Shapeable corrosion resistant aluminum alloys for structural components

Abstract

Described herein are formable, high strength, corrosion resistant aluminum alloy compositions and products, and methods of making and processing the same. Methods of making and processing the aluminum alloy product include casting an aluminum alloy and performing custom rolling and subsequent hot working steps. The resulting aluminum alloy compositions and products have high strength and formability characteristics while also exhibiting corrosion resistance.

Description

[0001] Priority Declaration

[0002] This application claims priority to U.S. Provisional Application No. 63 / 385,865, filed on December 2, 2022, the entire contents and disclosure of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to materials science, materials chemistry, metallurgy, aluminum alloys, aluminum manufacturing, and related fields. Specifically, the present disclosure provides a novel 7xxx series aluminum alloy having high formability and improved corrosion resistance. The present disclosure also provides various methods for producing and processing 7xxx series aluminum alloy products. Background Art

[0004] Aluminum alloys with high strength and high formability help improve product performance in many applications, such as automotive and other transportation applications (including but not limited to trucks, trailers, trains, aerospace and marine applications) and electronic applications. In some cases, such alloys should have high strength and high formability (for example, the ability to be formed into the desired shape), in addition to other properties. For example, the 7xxx series aluminum alloys have been widely used in such applications due to their improved combination of strength and formability and the ability to improve these properties through heat treatment. Because the density of aluminum alloys is typically 2.8 times lower than that of steel, the use of such materials can reduce the weight of vehicles and significantly improve their fuel economy. Even so, there are still some challenges in using aluminum alloys in automotive applications.

[0005] 7xxx series aluminum alloys with low copper (Cu) contents (e.g., Cu contents below 0.50 wt.%) are susceptible to stress corrosion cracking (SCC). This may be because the MgZn2 phase is highly anodic with respect to the aluminum matrix, creating spaces in the microstructure where environmental factors can significantly affect the aluminum alloy. Cu can act as a cathodic element in the microstructure; therefore, the difference between the particles and the matrix is ​​reduced. Therefore, 7xxx series alloys with lower Cu contents can be more susceptible to stress corrosion cracking (SCC). Summary of the Invention

[0006] The embodiments covered by this disclosure are defined by the claims, not by this Summary. This Summary is a high-level overview of various aspects of the invention and introduces some of the concepts further described in the Detailed Description below. This Summary is not intended to identify key features 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. This subject matter should be understood with reference to the entire specification, any or all of the drawings, and the corresponding sections of each claim.

[0007] Described herein are novel aluminum alloy compositions and methods for producing formable, high-strength, corrosion-resistant aluminum alloy products, the methods comprising casting a molten aluminum alloy to form an ingot or slab, hot rolling the ingot or slab to produce a plate, solution heat treating the plate to form a solution plate, pre-aging the solution plate to form a pre-aged plate, and subjecting the pre-aged plate to at least one paint bake heat treatment to form an aluminum alloy product, wherein the aluminum alloy comprises Mg and Cu, and the aluminum alloy product has a service strength of at least 370 MPa. In some embodiments, homogenization and cold rolling are optional, for example, the method may include casting, hot rolling, solution heat treatment, pre-aging, and aging. In some embodiments, the method may include the steps of casting, hot rolling, cold rolling, solution heat treatment, pre-aging, and aging. In some embodiments, the method may include casting, homogenization, hot rolling, solution heat treatment, pre-aging, and aging. In some embodiments, the method may include casting, homogenization, hot rolling, cold rolling, solution heat treatment, pre-aging, and aging. In some embodiments, pre-aging is performed at a temperature of 50 to 200°C for a period of 1 to 24 hours. In some embodiments, the plate may be cold rolled prior to solution treatment. In some embodiments, homogenization comprises heating the ingot or slab to a temperature of at least 450°C and maintaining the ingot or slab at a temperature of at least 450°C for a period of at least 90 minutes. In some embodiments, the ingot or slab may be hot rolled to a thickness of less than 7 mm and cold rolled to a thickness of less than 4 mm. In some embodiments, the method may include further steps, such as artificial aging the pre-aged plate prior to at least one paint bake treatment. In some embodiments, artificial aging may be performed at a temperature of 80 to 250°C for a period of 30 minutes to 72 hours. In some embodiments, the methods and compositions may include preparing an aluminum alloy product. The aluminum alloy product may have an ultimate tensile strength of at least 420 MPa after a 40-day immersion test in accordance with SCC-ASTM G47.

[0008] In some embodiments, the aluminum alloy includes 0 to 0.25 wt. % Si, 0 to 0.40 wt. % Fe, 0.0 to 0.40 wt. % Cu, 0.0 to 0.30 wt. % Mn, 0.0 to 3.6 wt. % Mg, 0.0 to 0.10 wt. % Cr, 0.0 to 4.5 wt. % Zn, 0.0 to 0.10 wt. % Ti, 0.0 to 0.20 wt. % Zr, up to 0.15 wt. % impurities, and Al, wherein Cu and Mg are present in amounts less than 3.6 wt. %. In some embodiments, the aluminum alloy includes 0 to 0.25 wt. % Si, 0.0 to 0.40 wt. % Fe, 0.0 to 0.40 wt. % Cu, 0.10 to 0.30 wt. % Mn, 2.3 to 3.6 wt. % Mg, 0.0 to 0.10 wt. % Cr, 3.5 to 4.5 wt. % Zn, 0.0 to 0.10 wt. % Ti, 0.0 to 0.20 wt. % Zr, up to 0.15 wt. % impurities, and Al, wherein the total amount of Cu and Mg present is less than 3.6 wt. %. In some embodiments, the aluminum alloy includes 0 to 0.25 wt. % Si, 0.0 to 0.40 wt. % Fe, 0.11 to 0.40 wt. % Cu, 0.10 to 0.30 wt. % Mn, 2.3 to 3.6 wt. % Mg, 0.0 to 0.10 wt. % Cr, 3.5 to 4.5 wt. % Zn, 0.0 to 0.10 wt. % Ti, 0.0 to 0.20 wt. % Zr, up to 0.15 wt. % impurities, and Al, wherein the total amount of Cu and Mg present is less than 3.6 wt. %. In some embodiments, the aluminum alloy includes 0 to 0.25 wt. % Si, 0.0 to 0.40 wt. % Fe, 0.0 to 0.40 wt. % Cu, 0.10 to 0.30 wt. % Mn, 2.3 to 3.6 wt. % Mg, 0.0 to 0.10 wt. % Cr, 3.5 to 4.5 wt. % Zn, 0.0 to 0.10 wt. % Ti, 0.05 to 0.20 wt. % Zr, up to 0.15 wt. % impurities, and Al, wherein the total amount of Cu and Mg present is less than 3.6 wt. %.

[0009] In some embodiments, the method may include at least one paint bake, such as at least two paint bakes. In some embodiments, the method may include at least one paint bake, wherein at least one paint bake is performed at a temperature of 75 to 250° C. for 15 minutes to 3 hours. In some embodiments, the method may include at least one paint bake, wherein at least one paint bake is performed at a temperature of 100 to 200° C. for 15 minutes to 2 hours. In some embodiments, the method may include at least one paint bake, wherein at least one paint bake is performed at a temperature of 150 to 180° C. for 15 minutes to 45 minutes.

[0010] In some embodiments, the aluminum alloy product is formable at room temperature. In some embodiments, the aluminum alloy product is formable at temperatures below room temperature. In some embodiments, the aluminum alloy product has a service strength of at least 390 MPa in the T4 temper after at least two paint bake cycles. In some embodiments, the aluminum alloy product has a service strength of at least 400 MPa in the T6 temper after at least two paint bake cycles.

[0011] Further aspects, objects and advantages will become more apparent upon consideration of the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figures 1A-1C Provided are graphs of yield strength, ultimate tensile strength, and total elongation of aluminum alloy compositions described herein during natural aging response at 2.0 mm water quench (WQ) (1A), 2.4 mm (AQ) (1B), and 2.4 mm WQ (1C), according to some embodiments described herein.

[0013] Figures 2A-2B Provided are graphs of yield strength, ultimate tensile strength, and total elongation of aluminum alloy compositions after multiple paint bake cycles and T4 temper (2A) or T6 temper (2B) conditions according to some embodiments described herein.

[0014] Figure 3 Winding bend graphs are provided for aluminum alloys, such as those described herein, after T4 and T6 tempering according to some embodiments described herein compared to Comparative Example 1.

[0015] Figures 4A-4B Provided are photographs (4A) and die depths (4B) of various rivet and die designs in the aluminum alloys described herein, according to some embodiments described herein.

[0016] Figure 5 Provided are photographs of 2.0 mm WQ, 2.4 mm AC, and 2.4 mm WQ aluminum alloys at 30 kA and 34 Ka according to some embodiments described herein.

[0017] Figures 6A-6B A graph is provided of forming depth (6A) and resulting values ​​(6B) of Swift cupping tests for Example 1 and Comparative Example 3 aluminum alloys described herein, according to some embodiments described herein.

[0018] Figures 7A-7B Provided are graphs of forming depth (7A) and resulting values ​​(7B) for cupping tests of Example 1 and Comparative Example 3 aluminum alloys as described herein, according to some embodiments described herein.

[0019] Figure 8A graph comparing minor strain to major strain for the aluminum alloys of Examples 1-3 and Example 1 is provided, according to some embodiments described herein.

[0020] Figures 9A-9B A graph (9A) of stress versus strain for Comparative Examples 1-3 and Example 1 and a photograph (9B) of formability for Comparative Examples 1-3 and Example 1 are provided, according to some embodiments described below.

[0021] Figure 10 Provided are graphical representations of the rebound portion of Comparative Examples 1-3 and Example 1, according to some embodiments described herein.

[0022] Figures 11A-11C Provided are graphs of maximum intergranular corrosion (IGC) of aluminum alloys after 24 and 48 hours ( 11A ) and pitting micrographs of 2.4 mm WQ T4+PB ( 11B ) and 2.4 mm AQ T4+PB ( 11C ), according to some embodiments described herein.

[0023] Figure 12 Provided are microscopic images of exfoliation corrosion testing of aluminum alloys according to some embodiments described herein.

[0024] Figures 13A-13C Provided are graphs of maximum tensile stress (13A), maximum axial strain (13B), and resulting data (13C), according to some embodiments described herein.

[0025] Figure 14 Provided are scanning transition electron microscopy (STEM) images of aluminum alloy compositions described herein, according to some embodiments described herein. DETAILED DESCRIPTION

[0026] Described herein are new 7xxx series aluminum alloys that exhibit high corrosion resistance while maintaining a high strength-to-weight ratio, formability, and weldability. The addition of, among other things, minor alloying elements (zirconium (Zr)) and major constituents (such as copper (Cu) and magnesium (Mg)) improves the corrosion resistance and reduces stress corrosion cracking of aluminum alloy products without significantly reducing strength or formability. Without being bound by any particular theory, it is believed that the addition of copper, magnesium, and the minor element zirconium creates more nucleation sites in the microstructure, thereby reducing intergranular corrosion and stress corrosion cracking in the aluminum alloy.

[0027] Aluminum alloys exhibit good uniform corrosion resistance due to the presence of a passive film (e.g., a few nanometers thick) naturally formed by oxidation in air. However, when exposed to a corrosive environment (e.g., a chloride-containing electrolyte), the passive film can be easily destroyed in localized locations, leading to localized corrosion. 7xxx series aluminum alloys, particularly those with low copper content, are susceptible to SCC in corrosive environments. For example, heat treatment and tempering can improve SCC resistance in certain 7xxx series aluminum alloys.

[0028] The new 7xxx series aluminum alloy described herein contains higher contents of Cu, Mg and the minor element Zr to improve its SCC resistance while maintaining higher strength and formability. 7xxx series aluminum alloys containing higher contents of the major elements Cu and Mg (e.g., 0.10 to 0.40 wt.% and greater than 2.0 wt.%, respectively) and the minor element Zr (e.g., 0.01 to 0.20 wt.%), as described herein, can significantly improve their SCC resistance. In addition, this article also introduces an improved method for producing high-strength aluminum alloys. For example, by adding 0.01 wt.% to 0.20 wt.% Zr, the natural aging of the aluminum alloy described herein can be improved. In fact, compared with conventional 7xxx series aluminum alloys, 7xxx series aluminum alloys with added Zr elements and increased Cu and Mg contents improve room temperature formability and reduce the SCC of the alloy. The 7xxx series aluminum alloys described in this article have reduced grain boundary segregation due to the addition of higher contents of Cu, Mg and Zr, which synergistically reduces intergranular corrosion, improves SCC resistance, and ultimately improves the strength and room temperature formability of the aluminum alloy.

[0029] Definition and Explanation:

[0030] As used herein, the terms "invention," "described invention," "the present invention," and "the present invention" are intended to refer broadly to the entire subject matter of this patent application and its claims. Statements containing these terms should be understood as not limiting the subject matter described herein or restricting its meaning or scope.

[0031] In this specification, reference is made to alloys identified by aluminum industry designations, such as "Series" or "7xxx." For the most commonly used naming and identifying numerical designation system for aluminum and its alloys, refer to the International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys or the Registration Record of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot, published by the Aluminum Association.

[0032] The following aluminum alloys are described by their elemental composition (weight percentage, i.e., wt. %) based on the total weight of the alloy. In certain examples of each alloy, the remainder of the composition is aluminum, with a maximum wt. % of impurities added up to 0.15%. The wt. % of the aluminum alloy totals 100 wt. %, of which Al may be included to bring the total to 100 wt. %.

[0033] As used herein, the meaning of "a", "an" or "the" includes both the singular and the plural, unless the context clearly dictates otherwise.

[0034] As used herein, the thickness of the plate is generally greater than 15 mm to 200 mm. For example, the plate can refer to an aluminum alloy product having a thickness greater than 15 mm, greater than 20 mm, greater than 25 mm, greater than 30 mm, greater than 35 mm, greater than 40 mm, greater than 45 mm, greater than 50 mm, greater than 100 mm, or up to 200 mm.

[0035] As used herein, the thickness of the plate (also referred to as sheet material) is typically 4 mm to 15 mm. For example, the thickness of the plate can be 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm or 15 mm.

[0036] As used herein, sheet generally refers to aluminum products having a thickness of less than 4 mm (eg, less than 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, less than 0.3 mm, or less than 0.1 mm). For example, the thickness of the sheet material can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 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 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, 3.9 mm or 4 mm.

[0037] As mentioned above, formability refers to the ability of a material to be deformed into a desired shape without breaking, tearing, necking, earing, or forming defects such as wrinkling, springback, or undercutting. In engineering, formability can be categorized based on the deformation mode. Deformation modes include drawing, stretching, bending, and stretch flanging.

[0038] Alloy tempers or conditions may be mentioned in this application. For descriptions of the most commonly used alloy tempers, see "American National Standards (ANSI) H35 on Alloy and Temper Designation Systems". The F temper or temper refers to the manufactured aluminum alloy. The O temper or temper refers to the annealed aluminum alloy. The Hxx temper or temper, also referred to herein as the H temper, refers to a non-heat-treatable aluminum alloy that has been subjected to or not subjected to a heat treatment (e.g., annealing) after cold rolling. Suitable H tempers include HX1, HX2, HX3, HX4, HX5, HX6, HX7, HX8, or HX9 tempers. The T1 temper or temper refers to an aluminum alloy that has been cooled from hot working and naturally aged (e.g., at room temperature). The T2 temper or temper refers to an aluminum alloy that has been cooled from hot working, cold worked, and naturally aged. The T3 temper or temper refers to an aluminum alloy that has been solution heat treated, cold worked, and naturally aged. The T4 temper or temper refers to an aluminum alloy that has been solution heat treated and naturally aged. The T5 temper or quench refers to aluminum alloys that have been cooled from hot working and artificially aged (at elevated temperatures). The T6 temper or quench refers to aluminum alloys that have been solution heat treated and artificially aged. The T7 temper or quench refers to aluminum alloys that have been solution heat treated and artificially overaged. The T8x temper or quench refers to aluminum alloys that have been solution heat treated, cold worked, and artificially aged. The T9 temper or quench refers to aluminum alloys that have been solution heat treated, artificially aged, and cold worked. The W temper or quench refers to the condition of an aluminum alloy after solution heat treatment.

[0039] As used herein, the terms "cast metal product," "cast product," "cast aluminum alloy product," and the like are used interchangeably to refer to products produced by direct chill casting (including direct chill co-casting) or semi-continuous casting, continuous casting (including, for example, using a twin-belt caster, twin-roll caster, block caster, or any other continuous casting machine), electromagnetic casting, hot top casting, or any other casting method.

[0040] As used herein, the meaning of "room temperature" can include temperatures between 15°C and 30°C, for example, 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 or 30°C.

[0041] All ranges disclosed herein should be understood to encompass any endpoints, as well as any and all subranges contained therein. For example, a range specified as "1 to 10" should be considered to include any and all subranges between a minimum of 1 and a maximum of 10 (inclusive of 1 and 10); that is, all subranges have a starting value of at least 1 or greater, such as 1 to 6.1, and an ending value of no more than 10 or less, such as 5.5 to 10.

[0042] Alloy composition

[0043] The properties of aluminum alloys depend in part on the composition of the aluminum alloy. In some aspects, the alloy composition may affect or even determine whether the alloy has the properties to meet the intended application.

[0044] The alloys and products described herein are novel aluminum compositions that exhibit desirable mechanical and physical properties, such as formability, strength, and a fine microstructure. The properties of the compositions are at least partially dependent on the elemental composition of the aluminum.

[0045] In some examples, the aluminum alloys described herein may have the elemental compositions shown in Table 1.

[0046] Table 1

[0047]

[0048] In some examples, the aluminum alloys described herein may have the elemental compositions shown in Table 2.

[0049] Table 2

[0050]

[0051] In some examples, the aluminum alloys described herein may have the elemental compositions shown in Table 3.

[0052] Table 3

[0053]

[0054] In some examples, the aluminum alloys described herein may have the elemental compositions shown in Table 4.

[0055] Table 4

[0056]

[0057]

[0058] Silicon (Si)

[0059] In some instances, the aluminum alloys described herein include Si in an amount up to 0.25%, such as 0.00% to 0.25%, 0.01% to 0.25%, 0.05% to 0.25%, 0.00% to 0.15%, or 0.00% to 0.20%, based on the total weight of the alloy. For example, the alloy can include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, or starting at 0.25% Si. In some cases, the alloy contains no Si (ie, 0%). All values ​​are expressed in wt.%.

[0060] Iron (Fe)

[0061] In some examples, the aluminum alloys described herein further include Fe in an amount up to 0.40%, for example, 0.00% to 0.40%, 0.10% to 0.40%, 0.00% to 0.30%, or 0.10% to 0.40%, based on the total weight of the alloy. For example, the alloy may include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, %.

[0062] Copper (Cu)

[0063] In some examples, the aluminum alloys described herein include Cu in an amount up to 0.40%, for example, 0.00% to 0.40%, 0.00% to 0.30%, or 0.11% to 0.40%, based on the total weight of the alloy. For example, the alloy may include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.70%, 0.71%, 0. %.

[0064] Manganese (Mn)

[0065] In some examples, the aluminum alloys described herein may include Mn in an amount up to 0.30%, eg, 0.00% to 0.30%, 0.05% to 0.30%, or 0.10% to 0.30%, based on the total weight of the alloy. For example, the alloy can include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29% or 0.30% Mn. In some cases, the alloy contains no Mn (i.e., 0%). All are expressed in wt.%.

[0066] Magnesium (Mg)

[0067] In some examples, the aluminum alloys described herein may include Mg in an amount up to 3.60%, eg, 0.00% to 3.60%, 1.00% to 3.60%, 2.00% to 3.60%, or 2.30% to 3.60%, based on the total weight of the alloy. For example, the alloys described herein may include starting at 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.70%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.80%, 0.81%, 0.82%, 0.83%, 36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.70%, 0.71%, 0.72%, 0.73%, 0. 74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.80%, 0.81%, 0.82%, 0.83%, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.90%, 0.91%, 0.92%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.00%, 1.01%, 1.02%, 1.03%, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, 1.09%, 1.10%, 1.11%, 1. 1.12%, 1.13%, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%, 1.20%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29%, 1.30%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%, 1.36%, 1.37%, 1.38%, 1.39%, 1.40%, 1.41%, 1.42%, 1.43%, 1.44%, 1.45%, 1.46%, 1.47%, 1.48%, 1.49%, 1.50％、1.51％、1.52％、1.53％、1.54％、1.55％、1.56％、1.57％、1.58％、1.59％、1.60％、1.61％、1.62％、1.63％、1.64％、1.65％、1.66％、1.67％、1.68％、1.69％、1.70％、1.71％、1.72％、1.73％、1.74％、1.75％、1.76％、1.77％、1.78％、1.79％、1.80％、1.81％、1.82％、1.83％、1.84％、1.85％、1.86％、1.87％、1.88％、1.89％、1.90％、1.91％、1.92％、1.93％、1.94％、1.95％、1.96％、1.97％、1.98％、1.99％、2.00％、2.01％、2.02％、2.03％、2.04％、2.05％、2.06％、2.07％、2.08％、2.09％、2.10％、2.11％、2.12％、2.13％、2.14％、2.15％、2.16％、2.17％、2.18％、2.19％、2.20％、2.21％、2.22％、2.23％、2.24％、2.25％、2.26％、2.27％、2.28％、2.29％、2.30％、2.31％、2.32％、2.33％、2.34％、2.35％、2.36％、2.37％、2.38％、2.39％、2.40％、2.41％、2.42％、2.43％、2.44％、2.45％、2.46％、2.47％、2.48％、2.49％、2.50％、2.51％、2.52％、2.53％、2.54％、2.55％、2.56％、2.57％、2.58％、2.59％、2.60％、2.61％、2.62％、2.63％、2.64％、2.65％、2.66％、2.67％、2.68％、2.69％、2.70％、2.71％、2.72％、2.73％、2.74％、2.75％、2.76％、2.77％、2.78％、2.79％、2.80％、2.81％、2.82％、2.83％、2.84％、2.85％、2.86％、2.87％、2.88％、2.89％、2.90％、2.91％、2.92％、2.93％、2.94％、2.95％、2.96％、2.97％、2.98％、2.99％、3.00％、3.01％、3.02％、3.03％、3.04％、3.05％、3.06％、3.07％、3.08％、3.09％、3.10％、3.11％、3.12％、3.13％、3.14％、3.15％、3.16%, 3.17%, 3.18%, 3.19%, 3.20%, 3.21%, 3.22%, 3.23%, 3.24%, 3.25%, 3.26%, 3.27%, 3.28%, 3.29%, 3.30%, 3.31%, 3.32%, 3.33%, 3.34%, 3.35%, 3.36%, 3.37%, 3.38% , 3.39%, 3.40%, 3.41%, 3.42%, 3.43%, 3.44%, 3.45%, 3.46%, 3.47%, 3.48%, 3.49%, 3.50%, 3.51%, 3.52%, 3.53%, 3.54%, 3.55%, 3.56%, 3.57%, 3.58%, 3.59% or 3.60% Mg. All expressed in wt.%.

[0068] Chromium (Cr)

[0069] In some examples, the aluminum alloys described herein include Cr in an amount up to 0.10% based on the total weight of the alloy, e.g., 0.01% to 0.10%, 0.05% to 0.10%, 0.01% to 0.05%, or 0.01% to 0.05%. For example, the alloy may include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.10% Cr. In some cases, the alloy contains no Cu (i.e., 0%). All are expressed in wt.%.

[0070] Zinc (Zn)

[0071] In some examples, the aluminum alloys described herein include Zn in an amount up to 4.50%, e.g., 0.00% to 4.50%, 0.50% to 4.00%, 1.50% to 4.50%, 2.50% to 4.50%, or 3.50% to 4.50%, based on the total weight of the alloy. For example, the alloy may contain 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%. , 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.70%, 0.71%, 0.72%, 0.73%, 0. 74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.80%, 0.81%, 0.82%, 0.83%, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.90%, 0.91%, 0.92%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.00%, 1.01%, 1.02%, 1.03%, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, 1.09%, 1.10%, 1.11% , 1.12%, 1.13%, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%, 1.20%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29%, 1.30%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%, 1.36%, 1.37%, 1.38%, 1.39%, 1.40%, 1.41%, 1.42%, 1.43%, 1.44%, 1.45%, 1.46%, 1.47%, 1.48%, 1.49％、1.50％、1.51％、1.52％、1.53％、1.54％、1.55％、1.56％、1.57％、1.58％、1.59％、1.60％、1.61％、1.62％、1.63％、1.64％、1.65％、1.66％、1.67％、1.68％、1.69％、1.70％、1.71％、1.72％、1.73％、1.74％、1.75％、1.76％、1.77％、1.78％、1.79％、1.80％、1.81％、1.82％、1.83％、1.84％、1.85％、1.86％、1.87％、1.88％、1.89％、1.90％、1.91％、1.92％、1.93％、1.94％、1.95％、1.96％、1.97％、1.98％、1.99％、2.00％、2.01％、2.02％、2.03％、2.04％、2.05％、2.06％、2.07％、2.08％、2.09％、2.10％、2.11％、2.12％、2.13％、2.14％、2.15％、2.16％、2.17％、2.18％、2.19％、2.20％、2.21％、2.22％、2.23％、2.24％、2.25％、2.26％、2.27％、2.28％、2.29％、2.30％、2.31％、2.32％、2.33％、2.34％、2.35％、2.36％、2.37％、2.38％、2.39％、2.40％、2.41％、2.42％、2.43％、2.44％、2.45％、2.46％、2.47％、2.48％、2.49％、2.50％、2.51％、2.52％、2.53％、2.54％、2.55％、2.56％、2.57％、2.58％、2.59％、2.60％、2.61％、2.62％、2.63％、2.64％、2.65％、2.66％、2.67％、2.68％、2.69％、2.70％、2.71％、2.72％、2.73％、2.74％、2.75％、2.76％、2.77％、2.78％、2.79％、2.80％、2.81％、2.82％、2.83％、2.84％、2.85％、2.86％、2.87％、2.88％、2.89％、2.90％、2.91％、2.92％、2.93％、2.94％、2.95％、2.96％、2.97％、2.98％、2.99％、3.00％、3.01％、3.02％、3.03％、3.04％、3.05％、3.06％、3.07％、3.08％、3.09％、3.10％、3.11％、3.12％、3.13％、3.14％、3.15%, 3.16%, 3.17%, 3.18%, 3.19%, 3.20%, 3.21%, 3.22%, 3.23%, 3.24%, 3.25%, 3.26%, 3.27%, 3.28%, 3.29%, 3.30%, 3.31%, 3.32%, 3.33%, 3.34%, 3.35%, 3.36%, 3.37%, 3.38%, 3.39%, 3.40%, 3.41%, 3.42%, 3.43%, 3.44%, 3.45%, 3.46%, 3.47%, 3.48%, 3. 49%, 3.50%, 3.51%, 3.52%, 3.53%, 3.54%, 3.55%, 3.56%, 3.57%, 3.58%, 3.59%, 3.60%, 3.61%, 3.62%, 3.63%, 3.64%, 3.65%, 3.66%, 3.67%, 3.68%, 3.69%, 3.70%, .371%, 3.72%, 3.73%, 3.74%, 3.75%, 3.76%, 3.77%, 3.78%, 3.79%, 3.80%, 3.81%, 3.82%, 3. 83%, 3.84%, 3.85%, 3.86%, 3.87%, 3.88%, 3.89%, 3.90%, 3.91%, 3.92%, 3.93%, 3.94%, 3.95%, 3.96%, 3.97%, 3.98%, 3.99%, 4.00%, 4.01%, 4.02%, 4.03%, 4.04%, 4.05%, 4.06%, 4.07%, 4.08%, 4.09%, 4.10%, 4.11%, 4.12%, 4.13%, 4.14%, 4.15%, 4.16%, 4. %, 4.48%, 4.49%, or 4.50% Zn. In some cases, the alloy contains no Zn (i.e., 0%). All are expressed in wt.%.

[0072] Tin (titanium)

[0073] In some examples, the aluminum alloys described herein include Ti in an amount up to 0.10% based on the total weight of the alloy, e.g., 0.00% to 0.10%, 0.01% to 0.10%, or 0.05% to 0.10%. For example, the alloy may include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.10% Ti. In some cases, the alloy contains no Ti (i.e., 0%). All are expressed in wt.%.

[0074] Zirconium (Zr)

[0075] In some instances, the aluminum alloys described herein include Zr in an amount up to 0.20% based on the total weight of the alloy, such as 0.00% to 0.20%, 0.01% to 0.20%, or 0.05% to 0.20%. For example, the alloy may include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, or 0.20% Zr. In some cases, the alloy contains no Zr (i.e., 0%). All are expressed in wt.%.

[0076] In some non-limiting examples, the combination of Cu and Mg can improve the corrosion resistance of the aluminum alloy product. In some instances, the combined amount of Cu and Mg in the composition is 0.00 wt.% to 3.6 wt.% (e.g., 1.0 wt.% to 3.0 wt.%, 1.5 wt.% to 3.6 wt.%, or 2.30 wt.% to 3.60 wt.%). For example, the combined amount of Cu and Mg can be 0.01 wt.%, 0.02 wt.%, 0.03 wt.%, 0.04 wt.%, 0.05 wt.%, 0.06 wt.%, 0.07 wt.%, 0.08 wt.%, 0.09 wt.%, 0.10 wt.%, 0.11 wt.%, 0.12 wt.%, 0.13 wt.%, 0.14 wt.%, 0.15 wt.%, 0.16 wt.%, 0.17 wt.%, 0.18 wt.%, 0.19 wt.%, 0.20 wt.%, 0.21 wt.%, 0.22 wt.%, 0.23 wt.%, 0.24 wt.%, 0.25 wt.%, 0.26 wt.%, 0.27 wt.%, 0.28 wt.%, 0.29wt.%, 0.30 wt.%, 0.31 wt.%, 0.32 wt.%, 0.33 wt.%, 0.34 wt.%, 0.35 wt.%, 0.36wt.%, 0.37 wt.%, 0.38 wt.%, 0.39 wt.%, 0.40 wt.%, 0.41 wt.%, 0.42 wt.%, 0.43wt.%, 0.44 wt.%, 0.45 wt.%, 0.46 wt.%, 0.47 wt.%, 0.48 wt.%, 0.49 wt.%, 0.50wt.%, 0.51 wt.%, 0.52 wt.%, 0.53 wt.%, 0.54 wt.%, 0.55 wt.%, 0.56 wt.%, 0.57wt.%, 0.58 wt.%, 0.59 wt.%, 0.60 wt.%, 0.61 wt.%, 0.62 wt.%, 0.63 wt.%, 0.64wt.%, 0.65 wt.%, 0.66 wt.%, 0.67 wt.%, 0.68 wt.%, 0.69 wt.%, 0.70 wt.%, 0.71wt.%, 0.72 wt.%, 0.73 wt.%, 0.74 wt.%, 0.75 wt.%, 0.76 wt.%, 0.77 wt.%, 0.78wt.%, 0.79 wt.%, 0.80 wt.%, 0.81 wt.%, 0.82 wt.%, 0.83 wt.%, 0.84 wt.%, 0.85wt.%, 0.86 wt.%, 0.87 wt.%, 0.88 wt.%, 0.89 wt.%、0.90 wt.%、0.91 wt.%、0.92wt.%、0.93 wt.%、0.94 wt.%、0.95 wt.%、0.96 wt.%、0.97 wt.%、0.98 wt.%、0.99wt.%、1.00 wt.%、1.01 wt.%、1.02 wt.%、1.03 wt.%、1.04 wt.%、1.05 wt.%、1.06wt.%、1.07 wt.%、1.08 wt.%、1.09 wt.%、1.10 wt.%、1.11 wt.%、1.12 wt.%、1.13wt.%、1.14 wt.%、1.15 wt.%、1.16 wt.%、1.17 wt.%、1.18 wt.%、1.19 wt.%、1.20wt.%、1.21 wt.%、1.22 wt.%、1.23 wt.%、1.24 wt.%、1.25 wt.%、1.26 wt.%、1.27wt.%、1.28 wt.%、1.29 wt.%、1.30 wt.%、1.31 wt.%、1.32 wt.%、1.33 wt.%、1.34wt.%、1.35 wt.%、1.36 wt.%、1.37 wt.%、1.38 wt.%、1.39 wt.%、1.40 wt.%、1.41wt.%、1.42 wt.%、1.43 wt.%、1.44 wt.%、1.45 wt.%、1.46 wt.%、1.47 wt.%、1.48wt.%、1.49 wt.%、1.50 wt.%、1.51 wt.%、1.52 wt.%、1.53 wt.%、1.54 wt.%、1.55wt.%、1.56 wt.%、1.57 wt.%、1.58 wt.%、1.59 wt.%、1.60 wt.%、1.61 wt.%、1.62wt.%、1.63 wt.%、1.64 wt.%、1.65 wt.%、1.66 wt.%、1.67 wt.%、1.68 wt.%、1.69wt.%、1.70 wt.%、1.71 wt.%、1.72 wt.%、1.73 wt.%、1.74 wt.%、1.75 wt.%、1.76wt.%、1.77 wt.%、1.78 wt.%、1.79 wt.%、1.80 wt.%、1.81 wt.%、1.82 wt.%、1.83wt.%、1.84 wt.%、1.85 wt.%、1.86 wt.%、1.87 wt.%、1.88 wt.%、1.89 wt.%、1.90wt.%、1.91 wt.%、1.92 wt.%、1.93 wt.%、1.94 wt.%、1.95 wt.%、1.96 wt.%、1.97wt.%、1.98 wt.%、1.99 wt.%、2.00wt.%、2.01wt.%、2.02wt.%、2.03wt.%、2.04wt.%、2.05wt.%、2.06wt.%、2.07wt.%、2.08wt.%、2.09wt.%、2.10wt.%、2.11wt.%、2.12wt.%、2.13wt.%、2.14wt.%、2.15wt.%、2.16wt.%、2.17wt.%、2.18wt.%、2.19wt.%、2.20wt.%、2.21wt.%、2.22wt.%、2.23wt.%、2.24wt.%、2.25wt.%、2.26wt.%、2.27wt.%、2.28wt.%、2.29wt.%、2.30wt.%、2.31wt.%、2.32wt.%、2.33wt.%、2.34wt.%、2.35wt.%、2.36wt.%、2.37wt.%、2.38wt.%、2.39wt.%、2.40wt.%、2.41wt.%、2.42wt.%、2.43wt.%、2.44wt.%、2.45wt.%、2.46wt.%、2.47wt.%、2.48wt.%、2.49wt.%、2.50wt.%、2.51wt.%、2.52wt.%、2.53wt.%、2.54wt.%、2.55wt.%、2.56wt.%、2.57wt.%、2.58wt.%、2.59wt.%、2.60wt.%、2.61wt.%、2.62wt.%、2.63wt.%、2.64wt.%、2.65wt.%、2.66wt.%、2.67wt.%、2.68wt.%、2.69wt.%、2.70wt.%、2.71wt.%、2.72wt.%、2.73wt.%、2.74wt.%、2.75wt.%、2.76wt.%、2.77wt.%、2.78wt.%、2.79wt.%、2.80wt.%、2.81wt.%、2.82wt.%、2.83wt.%、2.84wt.%、2.85wt.%、2.86wt.%、2.87wt.%、2.88wt.%、2.89wt.%、2.90wt.%、2.91wt.%、2.92wt.%、2.93wt.%、2.94wt.%、2.95wt.%、2.96wt.%、2.97wt.%、2.98wt.%、2.99wt.%、3.00wt.%、3.01wt.%, 3.02wt.%, 3.03wt.%, 3.04wt.%, 3.05wt.%, 3.06wt.%, 3.07wt.%, 3.08wt .%, 3.09wt.%, 3.10wt.%, 3.11wt.%, 3.12wt.%, 3.13wt.%, 3.14wt.%, 3.15wt.%, 3 .16wt.%, 3.17wt.%, 3.18wt.%, 3.19wt.%, 3.20wt.%, 3.21wt.%, 3.22wt.%, 3.23w t.%, 3.24wt.%, 3.25wt.%, 3.26wt.%, 3.27wt.%, 3.28wt.%, 3.29wt.%, 3.30wt.%, 3 %. .31 wt.%, 3.32 wt.%, 3.33 wt.%, 3.34 wt.%, 3.35 wt.%, 3.36 wt.%, 3.37 wt.%, 3.38 wt.%, 3.39 wt.%, 3.40 wt.%, 3.41 wt.%, 3.42 wt.%, 3.43 wt.%, 3.44 wt.%, 3.45 wt.%, 3.46 wt.%, 3.47 wt.%, 3.48 wt.%, 3.49 wt.%, 3.50 wt.%, 3.51 wt.%, 3.52 wt.%, 3.53 wt.%, 3.54 wt.%, 3.55 wt.%, 3.56 wt.%, 3.57 wt.%, 3.58 wt.%, 3.59 wt.% or 3.60 wt.%.

[0077] The presence of Cu in an amount of at least 0.10 wt.%, Mg in an amount of at least 2.8 wt.%, and Cu as the main alloying element (in addition to Al), combined with the processing conditions described below, can produce an aluminum alloy product with excellent strength and formability. In some cases, this combination results in an aluminum alloy product with high corrosion resistance.

[0078] Secondary elements

[0079] Optionally, the aluminum alloys described herein may also include other minor elements (sometimes referred to as impurities) in amounts of 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, or 0.01% or less. These impurities may include, but are not limited to, V, Ni, Hf, Zr, Sn, Ga, Ca, Bi, Na, Pb, or combinations thereof. Thus, V, Ni, Hf, Zr, Sn, Ga, Ca, Bi, Na, or Pb may be present in the alloy in amounts of 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, or 0.01% or less. The sum of all impurities does not exceed 0.15% (e.g., 0.1%). All are expressed in wt.%. The remaining percentage of each alloy may be aluminum.

[0080] The aluminum alloys described herein may contain at least 40 wt.% recycled content. For example, the aluminum alloys may contain at least 45 wt.%, at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, or at least 95 wt.% recycled content.

[0081] Processing methods

[0082] Optionally, aluminum alloy products suitable for use in the methods described herein include 7xxx series aluminum alloys. In some cases, the 7xxx series aluminum alloys used in the methods described herein may be 7xxx series aluminum alloys registered with the Aluminum Association and may optionally be modified to include amounts of Zr, Mg, Zn, and / or any other elements, as described above. The 7xxx series aluminum alloys may include, for example, AA7003, AA7004, AA7204, AA7005, AA7108, AA7108A, AA7009, AA7010, AA7012, AA7014, AA7015, AA7016, AA7116, AA7017, AA7018, AA7019, AA7019A, AA7020, AA7021, AA7022, AA7122, AA7123, AA7124, AA7125, AA7126, AA7127, AA7128, AA7129, AA7130, AA7131, AA7132, AA7133, AA7134, AA7135, AA7136, AA7137, AA7138, AA7139, AA7140, AA7141, AA7142, AA7143, AA7144, AA7145, AA7146, AA7147, AA7148, AA7149, AA7150, AA7151 7023, AA7024, AA7025, AA7026, AA7028, AA7029, AA7129, AA7229, AA7030, AA7031, AA7032, AA7033, A A7034, AA7035, AA7035A, AA7036, AA7136, AA7037, AA7039, AA7040, AA7140, AA7041, AA7042, AA7046 ,AA7046A,AA7047,AA7049,AA7049A,AA7149,AA7249,AA7349,AA7449,AA7050,AA7050A,AA7150,AA 7055, AA7155, AA7255, AA7056, AA7060, AA7064, AA7065, AA7068, AA7168, AA7072, AA7075, AA7175, A A7475, AA7076, AA7178, AA7278, AA7278A, AA7081, AA7181, AA7085, AA7185, AA7090, AA7093, AA7095, AA7099 or AA7199, optionally modified to include at least 0.1 wt.% Zr, at least 2.3 wt.% magnesium (Mg), at least 0.1 wt.% copper (Cu) and zinc (Zn) as main alloying elements.

[0083] In some examples, the alloy is a monomeric alloy. In some examples, the alloy is a clad aluminum alloy having a core layer and / or two cladding layers. In some cases, the core layer may be different from one or both cladding layers. The core layer may be, for example, an aluminum alloy as described herein (e.g., an aluminum alloy comprising at least 0.1 wt.% Zr, at least 2.3 wt.% Mg, at least 0.1 wt.% Cu, and Zn as primary alloying elements other than Al).

[0084] Casting

[0085] The alloys may be cast using any suitable casting process. For example, molten aluminum alloy compositions including the aluminum alloys described herein may be cast using a continuous casting (CC) process, which may include, but is not limited to, using a twin-belt caster, a twin-roll caster, or a block caster. In some examples, the casting process is performed using a CC process to form cast products such as billets, slabs, strip, and the like.

[0086] In some cases, the resulting cast aluminum alloy product may exit the caster at a temperature (e.g., caster exit temperature) of 370° C. to 450° C. For example, the caster exit temperature of the cast aluminum alloy product may be 370° C., 380° C., 390° C., 400° C., 410° C., 420° C., 430° C., 440° C., 450° C., or any temperature therebetween.

[0087] The thickness of the cast aluminum alloy product can be 5mm to 50mm (for example, 10mm to 45mm, 15mm to 40mm or 20mm to 35mm), for example 10mm. For example, the thickness of the cast aluminum alloy product can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm, 41mm, 42mm, 43mm, 44mm, 45mm, 46mm, 47mm, 48mm, 49mm or 50mm.

[0088] The cast aluminum alloy product may then be subjected to further processing steps. In some non-limiting examples, the processing methods include hot rolling, coiling, coil cooling, further processing, solutionizing, and / or aging. In some cases, further processing may include homogenizing and hot rolling to final specifications. In other cases, further processing steps may include homogenizing, cooling, and cold rolling to final specifications. In still other cases, further processing steps may include cold rolling to final specifications.

[0089] Hot Rolling

[0090] After the casting step, a hot rolling step can be performed. In some cases, the hot rolling step can be performed immediately after casting. The hot rolling step can include a hot reversible rolling mill operation and / or a hot tandem rolling mill operation. The hot rolling step can be performed in a temperature range of 250°C to 500°C (e.g., 300°C to 400°C or 350°C to 430°C). For example, the hot rolling step can be performed at 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C or any temperature therebetween.

[0091] In the hot rolling step, the cast aluminum alloy product can be hot rolled to a thickness of 15 mm or less (e.g., from 2 mm to 10 mm), thereby providing an aluminum alloy hot strip. For example, the cast aluminum alloy product can be hot rolled to a gauge of 15 mm or less, a gauge of 14 mm or less, a gauge of 13 mm or less, a gauge of 12 mm or less, a gauge of 11 mm or less, a gauge of 10 mm or less, a gauge of 9 mm or less, a gauge of 8 mm or less, a gauge of 7 mm or less, a gauge of 6 mm or less, a gauge of 5 mm or less, a gauge of 4 mm or less, a gauge of 3 mm or less, or a gauge of 2 mm or less. In some cases, the percentage reduction in thickness caused by the hot rolling step can be at least 40% (e.g., from 40% to 50%). For example, the thickness of the cast aluminum alloy product can be reduced by 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%. In some cases, the aluminum alloy hot strip may exit a hot reversing mill and / or a hot tandem mill (i.e., a hot rolling mill) at a temperature of 300° C. to 400° C. For example, the hot rolling exit temperature of the aluminum alloy hot strip may be 300° C., 310° C., 320° C., 330° C., 340° C., 350° C., 360° C., 370° C., 380° C., 390° C., 400° C., or any temperature therebetween.

[0092] Coil taking-up and coil cooling

[0093] Optionally, the aluminum alloy hot strip can be coiled into a hot strip coil after exiting the hot rolling mill. In some further examples, the hot strip coil is cooled in air (referred to as coil cooling). The coil cooling step can be performed at a rate of 12.5°C / hour (°C / h) to 3600°C / h. For example, the coil cooling step can be performed at 12.5°C / h, 25°C / h, 50°C / h, 100°C / h, 200°C / h, 400°C / h, 800°C / h, 1600°C / h, 3200°C / h, 3600°C / h, or any rate therebetween. The hot strip coil can be cooled to a temperature of 300°C to 400°C. For example, the hot strip coil can be cooled to a temperature of 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, or 400°C.

[0094] In some examples, the air-cooled coil can be stored for a period of time. For example, the coil can be maintained at a temperature of 300° C. to 400° C. for 1 hour or more (e.g., 2 hours or more, 5 hours or more, 10 hours or more, 1 day or more, 2 days or more, or 1 week or more).

[0095] Homogenization, hot rolling to final gauge, coil cooling and cold rolling to final gauge

[0096] Optionally, a homogenization step may be performed after hot rolling, coiling, and coil cooling. The homogenization step may include heating the hot coil to a peak metal temperature (PMT) of at least 450°C (e.g., at least 460°C, at least 470°C, at least 480°C, at least 490°C, at least 500°C, at least 510°C, at least 520°C, at least 530°C, at least 540°C, at least 550°C, at least 560°C, at least 570°C, or at least 580°C). For example, the hot coil may be heated to a temperature of 450°C to 580°C, 460°C to 575°C, 465°C to 570°C, 470°C to 565°C, 475°C to 555°C, or 480°C to 550°C. In some cases, the heating rate of the PMT can be 100° C. / hour or less, 75° C. / hour or less, 50° C. / hour or less, 40° C. / hour or less, 30° C. / hour or less, 25° C. / hour or less, 20° C. / hour or less, or 15° C. / hour or less. In other cases, the heating rate of the PMT can be 10° C. / min to 100° C. / min (e.g., 10° C. / min to 90° C. / min, 15° C. / min to 70° C. / min, 20° C. / min to 60° C. / min, 20° C. / min to 50° C. / min, or 30° C. / min to 40° C. / min).

[0097] The hot coil is then allowed to soak (i.e., remain at the specified temperature) for a period of time. According to one non-limiting example, the hot coil is allowed to soak for up to 36 hours (e.g., 30 minutes, 2 hours, or 36 hours). For example, the hot coil can be soaked at the indicated temperature for 30 minutes, 60 minutes (i.e., 1 hour), 90 minutes, 120 minutes (i.e., 2 hours), 150 minutes, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, 31 hours, 32 hours, 33 hours, 34 hours, 35 hours, 36 hours, or any time therebetween.

[0098] In some non-limiting examples, no homogenization step is performed.

[0099] Optionally, the homogenized hot strip coil can be hot rolled to provide an aluminum alloy product of final specifications. The step of hot rolling to the final specifications can be performed using, for example, a finishing mill after the homogenization step. The hot rolling step can be performed in a temperature range of 250°C to 500°C (e.g., 300°C to 400°C or 350°C to 430°C). For example, the hot rolling step can be performed at 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C or any temperature therebetween.

[0100] The hot rolling to final gauge step can further reduce the thickness of the hot strip to a final gauge of 0.5 mm to 6 mm. For example, the hot rolling to final gauge step can provide an aluminum alloy product having a size of 6 mm or less, 5.5 mm or less, 5 mm or less, 4.5 mm or less, 4 mm or less, 3.5 mm or less, 3 mm or less, 2.5 mm or less, 2 mm or less, 1.5 mm or less, 1 mm or less, 0.5 mm, or any size therebetween.

[0101] Optionally, after the homogenization process, the homogenized hot strip coil may be subjected to coil cooling and cold rolling. The homogenized hot strip coil may be cooled in air at a rate of 12.5°C / hour (°C / h) to 3600°C / h. For example, the coil cooling step may be performed at 12.5°C / h, 25°C / h, 50°C / h, 100°C / h, 200°C / h, 400°C / h, 800°C / h, 1600°C / h, 3200°C / h, 3600°C / h, or any rate therebetween. After the coil is cooled, a cold rolling step may optionally be performed. In the cold rolling step, the homogenized hot strip coil may be cold rolled to a thickness of 0.1 mm to 6 mm (e.g., 0.5 mm to 5 mm). For example, the homogenized hot strip coil may be cold rolled to a thickness of less than 4 mm to provide an aluminum alloy product of final specifications. For example, the thickness of the final gauge aluminum alloy product can be 6 mm or less, 5.5 mm or less, 5 mm or less, 4.5 mm or less, 4 mm or less, 3.5 mm or less, 3 mm or less, 2.5 mm or less, 2 mm or less, 1.5 mm or less, 1 mm or less, 0.5 mm, or any value therebetween. Optionally, the cold rolling step can be performed without a homogenization step and / or a hot rolling step.

[0102] In some cases, an exemplary sequence of steps for further processing the hot-strip coil to provide the aluminum alloy product of final specifications includes: homogenizing the hot-strip coil to provide the homogenized hot-strip coil; and hot rolling the homogenized hot-strip coil to provide the aluminum alloy product of final specifications. In other cases, an exemplary sequence of steps for further processing the hot-strip coil to provide the aluminum alloy product of final specifications includes: homogenizing the hot-strip coil to provide the homogenized hot-strip coil, cooling the homogenized hot-strip coil, and cold rolling the homogenized hot-strip coil to provide the aluminum alloy product of final specifications. In still other cases, further processing the hot-strip coil to provide the aluminum alloy product of final specifications includes cold rolling the hot-strip coil to provide the aluminum alloy product of final specifications.

[0103] solid solution

[0104] Method described herein further includes the step of solutionizing the aluminum alloy product of final specification. The solutionizing step may include heating or cooling the aluminum alloy product of final specification to 450°C or higher solution temperature (e.g., from 460°C to 600°C, from 465°C to 575°C, from 470°C to 550°C, from 475°C to 525°C or from 480°C to 500°C) as needed. The aluminum alloy product of final specification can be soaked for a period of time at the solution temperature. In some aspects, the aluminum alloy product of final specification is allowed to soak for at least 30 seconds (e.g., 60 seconds to 120 minutes, including 60 seconds and 120 minutes). For example, the final gauge aluminum alloy product may be soaked at 450° C. or greater for 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds, 65 seconds, 70 seconds, 75 seconds, 80 seconds, 85 seconds, 90 seconds, 95 seconds, 100 seconds, 105 seconds, 110 seconds, 115 seconds, 120 seconds, 125 seconds, 130 seconds, 135 seconds, 140 seconds, 145 seconds, 150 seconds, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes, 90 minutes, 95 minutes, 100 minutes, 105 minutes, 110 minutes, 115 minutes, 120 minutes, or any time therebetween. In certain aspects, solution treatment is performed immediately after the hot rolling step or the cold rolling step.

[0105] Quenching

[0106] The methods described herein include a quenching step. As used herein, the term "quenching" can include rapidly reducing the temperature of the final aluminum alloy product that has been solutionized as described above. In the quenching step, the product can be quenched with a liquid (e.g., water), a gas (e.g., air), any other suitable quenching medium, or any combination thereof. In some aspects, the product can be quenched with water having a temperature between 40° C. and 75° C. In some aspects, the product is quenched using forced air.

[0107] In certain aspects, the product can be cooled to a temperature of 25°C to 65°C during the quenching step, depending on the selected specifications, and the quenching rate can vary from 50°C / s to 400°C / s. For example, the quenching rate can be 50°C / s to 375°C / s, 60°C / s to 375°C / s, 70°C / s to 350°C / s, 80°C / s to 325°C / s, 90°C / s to 300°C / s, 100°C / s to 275°C / s, 125°C / s to 250°C / s, 150°C / s to 225°C / s, or 175°C / s to 200°C / s.

[0108] Pre-aging

[0109] In some cases, a pre-aging step may be performed. Without being bound by theory, the pre-aging step may at least partially prevent changes in the mechanical properties of the aluminum alloy product due to natural aging. Optionally, the pre-aging step may be performed before the solutionizing step or after the solutionizing step. The pre-aging step may include heating the aluminum alloy product of final specifications to a pre-aging temperature of 50°C to 300°C (e.g., 75°C to 250°C, 100°C to 300°C, 100°C to 275°C, or 100°C to 250°C). For example, the pre-aging step may include heating the final gauge aluminum alloy product to the following temperatures: 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 166°C, 170°C, 171°C, 172°C, 173°C, 174°C, 175°C, 176°C, 177°C, 178°C, 179°C, 180°C, 181°C, 182°C, 183°C, 184°C, 185°C, 186°C, 187°C, 188°C, 189°C, 190°C, 191°C, 192°C, 193°C The final specification aluminum alloy product can be maintained at the pre-aging temperature for a period of up to 72 hours (e.g., from 1 hour to 72 hours). For example, the final specification aluminum alloy product may be maintained for 72 hours or less, 60 hours or less, 48 ​​hours or less, 36 hours or less, 24 hours or less, 12 hours or less, 6 hours or less, 5 hours or less, 4 hours or less, 3 hours or less, 2 hours or less, 1 hour or less, or any time therebetween.

[0110] aging

[0111] After the solution treatment, quenching and / or pre-aging steps, one or more aging steps may be performed. Aging may include one or more of natural aging, artificial aging, paint baking and post-forming heat treatment.

[0112] Optionally, aging may include a natural aging step. Natural aging may include holding the final aluminum alloy product at room temperature for a period of time. For example, the final aluminum alloy product may be held at room temperature for up to 12 weeks (e.g., 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, or 12 weeks).

[0113] The aluminum alloy products prepared according to the methods described herein may be delivered after optional pre-aging and natural aging. The aluminum alloy products may achieve high yield strength after processing by the end user, such as by deformation (e.g., stamping, pressing, forming, or any suitable deformation process) and / or by aging or heat treatment (e.g., coating and varnishing, artificial aging, post-forming heat treatment, or any suitable end-user heat treatment). Optionally, after the optional pre-aging and / or natural aging steps, the aluminum alloy products described herein may also undergo, for example, a forming process, a coating process, an artificial aging step, and / or a varnishing process.

[0114] Optionally, aging may include an artificial aging step. Artificial aging may include heating the final aluminum alloy product to an artificial aging temperature of 80°C to 250°C (e.g., 80°C to 225°C, 100°C to 225°C, 100°C to 225°C, 110°C to 220°C, 115°C to 210°C, or 120°C to 210°C, 125°C to 225°C, 140°C to 225°C, 160°C to 225°C, 180°C to 225°C, 200°C to 225°C, and combinations of all endpoints). The artificial aging step may include maintaining the artificial aging temperature for 30 minutes to 72 hours (e.g., 1 hour, 2 hours, 4 hours, 8 hours, 10 hours, 12 hours, 15 hours, 20 hours, 24 hours, 30 hours, 48 ​​hours, 60 hours, or 72 hours, including combinations of all endpoints).

[0115] In some aspects, an optional coating procedure (e.g., spray painting, electrophoretic coating, or zinc phosphating, etc.) can be performed. After coating, the aluminum alloy product of the final specification can be further heat treated, including baking paint, post-forming heat treatment, any suitable OEM heat treatment process, or any combination thereof. Baking paint can further strengthen the aluminum alloy product, thereby providing a high-strength aluminum alloy product with an optional complex formed shape. In some cases, the baking paint procedure can include heating the aluminum alloy product to a baking paint temperature of 75°C to 250°C, and maintaining the aluminum alloy product at the baking paint temperature for up to 3 hours (e.g., 15 minutes to 2 hours, 15 minutes to 45 minutes, or 30 minutes to 1 hour). In some aspects, at least one baking paint step can be performed at a temperature of 75 to 250°C for 15 minutes to 3 hours, at a temperature of 100 to 200°C for 15 minutes to 2 hours, or at a temperature of 150 to 180°C for 15 minutes to 45 minutes.

[0116] In some further cases, a post-forming heat treatment may be performed. The post-forming heat treatment procedure may include heating the aluminum alloy product of the final specification to a post-forming heat treatment temperature of 100°C to 250°C and maintaining the temperature for 1 hour to 24 hours (e.g., 2 hours to 12 hours). In some embodiments, the method for forming an aluminum alloy as described herein may include at least one paint treatment. In some embodiments, the method for manufacturing the aluminum alloy as described herein may include at least 2 paint treatments. The method for manufacturing an aluminum alloy as described herein may include 1 to 5 paint treatments. For example, the method for manufacturing an aluminum alloy as described herein may include 1 paint treatment, 2 paint treatments, 3 paint treatments, 4 paint treatments, 5 paint treatments, or more than 5 paint treatments.

[0117] Alloy product characteristics

[0118] The aluminum alloy products described above can have high strength and formability characteristics before and after aging. In some aspects, the aluminum alloy products are formable at temperatures below room temperature (e.g., from 0 to 15° C.). In some aspects, the aluminum alloy products are formable at ambient (room temperature) and at temperatures up to 40° C.

[0119] The aluminum alloy product may have a service strength (yield strength put into service after final heat treatment (including natural and artificial aging)) of at least 390 MPa (e.g., at least 395 MPa, at least 400 MPa, at least 405 MPa, at least 410 MPa, at least 415 MPa, at least 420 MPa, at least 425 MPa, at least 430 MPa, at least 435 MPa, at least 440 MPa, at least 445 MPa, at least 450 MPa, at least 455 MPa, at least 460 MPa, at least 465 MPa, at least 470 MPa, at least 475 MPa, and up to 500 MPa) in the T4 temper (e.g., after at least two paint bake cycles).

[0120] In some cases, the elongation and yield strength of the aluminum alloy product after aging are increased compared to the elongation and yield strength achieved by the aluminum alloy product before aging. The increase in elongation can be at least 1% (e.g., from 1.5% to 5% or from 2% to 3%). For example, the increase in elongation can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or greater than 5%.

[0121] The increase in yield strength can be at least 15 MPa (e.g., from 15 MPa to 150 MPa). For example, the increase in yield strength can be 15 MPa, 16 MPa, 17 MPa, 18 MPa, 19 MPa, 20 MPa, 21 MPa, 22 MPa, 23 MPa, 24 MPa, 25 MPa, 26 MPa, 27 MPa, 28 MPa, 29 MPa, 30 MPa, 31 MPa, 32 MPa, 33 MPa, 34 MPa, 35 MPa, 36 MPa, 37 MPa, 38 MPa, 39 MPa, 40 MPa, 41 MPa, 42 MPa, 43 MPa, 44 MPa, 45 MPa, 46 MPa, 47 MPa, 48 MPa, 49 MPa. , 50MPa, 51MPa, 52MPa, 53MPa, 54MPa, 55MPa, 56MPa, 57MPa, 58MPa, 59MPa, 60MPa, 61MPa, 62MPa, 63MPa, 64MPa, 65MPa, 66MPa, 67MPa, 68 MPa, 69MPa, 70MPa, 71MPa, 72MPa, 73MPa, 74MPa, 75MPa, 76MPa, 77MPa, 78MPa, 79MPa, 80MPa, 81MPa, 82MPa, 83MPa, 84MPa, 85MPa, 86MPa , 87MPa, 88MPa, 89MPa, 90MPa, 91MPa, 92MPa, 93MPa, 94MPa, 95MPa, 96MPa, 97MPa, 98MPa, 99MPa, 100MPa, 101MPa, 102MPa, 103MPa, 104M Pa, 105MPa, 106MPa, 107MPa, 108MPa, 109MPa, 110MPa, 111MPa, 112MPa, 113MPa, 114MPa, 115MPa, 116MPa, 117MPa, 118MPa, 119MPa, 120 MPa, 121 MPa, 122 MPa, 123 MPa, 124 MPa, 125 MPa, 126 MPa, 127 MPa, 128 MPa, 129 MPa, 130 MPa, 131 MPa, 132 MPa, 133 MPa, 134 MPa, 135 MPa, 136 MPa, 137 MPa, 138 MPa, 139 MPa, 140 MPa, 141 MPa, 142 MPa, 143 MPa, 144 MPa, 145 MPa, 146 MPa, 147 MPa, 148 MPa, 149 MPa, 150 MPa or more.

[0122] In some examples, the aluminum alloy product can have a yield strength greater than 350 MPa after processing according to the methods described herein. For example, the aluminum alloy product can have a yield strength of 360 MPa or greater, 365 MPa or greater, 370 MPa or greater, 375 MPa or greater, 380 MPa or greater, 385 MPa or greater, 390 MPa or greater, 395 MPa or greater, 400 MPa or greater, 405 MPa or greater, 410 MPa or greater, 415 MPa or greater, 420 MPa or greater, 425 MPa or greater, 430 MPa or greater, 435 MPa or greater, 440 MPa or greater, 445 MPa or greater, 450 MPa or greater, 455 MPa or greater, 460 MPa or greater, 470 MPa or greater, 480 MPa or greater, 490 MPa or greater, 500 MPa or greater, 515 MPa or greater, 520 MPa or greater, 530 MPa or greater, 540 MPa or greater, 550 MPa or greater, 560 MPa or greater, 570 MPa or greater, 580 MPa or greater, 590 MPa or greater, 600 MPa or greater, 610 MPa or greater, 615 MPa or greater, 620 MPa or greater, 630 MPa or greater, 640 MPa or greater, 650 MPa or greater, 660 MPa or greater, 670 MPa or greater, 680 MPa or greater, 690 MPa or greater, 700 MPa or greater, 710 MPa or greater, 720 MPa or greater, 720 MPa or greater, 730 MPa or greater, 735 MPa or greater, 740 MPa or greater, a or greater, 465 MPa or greater, 470 MPa or greater or 475 MPa or greater, 480 MPa or greater, 485 MPa or greater, 490 MPa or greater, 495 MPa or greater, 500 MPa or greater, 505 MPa or greater, 510 MPa or greater, 515 MPa or greater, 520 MPa or greater, 525 MPa or greater, 530 MPa or greater, 535 MPa or greater, 540 MPa or greater, 545 MPa or greater, 550 MPa or greater, 555 MPa or greater, 560 MPa or greater, 565 MPa or greater, 570 MPa or greater, or 575 MPa or greater.

[0123] The increase in ultimate tensile strength may be at least 5 MPa (eg, from 15 MPa to 50 MPa). For example, the increase in yield strength can be 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, 16 MPa, 17 MPa, 18 MPa, 19 MPa, 20 MPa, 21 MPa, 22 MPa, 23 MPa, 24 MPa, 25 MPa, 26 MPa, 27 MPa, 28 MPa, 29 MPa, 30 MPa, 31 MPa, 32 MPa, 33 MPa, 34 MPa, 35 MPa, 36 MPa, 37 MPa, 38 MPa, 39 MPa, 40 MPa, 41 MPa, 42 MPa, 43 MPa, 44 MPa, 45 MPa, 46 MPa, 47 MPa, 48 MPa, 49 MPa, 50 MPa or more.

[0124] In some examples, the aluminum alloy product, after processing according to the methods described herein, can have an ultimate tensile strength greater than 350 MPa. For example, the aluminum alloy product, after processing according to the methods described herein, can have a yield strength of 360 MPa or greater, 365 MPa or greater, 370 MPa or greater, 375 MPa or greater, 380 MPa or greater, 385 MPa or greater, 390 MPa or greater, 395 MPa or greater, 400 MPa or greater, 405 MPa or greater, 410 MPa or greater, 415 MPa or greater, 420 MPa or greater, 425 MPa or greater, 430 MPa or greater, 435 MPa or greater, 440 MPa or greater, 445 MPa or greater, 450 MPa or greater, 455 MPa or greater, 460 MPa or greater, 470 MPa or greater, 480 MPa or greater, 490 MPa or greater, 500 MPa or greater, 510 MPa or greater, 520 MPa or greater, 530 MPa or greater, 540 MPa or greater, 550 MPa or greater, 560 MPa or greater, 570 MPa or greater, 580 MPa or greater, 590 MPa or greater, 600 MPa or greater, 610 MPa or greater, 620 MPa or greater, 630 MPa or greater, 640 MPa or greater, 650 MPa or greater, 660 MPa or greater, 670 MPa or greater, 680 MPa or greater, 690 MPa or greater, 700 MPa or greater, 710 MPa or greater, 720 MPa or greater, 730 MPa or greater, 740 MPa or greater, 750 MPa or greater, 760 a or greater, 465 MPa or greater, 470 MPa or greater or 475 MPa or greater, 480 MPa or greater, 485 MPa or greater, 490 MPa or greater, 495 MPa or greater, 500 MPa or greater, 505 MPa or greater, 510 MPa or greater, 515 MPa or greater, 520 MPa or greater, 525 MPa or greater, 530 MPa or greater, 535 MPa or greater, 540 MPa or greater, 545 MPa or greater, 550 MPa or greater, 555 MPa or greater, 560 MPa or greater, 565 MPa or greater, 570 MPa or greater, or 575 MPa or greater.

[0125] How to use

[0126] The alloy products and methods described herein can be used for automotive and / or transportation applications, including motor vehicles, aircraft and railway applications, or any other intended application. In some instances, the products and methods can be used to prepare motor vehicle body parts products, such as bumpers, side beams, roof beams, cross beams, pillar reinforcements (such as A-pillars, B-pillars and C-pillars), inner panels, outer panels, side panels, inner hoods, outer hoods or trunk lid panels. The aluminum alloy products and methods described herein can also be used for aircraft or railway vehicle applications, such as preparing exterior and interior panels.

[0127] The products and methods described herein can also be used in electronic applications, such as for preparing external and internal packaging. For example, the products and methods described herein can also be used to prepare housings for electronic devices, including mobile phones and tablet computers. In some examples, the products can be used to prepare housings for mobile phones (e.g., smartphones) and tablet computer chassis.

[0128] In certain aspects, the products and methods can be used to prepare aerospace fuselage component products. For example, the disclosed products and methods can be used to prepare aircraft fuselage components, such as skin alloys.

[0129] The products and methods may be used for any other intended purpose.

[0130] Example

[0131] Example 1: Mechanical properties of highly formable and high-strength aluminum alloys

[0132] Using the methods described herein and further described below, a cast aluminum alloy product (referred to herein as "Example 1") was prepared from an aluminum alloy composition comprising 0.11 wt.% Si, 0.21 wt.%, 0.20 wt.%, 0.10 wt.%, 3.29 wt.%, 0.0 wt.% Cr, 4.34 wt.% Zn, 0.02 wt.% Ti, 0.1 wt.% Zr, up to 0.15 wt.% impurities, and the balance being aluminum. Mechanical testing was performed on the samples of Example 1. In some cases, an additional paint bake step was employed in which the aluminum alloy product was heated to a temperature of 180°C and held at that temperature for 30 minutes. In some cases, additional tempering was employed on the aluminum alloy to compare the mechanical properties of the aluminum alloy products under different methods of producing the aluminum alloy products. In some cases, some steps were omitted from the production method, while some steps were optional to further test the production method and the corresponding mechanical properties of the alloy.

[0133] Figures 1A-1C Provided are graphs of yield strength, ultimate tensile strength, and total elongation during natural aging for aluminum alloy compositions described herein using water quenching (WQ) at 2.0 mm gauge (1A), air quenching (AQ) at 2.4 mm gauge (1B), and WQ at 2.4 mm gauge (1C), according to some embodiments described herein. Example 1 aluminum alloy was prepared using the methods described herein and subjected to T4 tempering and pre-aging (denoted as PX in some cases) to investigate the effects of natural aging on the alloy. Figure 1A The results show that the aluminum alloy of Example 1 prepared according to the described method, after further rolling to 2.0 mm and water quenching (WQ), had an initial yield stress of 292 MPa, which increased to 312 MPa after 5.5 months of natural aging. The ultimate tensile strength was initially 438 MPa, which increased to 458 MPa after 5.5 months. In addition, the total elongation increased from 18.9% to 22.4% within 5.5 months. Figure 1B The results show that the aluminum alloy of Example 1 prepared by the method described herein was further rolled to 2.4 mm (AQ) with an initial yield stress of 301 MPa, which increased to 317 MPa after 5.5 months. Over the same 5.5 months, the ultimate tensile strength increased from 434 MPa to 454 MPa, while the total elongation increased from 18.2% to 19.6%. Figure 1CThe results show that the aluminum alloy of Example 1 prepared by the method described herein, when further rolled to 2.4 mm (WQ), had an initial yield stress of 308 MPa, which increased to 323 MPa after 5.5 months. Over the same 5.5 months, the ultimate tensile strength increased from 440 MPa to 455 MPa, while the total elongation increased from 18.2% to 20.9%. These results demonstrate that the aluminum alloy described herein and produced by the method described above improves in mechanical properties with natural aging.

[0134] Figures 2A-2B A graph is provided of the yield strength (YS), ultimate tensile strength (UTS), and total elongation (TE) of aluminum alloy compositions after multiple paint bake cycles and T4 temper (2A) or T6 temper (2B) conditions according to some embodiments described herein. Example 1 The aluminum alloy had an initial average yield strength (YS) of 295 MPa, an ultimate tensile strength of 444 MPa, and a total elongation of 20.1% ( TE) after 2 months of natural aging. Figure 2A ). After 1 paint bake cycle, the yield strength increased to 369 MPa, the ultimate tensile strength (UTS) decreased to 434 MPa, and the total elongation (TE) decreased to 12.8%. With the inclusion of additional paint bake cycles, the yield strength further increased to 388 MPa, the ultimate tensile strength increased to 449 MPa, and the total elongation further decreased to 11.8%. After another paint bake cycle, the yield strength was 389 MPa, the ultimate tensile strength was 449 MPa, and the total elongation was 12.9%. Example 1 The aluminum alloy was processed the same as above and then subjected to T6 tempering. The alloy had improved mechanical properties, including a yield strength of 441 MPa, a UTS of 495 MPa, and a TE of 14.0% ( Figure 2B After a single paint bake, the aluminum alloy exhibited a YS of 406 MPa, a UTS of 464 MPa, and a TE of 15.2%. After a second paint bake, these three properties decreased to a YS of 398 MPa, a UTS of 458 MPa, and a TE of 12.5%. After a third paint bake cycle, the resulting aluminum alloy exhibited a UTS of 452 MPa, a YS of 392 MPa, and a TE of 13.0%. These results suggest that the mechanical properties of the aluminum alloy in the T4 temper may improve with additional paint bake cycles, while those in the T6 temper may decline with additional paint bake cycles.

[0135] Figure 3A winding bend graph is provided for an aluminum alloy described herein, for example, after T4 and T6 tempering, according to some embodiments described herein, compared to Comparative Example 1. The Example 1 aluminum alloy undergoes a longitudinal winding bend of 0.81, a transverse winding bend of 1.02 r / t, and a d-direction winding bend of 0.81 r / t in the T4 temper. The same aluminum alloy in the T6 temper has a longitudinal r / t of 0.89, a transverse r / t of 1.15, and a d-direction r / t of 0.89. Comparative Example 1 has an r / t of 0.4 or less in each of the three directions in the T4 temper, while Comparative Example 1 has an r / t of 0.7 or less in each of the three directions in the T82 temper. The aluminum alloy of Example 1 has a higher winding bend rating than currently available alloys in similar tempering conditions.

[0136] Figures 4A-4B Provided are photos (4A) and die depths (4B) of various rivet and die designs in the aluminum alloys described herein according to some embodiments described herein. Example 1 An aluminum alloy was rolled into 2.0 mm thick plates in the T4 temper. Two rivet lengths and three die designs of varying depths were tested. From the die photos ( Figure 4A ) It can be seen that the 5x6H4 / DG10-180 exhibited cracking and decreased performance compared to the 5x6H4 / DC10-150 mold. In addition, the 5x5H4 / DP10-200 exhibited cracking during the run. The flat mold showed no cracking at a depth of 150mm, but began to exhibit severe cracking at a depth of 160mm ( Figure 4B The 5x5H4 convex head mold did not show severe cracking until its maximum depth reached 175 mm.

[0137] Figure 5 Photographs of 2.0 mm WQ, 2.4 mm AC, and 2.4 mm WQ aluminum alloys at 30 kA and 34 kA according to some embodiments described herein are provided. Spot welds were formed on 2.0 mm WQ, 2.4 mm WQ, and 2.4 mm AC samples of the aluminum alloy of Example 1. The results show that no visible cracking or pinholes were observed in any of the spot welds at any current. The 2.0 mm WQ exhibited spatter at 30 kA to 33 kA, while the 2.4 mm AC wire also exhibited spatter in the 32 kA to 34 kA range. The 2.4 mm WQ exhibited no spatter during testing, and the weld dimensions were good.

[0138] In order to further test the aluminum alloy of Example 1, the flat ( Figure 6A and 6B ) and round ( Figure 7A and 7B ) was tested for formability. Flat ( Figure 6A and 6B) The results of the formability tests show that natural aging after 150 hours has no effect on the forming depth of the aluminum alloy of Example 1 when naturally aged, pre-aged, and not T6 tempered. The forming depth of Comparative Example 1 after 24 hours of natural aging under similar conditions was reduced from 55 mm to less than 30 mm. In addition, under pre-aging, the forming depth of each of the Comparative Example 1 tests was reduced, while Example 1 did not experience any cracking under the test conditions. Round bottom test ( Figure 7A and 7B ) with the exception of pre-aging and T6 tempering. Under these conditions, the forming depth was significantly reduced to below 33 mm. The Example 1 aluminum alloy was able to fully draw cup-shaped specimens under natural aging, pre-aging, and T6 tempering, while comparable alloy compositions exhibited a sharp drop in formability after one day of natural aging.

[0139] Figure 8 A graph of minor strain versus major strain is provided for the aluminum alloys of Comparative Examples 1-3 and Example 1, according to some embodiments described herein. The Example 1 alloy has a lower forming limit curve than the aluminum alloys of Comparative Examples 1-3. Compared to the Comparative Examples 1-3 shown in Table 5, the Example 1 alloy has a lower forming limit curve but nearly doubles the strength.

[0140] Table 5

[0141]

[0142] In order to test the practical application of the alloy composition compared with Comparative Examples 1-3, forming tests were carried out ( Figures 9A-9B ). The comparative example alloy did not crack when drawn to a depth of 90 mm, while Example 1 cracked when drawn to a depth of 75 mm. Example 1 also experienced a stress greater than 600 MPa at a strain of 0.40, while the comparative alloy experienced a stress less than 500 MPa at the same strain. In order to further evaluate the forming of the aluminum alloy, a rebound test ( Figure 10 ). The stronger material (i.e., the Example 1 alloy) exhibited higher springback, while the thinner gauge material showed a similar trend. Although not shown here, varying the forming speed did not produce any significant effect.

[0143] 7xxx series aluminum alloys are known to be susceptible to intergranular corrosion. Without being bound by any particular theory, it is believed that the lack of Zr and the low levels of Cu and Mg may cause the alloys to be susceptible to IGC. Therefore, the aluminum alloys described herein have Zr added and Cu and Mg increased to improve the IGC of the alloys, such as Figures 11A-11CAs shown. For example, under T4 tempering and paint treatment, the IGC depth of the 2.0mm and WQ alloys was 23mm after 24 hours, which decreased to 16mm after 48 hours. After T6 tempering, the IGC depth was 24mm after 24 hours, which decreased to 19mm after 48 hours. Compared with the T4 tempered alloy, the IGC of the alloy after T6 tempering and paint treatment has increased IGC. In addition, the IGC depth of the 2.4mm WQ and AQ alloy samples increased compared to the 2.0mm WQ sample. For example, the IGC of the 2.4mm WQ sample under T6 tempering was 22mm at 24 hours, which increased to 56mm after 48 hours. Interestingly, the IGC depth of the 2.4mm AQ sample under T6 tempering decreased between the 24 and 48 hour time periods. Microscope images ( Figure 11B and Figure 11C ) showed that the T4 sample, which had been treated with a different paint finish, showed pitting. The results showed that no IGC was observed after 48 hours, and the maximum value was less than 60mm.

[0144] Figure 12 Microscopic images of exfoliation corrosion testing of aluminum alloys according to some embodiments described herein are provided. A 2.4 mm WQ alloy was imaged at three separate locations after a T4 temper and an additional paint bake treatment to test the alloy for exfoliation corrosion. The results in Table 6 further demonstrate that the alloy exhibited moderate and shallow corrosion ratings at both 24 and 48 hours of exfoliation treatment. Furthermore, the results indicate that the T4 temper with paint bake treatment exhibited better overall performance compared to the T6 and T6 with paint bake treatments. The results are summarized in Table 6 below.

[0145] Table 6

[0146]

[0147] Additional stress corrosion cracking (SCC) testing was performed to evaluate the aluminum alloy compositions described herein and additional steps in the method of making the aluminum alloys. The SCC test performed was SCC-ASTM-G47 as an alternative to the 40-day immersion test. Figures 13A-13C. The results show that the Example 1 alloy has relatively similar maximum tensile stresses under pre-exposed, stress-free and stressed conditions. For example, T4+PB has about 440MPa under the three conditions, while the T6+PB sample has a slight improvement. In addition, under the three test conditions, the 2.4mm AQ sample alloy under T4+PB has about 435MPa, while T6+PB has about 450MPa. The maximum axial strain shows that the results of the three test conditions are similar, showing relatively similar results, among which the maximum axial strains of 2.4mm WQ and 2.4mm AQ of T4+PB are slightly higher than that of the T6+PB test group. However, the results show that no SCC failure occurred in all stressed samples, and the residual strength in each case exceeded 80%.

[0148] Took additional steps to use STEM ( Figure 14 ) The microstructure of the aluminum alloy of T4 2mm WQ, 2.4mm WQ and 2.4mm AQ samples was evaluated. The results showed that no difference was observed in the precipitate formation between the 2.0mm and 2.4mm specifications. There was no evidence of grain boundary precipitates at lower quenching rates (due to low solute content, the quench sensitivity was lower). Due to the low solute content in the microstructure, the Example 1 alloy may be less sensitive to quenching and does not show much change in the tensile bending behavior of WQ compared to FAC. The alloy of Example 1 was stabilized by pre-aging treatment, showed potential for cold forming and had improved yield strength after direct paint baking simulation, and retained improved mechanical properties after multiple paint baking treatments and T6 tempering.

[0149] Implementation Plan

[0150] Embodiment 1: A method for producing an aluminum alloy product, the method comprising casting a molten aluminum alloy to form an ingot or slab, hot rolling the ingot or slab to produce a plate, solution heat treating the plate to form a solutionized plate, pre-aging the solutionized plate to form a pre-aged plate, and subjecting the pre-aged plate to at least one paint bake heat treatment to form an aluminum alloy product, wherein the aluminum alloy contains Mg and Cu, and the aluminum alloy product has a service strength of at least 370 MPa.

[0151] Embodiment 2: A method as described in Embodiment 1, wherein the aluminum alloy comprises: up to 0.25 wt.% Si, up to 0.4 wt.% Fe, up to 0.4 wt.% Cu, up to 0.3 wt.% Mn, up to 3.6 wt.% Mg, up to 0.1 wt.% Cr, up to 4.5 wt.% Zn, up to 0.1 wt.% Ti, up to 0.2 wt.% Zr, up to 0.15 wt.% impurities, and Al, wherein the total amount of Cu and Mg present is less than 3.6 wt.%.

[0152] Embodiment 3: A method as described in Embodiment 1, wherein the aluminum alloy comprises: 0 to 0.25 wt.% Si, 0 to 0.4 wt.% Fe, 0 to 0.4 wt.% Cu, 0.1 to 0.3 wt.% Mn, 2.3 to 3.6 wt.% Mg, 0 to 0.1 wt.% Cr, 3.5 to 4.5 wt.% Zn, up to 0.1 wt.% Ti, up to 0.2 wt.% Zr, up to 0.15 wt.% impurities, and Al, wherein the total amount of Cu and Mg present is less than 3.6 wt.%.

[0153] Embodiment 4: A method as described in Embodiment 1, wherein the aluminum alloy comprises: 0 to 0.25 wt.% Si, 0 to 0.4 wt.% Fe, 0.11 to 0.4 wt.% Cu, 0.1 to 0.3 wt.% Mn, 2.3 to 3.6 wt.% Mg, 0 to 0.1 wt.% Cr, 3.5 to 4.5 wt.% Zn, up to 0.1 wt.% Ti, up to 0.2 wt.% Zr, up to 0.15 wt.% impurities, and Al, wherein the total amount of Cu and Mg present is less than 3.6 wt.%.

[0154] Embodiment 5: A method as described in Embodiment 1, wherein the aluminum alloy comprises: 0 to 0.25 wt.% Si, 0 to 0.4 wt.% Fe, 0 to 0.4 wt.% Cu, 0.1 to 0.3 wt.% Mn, 2.3 to 3.6 wt.% Mg, 0 to 0.1 wt.% Cr, 3.5 to 4.5 wt.% Zn, up to 0.1 wt.% Ti, 0.05 to 0.2 wt.% Zr, up to 0.15 wt.% impurities, and Al, wherein the total amount of Cu and Mg present is less than 3.6 wt.%.

[0155] Embodiment 6: The method of any of the preceding embodiments, further comprising homogenizing the ingot or slab prior to the hot rolling.

[0156] Embodiment 7: The method according to any one of the preceding embodiments, wherein the at least one paint bake heat treatment is performed at a temperature of 75 to 250° C. for a period of 15 minutes to 3 hours.

[0157] Embodiment 8: The method according to any one of the preceding embodiments, wherein the at least one paint bake heat treatment is performed at a temperature of 100 to 200° C. for a period of 15 minutes to 2 hours.

[0158] Embodiment 9: The method according to any one of the preceding embodiments, wherein the at least one paint bake heat treatment is performed at a temperature of 150 to 180° C. for a period of 15 to 45 minutes.

[0159] Embodiment 10: The method of any of the preceding embodiments, wherein the aluminum alloy product is formable at room temperature.

[0160] Embodiment 11: The method of any of the preceding embodiments, wherein the aluminum alloy product is formable at a temperature below room temperature.

[0161] Embodiment 12: The method of any of the preceding embodiments, wherein the aluminum alloy product has a service strength of at least 390 MPa in the T4 temper after at least two paint bake cycles.

[0162] Embodiment 13: The method of any of the preceding embodiments, wherein the aluminum alloy product has a service strength of at least 400 MPa in the T6 temper after at least two paint bake cycles.

[0163] Embodiment 14: The method of any of the preceding embodiments, wherein the pre-aging is performed at a temperature of 50 to 200°C for a period of 1 to 24 hours.

[0164] Embodiment 15: The method of any of the preceding embodiments, wherein the sheet is cold rolled prior to the solution heat treatment.

[0165] Embodiment 16: The method of Embodiment 6, wherein the homogenizing comprises heating the ingot or slab to a temperature of at least 450°C and maintaining the ingot or slab at a temperature of at least 450°C for a period of at least 90 minutes.

[0166] Embodiment 17: The method of any of the preceding embodiments, wherein the ingot or slab is hot rolled to a thickness of less than 7 mm and then cold rolled to a thickness of less than 4 mm.

[0167] Embodiment 18: The method of any of the preceding embodiments, further comprising artificially aging the pre-aged sheet prior to at least one paint bake treatment.

[0168] Embodiment 19: The method of Embodiment 18, wherein the pre-aged sheet is artificially aged at a temperature of 100 to 250°C for a period of 1 to 72 hours.

[0169] Embodiment 20: An aluminum alloy product prepared according to the method of any one of the preceding embodiments.

[0170] Embodiment 21: The aluminum alloy product of Embodiment 20, wherein the aluminum alloy product has an ultimate tensile strength of at least 420 MPa after 40 days of immersion testing according to SCC-ASTM G47.

[0171] All of the above patents, publications, and abstracts are incorporated herein by reference in their entirety. Various embodiments have been described to achieve the various objectives of the present invention. It should be understood that these embodiments are merely illustrative of the principles of the present invention. Various modifications and alterations will be apparent to those skilled in the art without departing from the spirit and scope of the present invention as defined in the following claims.

Claims

1. A method for producing an aluminum alloy product, the method comprising: casting the molten aluminum alloy into ingots or slabs; hot rolling the ingot or the slab to produce a plate; performing a solution heat treatment on the plate to form a solution plate; pre-aging the solutionized plate to form a pre-aged plate; and performing at least one baking paint heat treatment on the pre-aged plate to form the aluminum alloy product; wherein the aluminum alloy comprises Mg and Cu; and The aluminum alloy product has a service strength of at least 370 MPa.

2. The method of claim 1, wherein the aluminum alloy comprises: Up to 0.25wt.% Si, Up to 0.4wt.% Fe, Up to 0.4wt.% Cu, Up to 0.3wt.% Mn, Up to 3.6wt.%Mg, Up to 0.1wt.% Cr, Up to 4.5wt.% Zn, Up to 0.1wt.% Ti, Up to 0.2wt.% Zr, Up to 0.15 wt.% impurities, and Al， The total amount of Cu and Mg present is less than 3.6 wt.%.

3. The method of any one of the preceding claims, wherein the aluminum alloy comprises: 0 to 0.25 wt. % Si, 0 to 0.4wt.% Fe, 0 to 0.4wt.% Cu, 0.1 to 0.3 wt.% Mn, 2.3 to 3.6 wt.% Mg, 0 to 0.1wt.% Cr, 3.5 to 4.5 wt.% Zn, Up to 0.1wt.% Ti, Up to 0.2wt.% Zr, Up to 0.15 wt.% impurities, and Al， The total amount of Cu and Mg present is less than 3.6 wt.%.

4. The method of any one of the preceding claims, wherein the aluminum alloy comprises: 0 to 0.25 wt. % Si, 0 to 0.4wt.% Fe, 0.11 to 0.4 wt.% Cu, 0.1 to 0.3 wt.% Mn, 2.3 to 3.6 wt.% Mg, 0 to 0.1wt.% Cr, 3.5 to 4.5 wt.% Zn, Up to 0.1wt.% Ti, Up to 0.2wt.% Zr, Up to 0.15 wt.% impurities, and Al， The total amount of Cu and Mg present is less than 3.6 wt.%.

5. The method of any one of the preceding claims, wherein the aluminum alloy comprises: 0 to 0.25 wt. % Si, 0 to 0.4wt.% Fe, 0 to 0.4wt.% Cu, 0.1 to 0.3 wt.% Mn, 2.3 to 3.6 wt.% Mg, 0 to 0.1wt.% Cr, 3.5 to 4.5 wt.% Zn, Up to 0.1wt.% Ti, 0.05 to 0.2 wt.% Zr, Up to 0.15 wt.% impurities, and Al， The total amount of Cu and Mg present is less than 3.6 wt.%.

6. The method of any one of the preceding claims, wherein the method further comprises homogenizing the ingot or slab prior to the hot rolling.

7. The method according to any one of the preceding claims, wherein the at least one paint bake heat treatment is carried out at a temperature of 75 to 250°C for a period of 15 minutes to 3 hours.

8. The method according to any one of the preceding claims, wherein the at least one paint bake heat treatment is carried out at a temperature of 100 to 200°C for a period of 15 minutes to 2 hours.

9. The method according to any one of the preceding claims, wherein the at least one paint bake heat treatment is carried out at a temperature of 150 to 180°C for a period of 15 to 45 minutes.

10. A method as claimed in any preceding claim, wherein the aluminium alloy product is formable at room temperature.

11. A method as claimed in any one of the preceding claims, wherein the aluminium alloy product is formable at a temperature below room temperature.

12. The method of any one of the preceding claims, wherein the aluminium alloy product has a service strength of at least 390 MPa in the T4 temper after at least two paint bake cycles.

13. A method as claimed in any one of the preceding claims, wherein the aluminium alloy product has an in-service strength of at least 400 MPa in the T6 temper after at least two paint bake cycles.

14. The method of any one of the preceding claims, wherein the pre-aging is carried out at a temperature of 50 to 225°C for a period of 0.5 to 24 hours.

15. A method as claimed in any one of the preceding claims wherein the sheet is cold rolled prior to the solution heat treatment.

16. The method of claim 6, wherein the homogenizing comprises heating the ingot or slab to a temperature of at least 450°C and maintaining the ingot or slab at a temperature of at least 450°C for a period of at least 90 minutes.

17. A method as claimed in any preceding claim wherein the ingot or slab is hot rolled to a thickness of less than 10 mm and then cold rolled to a thickness of less than 4 mm.

18. The method of any one of the preceding claims, further comprising artificially aging the pre-aged sheet prior to the at least one paint bake treatment.

19. The method of claim 18, wherein the pre-aged sheet is artificially aged at a temperature of 100 to 250°C for a period of 0.5 to 72 hours.

20. An aluminium alloy product produced according to the method of any preceding claim.

21. The aluminum alloy product of claim 20, wherein the aluminum alloy product has an ultimate tensile strength of at least 420 MPa after 40 days of immersion testing according to SCC-ASTM G47.

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