CN116529412A - Method for manufacturing 2XXX series aluminum alloy products - Google Patents

Abstract

Described herein is an aging process for a solution heat treated and quenched 2XXX series aluminum alloy wrought product, the aging process comprising the steps of: (1) Aging the product in a first aging step at one or more temperatures in the range of 90 ℃ to 120 ℃ for an accumulated period of at least 10 hours; and (2) subsequently aging the product in a second aging step at one or more temperatures in the range of 150 ℃ to 205 ℃ for an accumulated period of at least 4 hours. The wrought aluminum alloy can be processed into various product forms, such as sheets, slabs, extruded products, or wrought products.

Description

Method for manufacturing 2XXX series aluminum alloy products

Cross References to Related Applications

This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63/198,906, filed November 20, 2020, the contents of which are hereby incorporated by reference in their entirety.

technical field

The invention relates to a method for manufacturing 2XXX series aluminum alloy forged and rolled products, and in particular to an improved aging process. Products made from this alloy are well suited for use in aerospace applications, but are not limited to that application. Aluminum alloys can be processed into various product forms such as sheet, sheet, plate, extruded or forged.

Background technique

Aerospace applications often require a very specific set of properties. High strength alloys are generally required, but depending on the desired intended use, other properties such as high fracture toughness or ductility, and good corrosion resistance are also required.

One important property is the stress corrosion cracking ("SCC") resistance of the product, especially when loaded in the short transverse (ST) orientation. Historically, most in-service failures of SCCs involving aluminum alloys in high-strength alloys (e.g., aircraft structures) have been due to assembly or residual stresses acting in the short transverse direction relative to the grain flow direction of the product. This is often more troublesome for parts machined from relatively thick section rolled plate, extrusions, or forgings of complex shape where short transverse grain orientations may be exposed. Broad generalizations relating susceptibility to SCC and strength or fracture toughness in high-strength alloy classes, including the 2XXX series aluminum alloys, appear to be impossible. Control over alloy processing and heat treatment is key to ensuring high SCC resistance without appreciable loss of mechanical properties. Thick-section products of naturally aged T3 and T4 tempered 2XXX series aluminum alloys have low SCC resistance ratings in the short transverse direction. Such products are rated higher in other directions, as are thin section products in all directions. These differences are related to the effect of the quenching rate (mainly determined by the section thickness) on the amount of precipitation that occurs during quenching.

Artificial aging of 2XXX series aluminum alloys to a precipitation hardened T8 temper provides relatively high spalling and SCC resistance and very good high temperature performance with a modest increase in strength compared to their naturally aged counterparts. This tempering requires drawing or cold working by other means after quenching from solution heat treatment temperatures and prior to artificial aging (for example, 2XXX alloys are solution heat treated, quenched, and subsequently cold worked or cold formed. Optionally , cold working is applied in one or more cold working steps applied after solution heat treatment and quenching, optionally after further natural aging and before final artificial aging or after two artificial aging between steps.

The response to age hardening is enhanced by strain hardening induced by stretching or otherwise cold working prior to artificial aging (T8 temper) and the yield strength can be increased very significantly as compared to the T6 temper. On the other hand, T6 temper involves solution heat treated, quenched and artificially aged wrought products with little or no cold work such that cold work is not considered to affect the mechanical property limits. What is needed is a high strength 2XXX series aluminum alloy with very high resistance to stress corrosion cracking.

Contents of the invention

The embodiments covered by the invention are defined by the claims, not this summary. This summary is a high-level overview of aspects of the invention and introduces concepts that are further described below in the Detailed Description section. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the appropriate portion of the entire specification, any or all drawings and each claim.

This paper describes an aging process for solution heat-treated and quenched 2XXX series aluminum alloy wrought-rolled products. and (2) subsequently 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 period of at least 10 hours; A cumulative period of 4 hours, and preferably a cumulative period of at least 8 hours in the range of 150°C to 195°C.

Also described herein is a method of making a 2XXX series aluminum alloy wrought product, the method comprising the steps of: (i) casting an ingot of the 2XXX series aluminum alloy as described herein; (ii) preforming the ingot heating and/or homogenizing; (iii) hot working said ingot into a hot worked wrought product by one or more methods selected from the group consisting of rolling, extrusion and forging; (iv) Optionally cold working said hot worked wrought product; (v) subjecting said wrought product to solution heat treatment ("SHT"); (vi) subjecting said SHT product to rapid cooling or quenching; ( vii) optionally cold working or cold forming the SHT and quenched product; and (viii) artificial aging and optionally cold working or cold forming the SHT, quenched product according to the methods described herein.

This article further describes wrought and rolled 2XXX series aluminum alloy products. In some examples, the wrought 2XXX series aluminum alloy product, optionally clad on one or both sides, has a cross-sectional thickness of 1.6 mm to 12 mm, and preferably 1.6 mm to 8 mm, and is aged to achieve (1 ) a conventional tensile yield strength (MPa) greater than 400 MPa measured in the L direction; or (2) improved IGC resistance measured without cladding showing predominantly pitting and inadvertent IGC.

In some examples, a wrought 2XXX series aluminum alloy product with a cross-sectional thickness from 12 mm to 250 mm, and preferably from 12 mm to 130 mm, is aged to achieve (1) conventional tensile measured in the L direction at quarter thickness Yield strength (MPa) greater than 380MPa+0.57(120-t)MPa, where t is the thickness of the product (mm); or (2) No failure due to stress corrosion cracking according to ASTM G47 at a short transverse stress level of 250MPa The minimum useful life is at least 20 days, preferably at least 25 days.

Optionally, wrought 2XXX series aluminum alloy products having a cross-sectional thickness from 12 mm to 250 mm, and preferably from 12 mm to 130 mm, are aged to achieve (1) a conventional tensile yield measured in the L direction at quarter thickness Strength (MPa) greater than 380 MPa + 0.57(120-t) MPa, where t is the thickness of the product (mm); or (2) Improved resistance to IGC measured without coating, which shows predominantly pitting corrosion and negligent IGC.

Other objects and advantages of the invention will become apparent from the following detailed description of the non-limiting examples and accompanying drawings.

Detailed ways

As understood herein, unless otherwise indicated, aluminum alloy nomenclature and temper nomenclature refer to Aluminum Standards and Data and the Registration as published in 2019 by the Aluminum Association. Records) by the Aluminum Association and are well known to those skilled in the art, for example as "Teal Sheet". Temper nomenclature is specified in European Standard EN515.

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

As used herein, the term "about" when used to describe a compositional range or amount of an alloying additive means that the actual amount of the alloying additive may vary from the nominally expected amount due to factors such as those understood by those skilled in the art, such as standard processing variations.

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 Cr-free aluminum alloys.

As used herein, the meaning of "a", "an" or "the" includes both singular and plural referents unless the context clearly dictates otherwise.

All ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of "1 to 10" shall be considered to include any and all subranges between (and including) a minimum value of 1 and a maximum value of 10; that is, all subranges start with a minimum value of 1 or Start with a larger number, such as 1 to 6.1, and end with a maximum value of 10 or less, such as 5.5 to 10.

For the purposes herein, a sheet product or sheet material (also referred to herein as "sheet") shall be understood as a rolled product having a thickness of not less than 1.3 mm (0.05 inches) and not more than 6.3 mm (0.25 inches). For example, the sheet can have 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm , 2.8mm, 2.9mm, 3.0mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4.0mm, 4.1mm, 4.2mm, 4.3mm, 4.4 mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5.0mm, 5.1mm, 5.2mm, 5.3mm, 5.4mm, 5.5mm, 5.6mm, 5.7mm, 5.8mm, 5.9mm, 6.0mm, 6.1mm, 6.2mm or 6.3mm thickness. See Aluminum Standard and Data, the Aluminum Association, Chapter 5 Terminology, 1997.

For the purposes herein, plate or plate product (also referred to herein as "plate") shall be understood as a rolled product having a thickness greater than 6.3 mm (0.25 inches). For example, a sheet material or sheet product may have a thickness greater than 6.3mm, greater than 6.4mm, greater than 6.5mm, greater than 6.6mm, greater than 6.7mm, greater than 6.8mm, greater than 6.9mm, greater than 7.0mm, greater than 7.1mm, greater than 7.2mm, greater than 7.3mm, greater than 7.4mm, greater than 7.5mm, greater than 7.8mm, greater than 7.9mm, greater than 8.0mm, greater than 10.0mm, greater than 15.0mm, greater than 20.0mm, greater than 25.0mm, greater than 30.0mm, greater than 35.0mm, greater than 40.0mm , a thickness greater than 45.0mm, greater than 50.0mm or greater than 100.0mm. See Aluminum Standard and Data, the Aluminum Association, Chapter 5 Terminology, 1997.

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

It is an object of the present disclosure to provide a method of manufacturing wrought products of aluminum alloys of the 2XXX series with improved properties at least in the short transverse direction (ST direction). As used herein, a wrought product is a cast aluminum alloy that has been solution heat treated, quenched, and then cold worked or formed.

Another object of the present disclosure is to provide a method of manufacturing a 2XXX series aluminum alloy wrought product having at least improved SCC resistance in the ST direction.

These and other objects and further advantages are met or exceeded by the present disclosure, which provides an aging process for solution heat treated and quenched 2XXX series aluminum alloy wrought products, said aging process comprising the following sequence of steps:

(1) The product is subjected to a temperature 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 a cumulative period of at least 10 hours; and

(2) The product is then subjected to a second aging step at 150°C to 205°C (for example, 155°C to 200°C, 150°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) for a cumulative period of at least 4 hours, and preferably at 150°C to 195°C (e.g., 150°C to 190°C, 155°C to 195°C, 151°C to 194°C or 150°C to 194°C) for a cumulative period of at least 8 hours to increase the strength and corrosion resistance of the alloy product. In some cases, the second aging step lasts at least 12 hours (e.g., 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, A cumulative period of time of at least 84 hours, at least 96 hours, at least 108 hours, at least 120 hours, at least 132 hours, or up to and including 144 hours).

In addition to the multi-step aging processes described above, the aging processes described herein may include any desired number of aging steps. For example, the aging process may include two steps, three steps, four steps, five steps, six steps, seven steps, eight steps, nine steps, ten steps or more steps. The aging step may include heating the aluminum alloy wrought product to any desired temperature and maintaining the aluminum alloy wrought product at the desired temperature for any desired period of time. As stated herein, all ranges describing processes, properties, compositions, characteristics, etc. include any and all endpoints and any and all subranges subsumed therein.

Among them, in the prior art, the 2XXX series aluminum alloy forged products after solution heat treatment and quenching are artificially aged at a relatively high temperature in a single-step aging process to reach T6 or T8 tempering, and it is found that according to the disclosure of this article , improvements in performance (especially in the ST direction) can be achieved after application of an aging process comprising a first step, stage or treatment at a relatively low temperature for at least 10 hours and preferably for at least 24 hours A cumulative period of time, followed by a second step, stage or treatment at a higher temperature than that of said first step and for a cumulative period of at least 8 hours.

In some cases, when the temperature of the 2XXX series aluminum alloys ranges from 150°C to 400°C, when measured during cooling, between 100°C/min and 1000°C/min (eg, 110 ℃/min to 900℃/min, 100℃/min to 800℃/min, 110℃/min to 700℃/min or 120℃/min to 600℃/min), more preferably between 200℃/min and 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 a thickness range of 1.6 mm to 12 mm 2XXX series aluminum alloy plates are cooled (ie quenched) from solution heat treatment. For example, the cooling rate is similar to that using water quenching on 120 mm thick 2XXX series aluminum alloy plates.

The aging process achieves improved metallurgical properties in the ST direction. In particular, 2XXX series aluminum alloy wrought and rolled products are more resistant to stress corrosion cracking. The improvement in SCC resistance in the ST direction is especially evident in thicker gauge wrought products. "ST stress corrosion cracking resistance" means after 20 days of alternating immersion testing in accordance with ASTM G47 at a net stress of 250 megapascals (MPa) in the ST direction, and where the test requires at least 3 specimens, at least three Two out of 2XXX series aluminum alloy product samples did not fail. In one embodiment, all three samples did not fail after 20 days in the ST direction under a net stress of 250 MPa and according to the ASTM G47 alternating immersion test. In another embodiment, all three samples did not fail after 25 days in the ST direction under a net stress of 250 MPa and according to the ASTM G47 alternate immersion test.

The aging process as described herein achieves an improved balance of engineering properties in 2XXX series aluminum alloy wrought products as SCC corrosion resistance is improved and mechanical strength levels are maintained at least until aging at 190°C in a one-step aging process The level of the 12-hour counterpart. The counterparts are wrought products of the same thickness and of similar alloy composition and identical thermomechanical history except for the final aging treatment.

In one embodiment of the aging process, the wrought product is aged in a first aging step at one or more temperatures in the range of 90°C to 120°C for a cumulative duration of at least 10 hours and more preferably at least 24 hours period. In a preferred embodiment of the first aging step, the wrought product is aged for a cumulative period of no longer than 144 hours, and preferably no longer than 96 hours, and more preferably no longer than 64 hours.

In one embodiment of the aging process, the wrought product is aged in a second aging step at one or more temperatures in the range of 150°C to 195°C for a cumulative duration of at least 8 hours and more preferably at least 12 hours period. In a preferred embodiment of the second aging step, the wrought product is aged for a cumulative period of no longer than 144 hours, and preferably no longer than 96 hours. In a preferred embodiment of the second aging step, the wrought product is aged at one or more temperatures in the range of about 160°C to 190°C.

In one embodiment of the aging process, aging of the wrought product may be accomplished in a single programmable furnace for convenience, as is known in the art for other aging treatments of other heat treatable aluminum alloys.

In another embodiment of the aging process, the wrought product is cooled to, for example, ambient temperature at the end of the first aging step, and reheated to a second aging step to complete the aging cycle as described herein to achieve improvement metallurgical properties. For logistical reasons, this intermediate cooling to ambient temperature can be carried out; however, if desired, an intermediate cold working operation can also be carried out, in particular to strengthen the subsequent Tensile manipulation of aging kinetics and increasing strength levels. Preferably, said stretch is in the range of about 0.5% to 6%, more preferably about 1% to 3% of its original length.

The aging process according to the present invention can be used for a wide range of 2XXX series aluminum alloy wrought and rolled products.

In one embodiment, the 2XXX series aluminum alloy wrought products at least comprise the following main components (by weight): about 3.0% to 5.5% Cu, about 0.15% to 1.0% Mn, about 0.2% to 1.8% Mg and up to about 0.7% Ag, impurities up to 0.15% and aluminum, with preferred compositional ranges as described and/or claimed herein. The term "comprising/comprising" in the context of aluminum alloys is understood to mean that the alloy may contain further alloying elements, as exemplified below.

In another embodiment, the 2XXX series aluminum alloy wrought products have the following composition (by weight %):

Cu about 3.0% to 5.5%;

Mn about 0.15% to 1.0%;

Mg about 0.2% to 1.8%;

Ag up to about 0.7%;

Zn up to about 1.0%;

Fe up to about 0.3%;

Si up to about 0.2%;

Ti about 0.01% to 0.2%;

and optionally one or more dispersion forming elements selected from the group consisting of about 0.05% to 0.25% Cr, about 0.05% to 0.25% Zr, about 0.05% to 0.25% V, about 0.05% to 0.4 % Hf and about 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; impurities up to 0.15% , and aluminum; and having a preferred narrower compositional range as described and/or claimed herein. Typically, impurities may be present at up to 0.05% each and in a total of up to 0.15%.

Cu is the major alloying element in the 2XXX series alloys and for the methods or processes described herein it should be in the range of about 3.0% to 5.5%. A preferred lower limit for the Cu content is about 3.5%. A preferred upper limit for the Cu content is about 5.1%. In one embodiment, the Cu content is in the range of about 3.0% to 4.4%, and 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%, and 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%).

Mn is another important alloying element in 2XXX series aluminum alloys and should be in the range of about 0.15% to 1.0%. In one embodiment, the Mn content is from about 0.15% to 0.8%, and preferably from 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 in the range of 0.21% to 0.79%).

Mg is another important alloying element and should be added at about 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%) ) range exists. A preferred lower limit for the Mg content is about 0.4%. A preferred upper limit for the Mg content is about 1.4%.

Ag can be added in the range of up to about 0.7% to further enhance the strength after artificial aging. A preferred lower limit for purposeful Ag addition would be about 0.05%, and more preferably about 0.2%. A preferred upper limit is about 0.7%. For example, Ag may be added in an amount 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%.

In one embodiment, Ag is an impurity element and it may be present up to about 0.05%, and preferably up to about 0.03%.

Zn in the range of up to about 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%) can be purposefully added to further enhance aging The strength in the process, and if added, can replace some purposeful Ag. A preferred lower limit for purposeful Zn addition would be 0.2%, and more preferably about 0.3%. A preferred upper limit will be about 0.5%.

In one embodiment, Zn is an impurity element and it may be present up to about 0.25%, and preferably up to about 0.15%.

Optionally, dispersion forming elements may be added to the aluminum alloys to control the evolution of the grain structure or grain size during thermal processing operations such as hot rolling, extrusion or forging. If added, the one or more dispersion forming elements may be selected from the group consisting of about 0.05% to 0.25% Cr (eg, 0.05% to 0.2%, 0.05% to 0.15%, or 0.09% to 0.24%) , up to about 0.15% Zr or about 0.05% to 0.25% Zr (for example, 0.05% to 0.2%, 0.05% to 0.15% or 0.09% to 0.24%), about 0.05% to 0.25% V (for example, 0.05% to 0.2%, 0.05% to 0.15%, or 0.09% to 0.24%), about 0.05% to 0.4% Hf (e.g., 0.05% to 0.35%, 0.05% to 0.25%, or 0.09% to 0.39%), and/or about 0.05% to 0.4% Sc (eg, 0.05% to 0.35%, 0.05% to 0.25%, or 0.09% to 0.39%).

During the casting process of 2XXX series aluminum alloys, Ti can be added to the alloy product for grain refinement purposes. The amount of Ti added should not exceed about 0.2%, and preferably it should not exceed 0.15% (eg, 0.05% to 0.2%, 0.05% to 0.15%, 0.1% to 0.15%, or 0.09% to 0.15%). The preferred lower limit for Ti addition is about 0.01%. Ti can be added as a sole element or as a casting aid with B (eg _TiB2 ) or C (TiC) for grain size control. Ti addition at the higher end of the range (ie above about 0.08%) can further improve the SCC resistance and strength of the product.

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

Si is also a common impurity in aluminum alloys and can be tolerated up to about 0.2% (eg, 0.05% to 0.2%, 0.1% to 0.2%, 0.05% to 0.15%, or 0.05% to 0.1%). It is preferably maintained to a level of at most 0.15% and more preferably at most 0.1%.

The balance is aluminum and normal and/or unavoidable impurities. Typically, impurities may be present at up to 0.05% each and in a total of up to 0.15%. In one embodiment, the impurities may be present at up to 0.03% each and up to 0.1% in total. For the purposes of the present invention, unavoidable impurities include other elements such as Be or Ca that may be added during the casting operation. These elements are commonly referred to as deoxidizers and are used to control or limit the oxidation of molten aluminum. These elements are considered to be trace elements or impurities typically added in amounts less than 0.01%, preferably added in amounts of less than about 100 ppm, such as 10 to 80 ppm Ca and/or up to about 20 ppm Be.

The 2XXX series aluminum alloy wrought products processed according to the methods described herein are hot-worked products after casting, and include rolled products (ie, sheet or plate), extruded products, and forged products. Forged products are die forged or hand forged.

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

In one embodiment, the 2XXX series aluminum alloy wrought product processed or manufactured according to the present invention is a thick product having a cross-sectional thickness of at least 12 mm. Wrought products may be rolled products, forged products or extruded products. In one embodiment the thick wrought product is a plate product having a cross-sectional thickness of at least 12mm and preferably at least 25mm. In another embodiment, the thick wrought product is a plate product having a cross-sectional thickness of at least 38mm. The improved properties described herein can be achieved with thick wrought products having a cross-sectional thickness of up to 250 mm. In one embodiment, the thick wrought product is a plate product having a cross-sectional thickness of at most 250 mm. In another embodiment, the thick wrought product is a plate product having a cross-sectional thickness of at most 180 mm. In another embodiment, the thick wrought product is a plate product having a cross-sectional thickness of at most 130 mm. As used in this paragraph, thickness refers to the minimum thickness of the product, recognizing that some portions of the product may be legalized to a thickness slightly greater than the specified minimum thickness.

In one embodiment, the 2XXX series aluminum alloy product has a thickness in the range of 1.6 mm to 12 mm and achieves a conventional yield strength (MPa) measured in the longitudinal direction relative to the rolling direction (ie, the L direction) Greater than 400MPa.

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 cladding, which shows mainly is pitting and inadvertent IGC (eg, pitting accounts for greater than 50%, preferably greater than 70%, and more preferably greater than 90% of total corrosion attack). In some cases, described herein are wrought 2XXX series aluminum alloy products, optionally having cladding on at least one or both sides of the wrought aluminum alloy product. As noted, the wrought aluminum alloy product may have a cross-sectional thickness of 1.6mm to 12mm (and preferably 1.6mm to 8mm) and may be aged according to the methods described herein to obtain a Typical tensile yield strength (MPa) in excess of 400 MPa, and/or improved IGC resistance measured without cladding, showing predominantly pitting and inadvertent IGC.

In one embodiment, the 2XXX series aluminum alloy product has a thickness of at least 12 mm and achieves no failure due to stress corrosion cracking (SCC) measured according to ASTM G47-98 at a short transverse (ST) stress level of 250 MPa The minimum lifespan is at least 20 days (preferably at least 25 days). In certain aspects, described herein are wrought 2XXX series aluminum alloy products having a cross-sectional thickness of 12mm to 250mm (and preferably 12mm to 130mm). Wrought aluminum alloy products with a thickness of 12 mm to 250 mm may be aged according to the methods described herein to achieve a conventional tensile yield strength greater than 380 MPa + 0.57 (120-t) MPa measured in the L direction at a quarter thickness (where t is the quarter thickness of the wrought and rolled aluminum alloy product in mm). Furthermore, the wrought aluminum alloy product may exhibit a minimum service life of at least 20 days (preferably at least 25 days) without failure due to stress corrosion cracking according to ASTM G47 at a short transverse stress level of 250 MPa.

In one embodiment, the 2XXX series aluminum alloy product has a thickness of at least 12 mm and achieves a conventional tensile yield strength (MPa) greater than 380 MPa+0.57(120-t) measured in the L direction at quarter thickness MPa (where t is the thickness of the product in mm). In some non-limiting examples, the wrought aluminum alloy product may be a wrought 2XXX series aluminum alloy product having a cross-sectional thickness of from 12mm to 250mm (preferably from 12mm to 130mm), and may be manufactured according to the methods described herein Aging is performed to achieve a conventional tensile yield strength greater than 380 MPa + 0.57(120-t) MPa measured in the L direction at quarter thickness. Wrought aluminum alloy products may further exhibit improved IGC resistance measured without cladding, showing predominantly pitting type corrosion attack and negligent IGC.

Depending on the end use of the 2XXX series aluminum alloy wrought products processed according to the methods described herein, the present disclosure also includes embodiments in which the 2XXX series aluminum alloy wrought products may be provided with cladding, particularly for thinner gauge rolled product. Such clad products use a core of 2XXX series aluminum matrix alloy and a generally higher purity cladding which, inter alia, further protects the 2XXX series aluminum alloy core from corrosion. Cladding includes, but is not limited to, substantially unalloyed aluminum or aluminum containing no more than 0.1% or 1% of all other elements. The aluminum alloys designated herein as the Type 1xxx series include all Aluminum Association (AA) alloys, including subclasses of Type 1000, Type 1100, Type 1200, and Type 1300. Thus, the cladding on the core 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 . In addition, alloys of the AA7000 series alloys, such as 7072 with zinc (0.8% to 1.3%) can be used as cladding, and alloys of the AA6000 series alloys (such as 6003 or 6253, which usually contain more than 1% alloying additives) can be used For cladding. Other alloys may also be used as claddings as long as they provide particularly adequate general corrosion protection to the core alloy. The one or more cladding layers are typically much thinner than the core, with each cladding layer comprising 1% to 15% of the total composite thickness. The cladding more typically comprises around 1% to 10% of the total composite thickness.

In a further aspect, described herein is a method of producing a 2XXX series aluminum alloy wrought product, the method comprising the following steps in the following order:

a. Casting ingots of 2XXX series aluminum alloys as described and/or claimed herein;

b. preheating and/or homogenizing the ingot;

c. hot working said ingot into a hot worked wrought product by one or more methods selected from the group consisting of rolling, extrusion and forging;

d. optionally cold working said hot worked wrought product;

e. subjecting said wrought product to a solution heat treatment ("SHT");

f. Rapid cooling or quenching of said SHT product, preferably by one of spray quenching or immersion quenching in water or other quenching medium;

g. optionally subjecting said product to natural aging;

h. optionally cold working said SHT and quenched products;

i. Artificial aging and optionally cold working of said SHT and quenched products to achieve improved metallurgical properties of wrought products, preferably to a T8 temper.

According to the present invention, the artificial aging includes the following steps in the following order: (1) aging the product at one or more temperatures in the range of 90°C to 120°C in the first aging process for at least 10 hours cumulative time period; and (2) subsequently 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 period of at least 4 hours, and preferably at 150°C to 195°C In range for a cumulative period of at least 8 hours.

The 2XXX series aluminum alloys may be supplied in the form of ingots or slabs or billets for casting by conventional casting techniques in the field of foundry products, such as Direct Chill (DC) casting, Electromagnetic Casting (EMC) casting or Electromagnetic Stirring (EMS ) casting to make suitable wrought products. Slabs made by continuous casting, such as belt casters or roll casters, may also be used, which may be particularly advantageous when producing rolled end products of thinner gauges (eg, up to 12mm thick). Grain refiners, such as those containing Ti and B or Ti and C, may also be used, as is well known in the art. The Ti content in the aluminum alloy is at most about 0.2%, and preferably at most about 0.15%, and more preferably in the range of about 0.01% to 0.12%. Ti can be added as a sole element or as a casting aid with boron or carbon for grain size control. After the aluminum alloy ingot is cast, it is typically peeled to remove the segregation zone near the as-cast surface of the ingot.

The purpose of the homogenization heat treatment has at least the following goals: (i) dissolve as much as possible of the coarse soluble phase formed during solidification, and (ii) reduce the concentration gradient to facilitate the dissolution step. Preheating also fulfills some of these objectives. A typical preheat treatment for the 2xxx series alloys will be a temperature of about 420°C to 505°C with a soak time in the range of about 3 to 50 hours, more typically about 3 to 20 hours. Ordinary homogenization and/or preheating processes can also be performed in one or more steps if desired, and are generally performed at temperatures in the range of about 400°C to 505°C. For example, in a two-step process, there is a first step between about 480°C and 500°C and a second step between 450°C and 490°C to optimize the dissolution process of the various phases, depending on exact alloy composition. In either case, segregation of alloying elements in the as-cast ingot is reduced, and soluble elements are dissolved. If the treatment is carried out at a temperature lower than 400°C, the resulting homogenization effect is insufficient. If the temperature is higher than 505 °C, eutectic melting may occur, leading to poor pore formation. The soak time at the homogenization temperature ranges from about 1 to 50 hours, and more typically from about 2 to 20 hours. Applicable heating rates are those routine in the art.

After the preheating and/or homogenization operations, the raw material is thermally processed by one or more methods selected from the group consisting of rolling, extrusion and forging. The hot rolling method is preferred for the present invention.

In one embodiment, the sheet material is hot rolled to a final hot rolled gauge.

In one embodiment, a thermal processing step may be performed to provide intermediate thickness stock. Thereafter, this intermediate gauge stock can be cold worked to a thinner gauge, for example by rolling. Depending on the amount of cold working, an intermediate anneal may be used before or during the cold working operation.

The next process step is solution heat treatment ("SHT") of the hot worked product and optionally the cold worked product. The product should be heated to solidify as much as possible of all or substantially all of the portion of soluble Cu, Mg and optionally Ag. SHT is preferably carried out at a temperature in the range of about 450°C to 505°C for a time sufficient to bring the solution effect close to equilibrium, with typical soak times in the range of about 5 minutes to 300 minutes, more preferably in the range of about 5 minutes to 120 in the range of minutes. Solution heat treatment is usually performed in a batch furnace. After SHT, it is important to cool the aluminum alloy product to a temperature of 100°C or lower, preferably to ambient temperature, at a high cooling rate to prevent or minimize secondary phases (e.g., _Al2CuMg and _I2Cu ) precipitated uncontrollably. The cooling rate should preferably not be too high to allow for sufficient flatness and acceptable levels of residual stress in the product. Suitable cooling rates can be achieved using the use of water, such as water immersion or water spraying.

SHT and quenched products can be further cold worked. "Cold working" means working or forming an aluminum alloy product at temperatures not considered hot working temperatures, generally below about 120°C (eg, at ambient temperature).

Cold working and/or stretching may be performed to develop sufficient strength, relieve internal stress and/or straighten the product. For example, stretching may be performed within a range of about 0.5% to 11% of its original length to relieve residual stress therein 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%.

In one embodiment, SHT and quenched products are naturally aged, eg to a T3X temper, eg T39 or T351, and subsequently subjected to a cold deformation or cold forming process, eg by an aircraft manufacturer or supplier, to produce structural components. After such cold working operations, the product is artificially aged according to the methods described herein. Such cold working operations include, but are not limited to, bending operations, roll forming operations, or electrohydraulic forming operations. The cold deformation step can be performed by stretching, cold compression, bending, rolling, roll forming or any quasi-static or high-speed cold deformation (usually below 0.008 s-1 quasi-static speed, such as usually up to 100 to a maximum of 150 s-1 or higher speeds), the total deformation range is usually up to a maximum of 10%, but not limited thereto.

In a next step the wrought product is artificially aged according to methods as described and/or claimed herein to increase strength and achieve improved metallurgical properties such as SCC resistance.

Next, the desired final or near-net structural shape can be machined from the wrought product aged according to the invention.

SHT, quenching, cold working and artificial aging according to the methods described herein are also used to make shapes made by extrusion or forging process steps.

Another aspect of the present disclosure relates to aircraft structural members made from 2XXX series aluminum alloy wrought products fabricated and aged according to the methods described herein.

The 2XXX series aluminum alloy products manufactured according to these methods can especially be used in a thickness range up to about 12 mm to have excellent properties for airframe sheets. In a sheet thickness range of about 12mm to 76mm, the performance of the vane, such as the lower vane, will be excellent. Sheet thickness ranges are also available for stringers or to form integral flaps and stringers for aircraft wing structures. Excellent properties are obtained when processed to thicker gauges in excess of about 60mm to 250mm for machining from sheet stock into integral parts, or to form integral spars for aircraft wing structures or in the form of ribs for aircraft wings structure. Thicker gauge products can also be used as mold plates, for example in molds for the manufacture of shaped plastic products, eg by die casting or injection moulding. Alloy products as described herein may also be provided in the form of stage extruded or extruded spars for use in aircraft structures, or in the form of forged spars for use in aircraft wing structures.

The invention will now be illustrated with reference to the following non-limiting examples according to the invention.

Example

Example 1.

On an industrial processing scale, 33 mm thick plates were produced by DC casting ingots with chemical compositions as listed in Table 1 . The ingots were homogenized at 495°C for 21 hours and then hot rolled from a thickness of about 400mm to 33mm. Plates were solution heat treated at 495°C for 2 hours on laboratory scale; cooled by water quench; then artificially aged to a T8 temper using various aging practices according to standard industry practice and according to the methods described herein, see Table 2. In Table 2, aging practice 1 is the standard aging practice to achieve T8 conditions; aging practice 2 is the second industry practice, and aging practice 3 is according to the methods described herein.

After aging, the mechanical properties (tensile yield strength (YS), ultimate tensile strength (UTS) and elongation A _50mm ) in L and ST directions were determined according to ASTM B 557 at mid-thickness. The average values of the three samples are listed in Table 3.

The minimum life (days) without failure due to stress corrosion cracking (SCC) was tested according to ASTM G47-98 at a short transverse (ST) stress level of 250 MPa under constant load. The results are also listed in Table 3. The mean values of the three samples are listed in Table 3.

Table 1. Alloy composition (% by weight), and balance unavoidable impurities and aluminum.

Table 2. Applied aging practices.

Prescription practice Heat treatment time and temperature 1 12 hours at 190°C 2 140 hours at 160°C 3 48 hours at 100°C + 60 hours at 170°C

Table 3. Mechanical properties and SCC resistance of plates tested according to aging practice.

As can be seen from the results in Table 3, aging treatment according to the methods described herein significantly improves SCC resistance while maintaining relatively high mechanical properties.

Example 2.

On an industrial processing scale, 120 mm thick plates were produced by DC casting ingots with chemical compositions as listed in Table 4. The ingots were homogenized at 495°C for 36 hours and then hot rolled from a thickness of about 430mm to 120mm. Plates were solution heat treated at 495°C for 6 hours on a production scale; cooled by water quenching; stretched by 1.4% cold deformation in the L direction, followed by artificial aging using aging practices as described herein and outlined in Table 5 Temper to T8.

After aging treatment, the mechanical properties (tensile yield strength (YS), ultimate tensile strength ( UTS) and elongation A _50mm ). The average values of the three samples are listed in Table 6.

Tested Minimum life (days) without failure due to stress corrosion cracking (SCC) measured at a short transverse (ST) stress level of 250 MPa under constant load according to ASTM G47-98. The results are also listed in Table 6. The mean values of the three samples are listed in Table 6.

Table 4. Alloy composition (weight %), and balance unavoidable impurities and aluminum.

Table 5. Applied aging practices.

Prescription practice Heat treatment time and temperature 3 48 hours at 100°C + 60 hours at 170°C

Table 6. Mechanical properties and SCC resistance of plates tested according to aging practice.

As can be seen from the results in Table 6, aging treatment as described herein also produces a combination of excellent SCC resistance and high mechanical properties for thicker plates.

illustrate

Description 1 is an aging process for a 2XXX series aluminum alloy forged and rolled product that has undergone solution heat treatment and quenching. and (2) subsequently 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 period of at least 10 hours; A cumulative period of 4 hours, and preferably a cumulative period of at least 8 hours in the range of 150°C to 195°C.

Statement 2 is the aging process as described in any preceding or following statement, wherein the aging process is the aging process of a 2XXX series aluminum alloy product that has been solution heat treated, quenched, and then cold worked or cold formed.

Statement 3 is the aging process as described in any preceding or subsequent statement, wherein cold working is applied in one or more cold working steps followed by solution heat treatment and quenching, optionally after further natural Applied after aging and before final artificial aging or between two artificial aging steps.

Statement 4 is an aging process as described in any preceding or subsequent statement wherein quenching from solution heat treatment for plate thicknesses ranging from 1.6 to 12 mm is by cooling similar to water quenching for plate thicknesses of 120 mm at intermediate thicknesses The cooling rate is carried out, and the cooling rate is preferably between 100°C/min and 1000°C/min, more preferably between 200°C/min and 600°C/min (when the cooling rate is between 400°C and 150°C temperature range when measured during cooling).

Statement 5 is an aging process as described in any preceding or subsequent statement, wherein the aging process is an aging process of processed product to provide a wrought product, solution heat treated, quenched and subsequently cold worked or cold formed 2XXX series Aluminum alloy products.

Statement 6 is the aging process of any preceding or subsequent statement, wherein said second aging step lasts for a cumulative period of at least 12 hours, and preferably lasts from 12 to 144 hours.

Statement 7 is the aging process as described in any preceding or subsequent statement, wherein the 2XXX series aluminum alloy comprises (in weight %): Cu 3.0% to 5.5%; Mn 0.15% to 1.0%; Mg 0.2% to 1.8% ; Ag up to 0.7%; Zr up to 0.25%, Zn up to 0.25%, impurities up to 0.15%, and aluminum.

Statement 8 is the aging process as described in any preceding or subsequent statement, wherein the 2XXX series aluminum alloy comprises (in weight %): Cu 3.0% to 5.5%; Mn 0.15% to 1.0%; Mg 0.2% to 1.8% Ag at most 0.7%; Zn at most 1.0%; Fe at most 0.3%; Si at most 0.2%; Ti 0.01% to 0.2%; optionally one or more dispersion-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; impurities up to 0.15%; and aluminum.

Statement 9 is the aging process of any preceding or subsequent statement, wherein the 2XXX series aluminum alloy comprises Ag in the range of 0.1% to 0.7%, and preferably in the range of 0.2% to 0.7%.

Statement 10 is the aging process of any preceding or subsequent statement, wherein the 2XXX series aluminum alloy comprises a Cu content in the range of 3.5% to 4.4%.

Statement 11 is the aging process of any preceding or subsequent statement, wherein the 2XXX series aluminum alloy comprises a Cu content in the range of 4.4% to 5.5%, and preferably in the range of 4.4% to 5.1%.

Statement 12 is the aging process of any preceding or subsequent statement, wherein said 2XXX series aluminum alloy is provided as a rolled product.

Statement 13 is the aging process of any preceding or subsequent statement, wherein the 2XXX series aluminum alloy product is an aircraft structural member.

Description 14 is a method of manufacturing a wrought product of 2XXX series aluminum alloys, said method comprising the steps of: (i) casting an ingot of a 2XXX series aluminum alloy having a composition as described in any preceding or subsequent description; (ii) said ingot is preheated and/or homogenized; (iii) said ingot is hot-worked by one or more methods selected from the group consisting of rolling, extrusion and forging into a hot-worked wrought product; (iv) optionally subjecting said hot-worked wrought product to cold working; (v) subjecting said wrought product to solution heat treatment ("SHT"); (vi) subjecting said SHT product to rapid cooling or quenching; (vii) optionally cold working or cold forming said SHT and quenched product; and (viii) artificial aging and optionally cold working or Cold forming to achieve improved metallurgical properties of the wrought product.

Specification 15 is a wrought 2XXX series aluminum alloy product as in any preceding or subsequent specification, optionally with cladding on one or both sides, wherein said product has a cross-section of from 1.6mm to 12mm and preferably from 1.6mm to 8mm Thicknesses of product are aged to achieve (1) a conventional tensile yield strength (MPa) greater than 400 MPa measured in the L direction; and/or (2) improved IGC resistance measured without cladding, which shows Mainly pitting and inadvertent IGC.

Statement 16 is a wrought 2XXX series aluminum alloy product as described in any preceding or subsequent specification, wherein said product having a cross-sectional thickness of from 12 mm to 250 mm, and preferably from 12 mm to 130 mm, is aged to achieve (1) at quarter The conventional tensile yield strength (MPa) measured in the L direction under one thickness is greater than 380MPa+0.57(120-t)MPa (t is the thickness of the product (mm)); and/or (2) in the short transverse direction of 250MPa The minimum service life without failure due to stress corrosion cracking according to ASTM G47 at the stress level is at least 20 days, preferably at least 25 days.

Statement 17 is a wrought 2XXX series aluminum alloy product as in any preceding specification, wherein said product having a cross-sectional thickness of from 12 mm to 250 mm, and preferably from 12 mm to 130 mm, is aged to (1) at a quarter The normal tensile yield strength (MPa) measured in the L direction under the thickness is greater than 380MPa+0.57(120-t)MPa (t is the thickness of the product (mm)); and (2) measured without cladding Improved resistance against IGC, which shows mainly pitting and inadvertent IGC.

All patents, publications and abstracts cited above are hereby incorporated by reference in their entirety. Various embodiments of the invention have been described in order to achieve the various objects of the invention. It should be realized that these embodiments are merely illustrative of the principles of the invention. Various modifications and alterations thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (20)

1. A process for aging a solution heat treated and quenched 2XXX series aluminum alloy wrought product, the aging process comprising the steps of:

(1) Aging the product in a first aging step at one or more temperatures in the range of 90 ℃ to 120 ℃ for an accumulated period of at least 10 hours; and

(2) The product is then aged in a second aging step at one or more temperatures in the range of 150 ℃ to 205 ℃ for a cumulative period of at least 4 hours, and preferably in the range of 150 ℃ to 195 ℃ for a cumulative period of at least 8 hours.

2. The aging process of claim 1, wherein the aging process is an aging process of a 2XXX series aluminum alloy product that is solution heat treated, quenched, and subsequently cold worked or cold formed.

3. The aging process according to claim 1 or 2, wherein cold working is applied in one or more cold working steps after solution heat treatment and quenching, optionally after further natural aging, and before final artificial aging or between two artificial aging steps.

4. The aging process according to any one of claims 1 to 3 wherein the quenching from solution heat treatment for sheet material having a thickness in the range of 1.6 to 12mm is performed at a rate between 100 ℃/min and 1000 ℃/min.

5. The aging process according to claim 4, wherein the quenching from solution heat treatment for sheet material having a thickness in the range of 1.6 to 12mm is performed at a rate between 200 ℃/min and 600 ℃/min.

6. The aging process of claim 1 or 2, wherein the aging process is an aging process of a processed product to provide a wrought product, a solution heat treated, quenched and then a cold worked or cold formed 2XXX series aluminum alloy product.

7. The aging process of any one of claims 1 to 6, wherein the second aging step lasts for a cumulative period of at least 12 hours.

8. The aging process of claim 7, wherein the second aging step lasts for an accumulated period of 12 hours to 144 hours.

9. The aging process of any one of claims 1 to 8 wherein said 2XXX series aluminum alloy comprises, in weight-%:

cu 3.0% to 5.5%;

mn 0.15% to 1.0%;

mg 0.2% to 1.8%;

ag is at most 0.7%;

zr is at most 0.25%;

zn is at most 0.25%;

impurities up to 0.15%; and

aluminum.

10. The aging process of any one of claims 1 to 8 wherein said 2XXX series aluminum alloy comprises, in weight-%:

cu 3.0% to 5.5%;

mn 0.15% to 1.0%;

mg 0.2% to 1.8%;

ag is at most 0.7%;

zn is at most 1.0%;

fe is at most 0.3%;

si is at most 0.2%;

ti 0.01% to 0.2%;

optionally one or more dispersion 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; impurities up to 0.15%; and aluminum.

11. The aging process according to any one of claims 1 to 10, wherein the 2XXX series aluminium alloy comprises Ag in the range of 0.1 to 0.7% and preferably in the range of 0.2 to 0.7%.

12. The aging process of any one of claims 1 to 11 wherein said 2XXX series aluminum alloy includes a Cu content in the range of 3.5% to 4.4%.

13. The aging process of any one of claims 1 to 12 wherein said 2XXX series aluminum alloy includes a Cu content in the range of 4.4% to 5.5%.

14. The aging process of claim 13 wherein the 2XXX series aluminum alloy includes a Cu content in the range of 4.4% to 5.1%.

15. The aging process of any one of claims 1 to 14 wherein said 2XXX series aluminum alloy is provided in the form of a rolled product.

16. The aging process of any one of claims 1 to 15 wherein said 2XXX series aluminum alloy product is an aircraft structural member.

17. A method of manufacturing a 2XXX series aluminum alloy wrought product, the method comprising the steps of:

(i) Casting an ingot of a 2XXX series aluminum alloy having a composition as defined in any of claims 1 or 9-14;

(ii) Preheating and/or homogenizing the ingot;

(iii) Hot working the ingot into a hot worked forged product by one or more methods selected from the group consisting of rolling, extruding, and forging;

(iv) Optionally cold working the hot worked wrought product;

(v) Subjecting the forged product to solution heat treatment ("SHT");

(vi) Rapidly cooling or quenching the SHT product;

(vii) Optionally cold working or cold forming the SHT and quenched product; and

(viii) The SHT, quenched product according to any of claims 1 to 6 is artificially aged and optionally cold worked or cold formed.

18. A wrought 2XXX series aluminium alloy product according to any one of claims 1 to 17, optionally with a cladding layer on one or both sides, wherein the product having a cross-sectional thickness of from 1.6mm to 12mm, and preferably from 1.6mm to 8mm, is aged to achieve:

(1) A conventional tensile yield strength (MPa) measured in the L-direction of greater than 400MPa; or (b)

(2) Improved IGC resistance measured without cladding, which shows predominantly pitting and inattentive IGC.

19. The wrought 2XXX series aluminum alloy product of any of claims 1-18, wherein the product having a cross-sectional thickness from 12mm to 250mm, and preferably from 12mm to 130mm, is aged to achieve:

(1) A conventional tensile yield strength (MPa) measured in the L direction at one-quarter thickness of greater than 380mpa+0.57 (120-t) MPa, where t is the thickness of the product in mm; or (b)

(2) The shortest service life according to ASTM G47 at a short transverse stress level of 250MPa without failure due to stress corrosion cracking is at least 20 days, preferably at least 25 days.

20. The wrought 2XXX series aluminum alloy product of any of claims 1-19, wherein the product having a cross-sectional thickness from 12mm to 250mm, and preferably from 12mm to 130mm, is aged to achieve:

(1) A conventional tensile yield strength (MPa) measured in the L direction at one-quarter thickness of greater than 380mpa+0.57 (120-t) MPa, where t is the thickness of the product in mm; or (b)

(2) Improved IGC resistance measured without cladding, which shows predominantly pitting and inattentive IGC.