidation of molten aluminum. These elements are considered trace elements or impurities and are typically added in amounts of less than 0.01%, preferably less than about 100 ppm, for example, 10-80 ppm of Ca and / or up to about 20 ppm of Be.

[0050] Wrought 2XXX series aluminum alloys processed according to the methods described herein are hot-worked products after casting and include rolled products (i.e., sheets or plates), extruded products, and forged products. Forged products are either die-forged or hand-forged.

[0051] In one embodiment, a 2XXX series aluminum alloy wrought material processed or manufactured according to the method described herein is in the form of a thin gauge plate product having a cross-sectional thickness in the range of 1.6 mm to 12 mm (e.g., 1.7 mm to 12 mm, 1.6 mm to 11.9 mm, 1.7 mm to 11 mm, 1.6 mm to 8 mm, 2 mm to 12 mm, 2 mm to 10 mm, or 2.5 mm to 9.5 mm).

[0052] In one embodiment, a 2XXX series aluminum alloy wrought material processed or manufactured according to the present invention is a thick-walled product having a cross-sectional thickness of at least 12 mm. The wrought material may be a rolled product, a forged product, or an extruded product. In one embodiment, the thick-walled wrought material is a plate product having a cross-sectional thickness of at least 12 mm, preferably at least 25 mm. In another embodiment, the thick-walled wrought material is a plate product having a cross-sectional thickness of at least 38 mm. The improvements in properties described herein may be achieved with thick-walled wrought materials having a cross-sectional thickness of up to 250 mm. In one embodiment, the thick-walled wrought material is a plate product having a cross-sectional thickness of up to 250 mm. In another embodiment, the thick-walled wrought material is a plate product having a cross-sectional thickness of up to 180 mm. In yet another embodiment, the thick-walled wrought material is a plate product having a cross-sectional thickness of up to 130 mm. It should be understood that, as used in this paragraph, thickness refers to the minimum thickness of the product, and portions of the product may exhibit thicknesses slightly greater than the stated minimum thickness.

[0053] In one embodiment, the 2XXX series aluminum alloy product has a thickness ranging from 1.6 mm to 12 mm and achieves a conventional yield strength (MPa) measured in the longitudinal direction (i.e., the L direction) relative to the rolling direction, exceeding 400 MPa.

[0054] In one embodiment, the 2XXX series aluminum alloy product has a thickness in the range of 1.6 mm to 12 mm and achieves improved intergranular corrosion (IGC) resistance measured without a skin, mainly exhibiting pitting corrosion and minor IGC (e.g., pitting corrosion accounts for more than 50%, preferably more than 70%, more than 90%, of the total corrosion). In some cases, the wrought 2XXX series aluminum alloy product having an optional skin layer on at least one or both sides of the wrought aluminum alloy product is described herein. As mentioned, the wrought aluminum alloy product can have a cross-sectional thickness of 1.6 mm to 12 mm (preferably 1.6 mm to 8 mm) and can be aged according to the method described herein to achieve a conventional tensile yield strength (MPa) above 400 MPa measured in the L direction, and / or improved IGC resistance measured without a skin, mainly exhibiting pitting corrosion and minor IGC.

[0055] In one embodiment, a 2XXX series aluminum alloy product has a thickness of at least 12 mm and achieves a minimum life without failure by stress corrosion cracking (SCC), measured in accordance with ASTM G47-98, at a thickness-direction (ST) stress level of 250 MPa. In a particular embodiment, a wrought 2XXX series aluminum alloy product having a cross-sectional thickness of 12 mm to 250 mm (preferably 12 mm to 130 mm) is described herein. A wrought aluminum alloy product having a thickness of 12 mm to 250 mm is aged according to the method described herein to achieve a conventional tensile yield strength greater than 380 MPa + 0.57 (120 - t) MPa (wherein t is one-quarter (mm) of the thickness of the wrought aluminum alloy product), measured in the L direction at 1 / 4 of the thickness. Furthermore, the wrought aluminum alloy product can exhibit a minimum lifespan of at least 20 days (preferably at least 25 days) without failure due to stress corrosion cracking, in accordance with ASTM G47, at a thickness-direction stress level of 250 MPa.

[0056] In one embodiment, a 2XXX series aluminum alloy product has a thickness of at least 12 mm and achieves a conventional tensile yield strength (MPa) exceeding 380 MPa + 0.57(120-t) MPa (where t is the thickness of the product (mm)), measured in the L direction at one-quarter of the thickness. In some non-limiting examples, the wrought aluminum alloy product may be a wrought 2XXX series aluminum alloy product with a cross-sectional thickness of 12 mm to 250 mm (preferably 12 mm to 130 mm) and, aged according to the method described herein, achieves a conventional tensile yield strength exceeding 380 MPa + 0.57(120-t) MPa, measured in the L direction at one-quarter of the thickness. The wrought aluminum alloy product may further demonstrate improved IGC resistance, measured without a skin, showing mainly pitting corrosion and minor IGC.

[0057] Depending on the end use of the 2XXX series aluminum alloy wrought material processed according to the method described herein, this disclosure also includes embodiments in which the 2XXX series wrought material may be provided with a sheathing, particularly for thinner gauge rolled products. Such sheathing products use a 2XXX series aluminum alloy core and a generally higher purity sheathing material that further protects the 2XXX series aluminum alloy core from corrosion. The sheathing material may include, but is not limited to, aluminum that is essentially unalloyed, or aluminum containing only 0.1% or less of any other element. In this invention, the aluminum alloys designated as 1xxx series include all alloys by the Aluminum Association (AA), including the subclassifications of the 1000, 1100, 1200, and 1300 series. Therefore, the outer layer on the core material may be selected from alloys such as 1060, 1045, 1100, 1200, 1230, 1135, 1235, 1435, 1145, 1345, 1250, 1350, 1170, 1175, 1180, 1185, 1285, 1188, or 1199. Furthermore, AA7000 series alloys, such as 7072 alloy containing zinc (0.8-1.3%), can function as an outer layer, and AA6000 series alloys, such as 6003 or 6253 alloys usually containing more than 1% alloy additives, can function as an outer layer. Other alloys may also be useful as outer layers, especially insofar as they provide sufficient overall corrosion protection to the core alloy. The outer layer(s) are usually considerably thinner than the core material, each constituting 1%-15% of the total thickness of the composite. The outer layer typically constitutes about 1% to 10% of the total thickness of the composite.

[0058] In a further embodiment, a method for manufacturing a 2XXX series aluminum alloy wrought material is described herein, the method comprising the steps in the following order. a. Cast an ingot of a 2XXX series aluminum alloy as described and / or claimed herein, b. Preheat and / or homogenize the ingot. c. The ingot is hot-worked into a hot-worked wrought material by one or more methods selected from the group consisting of rolling, extrusion, and forging. d. Optionally, the hot-worked wrought material is cold-worked. e. The wrought material is subjected to solution heat treatment ("SHT"). f. Preferably, the SHT product is quenched or hardened by jet quenching or immersion quenching in water or another quenching medium. g. Optionally, allow the product to expire naturally. h. Optionally, the SHT-treated and hardened product is cold-worked. i.SHT is performed, the hardened product is artificially aged, and optionally cold-worked to improve the metallurgical properties of the wrought material, preferably to the T8 state.

[0059] According to the present invention, artificial aging comprises the following steps in this order: (1) in a first aging step, the product is aged for at least 10 hours in cumulative time at one or more temperatures in the range of 90°C to 120°C; (2) subsequently, in a second aging step, the product is aged for at least 4 hours in cumulative time at one or more temperatures in the range of 150°C to 205°C, preferably at least 8 hours in cumulative time at one or more temperatures in the range of 150°C to 195°C.

[0060] 2XXX series aluminum alloys can be supplied as ingots, slabs, or billets for production into suitable wrought products by casting techniques common in the art for cast products, such as direct chill (DC) casting, electromagnetic casting (EMC) casting, and electromagnetic stirring (EMS) casting. Slabs resulting from continuous casting, such as belt casters or roll casters, may also be used, which may be particularly advantageous when producing rolled final products of thinner gauges (e.g., up to 12 mm thick). As is well known in the art, grain refiners containing, for example, Ti and B, or Ti and C, may also be used. The Ti content of the aluminum alloy is in the range of up to about 0.2%, preferably up to about 0.15%, and more preferably about 0.01% to 0.12%. Ti can be added as a single element or together with either boron or carbon, which are used as casting aids, for particle size control. After casting the aluminum alloy ingot, the surface of the ingot is generally machined to remove the separation zone near the as-cast surface of the ingot.

[0061] The objectives of homogenization heat treatment include at least the following: (i) dissolving as much of the coarse soluble phase formed during solidification as possible, and (ii) reducing the concentration gradient to facilitate the dissolution process. Preheating also achieves some of these objectives. Typical preheating for 2xxx alloys would be at a temperature of about 420°C to 505°C with an immersion time ranging from about 3 to 50 hours, more commonly from about 3 to 20 hours. A typical homogenization and / or preheating process can also be carried out in one or more steps, if desired, which is usually carried out in a temperature range of about 400°C to 505°C. For example, a two-step process may have a first step at about 480°C to 500°C and a second step at about 450°C to 490°C to optimize the dissolution process of various phases depending on the exact alloy composition. In either case, segregation of alloying elements in the as-cast ingot is reduced, and soluble elements are dissolved. If the process is carried out at temperatures below 400°C, the resulting homogenization effect is insufficient. If the temperature exceeds 505°C, eutectic melting may occur, potentially leading to the formation of undesirable pores. The immersion time at the homogenization temperature ranges from approximately 1 to 50 hours, more commonly from approximately 2 to 20 hours. The applicable heating rate is the normal heating rate in this art.

[0062] Following preheating and / or homogenization, the material is hot-worked by one or more methods selected from the group consisting of rolling, extrusion, and forging. Hot rolling is preferred in this invention.

[0063] In one embodiment, the plate material is hot-rolled to obtain the final hot-rolled thickness.

[0064] In one embodiment, a hot working process can be performed to provide a material of intermediate thickness. Subsequently, this material of intermediate thickness can be cold-worked to a thinner thickness, for example, by rolling. Depending on the amount of cold working, intermediate annealing may be used before or during the cold working process.

[0065] The next process step is solution heat treatment ("SHT") of hot-worked products and, optionally, cold-worked products. The product should be heated to immerse all or substantially all of the soluble Cu, Mg, and optionally Ag in a solution, as much as possible. Preferably, the SHT is carried out at a temperature range of about 450°C to 505°C for a typical immersion time ranging from about 5 minutes to 300 minutes, more preferably from about 5 minutes to 120 minutes, for a time sufficient for the solution effect to approach equilibrium. Solution heat treatment is usually carried out in a batch furnace. After SHT, it is important to cool the aluminum alloy product at a high cooling rate to a temperature of about 100°C or lower, preferably to ambient temperature, to prevent or minimize uncontrolled precipitation of secondary phases, such as Al2CuMg and Al2Cu. Preferably, the cooling rate should not be too high in order to allow sufficient flatness and acceptable levels of residual stress in the product. A suitable cooling rate can be achieved by using water, for example, water immersion or water jet.

[0066] Products that have been SHT-treated and quenched may be further cold-worked. "Cold working" means processing or shaping aluminum alloy products at temperatures not considered hot working temperatures, generally below approximately 120°C (for example, ambient temperature).

[0067] Cold working and / or stretching can produce appropriate strength, relieve internal stress, and / or straighten the product. For example, stretching to a range of about 0.5% to 11% of the original length can relieve internal residual stress and improve the flatness of the product. Preferably, the stretch is in the range of about 0.5% to 6%, more preferably about 1% to 3%.

[0068] In one embodiment, a SHT-treated and quenched product is naturally aged to a temper such as T3X, e.g., T39 or T351, and then subjected to a cold deformation or cold forming process, e.g., by an aircraft manufacturer or supplier, to produce a structural component. After such a cold working operation, the product is artificially aged according to the method described herein. Such cold working operations include, but are not limited to, bending, roll forming, or electro-hydraulic forming operations. The cold deformation process can be carried out by stretching, cold compression, bending, rolling, roll forming, or quasi-static or faster cold deformation (typically quasi-static speeds of less than 0.008 s⁻¹, e.g., typically up to 100-150 s⁻¹ or faster), and the total deformation range is typically up to 10%, but is not limited to that.

[0069] In the next step, the wrought material is artificially aged according to the methods described and / or claimed herein to increase its strength and achieve improved metallurgical properties, such as resistance to SCC.

[0070] Next, a desired final structural shape or near-net structural shape can be machined from the aged wrought material according to the present invention.

[0071] The SHT, quenching, cold working, and artificial aging methods described herein are also used in the production of profiles made by extrusion or forging processes.

[0072] Another aspect of this disclosure relates to aircraft structural members made from 2XXX series aluminum alloy wrought materials manufactured and aged according to the methods described herein.

[0073] 2XXX series aluminum alloy products manufactured using these methods can be used in a range of up to approximately 12 mm in thickness, exhibiting excellent properties as aircraft sheets, among several applications. In the thinner plate thickness range of approximately 12 mm to 76 mm, they exhibit excellent properties as wing plates, such as lower wing plates. The thinner plate thickness range can also be used for stringers, and can be used to form integrated wing panels and stringers for use in aircraft wing structures. When machined to thicker gauges of over approximately 60 mm to 250 mm, excellent properties are obtained for integrated parts machined from plates, or for forming integrated wing spars for use in aircraft wing structures, or for forming ribs for use in aircraft wing structures. Thicker gauge products can also be used as tooling plates, for example, as molds for manufacturing molded plastic products by die casting or injection molding. The alloy products described herein can also be supplied in the form of stepped extruded or extruded wing spars for use in aircraft structures, or in the form of forged wing spars for use in aircraft wing structures.

[0074] The present invention is illustrated by reference to the following non-limiting embodiments of the present invention. [Examples]

[0075] Example 1. On an industrial scale, 33 mm thick plate material was produced by DC casting of ingots having the chemical composition described in Table 1. The ingots were homogenized at 495°C for 21 hours, and then hot-rolled from a thickness of approximately 400 mm to 33 mm. On a laboratory scale, the plate material was solution-heat treated at 495°C for 2 hours, cooled with water, and then artificially aged to T8 temper using various aging practices according to both standard industrial manufacturing practices and the methods described herein. See Table 2. In Table 2, aging practice 1 is a standard aging practice to reach the T8 state, aging practice 2 is a second industrial practice, and aging practice 3 is according to the method described herein.

[0076] After aging treatment, the mechanical properties in the L and ST directions (tensile yield strength (YS), ultimate tensile strength (UTS), and elongation A) are measured. 50mm The thickness was measured at an intermediate thickness in accordance with ASTM B557. The average of the three samples is shown in Table 3.

[0077] Under steady load, the minimum lifespan (in days) without failure due to stress corrosion cracking (SCC), measured according to ASTM G47-98, was tested at a plate thickness direction (ST) stress level of 250 MPa. The results are shown in Table 3. The average of the three samples is shown in Table 3.

[0078] [Table 1] [Table 2] [Table 3] The results in Table 3 show that the aging treatment described herein significantly improves SCC resistance while maintaining relatively high mechanical properties.

[0079] Example 2. On an industrial scale, 120 mm thick plate material was produced by DC casting of ingots having the chemical composition described in Table 4. The ingots were homogenized at 495°C for 36 hours, and then hot-rolled from approximately 430 mm to 120 mm thick. On a production scale, the plate material was solution-heat treated at 495°C for 6 hours, cooled with water, and stretched by cold deformation of 1.4% in the L direction. Subsequently, it was artificially aged to T8 temper using the aging process described herein and outlined in Table 5.

[0080] After aging treatment, the mechanical properties in the L and ST directions (tensile yield strength (YS), ultimate tensile strength (UTS), and elongation A) are measured. 50mm The thickness was measured at an intermediate thickness (ST direction) or a quarter thickness (L direction) in accordance with ASTM B557. The average of the three samples is shown in Table 6.

[0081] Under steady load, the minimum lifespan (in days) without failure due to stress corrosion cracking (SCC), measured according to ASTM G47-98, was tested at a plate thickness direction (ST) stress level of 250 MPa. The results are shown in Table 6. The average of the three samples is shown in Table 6.

[0082] [Table 4] [Table 5] [Table 6] The results in Table 6 show that, even for thicker plates, the aging treatment described herein provides a combination of excellent SCC resistance and high mechanical properties.

[0083] Example Example 1 is an aging process for a solution-heat-treated and quenched 2XXX series aluminum alloy wrought material, the process comprising: (1) a first aging step in which the product is aged for at least 10 cumulative hours at one or more temperatures in the range of 90°C to 120°C; and (2) a second aging step in which the product is aged for at least 4 cumulative hours at one or more temperatures in the range of 150°C to 205°C, preferably at least 8 cumulative hours at one or more temperatures in the range of 150°C to 195°C.

[0084] Example 2 is an aging process described in either the preceding or following example, wherein the aging process is an aging process for a 2XXX series aluminum alloy product that has been solution-heat-treated, quenched, and subsequently cold-worked or cold-formed.

[0085] Example 3 is an aging process according to either of the preceding or following examples, wherein cold working is applied in one or more cold working steps that are optionally applied after solution heat treatment and quenching, after further natural aging, and either before final artificial aging or between two artificial aging steps.

[0086] Example 4 is an aging process described in either of the preceding or following examples, in which a plate with a thickness in the range of 1.6 to 12 mm is quenched after solution heat treatment at a cooling rate similar to that of a 120 mm thick plate with an intermediate thickness, preferably at 100°C / min to 1000°C / min, more preferably at 200°C / min to 600°C / min (when measured during cooling within the temperature range of 400°C to 150°C).

[0087] Example 5 is an aging process described in either the preceding or following example, wherein the aging process is an aging process for a processed product for providing a wrought material, i.e., a 2XXX series aluminum alloy product that has been solution-heat-treated, quenched, and subsequently cold-worked or cold-formed.

[0088] Example 6 is a aging process according to either the preceding or following example, wherein the second aging step is at least 12 hours, preferably 12 to 144 hours, in cumulative time.

[0089] Example 7 is an aging process described in either of the preceding or following examples, wherein a 2XXX series aluminum alloy contains, by weight percent, Cu 3.0%~5.5%, Mn 0.15%~1.0%, Mg 0.2%~1.8%, Ag up to 0.7%, Zr up to 0.25%, Zn up to 0.25%, impurities up to 0.15%, and aluminum.

[0090] Example 8 shows that the 2XXX series aluminum alloy contains, by weight %, Cu 3.0%~5.5%, Mn 0.15%~1.0%, Mg 0.2%~1.8%, Ag up to 0.7%, Zn up to 1.0%, Fe up to 0.3%, Si up to 0.2%, and Ti An aging process as described in either of the preceding or following examples, comprising 0.01% to 0.2%, optionally, one or more disperse-forming elements selected from the group consisting of (0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, 0.05% to 0.4% Sc), preferably 0.05% to 0.2% Cr, 0.05% to 0.15% Zr, 0.05% to 0.15% V, 0.05% to 0.25% Hf, 0.05% to 0.25% Sc), up to 0.15% impurities, and aluminum.

[0091] Example 9 is an aging process according to either of the preceding or following examples, wherein the 2XXX series aluminum alloy contains Ag in the range of 0.1% to 0.7%, preferably in the range of 0.2% to 0.7%.

[0092] Example 10 is an aging process described in either of the preceding or following examples, wherein a 2XXX series aluminum alloy contains a Cu content in the range of 3.5% to 4.4%.

[0093] Example 11 is an aging process according to either of the preceding or following examples, wherein the 2XXX series aluminum alloy contains a Cu content in the range of 4.4% to 5.5%, preferably in the range of 4.4% to 5.1%.

[0094] Example 12 is an aging process described in either the preceding or following example, for providing a 2XXX series aluminum alloy as a rolled product.

[0095] Example 13 is a aging process described in either the preceding or following example, in which a 2XXX series aluminum alloy product is an aircraft structural component.

[0096] Example 14 is a method for producing a wrought 2XXX series aluminum alloy, the method comprising the steps of (i) casting an ingot of a 2XXX series aluminum alloy having the composition described in either the preceding or succeeding example, (ii) preheating and / or homogenizing the ingot, (iii) hot working the ingot into a hot-worked wrought material by one or more methods selected from the group consisting of rolling, extrusion, and forging, (iv) optionally cold working the hot-worked wrought material, (v) solution heat treating the wrought material ("SHT"), (vi) quenching or quenching the SHT product, (vii) optionally cold working or cold forming the SHT and quenched product, and (viii) artificial aging the SHT, quenched and optionally cold-worked or cold-formed product according to either the preceding or succeeding example to improve the metallurgical properties of the wrought material.

[0097] Example 15 is a wrought 2XXX series aluminum alloy product according to either the preceding or succeeding example, having a leather layer on one or both sides, and having a cross-sectional thickness of 1.6 mm to 12 mm, preferably 1.6 mm to 8 mm, the product is aged to achieve (1) a conventional tensile yield strength (MPa) above 400 MPa as measured in the L direction, and / or (2) improved IGC resistance as measured without the leather layer, which mainly exhibits pitting corrosion and minor IGC.

[0098] Example 16 is a wrought 2XXX series aluminum alloy product described in either the preceding or succeeding example, wherein the product having a cross-sectional thickness of 12 mm to 250 mm, preferably 12 mm to 130 mm, is subjected to aging treatment to achieve (1) a conventional tensile yield strength (MPa) exceeding 380 MPa + 0.57 (120 - t) MPa measured in the L direction at one-quarter thickness (t is the thickness of the product (mm)), and / or (2) a minimum life without failure due to stress corrosion cracking for at least 20 days, preferably at least 25 days, at a plate thickness direction stress level of 250 MPa in accordance with ASTM G47.

[0099] Example 17 is a wrought 2XXX series aluminum alloy product described in any of the prior examples, wherein the product having a cross-sectional thickness of 12 mm to 250 mm, preferably 12 mm to 130 mm, is subjected to aging treatment to achieve (1) a conventional tensile yield strength (MPa) exceeding 380 MPa + 0.57 (120 - t) MPa measured in the L direction at one-quarter thickness (where t is the thickness of the product in mm), and (2) improved IGC resistance measured without a skin that mainly exhibits pitting corrosion and minor IGC.

[0100] 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. Many modifications and adaptations 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. Some embodiments of this disclosure are described in the following sections [1]-

[20] . [Item 1] An aging process for a solution-heat-treated and quenched 2XXX series aluminum alloy wrought material, (1) In the first aging process, the product is aged at one or more temperatures in the range of 90°C to 120°C for a cumulative time of at least 10 hours. (2) The aging process further comprising a second aging step in which the product is aged for at least 4 hours in cumulative time at one or more temperatures in the range of 150°C to 205°C, preferably at least 8 hours in cumulative time at one or more temperatures in the range of 150°C to 195°C. [Item 2] The aging process described in item 1, wherein the aging process is an aging process for a 2XXX series aluminum alloy product that has been solution-heat-treated, quenched, and subsequently cold-worked or cold-formed. [Item 3] The aging process described in item 1 or 2, wherein, optionally, cold working is applied after solution heat treatment and quenching, and after further natural aging, and either before final artificial aging or between two artificial aging steps. [Item 4] An aging process according to any one of items 1 to 3, wherein the quenching of a plate with a thickness in the range of 1.6 to 12 mm after solution heat treatment is carried out at a rate of 100°C / min to 1000°C / min. [Item 5] The aging process described in item 4, wherein the quenching of a plate with a thickness in the range of 1.6 to 12 mm is carried out at a rate of 200°C / min to 600°C / min. [Item 6] The aging process described in item 1 or 2, wherein the aging process is an aging process for a processed product for providing a wrought material, i.e., a 2XXX series aluminum alloy product that has been solution-heat-treated, quenched, and subsequently cold-worked or cold-formed. [Item 7] The aging process described in any one of items 1 to 6, wherein the second aging step is at least 12 hours in cumulative time. [Item 8] The aging process described in item 7, wherein the second aging process is between 12 and 144 hours in cumulative time. [Item 9] The aforementioned 2XXX series aluminum alloy, in weight %, Cu 3.0%~5.5%, Mn 0.15%~1.0%, Mg 0.2%~1.8%, Ag maximum 0.7%, Zr max. 0.25%, Zn max. 0.25%, Impurities up to 0.15%, and A aging process, including aluminum, as described in any one of items 1 through 8. [Item 10] The aforementioned 2XXX series aluminum alloy, in weight %, Cu 3.0%~5.5%, Mn 0.15%~1.0%, Mg 0.2%~1.8%, Ag maximum 0.7%, Zn max. 1.0%, Fe max. 0.3%, Si max. 0.2%, Ti 0.01%~0.2%, An aging process according to any one of items 1 to 8, optionally comprising one or more disperse-forming elements selected from the group consisting of 0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, and 0.05% to 0.4% Sc, preferably 0.05% to 0.2% Cr, 0.05% to 0.15% Zr, 0.05% to 0.15% V, 0.05% to 0.25% Hf, and 0.05% to 0.25% Sc, up to 0.15% impurities, and aluminum. [Item 11] The aging process according to any one of items 1 to 10, wherein the 2XXX series aluminum alloy contains Ag in the range of 0.1% to 0.7%, preferably in the range of 0.2% to 0.7%. [Item 12] The aging process described in any one of items 1 to 11, wherein the 2XXX series aluminum alloy contains a Cu content in the range of 3.5% to 4.4%. [Item 13] The aging process described in any one of items 1 to 12, wherein the 2XXX series aluminum alloy contains a Cu content in the range of 4.4% to 5.5%. [Item 14] The aging process described in item 13, wherein the 2XXX series aluminum alloy contains a Cu content in the range of 4.4% to 5.1%. [Item 15] A aging process according to any one of items 1 to 14, wherein the aforementioned 2XXX series aluminum alloy is provided as a rolled product. [Item 16] The aging process described in any one of items 1 to 15, wherein the 2XXX series aluminum alloy product is a structural component of an aircraft. [Item 17] A method for manufacturing a 2XXX series aluminum alloy wrought material, wherein the method is (i) Cast an ingot of a 2XXX series aluminum alloy having the composition described in item 1 or any one of items 9-14, (ii) Preheat and / or homogenize the ingot, (iii) Hot working the ingot into a hot-worked wrought material by one or more methods selected from the group consisting of rolling, extrusion, and forging, (iv) Optionally, the hot-worked wrought material is cold-worked, (v) The wrought material is subjected to solution heat treatment ("SHT"), (vi) The SHT product is rapidly cooled or hardened, (vii) Optionally, the SHT-treated and quenched product is cold-worked or cold-formed. (viii) The SHT-treated and quenched products, and optionally cold-worked or cold-formed products, are artificially aged according to any one of items 1 to 6. The manufacturing method, including the process. [Item 18] A wrought 2XXX series aluminum alloy product according to any one of items 1 to 17, having a leather layer on one or both sides as an option, and having a cross-sectional thickness of 1.6 mm to 12 mm, preferably 1.6 mm to 8 mm, is aged. (1) Conventional tensile yield strength (MPa) measured in the L direction, which exceeds 400 MPa, or (2) Improvement of IGC resistance, measured without a protective coating, which mainly exhibits pitting corrosion and mild IGC. The aluminum alloy product that achieves the above. [Item 19] The product having a cross-sectional thickness of 12 mm to 250 mm, preferably 12 mm to 130 mm, is aged, (1) A conventional tensile yield strength (MPa) greater than 380 MPa + 0.57(120-t) MPa, measured in the L direction at a thickness of 1 / 4, wherein t is the thickness (mm) of the product, or (2) Minimum lifespan without failure due to stress corrosion cracking, at a plate thickness stress level of 250 MPa, in accordance with ASTM G47, of at least 20 days, preferably at least 25 days. A wrought 2XXX series aluminum alloy product that meets any one of items 1 through 18. [Item 20] The product having a cross-sectional thickness of 12 mm to 250 mm, preferably 12 mm to 130 mm, is aged, (1) A conventional tensile yield strength (MPa) greater than 380 MPa + 0.57(120-t) MPa, measured in the L direction at a thickness of 1 / 4, wherein t is the thickness (mm) of the product, or (2) Improvement of IGC resistance, measured without a protective coating, which mainly exhibits pitting corrosion and mild IGC. A wrought 2XXX series aluminum alloy product that meets any one of items 1 through 19.

Claims

1. An aging process for a solution-heat-treated and quenched 2XXX-series aluminum alloy wrought material, (1) In the first aging process, the wrought material is aged at one or more temperatures in the range of 90°C to 120°C for a cumulative time of at least 10 hours. (2) Subsequently, the second aging process includes aging the wrought material for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C, The aforementioned 2XXX-type aluminum alloy wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 1.0%, Mg 0.2% to 1.8%, Ag maximum 0.05%, Zr maximum 0.25%, Zn maximum 0.25%, Impurities up to 0.15%, and The remaining part is made of aluminum. The aforementioned statute of limitations process.

2. An aging process for a solution-heat-treated and quenched 2XXX-series aluminum alloy wrought material, (1) In the first aging process, the wrought material is aged at one or more temperatures in the range of 90°C to 120°C for a cumulative time of at least 10 hours. (2) Subsequently, the second aging process includes aging the wrought material for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C, The aforementioned 2XXX-type aluminum alloy wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 0.5%, Mg 0.2% to 1.8%, Ag maximum 0.05%, Zn maximum 1.0%, Fe max. 0.3%, Si maximum 0.2%, Ti 0.01% to 0.2%, One or more optionally selected disperse-forming elements chosen from the group consisting of 0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, and 0.05% to 0.4% Sc. Up to 0.15% impurities, and The remaining part is made of aluminum. The aforementioned statute of limitations process.

3. An aging process for a solution-heat-treated and quenched 2XXX-series aluminum alloy wrought material, (1) In the first aging process, the wrought material is aged at one or more temperatures in the range of 90°C to 120°C for a cumulative time of at least 10 hours. (2) Subsequently, the second aging process includes aging the wrought material for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C, The aforementioned 2XXX-type aluminum alloy wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 1.0%, Mg 0.2% to 1.4%, Ag maximum 0.05%, Zn maximum 1.0%, Fe max. 0.3%, Si maximum 0.2%, Ti 0.01% to 0.2%, One or more optionally selected disperse-forming elements chosen from the group consisting of 0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, and 0.05% to 0.4% Sc. Up to 0.15% impurities, and The remaining part is made of aluminum. The aforementioned statute of limitations process.

4. The aging process according to any one of claims 1 to 3, wherein the aging process is an aging process for a wrought 2XXX-type aluminum alloy that has been solution-heat-treated, quenched, and subsequently cold-worked or cold-formed.

5. The aging process according to any one of claims 1 to 4, wherein cold working is applied in one or more cold working steps that are applied after solution heat treatment and quenching, and either before the second artificial aging step or between the first artificial aging step and the second artificial aging step.

6. The aging process according to any one of claims 1 to 5, wherein the quenching of a plate having a thickness in the range of 1.6 to 12 mm after solution heat treatment is carried out at a rate of 100°C / min to 1000°C / min.

7. The aging process according to claim 6, wherein the quenching of a plate with a thickness in the range of 1.6 to 12 mm after solution heat treatment is carried out at a rate of 200°C / min to 600°C / min.

8. The aging process according to any one of claims 1 to 7, wherein the second aging step is at least 12 hours in cumulative time.

9. The aging process according to claim 8, wherein the second aging step is 12 to 144 hours in cumulative time.

10. The aging process according to any one of claims 1 to 9, wherein the 2XXX-type aluminum alloy wrought material contains a Cu content in the range of 3.5% to 4.4%.

11. The aging process according to any one of claims 1 to 9, wherein the 2XXX-type aluminum alloy wrought material contains a Cu content in the range of 4.4% to 5.5%.

12. The aging process according to claim 11, wherein the 2XXX-type aluminum alloy wrought material contains a Cu content in the range of 4.4% to 5.1%.

13. The aging process according to any one of claims 1 to 12, wherein the 2XXX-type aluminum alloy wrought material is provided as a rolled product.

14. The aging process according to any one of claims 1 to 13, wherein the 2XXX-type aluminum alloy wrought material is a structural member of an aircraft.

15. A method for manufacturing a 2XXX-type aluminum alloy wrought material, wherein the method is (i) Cast an ingot of a 2XXX-type aluminum alloy having the composition described in any one of claims 1 to 3 and 10 to 12. (ii) Preheat and / or homogenize the ingot, (iii) The ingot is hot-worked into a hot-worked wrought material by one or more methods selected from the group consisting of rolling, extrusion, and forging. (iv) Optionally, the hot-worked wrought material is cold-worked, (v) The wrought material is subjected to solution heat treatment ("SHT"), (vi) The SHT-treated wrought material is rapidly cooled or quenched. (vii) Optionally, the SHT-treated and heat-treated wrought material is cold-worked or cold-formed. (viiii) The SHT-treated and heat-treated wrought material, and optionally cold-worked or cold-formed materials, are artificially aged according to any one of claims 1 to 3. The manufacturing method, including the process.

16. A 2XXX series aluminum alloy wrought material, The aforementioned wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 1.0%, Mg 0.2% to 1.8%, Ag maximum 0.05%, Zr maximum 0.25%, Zn maximum 0.25%, Impurities up to 0.15%, and The remaining part is made of aluminum, and It has a cross-sectional thickness of 12 mm to 250 mm. Solution heat treatment and quenching, (1) In the first aging process, the wrought material is aged for at least 10 hours in cumulative time at one or more temperatures in the range of 90°C to 120°C. (2) Subsequently, in the second aging process, the wrought material is aged for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C. (1) A tensile yield strength (MPa) in accordance with ASTM B557, which is greater than 380 MPa + 0.57(120-t) MPa, measured in the L direction at a thickness of 1 / 4, wherein t is the thickness (mm) of the wrought material, or (2) Minimum lifespan without failure due to stress corrosion cracking, at least 20 days in accordance with ASTM G47, at a plate thickness stress level of 250 MPa. It exhibits, The aforementioned wrought aluminum alloy.

17. A 2XXX series aluminum alloy wrought material, The aforementioned wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 0.5%, Mg 0.2% to 1.8%, Ag maximum 0.05%, Zn maximum 1.0%, Fe max. 0.3%, Si maximum 0.2%, Ti 0.01% to 0.2%, One or more optionally selected disperse-forming elements chosen from the group consisting of 0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, and 0.05% to 0.4% Sc. Up to 0.15% impurities, and The remaining part is made of aluminum, and It has a cross-sectional thickness of 12 mm to 250 mm. Solution heat treatment and quenching, (1) In the first aging process, the wrought material is aged for at least 10 hours in cumulative time at one or more temperatures in the range of 90°C to 120°C. (2) Subsequently, in the second aging process, the wrought material is aged for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C. (1) A tensile yield strength (MPa) in accordance with ASTM B557, which is greater than 380 MPa + 0.57(120-t) MPa, measured in the L direction at a thickness of 1 / 4, wherein t is the thickness (mm) of the wrought material, or (2) Minimum lifespan without failure due to stress corrosion cracking, at least 20 days in accordance with ASTM G47, at a plate thickness stress level of 250 MPa. It exhibits, The aforementioned wrought aluminum alloy.

18. A 2XXX series aluminum alloy wrought material, The aforementioned wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 1.0%, Mg 0.2% to 1.4%, Ag maximum 0.05%, Zn maximum 1.0%, Fe max. 0.3%, Si maximum 0.2%, Ti 0.01% to 0.2%, One or more optionally selected disperse-forming elements chosen from the group consisting of 0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, and 0.05% to 0.4% Sc. Up to 0.15% impurities, and The remaining part is made of aluminum, and It has a cross-sectional thickness of 12 mm to 250 mm. Solution heat treatment and quenching, (1) In the first aging process, the wrought material is aged for at least 10 hours in cumulative time at one or more temperatures in the range of 90°C to 120°C. (2) Subsequently, in the second aging process, the wrought material is aged for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C. (1) A tensile yield strength (MPa) in accordance with ASTM B557, which is greater than 380 MPa + 0.57(120-t) MPa, measured in the L direction at a thickness of 1 / 4, wherein t is the thickness (mm) of the wrought material, or (2) Minimum lifespan without failure due to stress corrosion cracking, at least 20 days in accordance with ASTM G47, at a plate thickness stress level of 250 MPa. It exhibits, The aforementioned wrought aluminum alloy.

19. A 2XXX series aluminum alloy wrought material, The aforementioned wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 1.0%, Mg 0.2% to 1.8%, Ag maximum 0.05%, Zr maximum 0.25%, Zn maximum 0.25%, Impurities up to 0.15%, and The remaining part is made of aluminum, and It has a cross-sectional thickness of 12 mm to 250 mm. Solution heat treatment and quenching, (1) In the first aging process, the wrought material is aged for at least 10 hours in cumulative time at one or more temperatures in the range of 90°C to 120°C. (2) Subsequently, in the second aging process, the wrought material is aged for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C. (1) A tensile yield strength (MPa) in accordance with ASTM B557, which is greater than 380 MPa + 0.57(120-t) MPa, measured in the L direction at a thickness of 1 / 4, wherein t is the thickness (mm) of the wrought material, exhibiting the above tensile yield strength. The aforementioned wrought aluminum alloy.

20. A 2XXX series aluminum alloy wrought material, The aforementioned wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 0.5%, Mg 0.2% to 1.8%, Ag maximum 0.05%, Zn maximum 1.0%, Fe max. 0.3%, Si maximum 0.2%, Ti 0.01% to 0.2%, One or more optionally selected disperse-forming elements chosen from the group consisting of 0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, and 0.05% to 0.4% Sc. Up to 0.15% impurities, and The remaining part is made of aluminum, and It has a cross-sectional thickness of 12 mm to 250 mm. Solution heat treatment and quenching, (1) In the first aging process, the wrought material is aged for at least 10 hours in cumulative time at one or more temperatures in the range of 90°C to 120°C. (2) Subsequently, in the second aging process, the wrought material is aged for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C. (1) A tensile yield strength (MPa) in accordance with ASTM B557, which is greater than 380 MPa + 0.57(120-t) MPa, measured in the L direction at a thickness of 1 / 4, wherein t is the thickness (mm) of the wrought material, exhibiting the above tensile yield strength. The aforementioned wrought aluminum alloy.

21. A 2XXX series aluminum alloy wrought material, The aforementioned wrought material is, by weight %, Cu 3.5% to 5.5%, Mn 0.15% to 1.0%, Mg 0.2% to 1.4%, Ag maximum 0.05%, Zn maximum 1.0%, Fe max. 0.3%, Si maximum 0.2%, Ti 0.01% to 0.2%, One or more optionally selected disperse-forming elements chosen from the group consisting of 0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, and 0.05% to 0.4% Sc. Up to 0.15% impurities, and The remaining part is made of aluminum, and It has a cross-sectional thickness of 12 mm to 250 mm. Solution heat treatment and quenching, (1) In the first aging process, the wrought material is aged for at least 10 hours in cumulative time at one or more temperatures in the range of 90°C to 120°C. (2) Subsequently, in the second aging process, the wrought material is aged for at least 4 hours in cumulative time at one or more temperatures within the range of 150°C to 205°C. (1) A tensile yield strength (MPa) in accordance with ASTM B557, which is greater than 380 MPa + 0.57(120-t) MPa, measured in the L direction at a thickness of 1 / 4, wherein t is the thickness (mm) of the wrought material, exhibiting the above tensile yield strength. The aforementioned wrought aluminum alloy.

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