ES2933801T3 - Corrosion resistant aluminum alloy of high mechanical strength and method for its manufacture - Google Patents

Abstract

High strength aluminum alloys and methods for manufacturing and processing such alloys are described. The aluminum alloys described herein exhibit improved strength, deformability, and corrosion resistance properties. In addition, aluminum alloys can be prepared from recycled materials. Aluminum alloy products prepared from the alloys described herein include strength-enhancing precipitates such as MgZn2/Mg(Zn,Cu)2, Mg2Si, and Al4Mg8Si7Cu2. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Corrosion resistant aluminum alloy of high mechanical strength and method for its manufacture

Field

The present disclosure relates to aluminum alloys and methods for manufacturing and processing them. The present disclosure additionally refers to aluminum alloys that exhibit high mechanical strength, formability, and corrosion resistance.

Background

Recyclable aluminum alloys with high mechanical strength are desirable to improve product performance in many applications, including transportation applications (including, without limitation, eg, trucks, trailers, trains, and ships), electronic applications, and car applications. For example, a high-strength aluminum alloy in trucks or trailers would be lighter than conventional steel alloys, providing significant emission reductions needed to meet new, stricter government emissions regulations. Such alloys must have high mechanical strength, high formability and corrosion resistance. Additionally, it is desirable that such alloys be formed from recycled content.

However, identification of the processing conditions and alloy compositions that will provide such an alloy, particularly with recycled content, have proven challenging. Alloy formation from recycled content can lead to higher zinc (Zn) and copper (Cu) content. Alloys with higher Zn content traditionally lack mechanical strength, and Cu-containing alloys are susceptible to corrosion. Document US2015316210 A1 discloses an aluminum alloy material for high pressure applications.

Compendium

The covered embodiments of the invention are defined by the claims, not in this summary. This summary is a high level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This compendium is not intended to identify key 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 is to be understood by reference to the appropriate parts of the entire specification, any drawing and each claim.

Aluminum alloys are described herein comprising 0.25-1.3% by weight of Si, 1.0-2.5% by weight of Mg, 0.5-1.5% by weight of Cu, up to 0.2% by weight of Fe, up to 3.0% by weight of Zn, up to 0.15% by weight of Zr, up to 0.5% by weight of Mn, up to 0.15% by weight of impurities, the balance being Al, where the ratio of Mg to Si is 1.5 to 1 to 3.5 to 1. In some cases, aluminum alloys may comprise 0.55-1.1% by weight of Si, 1.25-2.25% by weight of Mg, 0.6-1.0% by weight of Cu, 0.05-0.17% by weight of Fe, 1.5-3.0% in weight of Zn, up to 0.15% by weight of impurities, the balance being Al. In some cases, aluminum alloys may comprise 0.65-1.0% by weight of Si, 1.5-2.25% by weight of Mg, 0.6-1.0% by weight of Cu, 0.12-0.17% by weight of Fe, 2.0-3.0% by weight of Zn, up to 0.15% in weight of impurities, the remainder being Al.

The ratio of Mg to Si (i.e., the Mg/Si ratio) is 1.5 to 1 to 3.5 to 1. For example, the Mg/Si ratio can be 2.0 to 1 to 3.0 to 1. Optionally, the ratio of Zn to the Mg/Si ratio (i.e., the Zn/(Mg/Si) ratio) is 0.75 to 1 to 1.4 to 1. For example, the ratio Zn/(Mg/Si) can be from 0.8 to 1 to 1.1 to 1. Optionally, the ratio of Cu to the ratio of Zn/(Mg/Si) (i.e., the ratio Cu/[Zn /(Mg/Si)]) is 0.7 to 1 to 1.4 to 1, For example, the ratio Cu/[Zn/(Mg/Si)] is 0.8 to 1 to 1.1 to 1.

Also described herein are aluminum alloy products comprising the aluminum alloy as described herein. The aluminum alloy product may have a yield strength of at least about 340 MPa (eg, 360 MPa to 380 MPa) in the T6 temper. The aluminum alloy products described herein are corrosion resistant and can have an average intergranular corrosion pit depth of less than 100 pm at the T6 temper. Aluminum alloy products also show excellent bendability and can have an r/t (bendability) ratio of 0.5 or less at the T4 temper.

Optionally, the aluminum alloy product comprises one or more precipitates selected from the group consisting of MgZn2/Mg(Zn,Cu)2, Mg2Si, and AUMg8Si7Cu2. The aluminum alloy product may comprise MgZn2/Mg(Zn,Cu)2 in an average amount of at least 300,000,000 particles per mm2, Mg2Si in an average amount of at least 600,000,000 particles per mm2, and/or AUMg8SÍ7Cu2 in an average amount of at least 600,000,000 particles per mm2. In some examples, the aluminum alloy product comprises MgZn2/Mg(Zn,Cu)2, Mg2Si, and AUMg8Si7Cu2. A ratio of Mg2Si to AUMg8Si7Cu2 can be from 1:1 to 1.5:1, a ratio of Mg2Si to MgZn2/Mg(Zn,Cu)2 can be from 1.5:1 to 3:1, and a ratio of AUMg8Si7Cu2 to MgZn2/Mg(Zn,Cu)2 can be from 1.5:1 to 3:1.

Additionally described herein is a method for producing an aluminum alloy. The method comprises casting an aluminum alloy as described herein to form an aluminum alloy cast, homogenizing the aluminum alloy cast, hot rolling the homogenized aluminum alloy cast to provide a final gauge aluminum alloy and performing a final gauge aluminum alloy solution heat treatment. The method may further comprise pre-aging the final gauge aluminum alloy. Optionally, the aluminum alloy is cast from a molten aluminum alloy comprising scrap metal, such as scrap metal containing 6xxx series aluminum alloy, 7xxx series aluminum alloy, or a combination of this.

Brief description of the figures

Figure 1 is a graph showing an increase in magnesium-zinc precipitates with increased magnesium content in aluminum alloys prepared in accordance with certain aspects of the present disclosure.

Figure 2 is a differential scanning calorimetry plot of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 3 is a differential scanning calorimetry plot of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 4A is a transmission electron microscope micrograph showing types of precipitates in an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 4B is a transmission electron microscope micrograph showing types of precipitates in an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 5 is a graph showing the composition of an aluminum alloy precipitate in accordance with certain aspects of the present disclosure.

Figure 6 is a series of light micrographs showing the formation of precipitates after various processing steps of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 7 is a series of light micrographs showing the formation of precipitates after various processing steps of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 8 is a series of light micrographs showing the formation of precipitates after various processing steps of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 9 is a series of light micrographs showing the particle population and grain structure of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 10 is a series of light micrographs showing the particle population and grain structure of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 11 is a graph showing the electrical conductivities of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 12 is a graph showing the electrical conductivities of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 13 is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 14A is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 14B is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of aluminum alloys. agree to certain aspects of this disclosure.

Figure 15 is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 16A is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 16B is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 17A is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 17B is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 18A is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 18B is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) of alloys. aluminum according to certain aspects of the present disclosure.

Figure 19 is a graph showing load displacement data from a 90° bend test of aluminum alloys in accordance with certain aspects of the present disclosure.

Figure 20 is a graph showing load displacement data from a 90° bend test of aluminum alloys in accordance with certain aspects of the present disclosure.

Figure 21 is a graph showing load displacement data from a 90° fold test of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 22 is a series of light micrographs showing corrosion attack on aluminum alloys in accordance with certain aspects of the present disclosure.

Figure 23 is a series of light micrographs showing corrosion attack on aluminum alloys in accordance with certain aspects of the present disclosure.

Figure 24A is a light micrograph of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 24B is a light micrograph of an aluminum alloy in accordance with certain aspects of the present disclosure.

Figure 24C is a light micrograph of an aluminum alloy in accordance with certain aspects of the present disclosure.

Detailed description

High strength aluminum alloys and manufacturing and processing methods of such alloys are described herein. The aluminum alloys described herein exhibit improved strength, deformability, and corrosion resistance properties. Additionally, aluminum alloys can be made from recycled materials. Aluminum alloy products prepared from the alloys described herein include precipitates to improve strength, such as MgZn2/Mg(Zn,Cu)2, Mg2Si, and AUMg8Si7Cu2.

Definitions and Descriptions:

The terms "invention", "the invention", "this invention" and "the present invention" as used herein are intended to refer broadly to the entire subject matter of this patent application and the claims below.

In this description, reference is made to alloys that are identified by aluminum industry designations, such as "series" or "6xxx". To understand the most commonly used numerical designation system for naming and identifying aluminum and its alloys, see "International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys" or "Registration Record of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot", both published by The Aluminum Association.

As used herein, the meaning of “a”, “an”, “an” or “the” include both singular and plural references unless the context clearly dictates otherwise.

As used herein, a veneer generally has a thickness greater than about 6mm. For example, a sheet can refer to an aluminum product that has a thickness greater than 6mm, greater than 10mm, greater than 15mm, greater than 20mm, greater than 25mm, greater than 30mm, greater than 35mm , greater than 40 mm, greater than 45 mm, greater than 50 mm, or greater than 100 mm.

As used herein, the term "slab" indicates an alloy thickness in the range of about 5mm to about 50mm. For example, a slab may have a thickness of 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm or 50mm.

As used herein, a "shate" plate (also called a sheet metal) generally has a thickness of from about 4mm to about 15mm. For example, a plate may have a thickness of 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, or 15mm.

As used herein, a foil generally refers to an aluminum product that is less than about 4mm thick. For example, a sheet may have a thickness of less than 4mm, less than 3mm, less than 2mm, less than 1mm, less than 0.5mm, less than 0.3mm or less than 0.1mm.

In this application reference is made to the temper or condition of the alloy. To understand the most commonly used alloy temper descriptions, see "American National Standards ( ANSI) H35 on Alloy and Temper Designation Systems." An F condition or temper refers to an aluminum alloy as manufactured. An O condition or temper refers to an aluminum alloy after annealing. A T4 condition or quench refers to an aluminum alloy after solution heat treatment (SHT) (ie, solutionization) followed by natural aging. A T6 condition or quench refers to an aluminum alloy after solution heat treatment followed by artificial aging (AA). A T8x condition or temper refers to an aluminum alloy after solution heat treatment, followed by cold working and then artificial aging.

As used herein, terms such as "cast metal article", "cast article" and the like are interchangeable and refer to a product 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 caster), electromagnetic casting, casting hot top or any other casting method.

As used herein, the meaning of "ambient temperature" can include a temperature from 15°C to 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.

All ranges disclosed herein are to be understood as encompassing any and all subranges included therein. For example, a stated range of "1 to 10" should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subintervals beginning with a minimum value of 1 or more, e.g. eg, from 1 to 6.1, ending with a maximum value of 10 or less, e.g. e.g., from 5.5 to 10.

The following aluminum alloys are described in terms of their elemental composition in weight percent (wt%) based on the total weight of the alloy. The remainder of each alloy is aluminum, with a maximum weight % of 0.15% for the sum of the impurities.

Alloy Compositions

New aluminum alloys are described below. In certain aspects, the alloys exhibit high strength, high formability, and corrosion resistance. The properties of alloys are achieved due to the elemental compositions of the alloys, as well as the methods of processing the alloys to produce aluminum alloy products, including sheets, plates, and plates.

In certain aspects, for a combined effect of hardenability, formability and corrosion resistance, the alloy has a Cu content of 0.5% by weight to 1.5% by weight, a Zr content of 0.07% in wt to 0.12 wt%, and a controlled ratio of Si to Mg, as further described below.

Alloys can have the following elemental composition as given in Table 1:

Table 1

In some examples the alloys may have the following elemental composition as given in Table 2.

Table 2

In some examples the alloys may have the following elemental composition as given in Table 3.

Table 3

The disclosed alloy includes silicon (Si) in an amount of 0.25 % to 1.3% (eg, 0.55 % to 1.1% or 0.65% to 1.0%) based on in the total weight of the alloy. For example, the alloy may include 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, 0.31%, 0.32%, 0.33 %, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.4%, 0.41%, 0.42%, 0.43 %, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.5%, 0.51%, 0.52%, 0.53 %, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.6%, 0.61%, 0.62%, 0.63 %, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7%, 0.71%, 0.72%, 0.73 %, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.8%, 0.81%, 0.82%, 0.83 %, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.9%, 0.91%, 0.92%, 0.93 %, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.0%, 1.01%, 1.02%, 1.03 %, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, 1.09%, 1.1%, 1.11%, 1.12%, 1.13 %, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%, 1.2%, 1.21%, 1.22%, 1.23 %, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29%, or 1.3% of Si. All percentages are expressed in % by weight.

In some examples, the alloy described herein includes iron (Fe) in an amount up to 0.2% (eg, 0.05% to 0.17% or 0.12% to 0. 17%) 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%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0 .17%, 0.18%, 0.19%, or 0.2% Fe, In some cases, Fe is not present in the alloy (i.e., it is 0%), All percentages are in % in weigh,

In some examples, the alloy described herein includes manganese (Mn) in an amount up to 0.5% (eg, 0.05% to 0.3% or 0.05% to 0. 2%) 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%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0 .17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0 .27%, 0.28%, 0.29%, 0.3%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0 .37%, 0.38%, 0.39%, 0.4%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0 0.47%, 0.48%, 0.49%, or 0.5% Mn. In some cases, Mn is not present in the alloy (ie, it is 0%). All percentages are expressed in % by weight.

The disclosed alloy includes magnesium (Mg) in an amount of 1.0% to 2.5% (eg, 1.25% to 2.25% or 1.5% to 2.25%) based on in the total weight of the alloy. For example, the alloy may include 1.0%, 1.01%, 1.02%, 1.03%, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, 1.09%, 1.1%, 1.11%, 1.12%, 1.13%, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%, 1.2%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29%, 1.3%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%, 1.36%, 1.37%, 1.38%, 1.39%, 1.4%, 1.41%, 1.42%, 1.43%, 1.44%, 1.45%, 1.46%, 1.47%, 1.48%, 1.49%, 1.5%, 1.51%, 1.52%, 1.53%, 1.54%, 1.55%, 1.56%, 1.57%, 1.58%, 1.59%, 1.6%, 1.61%, 1.62%, 1.63%, 1.64%, 1.65%, 1.66%, 1.67%, 1.68%, 1.69%, 1.7%, 1.71%, 1.72%, 1.73%, 1.74%, 1.75%, 1.76%, 1.77%, 1.78%, 1.79%, 1.8%, 1.81%, 1.82%, 1.83%, 1.84%, 1.85%, 1.86%, 1.87%, 1.88%, 1.89%, 1.9%, 1.91%, 1.92%, 1.93%, 1.94%, 1.95%, 1.96%, 1.97%, 1.98%, 1.99%, 2, 0%, 2.01%, 2.02%, 2.03%, 2.04%, 2.05%, 2.06%, 2.07%, 2.08%, 2.09%, 2, 1%, 2.11%, 2.12%, 2.13%, 2.14%, 2.15%, 2.16%, 2.17%, 2.18%, 2.19%, 2, 2%, 2.21%, 2.22%, 2.23%, 2.24%, 2.25%, 2.26%, 2.27%, 2.28%, 2.29%, 2, 3%, 2.31%, 2.32%, 2.33%, 2.34%, 2.35%, 2.36%, 2.37%, 2.38%, 2.39%, 2, 4%, 2.41%, 2.42%, 2.43%, 2.44%, 2.45%, 2.46%, 2.47%, 2.48%, 2.49%, or 2 .5% of Mg. All percentages are expressed in % by weight.

The disclosed alloy includes copper (Cu) in an amount of 0.5% to 1.5% (eg, 0.6% to 1.0% or 0.6% to 0.9%) based on in the total weight of the alloy. For example, the alloy may include 0.5%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.6%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.8%, 0.81%, 0.82%, 0.83%, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.9%, 0.91%, 0.92

%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.0%, 1.01%, 1.02 %, 1.03%, 1.04%, 1.05%,

1.06%, 1.07%, 1.08%, 1.09%, 1.1%, 1.11%, 1.12%, 1.13%, 1.14%, 1.15%, 1, 16%, 1.17%, 1.18%, 1.19

%, 1.2%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29 %, 1.3%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%, 1.36%, 1.37%, 1.38%, 1.39 %, 1.4%, 1.41%, 1.42%, 1.43%, 1.44%, 1.45%, 1.46

%, 1.47%, 1.48%, 1.49%, or 1.5% Cu. All percentages are expressed in % by weight.

In some examples, the alloy described herein includes zinc (Zn) in an amount of up to

3.0% by weight (eg, 1.0% to 3.0%, 1.5% to 3.0%, or 2.0% to 3.0%) based on weight total 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%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21

%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, 0.31 %, 0.32%, 0.33%, 0.34%,

0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.4%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48

%, 0.49%, 0.5%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58 %, 0.59%, 0.6%, 0.61%,

0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75

%, 0.76%, 0.77%, 0.78%, 0.79%, 0.8%, 0.81%, 0.82%, 0.83%, 0.84%, 0.85 %, 0.86%, 0.87%, 0.88%,

0.89%, 0.9%, 0.91%, 0.92%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.0%, 1.01%, 1.02%, 1.03%, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, 1.09%, 1.1%, 1.11%, 1.12%, 1.13%, 1.14%, 1.15%,

1.16%, 1.17%, 1.18%, 1.19%, 1.2%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29

%, 1.3%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%, 1.36%, 1.37%, 1.38%, 1.39 %, 1.4%, 1.41%, 1.42%, 1.43%, 1.44%, 1.45%, 1.46%, 1.47%, 1.48%, 1.49 %, 1.5%, 1.51%, 1.52%, 1.53%, 1.54%, 1.55%, 1.56

%, 1.57%, 1.58%, 1.59%, 1.6%, 1.61%, 1.62%, 1.63%, 1.64%, 1.65%, 1.66 %, 1.67%, 1.68%, 1.69%, 1.7%, 1.71%, 1.72%, 1.73%, 1.74%, 1.75%, 1.76%, 1.77%, 1.78%, 1.79%, 1.8%, 1.81%, 1.82%, 1.83

%, 1.84%, 1.85%, 1.86%, 1.87%, 1.88%, 1.89%, 1.9%, 1.91%, 1.92%, 1.93 %, 1.94%, 1.95%, 1.96%,

1.97%, 1.98%, 1.99%, 2.0%, 2.01%, 2.02%, 2.03%, 2.04%, 2.05%, 2.06%, 2.07%, 2.08%, 2.09%, 2.1

%, 2.11%, 2.12%, 2.13%, 2.14%, 2.15%, 2.16%, 2.17%, 2.18%, 2.19%, 2.2 %, 2.21%, 2.22%, 2.23%,

2.24%, 2.25%, 2.26%, 2.27%, 2.28%, 2.29%, 2.3%, 2.31%, 2.32%, 2.33%, 2.34%, 2.35%, 2.36%, 2.37

%, 2.38%, 2.39%, 2.4%, 2.41%, 2.42%, 2.43%, 2.44%, 2.45%, 2.46%, 2.47 %, 2.48%, 2.49%, 2.5%,

2.51%, 2.52%, 2.53%, 2.54%, 2.55%, 2.56%, 2.57%, 2.58%, 2.59%, 2.6%, 2.61%, 2.62%, 2.63%, 2.64

%, 2.65%, 2.66%, 2.67%, 2.68%, 2.69%, 2.7%, 2.71%, 2.72%, 2.73%, 2.74 %, 2.75%, 2.76%, 2.77%,

2.78%, 2.79%, 2.8%, 2.81%, 2.82%, 2.83%, 2.84%, 2.85%, 2.86%, 2.87%, 2.88%, 2.89%, 2.9%, 2.91

%, 2.92%, 2.93%, 2.94%, 2.95%, 2.96%, 2.97%, 2.98%, 2.99%, or 3.0% Zn. In some cases, the Zn

it is not present in the alloy (ie, it is 0%). All percentages are expressed in % by weight.

Optionally, zirconium (Zr) may be included in the alloys described herein. In some examples, the alloys include Zr in an amount up to 0.15% by weight (eg, 0.07% to 0.15%, of

0.09% to 0.12%, or 0.08% to 0.11%) 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%, 0.1 %, 0.11%, 0.12%, 0.13%,

0.14%, or 0.15% Zr. In some examples, Zr is not present in the alloys (ie, it is 0%). All

the percentages are expressed in % by weight. In certain aspects, Zr is added to the compositions described above to form (Al,Si)3Zr dispersoids (DO22/DO23 dispersoids) and/or AbZr dispersoids (L12 dispersoids).

Optionally, the alloy compositions can additionally include other minor elements, to

sometimes called 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 each. These impurities may include, but are not limited to, Ga, V, Ni, Sc, Ag,

B, Bi, Li, Pb, Sn, Ca, Cr, Ti, Hf, Sr or combinations thereof. Consequently, Ga, V, Ni, Sc, Ag, B, Bi,

Li, Pb, Sn, Ca, Cr, Ti, Hf, or Sr may be present in an 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% (eg, 0.1%). All percentages are expressed in % by weight. The remaining percentage of the alloy

it's aluminum.

Suitable illustrative alloys may include, for example, 1.0% Si, 2.0-2.25% Mg, 0.6-0.7

% Cu, 2.5-3.0% Zn, 0.07-0.10% Mn, 0.14-0.17% Fe, 0.09-0.10% Zr, and up to 0.15% total impurities, balance being Al. In some cases, suitable illustrative alloys may include

0.55-0.65% Si, 1.5% Mg, 0.7-0.8% Cu, 1.55% Zn, 0.14-0.15% Mn, 0 0.16-0.18% Fe,

and up to 0.15% total impurities, balance being Al. In some cases, suitable illustrative alloys

may include 0.65% Si, 1.5% Mg, 1.0% Cu, 2.0-3.0% Zn, 0.14-0.15% Mn, 0.17% of faith

and up to 0.15% total impurities, the remainder being Al.

Alloy microstructure and properties

In certain aspects, the ratios of Cu, Mg and Si and the content of Zn are controlled to improve the strength.

to corrosion, mechanical resistance and formability. Zn content can control morphology

corrosion as described below, for example, inducing pitting corrosion and suppressing

intergranular corrosion (IGC).

The ratio of Mg to Si (also referred to herein as the Mg/Si ratio) is from 1.5:1 to 3.5:1 (eg, 1.75:1 to 3.0:1 or from 2.0:1 to 3.0:1). For example, the Mg/Si ratio can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.1: 1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3, 8:1, 3.9:1 or 4.0:1. In some non-limiting examples, an aluminum alloy having a Mg/Si ratio of 1.5:1 to 3.5:1 (eg, 2.0:1 to 3.0:1) may exhibit high mechanical resistance and greater formability.

In some non-limiting examples, an aluminum alloy having a Mg/Si ratio of 2.0:1-3.0:1 and a Zn content of 2.5wt-3.0wt% may exhibit IGC suppression typically observed in aluminum alloys having Mg and Si as predominant alloying elements, and can induce pitting corrosion instead. In some cases, pitting corrosion can be favorable over IGC due to a limited depth of attack, since IGC can occur along grain boundaries and propagate deeper into the aluminum alloy than pitting corrosion. . In some non-limiting examples, a ratio of Zn to Mg/Si ratio (ie, Zn/(Mg/Si) ratio) can be from 0.75:1 to 1.4:1 (eg ., from 0.8:1 to 1.1:1). For example, the Zn/(Mg/Si) ratio can be 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, 1.0:1 , 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.35:1 or 1.4:1.

In some other additional non-limiting examples, a ratio of Cu to the ratio Zn/(Mg/Si) (ie, the ratio Cu/[Zn/(Mg/Si)]) may be 0.7:1 to 1.4:1 (eg, the Cu/[Zn/(Mg/Si)] ratio can be from 0.8:1 to 1.1:1). For example, the ratio Cu/[Zn/(Mg/Si)] can be 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0 .95:1, 1.0:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.35 :1, or 1.4:1. In some non-limiting examples, the Cu/[Zn/(Mg/Si)] ratio can provide high strength, high deformability, and high corrosion resistance.

In certain aspects, Cu, Si and Mg can form precipitates in the alloy to result in an alloy with higher mechanical strength and improved corrosion resistance. These precipitates can form during aging procedures, after solution heat treatment. The Mg and Cu content can provide precipitation of an M/q phase or an M phase (eg, MgZn2/Mg(Zn,Cu)2), resulting in precipitates that can increase mechanical strength in the aluminum alloy. During the precipitation process, metastable Guinier Preston (GP) zones can form, which in turn transfer to p" needle-shaped precipitates (eg, magnesium silicide, Mg2Si) that contribute to precipitation hardening of the disclosed alloys.In certain aspects, the addition of Cu leads to the formation of lathe-shaped L- phase precipitation (eg, AUMg8Si7Cu2), which is a precursor to the formation of the Q'- phase precipitate and which additionally contributes to mechanical resistance.

In some examples, M phase precipitates, including MgZn2 and/or Mg(Zn,Cu)2, may be present in the aluminum alloy in an average amount of at least 300,000,000 particles per square millimeter (mm2). ). For example, the M phase precipitates may be present in an amount of at least 310,000,000 particles per mm2, at least 320,000,000 particles per mm2, at least 330,000. 000 particles per mm2, at least 340,000,000 particles per mm2, at least 350,000,000 particles per mm2, at least 360,000,000 particles per mm2, at least 370,000,000 particles per mm2, at least 380,000. 000 particles per mm2, at least 390,000,000 particles per mm2, or at least 400,000. 000 particles per mm2.

In some examples, L-phase precipitates, including AUMg8Si7Cu2, may be present in the aluminum alloy in an average amount of at least 600,000,000 particles per square millimeter (mm2). For example, the L-phase precipitates may be present in an amount of at least 610,000. 000 particles per mm2, at least 620,000,000 particles per mm2, at least 630,000,000 particles per mm2, at least 640,000,000 particles per mm2, at least 650,000,000 particles per mm2, at least 660,000. 000 particles per mm2, at least 670,000,000 particles per mm2, at least 680,000,000 particles per mm2, at least 690,000,000 particles per mm2, or at least 700,000,000 particles per mm2.

In some examples, p" phase precipitates, including Mg2Si, may be present in the aluminum alloy in an average amount of at least 600,000,000 particles per square millimeter (mm2). For example, phase precipitates p" may be present in an amount of at least 610,000,000 particles per mm2, at least 620,000,000 particles per mm2, at least 630,000,000 particles per mm2, at least 640,000,000 particles per mm2, at at least 650,000,000 particles per mm2, at least 660,000,000 particles per mm2, at least 670,000,000 particles per mm2, at least 680,000,000 particles per mm2, at least 690,000,000 particles per mm2, at least at least 700,000,000 particles per mm2, at least 710,000,000 particles per mm2, at least 720,000,000 particles per mm2, at least 730,000,000 particles per mm2, at least 740,000,000 particles per mm2, or at least 750,000,000 particles per mm2.

In some examples, the ratio of p'' phase precipitates (eg Mg2Si) to L phase precipitates (eg Al4MgsSi7Cu2) can be from 1:1 to 1.5 :1 (eg, 1.1:1 to 1.4:1). For example, the ratio of p" phase precipitates to L phase precipitates can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4 :1 or 1.5:1.

In some examples, the ratio of p" -phase precipitates (eg, Mg2Si) to M-phase precipitates (eg, MgZn2 and/or Mg(Zn,Cu)2) may be from 1.5:1 to 3:1 (eg, 1.6:1 to 2.8:1 or 2.0:1 to 2.5:1).For example, the ratio of the precipitates of the p" phase with respect to the precipitates of the M phase can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2, 0:1,2,1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8: 1,2,9:1, or 3.0:1.

In some examples, the ratio of L phase precipitates (eg Al4MgsSi7Cu2) to M phase precipitates (eg MgZn2 and/or Mg(Zn,Cu)2) may be from 1.5:1 to 3:1 (eg, from 1.6:1 to 2.8:1 or from 2.0:1 to 2.5:1). For example, the ratio of L phase precipitates to M phase precipitates can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9: 1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1 or 3.0:1.

The alloys described herein exhibit exceptional mechanical properties, as further provided below. The mechanical properties of aluminum alloys can be further controlled by various aging conditions depending on the intended use. As an example, the alloy can be produced (or provided) in the T4 temper or the T6 temper. T4 aluminum alloy articles which undergo solution heat treatment and naturally age can be provided. These T4 aluminum alloy items can optionally undergo one or more additional aging treatments to meet mechanical strength requirements upon receipt. For example, aluminum alloy articles can be provided in other tempers, such as the T6 temper, by subjecting the T4 alloy material to the appropriate aging treatment as described herein or in another manner known to those skilled in the art. technique. Illustrative properties in illustrative tempers are provided below.

In certain aspects, the aluminum alloy may have a yield strength of at least 340 MPa in the T6 temper. In non-limiting examples, the yield strength may be at least 350 MPa, at least 360 MPa, or at least 370 MPa. In some cases, the yield strength is 340 MPa to 400 MPa. For example, the yield strength can be 350 MPa to 390 MPa or 360 MPa to 380 MPa.

In certain aspects, the aluminum alloy can have a maximum tensile strength of at least 400 MPa in the T6 temper. In non-limiting examples, the maximum tensile strength may be at least 410 MPa, at least 420 MPa, or at least 430 MPa. In some cases, the maximum tensile strength is 400 MPa to 450 MPa. For example, the maximum tensile strength can be 410 MPa to 440 MPa or 415 MPa to 435 MPa.

In certain aspects, the aluminum alloy has sufficient ductility or toughness to meet a 90° bendability of 1.0 or less at the T4 temper (eg, 0.5 or less). In certain examples, the foldability ratio r/t is 1.0 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0, 4 or less, 0.3 or less, 0.2 or less, or 0.1 or less, where r is the radius of the tool (die) used and t is the thickness of the material.

In certain aspects, the aluminum alloy exhibits a uniform elongation of 20% or more at the T4 temper and a total elongation of 30% or more at the T4 temper. In certain aspects, the alloys exhibit a uniform elongation of 22% or more and a total elongation of 35% or more. For example, alloys may have a uniform elongation of 20% or more, 21% or more, 22% or more, 23% or more, 24% or more, 25% or more, 26% or more, 27% or more. , or 28% or more. Alloys may have a total elongation of 30% or more, 31% or more, 32% or more, 33% or more, 34% or more, 35% or more, 36% or more, 37% or more, 38% or more, 39% or more, or 40% or more.

In certain aspects, aluminum alloy exhibits adequate resistance to IGC, as measured by ISO 11846B. For example, pitting in aluminum alloys can be completely suppressed or enhanced so that the average intergranular corrosion pit depth of an alloy in the T6 temper is less than 100 pm. For example, the average intergranular corrosion pit depth may be less than 90 pm, less than 80 pm, less than 70 pm, less than 60 pm, less than 50 pm, or less than 40 pm.

Methods of preparation of aluminum alloys

In certain aspects, the disclosed alloy composition is a product of a disclosed method. Without intending to limit the disclosure, aluminum alloy properties are partially determined by the formation of microstructures during alloy preparation. In certain aspects, the method of preparation for an alloy composition can influence or even determine whether the alloy will have adequate properties for a desired application.

molding

The alloy described herein can be cast using a casting method. In some non-limiting examples, aluminum alloy as described herein may be cast from molten aluminum alloy including scrap alloys (e.g., from AA6xxx series aluminum alloy scrap, AA7xxx series aluminum alloy scrap or a combination of these). The casting process may include a direct chill (DC) casting process. Optionally, the ingot can be scarred prior to downstream processing. Optionally, the casting process may include a continuous casting (CC) process. The cast aluminum alloy can then be subjected to additional processing steps. For example, processing methods as described herein may include the steps of homogenization, hot rolling, solution heat treatment, and quenching. In some cases, the processing methods may also include a pre-aging step and/or an artificial aging step.

homogenization

The homogenization step may include heating an ingot prepared from an alloy composition described herein to achieve a peak metal temperature (PMT) of about, or at least about, 500° C (eg, 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 ingot can be heated to a temperature of 500°C to 600°C, 520°C to 580°C, 530°C to 575°C, 535°C to 570°C, 540°C to 565 °C, from 545 °C to 560 °C, or from 530 °C to 560 °C, or from 550 °C to 580 °C. In some cases, the heating rate for PMT may be 70°C/hour or less, 60°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 for PMT may be 10°C/min to 100°C/min (eg, 10°C/min to 90°C/min, 10°C/min to 70 °C/min, 10 °C/min to 60 °C/min, 20 °C/min to 90 °C/min, 30 °C/min to 80 °C/min, 40 °C/min to 70 °C/min, or from 50 °C/min to 60 °C/min).

The ingot is then allowed to homogenize (ie, held at the indicated temperature) for a period of time. According to a non-limiting example, the ingot is subjected to heat stabilization for up to 6 hours (eg, 30 minutes up to 6 hours, inclusive). For example, the ingot can be subjected to heat stabilization at a temperature of at least 500°C for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours, or anything in between.

hot rolled

After the homogenization step, a hot rolling step can be carried out to form a hot strip. In certain cases, ingots are deposited and hot rolled with an exit temperature ranging from 230°C to 300°C (eg 250°C to 300°C). For example, hot rolling cylinder outlet temperature can be 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270° C, 275°C, 280°C, 285°C, 290°C, 295°C, or 300°C.

In certain cases, the ingot can be hot rolled to a thickness of 4mm to 15mm (eg 5mm to 12mm thickness). For example, the ingot can be hot rolled to 4mm thickness, 5mm thickness, 6mm thickness, 7mm thickness, 8mm thickness, 9mm thickness, 10mm thickness, 11mm thickness mm, 12mm thickness, 13mm thickness, 14mm thickness, or 15mm thickness. In certain cases, the ingot may be hot rolled to a gauge greater than 15mm thick (eg sheet metal). In other cases, the ingot may be hot rolled to a gauge less than 4 mm (eg, a sheet).

dissolution heat treatment

After the hot rolling step, the hot strip can be air cooled and then solutionized in a solution heat treatment step. The solution heat treatment may include heating the final gauge aluminum alloy from room temperature to a temperature of 520°C to 590°C (e.g., 520°C to 580°C, 530°C to 570°C, 545°C to 575°C, 550°C to 570°C, 555°C to 565°C, 540°C to 560°C, 560°C to 580°C, or from 550°C to 575°C). End gauge aluminum alloy can be subjected to heat stabilization at temperature for a period of time. In certain aspects, the fine gauge aluminum alloy is subjected to heat stabilization for up to about 2 hours (eg, 10 seconds to 120 minutes, inclusive). For example, final gauge aluminum alloy can be heat set at the temperature of 525°C to 590°C for 20 seconds, 25 seconds, 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, or 120 minutes, or anything in between.

fast cooling

In certain aspects, the final gauge aluminum alloy can then be quenched to a temperature of 35°C at a quench rate that can range from 50°C/s to 400°C/s in a quench stage that is based on the selected caliber. For example, quench 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, from 90 °C/s to 300 °C/s, from 100 °C/s to 275 °C/s, from 125 °C/s to 250 °C/s, from 150 °C/s to 225 °C/s, or from 175 °C/s to 200 °C/s.

In the quench step, the final gauge aluminum alloy is quenched with a liquid (eg, water) and/or gas or other selected quench medium. In certain aspects, end gauge aluminum alloy can be quenched with water.

Pre-Aging

Optionally, a pre-aging stage can be carried out. The pre-aging stage may include heating the final gauge aluminum alloy after the quench stage to a temperature of 100°C to 160°C (eg, 105°C to 155°C, from 110°C to 150°C, 115°C to 145°C, 120°C to 140°C, or 125°C to 135°C). In certain aspects, the aluminum alloy sheet, sheet or plate is subjected to heat stabilization for up to three hours (eg, up to 10 minutes, up to 20 minutes, up to 30 minutes, up to 40 minutes, for up to 45 minutes, up to 60 minutes, up to 90 minutes, up to two hours, or up to three hours).

Aging

Fine gauge aluminum alloy can be aged naturally or artificially. In some examples, the final gauge aluminum alloy may be naturally aged over a period of time to result in the T4 temper. In certain respects, final gauge aluminum alloy in the T4 temper can be artificially aged (AA) from 180°C to 225°C (eg, 185°C, 190°C, 195°C, 200°C , 205 °C, 210 °C, 215 °C, 220 °C or 225 °C) for a period of time. Optionally, the fine gauge aluminum alloy can be artificially aged for a period of 15 minutes to 8 hours (eg, 15 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours). , 7 hours or 8 hours or anything in between) to result in a T6 temper.

Methods of use

The alloys and methods described herein may be used in automotive, electronic, and transportation applications, such as commercial vehicle, aircraft, or rail applications or other applications. For example, the alloys could be used for chassis, crossmembers, and internal chassis components (including, but not limited to, all components between the two C-channels on a commercial vehicle chassis) to gain mechanical strength, serving as a complete replacement. or partial steels of high mechanical resistance. In certain examples, the alloys can be used in T4 and T6 tempers.

In certain aspects, the alloys and methods can be used to prepare motor vehicle body part products. For example, the disclosed alloys and methods can be used to prepare automotive body parts, such as bumpers, side beams, roof beams, cross beams, pillar reinforcements (eg, A-pillars, B-pillars, and C-pillars). , interior panels, side panels, floor panels, tunnels, structure panels, reinforcement panels, interior hoods or trunk lid panels. The aluminum alloys and methods disclosed herein can also be used in rail or air vehicle applications to prepare, for example, exterior and interior panels. In certain aspects, the disclosed alloys can be used for other specialized applications, such as automotive battery sheets/plates.

The alloys and methods described can also be used to prepare housings for electronic devices, including mobile phones and tablet computers. For example, the alloys can be used to prepare casings for the outer skin of mobile phones (eg, smartphones) and tablet bottom chassis, with or without anodizing. The alloys can also be used to prepare other consumer electronics and product parts. Illustrative consumer electronics include mobile phones, audio devices, video devices, cameras, laptop computers, desktop computers, tablet computers, televisions, displays, home appliances, video recording and playback devices, and the like. Illustrative consumer electronics parts include outer casings (eg, fronts) and interior parts for consumer electronics.

The following examples will serve to further illustrate the present invention without, however, constituting a limitation thereof. Rather, it is to be clearly understood that various embodiments, modifications and equivalents of this may be resorted to which, after reading the description herein, may be suggested to those skilled in the art without departing from the spirit of the invention. During the studies described in the following examples, standard procedures were followed, unless otherwise indicated. Some of the procedures are described below for illustrative purposes.

examples

Example 1: Aluminum alloy compositions

Tables 4A and 4B below summarize examples of illustrative aluminum alloys and Table 5 provides the properties of the alloys, including yield strength (YS), intergranular corrosion (IGC) pitting depths, and the foldability of 90° (Flexion).

Table 4A

Everything is expressed in % by weight; total impurities up to 0.15% by weight; the rest Al.

Table 4B

Table 5

The properties of the alloys were achieved by controlling the ratios of the alloying elements. Alloy 1 represents comparative AA6xxx series aluminum alloys that exhibit high mechanical strength due to Mg2Si harden precipitates in the aluminum alloy. Alloy 2 represents comparative aluminum alloys that exhibit improved corrosion resistance and a slight decrease in strength with the addition of Zn. Alloys 1 and 2, where the Cu/[Zn/(Mg/Si)] ratio is not in the range of about 0.7 to about 1.4, exhibit significant IGC and fail a 90 fold test. °. Alloy 3 represents illustrative aluminum alloys where the Cu/[Zn/(Mg/Si)] ratios are closer to the 0.7 to 1.4 range than Alloy 2, exhibiting a decrease in strength with excellent formability and resistance to IGC. Alloy 4 represents illustrative aluminum alloys where the Cu/[Zn/(Mg/Si)] ratios are within the range of 0.7 to 1.4, but the Zn/(Mg/Si) ratios are not. within a range of 0.75 to 1.4, exhibiting significant IGC and poor formability, and higher mechanical strength compared to Alloy 3. Alloy 5 represents illustrative aluminum alloys where Mg/Si ratios , Zn/(Mg/Si) and Cu/[Zn/(Mg/Si)] are within the respective intervals, exhibiting high mechanical strength, good formability and good corrosion resistance.

In addition, illustrative alloys were produced according to the direct chill casting methods described herein. The alloy compositions are summarized in Table 6 below:

Table 6

Example 2: Aluminum alloy microstructure

Illustrative alloys were produced by direct chill casting and processed according to the methods described herein. As described above, the Mg and Cu content can provide precipitation of an M phase (eg, MgZn2/Mg(Zn,Cu)2), providing precipitates that can increase strength in aluminum alloy. Evaluation of M phase precipitates (eg MgZn2) were performed based on the Mg content in the illustrative alloys. Figure 1 is a graph showing an increase in Mg content from 1.0% by weight to 3.0% by weight. As evidenced in the graph, a mass fraction of the M phase precipitates (i) increases proportionally with increasing Mg content from 1.0% by weight to 1.5% by weight, (ii) remains constant when the Mg content increases. Mg content increases from 1.5% by weight to 2.0% by weight, (iii) increases proportionally with increasing Mg content from 2.0% by weight to 2.5% by weight, and (iv) reaches a plateau with a Mg content greater than 2.5% by weight. Increased M- phase precipitates provide higher mechanical strength in the illustrative alloys.

Figure 2 is a graph showing differential scanning calorimetry (DSC) analysis of illustrative Alloy 3 samples described above (referred to as "H1", "H2" and "H3"). The exothermic peak A indicates the formation of precipitates in the illustrative alloys and the endothermic peak B indicates melting points for the illustrative samples of Alloy 3.

Figure 3 is a graph showing DSC analysis of illustrative Alloy 5 samples described above (referred to as "H5", "H6" and "H7"). The exothermic peak A indicates M- phase precipitates. The exothermic peak B indicates p" (Mg2Si) precipitates, which show the formation of hardening precipitates during an artificial aging step and which correspond to the increase in mechanical resistance of alloys of illustrative aluminum The endothermic peak C indicates melting points for the illustrative samples of Alloy 5.

Figure 4A is a transmission electron microscope (TEM) micrograph showing three distinct phases of hardening precipitate, M (MgZn2) 410, p" (Mg2Si) 420, and L (Al4Mg8Si7Cu2) 430. A The combination of the three precipitate phases produces a yield strength of approximately 370 MPa at a T6 temper for a 10 mm gauge aluminum alloy (eg, Alloy 5.) Figure 4B is a TEM micrograph showing particles of precipitate containing Zr 440. Excess Zr in the illustrative alloys can cause the formation of coarse, needle-shaped particles.Coarse, needle-shaped precipitate particles containing Zr 440 can reduce the formability of the illustrative alloys. Similarly, too little Zr in the illustrative alloys may fail to provide the desired AbZr and/or (Al,Si)3Zr dispersoids.

Figure 5 is a graph showing the density of each different hardening precipitate phase, M (MgZn2), L (AUMg8Si7Cu2) and p "(Mg2Si), in number of precipitate particles per square millimeter (#/mm2) and as a fraction of the analyzed area, each distinct precipitate phase occupies (%) for Alloy C (see Table 6). The p" precipitates are predominant in both density and occupied area due to their shape. The smaller M and L precipitates occupy less area accordingly, and are present in densities comparable to the p" precipitates.

Figure 6 shows light micrographs of Alloy 3 samples as described above. Precipitates were analyzed in cast samples (top row), homogenized samples (middle row), and hot rolled samples reduced to 10 mm gauge (bottom row). Eutectic phase precipitates are evident in the melt samples. The precipitates did not completely dissolve after homogenization, as shown in the middle row of micrographs. Coarse precipitates (eg, greater than about 5 microns) are evident in hot rolled samples.

Figure 7 shows light micrographs of Alloy 3 samples described above after casting, homogenization, hot rolling to 10mm gauge, and various solution heat treatment procedures to achieve maximum dissolution of hardening precipitates during heating. solution heat treatment. Figure 7, panel A shows a sample of Alloy 3 solutionized at a temperature of 555 °C for 45 minutes. Figure 7, panel B shows a sample of Alloy 3 solutionized at 350 °C for 45 minutes, then at 500 °C for 30 minutes, and finally at 565 °C for 30 minutes. Figure 7, panel C shows a sample of Alloy 3 solutionized at 350 °C for 45 minutes, then at 500 °C for 30 minutes, and finally at 565 °C for 60 minutes. Figure 7, panel D shows a sample of Alloy 3 solutionized at a temperature of 560 °C for 120 minutes. Figure 7, panel E shows a sample of Alloy 3 solutionized at 500°C for 30 minutes, then at 570°C for 30 minutes. Figure 7, panel F shows a sample of Alloy 3 solutionized at 500°C for 30 minutes, then at 570°C for 60 minutes.

Figure 8 shows light micrographs of Alloy 5 samples as described above. The precipitates were analyzed in cast samples (upper row) and homogenized samples (lower row). Eutectic phase precipitates are evident in the melt samples. The precipitates did not completely dissolve after homogenization, as seen in the bottom row of micrographs. Alloy 5, however, exhibited less undissolved precipitates compared to Alloy 3 after homogenization, due to changes in solute levels (eg, Mg levels, Si levels, and Mg ratio /Yeah).

Figure 9 shows light micrographs of Alloy 5 samples described above after hot rolling to 10mm gauge. Figure 9, panels A, B and C show precipitate particles (seen as dark spots) in the illustrative alloy samples after hot rolling to 10mm gauge. Figure 9, panels D, E and F shows the grain structure after hot rolling of illustrative Alloy 5 samples at 10mm gauge. The grains did not fully recrystallize due to a low hot rolling exit temperature of about 280°C to about 300°C.

Figure 10 shows light micrographs of Alloy 5 samples described above after hot rolling to 10mm gauge, solution heat treatment and natural aging at T4 temper. Figure 10, panels A, B and C show very few precipitate particles in the illustrative alloy samples in the T4 temper. Figure 10, panels D, E and F shows a fully recrystallized grain structure of illustrative samples of Alloy 5 in the T4 temper.

Figure 11 is a graph showing the electrical conductivities of Alloy 3 samples after casting, homogenization, hot rolling, various solution heat treatment procedures, and artificial aging (AA). Electrical conductivity data (ie, conductivity as a percentage of International Annealed Copper Standard (%IACS)) show large amounts of precipitation after hot rolling. Various solution heat treatment procedures were evaluated in an attempt to dissolve the precipitates. The dissolution heat treatment was not effective in dissolving the precipitates. In addition, there was insufficient formation of hardening precipitate during artificial aging to provide optimum mechanical strength.

Figure 12 is a graph showing the electrical conductivities of Alloy 5 samples (referred to as "HR5", "HR6", and "HR7") after casting, homogenization, hot rolling, solution heat treatment and artificial aging. Electrochemical test data shows large amounts of precipitation after hot rolling. Various solution heat treatment procedures were evaluated in an attempt to dissolve the hardening precipitate. The dissolution heat treatment was effective in dissolving the precipitates. In addition, artificial aging provided a hardening precipitate formation that provides optimum mechanical strength.

Example 3: Mechanical properties of aluminum alloy

Figure 13 is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle) and total elongation (open diamond) for the Illustrative alloys A, B, and C described above. Alloys were quenched at 565°C for 45 minutes, pre-aged at 125°C for 2 hours, and artificially aged at 200°C for 4 hours to result in a T6 temper. Each alloy exhibited a yield strength greater than 370 MPa, a maximum tensile strength greater than 425 MPa, a uniform elongation greater than 10%, and a total elongation greater than 17%. Increasing the Zn content did not significantly affect the mechanical strength of the illustrative aluminum alloys, but it did improve intergranular corrosion resistance and formability.

Figure 14A is a graph showing the yield strength (left histogram in each set), the maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) for illustrative Alloy 3 samples in the T4 temper (referred to as "H1 T4", "H2 T4" and "H3 T4"). Figure 14B is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) for the Illustrative Alloy 3 samples in the T6 temper (referred to as "H1 T6", "H2 T6", and "H3 T6").

Figure 15 is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle) and total elongation (open diamond) for the Illustrative Alloy 3 samples in the T6 temper (referred to as "H1", "H2", and "H3") after various aging procedures, as indicated on the x-axis of the graph. As seen in the graph, a three-stage aging procedure was able to produce a high-strength (eg, 348 MPa) aluminum alloy. As also seen in the graph, aging at low temperatures (eg, less than 250°C) was not sufficient to produce harden precipitates in the alloy samples.

Figure 16A is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) for the Illustrative Alloy 4 samples in the T4 temper (referred to as "HR1", "HR2", "HR3", and "HR4"). Figure 16B is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) for the Illustrative Alloy 4 samples in the T6 temper after various aging procedures (referred to as "HR1", "HR2", "HR3", and "HR4"). As observed in the graph, a maximum mechanical resistance of 360 MPa was achieved. As also seen in the graph, aging at low temperatures (eg, less than 250°C) was not sufficient to produce harden precipitates in the alloy samples.

Figure 17A is a graph showing yield strength (left histogram in each set), ultimate tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) for the Illustrative Alloy 5 samples in the T4 temper after casting, homogenization, hot rolling to 10mm gauge, solution heat treatment, and various quench techniques (referred to as "HR5", "HR6" and "HR7" ). Air-cooled samples are referred to as "AC" and water quenched samples are referred to as "WQ" after hot rolling. Figure 17B is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) for the Illustrative Alloy 5 samples in T6 temper after casting, homogenization, hot rolling to 10mm gauge, solution heat treatment, various quenching techniques, and various aging procedures (referred to as "HR5", "HR6 and "HR7"). Air-cooled samples are referred to as "AC" and water quenched samples are referred to as "WQ" after hot rolling. Artificial aging to a T6 temper provided high strength aluminum alloys with a yield strength of about 360 MPa to about 370 MPa.

Figure 18A is a graph showing yield strength (left histogram in each set), ultimate tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) for the Illustrative Alloy 5 samples in the T4 temper (referred to as "HR5", "HR6", and "HR7") after casting, homogenization, hot rolling to 10 mm gauge, and solution heat treatment. Figure 18B is a graph showing yield strength (left histogram in each set), maximum tensile strength (right histogram in each set), uniform elongation (open circle), and total elongation (open diamond) for the Illustrative Alloy 5 samples in the T6 temper (referred to as "HR5", "HR6", and "HR7") after casting, homogenization, hot rolling to 10mm gauge, solution heat treatment, and various aging procedures , as indicated in the graph. Artificial aging to a T6 temper provided high strength aluminum alloys with a yield strength of about 360 MPa to about 370 MPa.

Figure 19 is a graph showing load displacement data for a 90° bend test formability of illustrative Alloy 5 samples as described above (designated "HR5", "HR6" and "HR7"). The samples tested in a direction longitudinal to a rolling direction are indicated by "-L", and the sample tested in a direction transverse to the rolling direction is indicated by "-T". Alloy 5 was subjected to casting, homogenization, hot rolling to 10 mm gauge, solution heat treatment, and natural aging for one week to provide the Alloy 5 specimens in the T4 temper. The samples were subjected to a 90° folding test and the load displacement (left axis) and maximum load (right axis) were recorded.

Figure 20 is a graph showing load displacement data for a test conformability 90° folding of illustrative Alloy 5 samples as described above (referred to as "HR5", "HR6" and "HR7"). The samples tested in a longitudinal direction with respect to a rolling direction are indicated by "-L", and the sample tested in a transverse direction with respect to the rolling direction are indicated by "-T". Alloy 5 was subjected to casting, homogenization, hot rolling to 10 mm gauge, solution heat treatment, pre-aging at 125 °C for 2 hours (referred to as "PX"), and natural aging for one week. to provide samples of Alloy 5 in the T4 temper. The samples were subjected to a 90° folding test and the load displacement (left axis) and maximum load (right axis) were recorded.

Figure 21 is a graph showing load displacement data for a 90° bend test formability of illustrative Alloy 5 samples as described above. The sample tested in a longitudinal direction with respect to a rolling direction is indicated by "-L" and the sample tested in a transverse direction with respect to the rolling direction is indicated by "-T". Samples were subjected to casting, homogenization, hot rolling to 10 mm gauge, solution heat treatment, pre-aging at 125°C for 2 hours, and natural aging for one month to provide Alloy 5 samples. in temple T4. The samples were subjected to a 90° folding test and the load displacement (left axis) and maximum load (right axis) were recorded. There were no significant changes in formability from one week of natural aging to one month of natural aging using pre-aging during production.

Figure 22 shows light micrographs showing the effects of corrosion tests on the alloys described above. The alloys were subjected to corrosion tests according to the ISO 11846B standard (eg, 24-hour immersion in a solution containing 3.0% by weight sodium chloride (NaCl) and 1.0% by volume of hydrochloric acid (HCl) in water). Figure 22, panel A, and Figure 22, panel B show the effects of corrosion tests on Comparative Alloy 2 described above. The corrosion morphology is an intergranular corrosion (IGC) attack. Figure 22, panels C, D and E show the effects of corrosion testing on illustrative Alloy 3 as described above. The corrosion morphology is a pitting attack. A pitting attack is a more desirable corrosion morphology that causes less damage to the alloy and indicates corrosion resistance in the illustrative alloys.

Figure 23 shows light micrographs showing the effects of corrosion testing on illustrative Alloy 4 samples as described above. As seen in the micrographs there is significant IGC attack due to the composition of Alloy 4, where the Cu/[Zn/(Mg/Si)] ratio is in the range of 0.7 to 1.4, but the Zn/(Mg/Si) ratio is not within the range of 0.75 to 1.4, resulting in significant IGC attack.

Figures 24A, 24B and 24C are light micrographs showing the results of corrosion tests on the illustrative alloys described above. Figure 24A shows the intergranular corrosion (IGC) attack on alloy A. Figure 24B shows the intergranular corrosion attack on alloy B. Figure 24C shows the intergranular corrosion attack on alloy C. As seen in the Figures 24A, 24B and 24C increasing Zn content changes the corrosion morphology from IGC to pitting, and the depth of corrosion attack decreases from approximately 150 pm (Alloy A, Figure 24A) to less than 100 pm (Alloy C , Figure 24C).

Various embodiments of the invention have been described in compliance with the various objects of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention.

Claims (16)

1. An aluminum alloy comprising 0.25-1.3 % by weight of Si, 1.0-2.5 % by weight of Mg, 0.5-1.5% by weight of Cu, up to 0.2 wt% Fe, up to 3.0 wt% Zn, up to 0.15 wt% Zr, up to 0.5 wt% Mn, up to 0.15 wt% impurities, balance Al , where the ratio of Mg to Si (Mg/Si ratio) is from 1.5 to 1 to 3.5 to 1. 2. The aluminum alloy of claim 1, comprising 0.55-1.1% by weight of Si, 1.25-2.25% by weight of Mg, 0.6-1.0% by weight of Cu, 0.05-0.17 wt% Fe, 1.5-3.0 wt% Zn, up to 0.15 wt% impurities, balance Al. The aluminum alloy of claim 1 or 2, comprising 0.65-1.0% by weight of Si, 1.5-2.25% by weight of Mg, 0.6-1.0% in Cu, 0.12-0.17 wt% Fe, 2.0-3.0 wt% Zn, up to 0.15 wt% impurities, balance Al. The aluminum alloy of any one of claims 1-3, comprising Zr and in particular, wherein Zr is present in an amount of 0.09-0.12% by weight. The aluminum alloy of any one of claims 1-4, comprising Mn and in particular, wherein Mn is present in an amount of 0.05-0.3% by weight. 6. The aluminum alloy of any one of claims 1-5, wherein the Mg/Si ratio is from 2.0 to 1 to 3.0 to 1. The aluminum alloy of claim 6, wherein the ratio of Zn to the Mg/Si ratio (the Zn/(Mg/Si) ratio) is from 0.75 to 1 to 1.4 to 1 and in particular, where the ratio Zn/(Mg/Si) is from 0.8 to 1 to 1.1 to 1. The aluminum alloy of claim 7, wherein the ratio of Cu to the ratio of Zn/(Mg/Si) (the ratio of Cu/[Zn/(Mg/Si)]) is from 0.7 to 1 to 1.4 to 1 and in particular, where the ratio Cu/[Zn/(Mg/Si)] is from 0.8 to 1 to 1.1 to 1. An aluminum alloy product comprising the aluminum alloy according to any one of claims 1-8. The aluminum alloy product of claim 9, wherein the aluminum alloy product comprises a yield strength of at least 340 MPa at a T6 temper and in particular, wherein the yield strength is from 360 MPa to 380 MPa in the T6 temper and/or where the aluminum alloy product comprises an average intergranular corrosion pit depth of less than 100 pm in a T6 temper and/or where the aluminum alloy product comprises an r/t ratio (pliability) of 0.5 or less at a T4 temper. 11. The aluminum alloy product of any one of claims 9 or 10, wherein the aluminum alloy product comprises one or more precipitates selected from the group consisting of MgZn2/Mg(Zn,Cu)2, Mg2Si, and Al4MgsSi7Cu2. 12. The aluminum alloy product of claim 11, wherein the aluminum alloy product comprises MgZn2/Mg(Zn,Cu)2 in an average amount of at least 300,000,000 particles per mm2 the aluminum alloy product. aluminum comprises Mg2Si in an average amount of at least 600,000,000 particles per mm2 and/or wherein the aluminum alloy product comprises AUMg8Si7Cu2 in an average amount of at least 600,000,000 particles per mm2. 13. The aluminum alloy product of any one of claims 11 or 12, wherein the aluminum alloy product comprises MgZn2/Mg(Zn,Cu)2, Mg2Si, and AUMg8Si7Cu2. 14. The aluminum alloy product of claim 13, wherein a ratio of Mg2Si to AUMg8Si7Cu2 is from 1:1 to 1.5:1 and/or wherein the ratio of Mg2Si to MgZn2/Mg( Zn,Cu)2 is from 1.5:1 to 3:1 and/or wherein the ratio of AUMg8Si7Cu2 to MgZn2/Mg(Zn,Cu)2 is from 1.5:1 to 3:1. 15. A method for producing an aluminum alloy, comprising: casting an aluminum alloy according to any one of claims 1-8, to form an aluminum alloy cast product; homogenize the aluminum alloy cast product; hot rolling to provide a final gauge aluminum alloy; and perform solution heat treatment of the final gauge aluminum alloy. The method of claim 15, further comprising pre-aging the final gauge aluminum alloy and/or wherein the aluminum alloy is cast from molten aluminum alloy comprising scrap metal and, where In particular, where the scrap metal comprises a 6xxx series aluminum alloy, a 7xxx series aluminum alloy, or a combination of these.