CN110892086B

CN110892086B - High-strength corrosion-resistant aluminum alloy and manufacturing method thereof

Info

Publication number: CN110892086B
Application number: CN201780093038.XA
Authority: CN
Inventors: S.K.达斯; H.阿赫梅德; W.温
Original assignee: Novelis Inc Canada
Current assignee: Novelis Inc Canada
Priority date: 2017-07-10
Filing date: 2017-07-10
Publication date: 2022-02-01
Anticipated expiration: 2037-07-10
Also published as: WO2019013744A1; CN110892086A; JP7191077B2; CA3069499A1; KR102434921B1; JP2020527648A; EP3652356B1; ES2933801T3; KR20200028411A; EP3652356A1; CA3069499C; BR112020000305A2

Abstract

High strength aluminum alloys and manufacture are disclosedAnd methods of processing such alloys. The aluminum alloys described herein exhibit improved mechanical strength, deformability, and corrosion resistance. Additionally, the aluminum alloy can be prepared from recycled materials. The aluminum alloy products made from the alloys described herein include precipitates to enhance strength, such as MgZn2/Mg (Zn, Cu)2, Mg2Si, and Al₄Mg₈Si₇Cu₂。

Description

High-strength corrosion-resistant aluminum alloy and manufacturing method thereof

Technical Field

The present disclosure relates to aluminum alloys and methods of making and processing the same. The present disclosure further relates to aluminum alloys exhibiting high mechanical strength, formability, and corrosion resistance.

Background

Recyclable aluminum alloys having high strength are desirable for improving product performance in a number of applications including: transportation (including but not limited to, for example, truck, trailer, train, and marine), electronics, and automotive applications. For example, high strength aluminum alloys in trucks or trailers will be lighter than conventional steel alloys, providing significant emissions reduction needed to meet new, more stringent government emissions regulations. Such alloys should exhibit high strength, high formability and corrosion resistance. Further, it is desirable that such alloys be formed from recycled inclusions.

However, identifying processing conditions and alloy compositions that will provide such alloys, particularly alloys with recycled inclusions, has proven to be a challenge. Formation of the alloy from the recovered inclusions can result in higher zinc (Zn) and copper (Cu) contents. Traditionally, higher Zn alloys lack strength, while Cu-containing alloys are susceptible to corrosion.

Disclosure of Invention

The encompassed embodiments of the present invention are defined by the claims and not by this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are otherwise described in the detailed description section 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 as an aid in isolation to determine the scope of the claimed subject matter. The subject matter should be understood with reference to appropriate portions of the entire specification, any or all of the drawings, and each claim.

Described herein are aluminum alloys comprising about 0.25 to 1.3 wt.% Si, 1.0 to 2.5 wt.% Mg, 0.5 to 1.5 wt.% Cu, up to 0.2 wt.% Fe, up to 3.0 wt.% Zn, up to 0.15 wt.% impurities, with the remainder being Al. In some cases, the aluminum alloy may include about 0.55 to 1.1 wt.% Si, 1.25 to 2.25 wt.% Mg, 0.6 to 1.0 wt.% Cu, 0.05 to 0.17 wt.% Fe, 1.5 to 3.0 wt.% Zn, up to 0.15 wt.% of impurities, with the remainder being Al. In some cases, the aluminum alloy may include about 0.65 to 1.0 wt.% Si, 1.5 to 2.25 wt.% Mg, 0.6 to 1.0 wt.% Cu, 0.12 to 0.17 wt.% Fe, 2.0 to 3.0 wt.% Zn, up to 0.15 wt.% of impurities, with the remainder being Al. Optionally, the aluminum alloys described herein may additionally comprise Zr and/or Mn. Zr may be present in an amount up to about 0.15 wt% (e.g., about 0.09 to 0.12 wt%). Mn can be present in an amount up to about 0.5 wt% (e.g., about 0.05 to 0.3 wt%).

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

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

Optionally, the aluminum alloy product comprises a material selected from the group consisting of MgZn₂/Mg(Zn,Cu)₂、Mg₂Si and Al₄Mg₈Si₇Cu₂One or more precipitates of the group. The aluminum alloy product may comprise an average amount of at least about 300,000,000 particles per millimeter²MgZn of₂/Mg(Zn,Cu)₂An average amount of at least about 600,000,000 particles/mm²Mg of (2)₂Si and/or an average amount of at least about 600,000,000 particles/mm²Al of (2)₄Mg₈Si₇Cu₂. In some examples, the aluminum alloy product includes MgZn₂/Mg(Zn,Cu)₂、Mg₂Si and Al₄Mg₈Si₇Cu₂。Mg₂Si and Al₄Mg₈Si₇Cu₂May be from about 1:1 to about 1.5:1, Mg₂Si and MgZn₂/Mg(Zn,Cu)₂May be about 1.5:1 to about 3:1, and Al₄Mg₈Si₇Cu₂With MgZn₂/Mg(Zn,Cu)₂The ratio of (a) may be about 1.5:1 to about 3: 1.

Methods of making aluminum alloys are additionally described herein. The method includes casting an aluminum alloy as described herein to form an aluminum alloy casting; homogenizing the aluminum alloy casting; hot rolling the homogenized aluminum alloy casting to provide a final gauge aluminum alloy; and solution heat treating the final gauge aluminum alloy. 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 from scrap metal containing a6xxx series aluminum alloy, a7xxx series aluminum alloy, or combinations thereof.

Drawings

Fig. 1 is a graph illustrating the increase in magnesium zinc precipitates with increasing magnesium content in aluminum alloys prepared according to certain aspects of the present disclosure.

Fig. 2 is a differential scanning calorimetry map of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 3 is a differential scanning calorimetry map of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 4A is a transmission electron microscope micrograph illustrating types of precipitates in an aluminum alloy according to certain aspects of the present disclosure.

Fig. 4B is a transmission electron microscope micrograph illustrating precipitate types in an aluminum alloy according to certain aspects of the present disclosure.

Fig. 5 is a diagram illustrating a precipitate composition of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 6 is a series of optical micrographs illustrating precipitate formation after various processing steps of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 7 is a series of optical micrographs illustrating precipitate formation after various processing steps of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 8 is a series of optical micrographs illustrating precipitate formation after various processing steps of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 9 is a series of optical micrographs illustrating a grain structure and a particle population of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 10 is a series of optical micrographs illustrating a grain structure and a particle population of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 11 is a graph illustrating electrical conductivity of aluminum alloys according to certain aspects of the present disclosure.

Fig. 12 is a graph illustrating electrical conductivity of aluminum alloys according to certain aspects of the present disclosure.

Fig. 13 is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 14A is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 14B is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 15 is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 16A is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 16B is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 17A is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 17B is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 18A is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 18B is a graph illustrating yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 19 is a graph illustrating load displacement data from a 90 ° bend test of an aluminum alloy, according to certain aspects of the present disclosure.

Fig. 20 is a graph illustrating load displacement data from a 90 ° bend test of an aluminum alloy, according to certain aspects of the present disclosure.

Fig. 21 is a graph illustrating load displacement data from a 90 ° bend test of an aluminum alloy, according to certain aspects of the present disclosure.

Fig. 22 is a series of optical micrographs illustrating corrosion attack in an aluminum alloy according to certain aspects of the present disclosure.

Fig. 23 is a series of optical micrographs illustrating corrosion attack in an aluminum alloy according to certain aspects of the present disclosure.

Fig. 24A is an optical micrograph of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 24B is an optical micrograph of an aluminum alloy according to certain aspects of the present disclosure.

Fig. 24C is an optical micrograph of an aluminum alloy according to certain aspects of the present disclosure.

Detailed Description

High strength aluminum alloys and methods of making and processing such alloys are described herein. The aluminum alloys described herein exhibit improved mechanical strength, deformability, and corrosion resistance. Additionally, aluminum alloys can be prepared from recycled materials. Aluminum alloy products made from the alloys described herein include precipitates, such as MgZn, to enhance strength₂/Mg(Zn,Cu)₂、Mg₂Si and Al₄Mg₈Si₇Cu₂。

Definition and description:

the terms "invention," "the invention," "this invention," and "the invention" as used herein are intended to refer broadly to all subject matter of the present patent application and the claims that follow. Statements containing these terms should be understood as not limiting the subject matter described herein or as not limiting the meaning or scope of the following patent claims.

In this specification, reference is made to alloys identified by the aluminium industry name such as "series" or "6 xxx". In order to understand The numbering nomenclature system most commonly used to name and identify Aluminum and its Alloys, please see either "International Alloy nomenclature and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys" (International Alloy Designations and Chemical Compositions Limits for Wrought Aluminum and Wrought Aluminum Alloys) "or" Registration records of Aluminum Association Alloy nomenclature and Chemical Composition Limits for Aluminum Alloys in The Form of Castings and ingots "(Registration records of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in The Form of Castings and ingots" both published by The Aluminum Association (Aluminum Association ").

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

As used herein, the thickness of the sheet material is typically greater than about 6 mm. For example, sheet material may refer to an aluminum product having 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 40mm, greater than 45mm, greater than 50mm, or greater than 100 mm.

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

As used herein, the thickness of a sheet (also referred to as a slab) is typically from about 4mm to about 15 mm. For example, the thickness of the sheet may be 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, or 15 mm.

As used herein, sheet material generally refers to an aluminum product having a thickness of less than about 4 mm. For example, the 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 0.1 mm.

Reference is made in this application to alloy tempers or conditions. For an understanding of the most common Alloy Temper descriptions, please see "" American National Standards (ANSI) H35(American National Standards (ANSI) H35 on Alloy and temperature Designation Systems ") for alloys and Temper Designation Systems". Condition F or temper refers to the aluminum alloy produced. O condition or temper refers to the annealed aluminum alloy. The T4 condition or temper refers to the aluminum alloy after Solution Heat Treatment (SHT) (i.e., solution) followed by natural aging. The T6 condition or temper refers to the aluminum alloy after solution heat treatment followed by Artificial Aging (AA). 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" are interchangeable and refer to a product made by direct chill casting (including direct chill co-casting) or semi-continuous casting, continuous casting (including, for example, by using a twin belt caster, twin roll caster, block caster or any other continuous caster), electromagnetic casting, hot top casting or any other casting method.

As used herein, "room temperature" can mean a temperature of about 15 ℃ to about 30 ℃, e.g., about 15 ℃, about 16 ℃, about 17 ℃, about 18 ℃, about 19 ℃, about 20 ℃, about 21 ℃, about 22 ℃, about 23 ℃, about 24 ℃, about 25 ℃, about 26 ℃, about 27 ℃, about 28 ℃, about 29 ℃, or about 30 ℃.

All ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of "1 to 10" should be considered to include any and all subranges between (and including) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more, e.g., 1 to 6.1, and ending with a maximum value of 10 or less, e.g., 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. In certain examples of each alloy, the remainder is aluminum, with the maximum wt% of the sum of the impurities being 0.15%.

Alloy composition

Described below are novel aluminum alloys. In certain aspects, the alloys exhibit high strength, high formability, and corrosion resistance. The properties of the alloy are obtained as a result of the elemental composition of the alloy and the method of processing the alloy to make aluminum alloy products, including sheets, plates, and sheets.

In certain aspects, the alloys have a Cu content of about 0.5 wt% to about 1.5 wt%, a Zr content of 0.07 wt% to about 0.12 wt%, and a controlled Si to Mg ratio for a combined effect of strengthening, formability, and corrosion resistance, as described further below.

The alloy may have the following elemental composition as provided in table 1:

TABLE 1

In some examples, the alloy may have the following elemental composition as provided in table 2.

TABLE 2

In some examples, the alloy may have the following elemental composition as provided in table 3.

TABLE 3

In some examples, the disclosed alloys include silicon (Si) in an amount of about 0.25% to about 1.3% (e.g., about 0.55% to about 1.1% or about 0.65% to about 1.0%) by total weight of the alloy. For example, the alloy may include about 0.25%, about 0.26%, about 0.27%, about 0.28%, about 0.29%, about 0.3%, about 0.31%, about 0.32%, about 0.33%, about 0.34%, about 0.35%, about 0.36%, about 0.37%, about 0.38%, about 0.39%, about 0.4%, 0.41%, about 0.42%, about 0.43%, about 0.44%, about 0.45%, about 0.46%, about 0.47%, about 0.48%, about 0.49%, about 0.5%, about 0.51%, about 0.52%, about 0.53%, about 0.54%, about 0.55%, about 0.56%, about 0.57%, about 0.58%, about 0.59%, about 0.6%, about 0.61%, about 0.62%, about 0.63%, about 0.64%, about 0.65%, about 0.66%, about 0.67%, about 0.84%, about 0.82%, about 0.83%, about 0.82%, about 0.81%, about 0.82%, about 0.75%, about 0.83%, about 0.82%, about 0.83%, about 0.82%, about 0.75%, about 0., About 0.87%, about 0.88%, about 0.89%, about 0.9%, about 0.91%, about 0.92%, about 0.93%, about 0.94%, about 0.95%, about 0.96%, about 0.97%, about 0.98%, about 0.99%, about 1.0%, about 1.01%, about 1.02%, about 1.03%, about 1.04%, about 1.05%, about 1.06%, about 1.07%, about 1.08%, about 1.09%, about 1.1%, about 1.11%, about 1.12%, about 1.13%, about 1.14%, about 1.15%, about 1.16%, about 1.17%, about 1.18%, about 1.19%, about 1.2%, about 1.21%, about 1.22%, about 1.23%, about 1.24%, about 1.25%, about 1.26%, about 1.27%, about 1.28%, about 1.29%, or about 1.3% Si. All percentages are expressed in wt%.

In some examples, the alloys described herein comprise iron (Fe) in an amount of up to about 0.2% (e.g., about 0.05% to about 0.17% or about 0.12% to about 0.17%) by total weight of the alloy. For example, the alloy may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, or about 0.2% Fe. In some cases, Fe is not present in the alloy (i.e., 0%). All percentages are expressed in wt%.

In some examples, the alloys described herein include manganese (Mn) in an amount of up to about 0.5% (e.g., about 0.05% to about 0.3% or about 0.05% to about 0.2%) by total weight of the alloy. For example, the alloy may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.2%, about 0.21%, about 0.22%, about 0.23%, about 0.24%, about 0.25%, about 0.26%, about 0.27%, about 0.28%, about 0.29%, about 0.3%, about 0.31%, about 0.32%, about 0.33%, about 0.34%, about 0.35%, about 0.36%, about 0.37%, about 0.38%, about 0.39%, about 0.4%, about 0.41%, about 0.42%, about 0.43%, about 0.44%, about 0.46%, about 0.47%, about 48%, or about 0.46%. In some cases, Mn is not present in the alloy (i.e., 0%). All percentages are expressed in wt%.

In some examples, the disclosed alloys include magnesium (Mg) in an amount of about 1.0% to about 2.5% (e.g., about 1.25% to about 2.25% or about 1.5% to about 2.25%) by total weight of the alloy. For example, the alloy may include about 1.0%, about 1.01%, about 1.02%, about 1.03%, about 1.04%, about 1.05%, about 1.06%, about 1.07%, about 1.08%, about 1.09%, about 1.1%, about 1.11%, about 1.12%, about 1.13%, about 1.14%, about 1.15%, about 1.16%, about 1.17%, about 1.18%, about 1.19%, about 1.2%, about 1.21%, about 1.22%, about 1.23%, about 1.24%, about 1.25%, about 1.26%, about 1.27%, about 1.28%, about 1.29%, about 1.3%, about 1.31%, about 1.32%, about 1.33%, about 1.34%, about 1.35%, about 1.36%, about 1.37%, about 1.38%, about 1.39%, about 1.4%, about 1.41%, about 1.43%, about 1.42%, about 1.33%, about 1.34%, about 1.35%, about 1.36%, about 1.37%, about 1.46%, about 1.51%, about 1.52%, about 1.51%, about 1.48%, about 1.51%, about 1.48%, about 1.51%, about 1.52%, about 1.48%, about 1.51%, about 1.50%, about 1%, about 1.50%, about 1., About 1.62%, about 1.63%, about 1.64%, about 1.65%, about 1.66%, about 1.67%, about 1.68%, about 1.69%, about 1.7%, about 1.71%, about 1.72%, about 1.73%, about 1.74%, about 1.75%, about 1.76%, about 1.77%, about 1.78%, about 1.79%, about 1.8%, about 1.81%, about 1.82%, about 1.83%, about 1.84%, about 1.85%, about 1.86%, about 1.87%, about 1.88%, about 1.89%, about 1.9%, about 1.91%, about 1.92%, about 1.93%, about 1.94%, about 1.95%, about 1.96%, about 1.97%, about 1.98%, about 1.99%, about 2.0%, about 2.01%, about 2.02%, about 2.03%, about 2.04%, about 2.05%, about 2.96%, about 2.97%, about 2.09%, about 2.98%, about 2.99%, about 2.0%, about 2.01%, about 2.02%, about 2.2.2.05%, about 2.08%, about 2.2.06%, about 2.2%, about 2.2.2%, about 2.08%, about 2.15%, about 2.06%, about 2%, about 2.2%, about 2.2.06%, about 2%, about 2.2%, about 2.1%, about 2%, about 2.2%, about 2%, about 2.06%, about 2.2%, about 2%, about 2.2.2%, about 2.06%, about 2.2.2%, about 2%, about 2.2%, about 2.2.2%, about 2%, about 2.2%, about 2%, about 2.1%, about 2.2%, about 2.06%, about 2%, about 2.2%, about 2%, about 2.1%, about 2.1.1%, about 2%, about 2.06%, about 2.2.2%, about 2%, about 2.3%, about 2%, about 2.1%, about 2%, about 2.1.1.1.1.1%, about 2%, about 2.2%, about 2.1.1%, about 2%, about 2.1%, about 2%, about 2.06%, about 2%, about 2.1.1.1.06%, about 2.1.1%, about 2%, about 2.2.06%, about 2%, about 2.1.1.1%, about 2.1%, about 2%, about 2.3%, about 2%, about 2.1.1.1%, about 2%, about 2.3%, about 2%, about 2.06%, about 2%, about 2.1.1.1.1.1%, about 2.1%, about 2%, about 2.1.1%, about 2.1%, about 2%, about 2.1%, about 2.1.1.06%, about 2.1.1.1.1%, about 2%, about 2.27%, about 2.28%, about 2.29%, about 2.3%, about 2.31%, about 2.32%, about 2.33%, about 2.34%, about 2.35%, about 2.36%, about 2.37%, about 2.38%, about 2.39%, about 2.4%, about 2.41%, about 2.42%, about 2.43%, about 2.44%, about 2.45%, about 2.46%, about 2.47%, about 2.48%, about 2.49%, or about 2.5% Mg. All percentages are expressed in wt%.

In some examples, the disclosed alloys include copper (Cu) in an amount of about 0.5% to about 1.5% (e.g., about 0.6% to about 1.0% or about 0.6% to about 0.9%) by total weight of the alloy. For example, the alloy may include about 0.5%, about 0.51%, about 0.52%, about 0.53%, about 0.54%, about 0.55%, about 0.56%, about 0.57%, about 0.58%, about 0.59%, about 0.6%, about 0.61%, about 0.62%, about 0.63%, about 0.64%, about 0.65%, about 0.66%, about 0.67%, about 0.68%, about 0.69%, about 0.7%, about 0.71%, about 0.72%, about 0.73%, about 0.74%, about 0.75%, about 0.76%, about 0.77%, about 0.78%, about 0.79%, about 0.8%, about 0.81%, about 0.82%, about 0.83%, about 0.84%, about 0.85%, about 0.86%, about 0.87%, about 0.88%, about 0.89%, about 0.9%, about 0.91%, about 0.92%, about 0.93%, about 0.83%, about 0.84%, about 1.0.01%, about 1.09%, about 1.95%, about 1.05%, about 1.06%, about 1.05%, about 1.95%, about 1.1.1%, about 1.05%, about 1., About 1.12%, about 1.13%, about 1.14%, about 1.15%, about 1.16%, about 1.17%, about 1.18%, about 1.19%, about 1.2%, about 1.21%, about 1.22%, about 1.23%, about 1.24%, about 1.25%, about 1.26%, about 1.27%, about 1.28%, about 1.29%, about 1.3%, about 1.31%, about 1.32%, about 1.33%, about 1.34%, about 1.35%, about 1.36%, about 1.37%, about 1.38%, about 1.39%, about 1.4%, about 1.41%, about 1.42%, about 1.43%, about 1.44%, about 1.45%, about 1.46%, about 1.47%, about 1.48%, about 1.49%, or about 1.5% Cu. All percentages are expressed in wt%.

In some examples, the alloys described herein include zinc (Zn) in an amount up to about 3.0% (e.g., about 1.0% to about 3.0%, about 1.5% to about 3.0%, or about 2.0% to about 3.0%) by total weight of the alloy. For example, the alloy may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.2%, about 0.21%, about 0.22%, about 0.23%, about 0.24%, about 0.25%, about 0.26%, about 0.27%, about 0.28%, about 0.29%, about 0.3%, about 0.31%, about 0.32%, about 0.33%, about 0.34%, about 0.35%, about 0.36%, about 0.37%, about 0.38%, about 0.39%, about 0.4%, about 0.41%, about 0.42%, about 0.43%, about 0.34%, about 0.35%, about 0.36%, about 0.37%, about 0.38%, about 0.47%, about 0.51%, about 0.52%, about 0.46%, about 0.47%, about 0.51%, about 0.53%, about 0.52%, about 0.46%, about 0.47%, about 0.51%, about 0.48%, about 0.52%, about 0.50%, about 0.48%, about 0.51%, about 0., About 0.63%, about 0.64%, about 0.65%, about 0.66%, about 0.67%, about 0.68%, about 0.69%, about 0.7%, about 0.71%, about 0.72%, about 0.73%, about 0.74%, about 0.75%, about 0.76%, about 0.77%, about 0.78%, about 0.79%, about 0.8%, about 0.81%, about 0.82%, about 0.83%, about 0.84%, about 0.85%, about 0.86%, about 0.87%, about 0.88%, about 0.89%, about 0.9%, about 0.91%, about 0.92%, about 0.93%, about 0.94%, about 0.95%, about 0.96%, about 0.97%, about 0.98%, about 0.99%, about 1.0%, about 1.01%, about 1.02%, about 1.03%, about 1.04%, about 1.05%, about 1.06%, about 1.97%, about 1.98%, about 1.1.1%, about 1.1.1.1%, about 1.09%, about 1.1%, about 1.1.1%, about 1.1%, about 1.1.1.1%, about 1%, about 1.1%, about 1.1.1%, about 1%, about 1.1%, about 1%, about 1.1%, about 1.1.1%, about 1%, about 1.1.1%, about 1%, about 1.9%, about 1%, about 1.1.1%, about 1.1%, about 1%, about 1.1%, about 1.1.1%, about 1%, about 1.1.1%, about 1.1%, about 1.1.1%, about 1%, about 1.1.1.1.1%, about 1.1.1%, about 1%, about 1.1%, about 1%, about 1.1%, about 1%, about 1.1.1.1.1%, about 1.1%, about 1%, about 1.1%, about 1.1.1.1.1.1.1.1.1%, about 1%, about 1.1.1.1%, about 1%, about 1.1.1.1.1.1.1.1%, about 1%, about 1.1.1%, about 1.1.1.1.1%, about 1%, about 1.1.1%, about 1%, about 1.1%, about 1%, about 1.1.1%, about 1%, about 1.1%, about 1.1.1%, about 1%, about 1.1%, about 1%, about 1.1.1.1.26%, about 1%, about 1.1%, about 1%, about, About 1.28%, about 1.29%, about 1.3%, about 1.31%, about 1.32%, about 1.33%, about 1.34%, about 1.35%, about 1.36%, about 1.37%, about 1.38%, about 1.39%, about 1.4%, about 1.41%, about 1.42%, about 1.43%, about 1.44%, about 1.45%, about 1.46%, about 1.47%, about 1.48%, about 1.49%, about 1.5%, about 1.51%, about 1.52%, about 1.53%, about 1.54%, about 1.55%, about 1.56%, about 1.57%, about 1.58%, about 1.59%, about 1.6%, about 1.61%, about 1.62%, about 1.63%, about 1.64%, about 1.65%, about 1.66%, about 1.67%, about 1.68%, about 1.69%, about 1.7%, about 1.71%, about 1.82%, about 1.81%, about 1.84%, about 1.78%, about 1.81%, about 1.82%, about 1.83%, about 1.82%, about 1.81%, about 1.83%, about 1.82%, about 1.83%, about 1.81%, about 1.82%, about 1.83%, about 1.82%, about 1.83%, about 1.81%, about 1.82%, about 1.83%, about 1.81%, about 1.82%, about 1.83%, about 1.81%, about 1.83%, about 1.82%, about 1.83%, about 1.76%, about 1.83%, about 1.81%, about 1.83%, about 1.82%, about 1.83%, about 1.81%, about 1.82%, about 1., About 1.93%, about 1.94%, about 1.95%, about 1.96%, about 1.97%, about 1.98%, about 1.99%, about 2.0%, about 2.01%, about 2.02%, about 2.03%, about 2.04%, about 2.05%, about 2.06%, about 2.07%, about 2.08%, about 2.09%, about 2.1%, about 2.11%, about 2.12%, about 2.13%, about 2.14%, about 2.15%, about 2.16%, about 2.17%, about 2.18%, about 2.19%, about 2.2%, about 2.21%, about 2.22%, about 2.23%, about 2.24%, about 2.25%, about 2.26%, about 2.27%, about 2.28%, about 2.29%, about 2.3%, about 2.31%, about 2.32%, about 2.33%, about 2.34%, about 2.35%, about 2.36%, about 2.27%, about 2.28%, about 2.29%, about 2.3%, about 2.31%, about 2.32%, about 2.33%, about 2.34%, about 2.35%, about 2.43%, about 2.54%, about 2.46%, about 2.52%, about 2.46%, about 2.52%, about 2.46%, about 2.43%, about 2.52%, about 2.43%, about 2.46%, about 2.52%, about 2.46%, about 2.52%, about 2.43%, about 2.46%, about 2.43%, about 2.52%, about 2.43%, about 2.52%, about 2.50%, about 2%, about 2.50%, about 2%, about 2.50%, about 2%, about 2.50%, about, About 2.58%, about 2.59%, about 2.6%, about 2.61%, about 2.62%, about 2.63%, about 2.64%, about 2.65%, about 2.66%, about 2.67%, about 2.68%, about 2.69%, about 2.7%, about 2.71%, about 2.72%, about 2.73%, about 2.74%, about 2.75%, about 2.76%, about 2.77%, about 2.78%, about 2.79%, about 2.8%, about 2.81%, about 2.82%, about 2.83%, about 2.84%, about 2.85%, about 2.86%, about 2.87%, about 2.88%, about 2.89%, about 2.9%, about 2.91%, about 2.92%, about 2.93%, about 2.94%, about 2.95%, about 2.96%, about 2.97%, about 2.98%, about 2.99%, or about 3.0% zinc. In some cases, Zn is not present in the alloy (i.e., 0%). All percentages are expressed in wt%.

Optionally, zirconium (Zr) may be included in the alloys described herein. In some examples, the alloy includes Zr in an amount of up to about 0.15% (e.g., about 0.07% to about 0.15%, about 0.09% to about 0.12%, or about 0.08% to about 0.11%) by total weight of the alloy. For example, the alloy may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, or about 0.15% Zr. In some examples, Zr is not present in the alloy (i.e., 0%). All percentages are expressed in wt%. In certain aspects, Zr is added to the above-described compositions to form (Al, Si)₃Zr Dispersion (DO)₂₂/DO₂₃Dispersion) and/or Al₃Zr Dispersion (L1)₂Dispersion).

Optionally, the alloy composition may additionally include other trace elements, sometimes referred to as impurities, each in an amount of about 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, Ga, V, Ni, Sc, Ag, B, Bi, Li, Pb, Sn, Ca, Cr, Ti, Hf, Sr, or combinations thereof. Thus, Ga, V, Ni, Sc, Ag, B, Bi, Li, Pb, Sn, Ca, Cr, Ti, Hf or Sr may be present in the alloy in the following amounts: 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, or 0.01% or less. In certain aspects, the sum of all impurities does not exceed 0.15% (e.g., 0.1%). All percentages are expressed in wt%. In certain aspects, the remaining percentage of the alloy is aluminum.

Suitable exemplary 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, with the remainder being Al. In some cases, a suitable exemplary alloy may include 0.55% to 0.65% Si, 1.5% Mg, 0.7% to 0.8% Cu, 1.55% Zn, 0.14% to 0.15% Mn, 0.16% to 0.18% Fe, and up to 0.15% total impurities, with the remainder being Al. In some cases, a suitable exemplary alloy may include 0.65% Si, 1.5% Mg, 1.0% Cu, 2.0% -3.0% Zn, 0.14-0.15% Mn, 0.17% Fe, and up to 0.15% total impurities, with the remainder being Al.

Microstructure and characteristics of the alloy

In certain aspects, Cu, Mg, and Si ratios and Zn content are controlled to enhance corrosion resistance, strength, and formability. The Zn content can control the corrosion morphology as described below by, for example, causing pitting corrosion and inhibiting intergranular corrosion (IGC).

In some examples, the ratio of Mg to Si (also referred to herein as the Mg/Si ratio) can be about 1.5:1 to about 3.5:1 (e.g., about 1.75:1 to about 3.0:1 or about 2.0:1 to about 3.0: 1). For example, the Mg/Si ratio can be about 1.5:1, about 1.6:1, about 1.7:1, about 1.8:1, about 1.9:1, about 2.0:1, about 2.1:1, about 2.2:1, about 2.3:1, about 2.4:1, about 2.5:1, about 2.6:1, about 2.7:1, about 2.8:1, about 2.9:1, about 3.0:1, about 3.1:1, about 3.2:1, about 3.3:1, about 3.4:1, about 3.5:1, about 3.6:1, about 3.7:1, about 3.8:1, about 3.9:1, or about 4.0: 1. In some non-limiting examples, aluminum alloys having a Mg/Si ratio of about 1.5:1 to about 3.5:1 (e.g., about 2.0:1 to about 3.0:1) may exhibit high strength and increased formability.

In some non-limiting examples, aluminum alloys having a Mg/Si ratio of about 2.0:1 to 3.0:1 and a Zn content of about 2.5 wt.% to about 3.0 wt.% may exhibit the inhibition of IGC that is typically observed in aluminum alloys having Mg and Si as the main alloying elements, but may cause pitting corrosion. In some cases, pitting is more advantageous than IGC due to the limited depth of attack, because IGC can occur along grain boundaries and propagate deeper into the aluminum alloy than pitting. In some non-limiting examples, the ratio of Zn to Mg/Si ratio (i.e., Zn/(Mg/Si) ratio) can be from about 0.75:1 to about 1.4:1 (e.g., from about 0.8:1 to about 1.1: 1). For example, the Zn/(Mg/Si) ratio can be about 0.75:1, about 0.8:1, about 0.85:1, about 0.9:1, about 0.95:1, about 1.0:1, about 1.05:1, about 1.1:1, about 1.15:1, about 1.2:1, about 1.25:1, about 1.3:1, about 1.35:1, or about 1.4: 1.

In some yet further non-limiting examples, the ratio of Cu to Zn/(Mg/Si) ratio (i.e., Cu/[ Zn/(Mg/Si) ] ratio) can be from about 0.7:1 to about 1.4:1 (e.g., the Cu/[ Zn/(Mg/Si) ] ratio can be from about 0.8:1 to about 1.1: 1). For example, the ratio of Cu/[ Zn/(Mg/Si) ] may be about 0.7:1, about 0.75:1, about 0.8:1, about 0.85:1, about 0.9:1, about 0.95:1, about 1.0:1, about 1.05:1, about 1.1:1, about 1.15:1, about 1.2:1, about 1.25:1, about 1.3:1, about 1.35:1, or about 1.4: 1. In some non-limiting examples, the ratio of Cu/[ Zn/(Mg/Si) ] can provide high strength, high deformability, and high corrosion resistance.

In certain aspects, Cu, Si, and Mg may form precipitates in the alloy, resulting in an alloy with higher strength and enhanced corrosion resistance. These precipitates may form during aging after solution heat treatment. The Mg and Cu content may provide an M/eta phase or an M phase (e.g., MgZn)₂/Mg(Zn,Cu)₂) To produce precipitates that increase the strength of the aluminum alloy. During the precipitation process, a metastable meniere-Preston (GP) region may form, which in turn is transferred into a β "acicular precipitate (e.g., magnesium silicide, Mg)₂Si) which contributes to precipitation strengthening of the disclosed alloys. In certain aspects, the addition of Cu results in the formation of lathe-like L-phase precipitates (e.g., Al)₄Mg₈Si₇Cu₂) Which is a precursor for the formation of the Q' precipitate phase and additionally contributes to strength.

In some examples, MgZn is included₂And/or Mg (Zn, Cu)₂The M-phase precipitate of (a) may be at least about 300,000,000 particles per square millimeter (mm)²) Is present in the aluminum alloy. For example, the M-phase precipitate may be at least about 310,000,000 particles/mm²At least about320,000,000 particles/mm²At least about 330,000,000 particles/mm²At least about 340,000,000 particles/mm²At least about 350,000,000 particles/mm²At least about 360,000,000 particles/mm²At least about 370,000,000 particles/mm²At least about 380,000,000 particles/mm²At least about 390,000,000 particles/mm²Or at least about 400,000,000 particles/mm²Is present in an amount.

In some examples, Al is included₄Mg₈Si₇Cu₂The L-phase precipitate of (a) may be at least about 600,000,000 particles per square millimeter (mm)²) Is present in the aluminum alloy. For example, the L-phase precipitate may be at least about 610,000,000 particles/mm²At least about 620,000,000 particles/mm²At least about 630,000,000 particles/mm²At least about 640,000,000 particles/mm²At least about 650,000,000 particles/mm²At least about 660,000,000 particles/mm²At least about 670,000,000 particles/mm²At least about 680,000,000 particles/mm²At least about 690,000,000 particles/mm²Or at least about 700,000,000 particles/mm²Is present in an amount.

In some examples, including Mg₂The beta' phase precipitates of Si may be at least about 600,000,000 particles per square millimeter (mm)²) Is present in the aluminum alloy. For example, the beta "phase precipitate may be at least about 610,000,000 particles/mm²At least about 620,000,000 particles/mm²At least about 630,000,000 particles/mm²At least about 640,000,000 particles/mm²At least about 650,000,000 particles/mm²At least about 660,000,000 particles/mm²At least about 670,000,000 particles/mm²At least about 680,000,000 particles/mm²At least about 690,000,000 particles/mm²At least about 700,000,000 particles/mm²At least about 710,000,000 particles/mm²At least about 720,000,000 particles/mm²At least about 730,000,000 particles/mm²At least about 740,000,000 particles/mm²Or at least about 750,000,000 particles/mm²Is present in an amount.

In some examples, a beta "phase precipitate (e.g., Mg)₂Si) with L-phase precipitates (e.g., Al)₄Mg₈Si₇Cu₂) The ratio of (a) can be about 1:1 to about 1.5:1 (e.g., about 1.1:1 to about 1.4: 1). For example, the ratio of β "phase precipitates to L phase precipitates may be about 1:1, about 1.1:1, about 1.2:1, about 1.3:1, about 1.4:1, or about 1.5: 1.

In some examples, a beta "phase precipitate (e.g., Mg)₂Si) and M phase precipitates (e.g., MgZn)₂And/or Mg (Zn, Cu)₂) The ratio of (a) may be about 1.5:1 to about 3:1 (e.g., about 1.6:1 to about 2.8:1 or about 2.0:1 to about 2.5: 1). For example, the ratio of β "phase precipitates to M phase precipitates may be about 1.5:1, about 1.6:1, about 1.7:1, about 1.8:1, about 1.9:1, about 2.0:1, about 2.1:1, about 2.2:1, about 2.3:1, about 2.4:1, about 2.5:1, about 2.6:1, about 2.7:1, about 2.8:1, about 2.9:1, or about 3.0: 1.

In some examples, L-phase precipitates (e.g., Al)₄Mg₈Si₇Cu₂) With M phase precipitates (e.g. MgZn)₂And/or Mg (Zn, Cu)₂) The ratio of (a) may be about 1.5:1 to about 3:1 (e.g., about 1.6:1 to about 2.8:1 or about 2.0:1 to about 2.5: 1). For example, the ratio of L phase precipitate to M phase precipitate may be about 1.5:1, about 1.6:1, about 1.7:1, about 1.8:1, about 1.9:1, about 2.0:1, about 2.1:1, about 2.2:1, about 2.3:1, about 2.4:1, about 2.5:1, about 2.6:1, about 2.7:1, about 2.8:1, about 2.9:1, or about 3.0: 1.

As additionally provided below, the alloys described herein exhibit excellent mechanical properties. Depending on the desired use, the mechanical properties of the aluminum alloy can be additionally controlled by various aging conditions. As one example, the alloy may be manufactured (or provided) in a T4 temper or a T6 temper. A solution heat treated and naturally aged T4 aluminum alloy article may be provided. These T4 aluminum alloy articles may optionally be subjected to additional one or more aging treatments to meet strength requirements as received. For example, the aluminum alloy article may be conveyed in other tempers, such as the T6 temper, by subjecting the T4 alloy material to appropriate aging as described herein or otherwise known to those skilled in the art. Exemplary characteristics in exemplary tempers are provided below.

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

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

In certain aspects, the aluminum alloy has sufficient ductility or toughness to meet a 90 ° bendability of 1.0 or less (e.g., 0.5 or less) in a T4 temper. In certain examples the r/t bendability ratio is about 1.0 or less, about 0.9 or less, about 0.8 or less, about 0.7 or less, about 0.6 or less, about 0.5 or less, about 0.4 or less, about 0.3 or less, about 0.2 or less, or about 0.1 or less, where r is the radius of the tool (mold) used and t is the thickness of the material.

In certain aspects, the aluminum alloy exhibits a uniform elongation of greater than or equal to 20% in a T4 temper and a total elongation of greater than or equal to 30% in a T4 temper. In certain aspects, the alloy exhibits a uniform elongation of greater than or equal to 22% and a total elongation of greater than or equal to 35%. For example, the alloy may exhibit 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. The alloy may exhibit a uniform 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, the aluminum alloy exhibits suitable resistance to IGC as measured by ISO 11846B. For example, pitting in aluminum alloys may be completely inhibited or improved such that the average intercrystalline corrosion pit depth of the alloy in a T6 temper is less than 100 μm. For example, the average intercrystalline etch pit depth can be less than 90 μm, less than 80 μm, less than 70 μm, less than 60 μm, less than 50 μm, or less than 40 μm.

Preparation method of aluminum alloy

In certain aspects, the disclosed alloy compositions are the product of the disclosed methods. Without wishing to limit the present disclosure, aluminum alloy properties are determined in part by the formation of microstructures during alloy preparation. In certain aspects, the method of making the alloy composition may influence or even determine whether the alloy has sufficient properties to meet the desired application.

Casting

The alloys described herein may be cast using a casting method. In some non-limiting examples, an aluminum alloy as described herein can be cast from a molten aluminum alloy that includes a scrap alloy (e.g., cast from AA6xxx series aluminum alloy scrap, AA7xxx series aluminum alloy scrap, or combinations thereof). For example, the casting process may comprise a Direct Chill (DC) casting process. Optionally, the ingot may be scalped prior to downstream processing. Optionally, the casting process may comprise a Continuous Casting (CC) process. The cast aluminum alloy may then be subjected to additional processing steps. For example, a processing method as described herein may include the steps of homogenizing, hot rolling, solution heat treating, and quenching. In some cases, the processing method may further include a pre-aging step and/or an artificial aging step.

Homogenization

The homogenization step can include heating an ingot prepared from the alloy composition described herein to obtain a Peak Metal Temperature (PMT) of about or at least about 500 ℃ (e.g., at least 520 ℃, at least 530 ℃, at least 540 ℃, at least 550 ℃, at least 560 ℃, at least 570 ℃, or at least 580 ℃). For example, the ingot can be heated to a temperature of about 500 ℃ to about 600 ℃, about 520 ℃ to about 580 ℃, about 530 ℃ to about 575 ℃, about 535 ℃ to about 570 ℃, about 540 ℃ to about 565 ℃, about 545 ℃ to about 560 ℃, about 530 ℃ to about 560 ℃, or about 550 ℃ to about 580 ℃. In some cases, the heating rate of the PMT may be about 70 degrees celsius/hour or less, 60 degrees celsius/hour or less, 50 degrees celsius/hour or less, 40 degrees celsius/hour or less, 30 degrees celsius/hour or less, 25 degrees celsius/hour or less, 20 degrees celsius/hour or less, or 15 degrees celsius/hour or less. In other cases, the heating rate of the PMT may be from about 10 degrees celsius/minute to about 100 degrees celsius/minute (e.g., from about 10 degrees celsius/minute to about 90 degrees celsius/minute, from about 10 degrees celsius/minute to about 70 degrees celsius/minute, from about 10 degrees celsius/minute to about 60 degrees celsius/minute, from about 20 degrees celsius/minute to about 90 degrees celsius/minute, from about 30 degrees celsius/minute to about 80 degrees celsius/minute, from about 40 degrees celsius/minute to about 70 degrees celsius/minute, or from about 50 degrees celsius/minute to about 60 degrees celsius/minute).

The ingot is then allowed to soak (i.e., remain at the indicated temperature) for a period of time. According to one non-limiting example, the ingot is allowed to soak for up to about 6 hours (e.g., about 30 minutes to about 6 hours inclusive). For example, the ingot may be soaked at a temperature of at least 500 ℃ for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours, or any time in between.

Hot rolling

After the homogenization step, a hot rolling step may be performed to form a hot rolled strip. In some cases, the ingot is laid down and hot rolled at an exit temperature in the range of about 230 ℃ to about 300 ℃ (e.g., about 250 ℃ to about 300 ℃). For example, the hot rolling exit temperature can be about 230 ℃, about 235 ℃, about 240 ℃, about 245 ℃, about 250 ℃, about 255 ℃, about 260 ℃, about 265 ℃, about 270 ℃, about 275 ℃, about 280 ℃, about 285 ℃, about 290 ℃, about 295 ℃, or about 300 ℃.

In some cases, the ingot may be hot rolled to a gauge of about 4mm to about 15mm thick (e.g., a gauge of about 5mm to about 12mm thick). For example, the ingot may be hot rolled to a gauge of about 4mm thick, a gauge of about 5mm thick, a gauge of about 6mm thick, a gauge of about 7mm thick, a gauge of about 8mm thick, a gauge of about 9mm thick, a gauge of about 10mm thick, a gauge of about 11mm thick, a gauge of about 12mm thick, a gauge of about 13mm thick, a gauge of about 14mm thick, or a gauge of about 15mm thick. In some cases, the ingot may be hot rolled to a gauge (i.e., sheet gauge) greater than 15mm thick. In other cases, the ingot may be hot rolled to a gauge of less than 4mm (i.e., sheet gauge).

Solution heat treatment

After the hot rolling step, the hot rolled strip may be cooled by air and then solutionized in a solution heat treatment step. Solution heat treatment can include heating the final gauge aluminum alloy from room temperature to a temperature of about 520 ℃ to about 590 ℃ (e.g., about 520 ℃ to about 580 ℃, about 530 ℃ to about 570 ℃, about 545 ℃ to about 575 ℃, about 550 ℃ to about 570 ℃, about 555 ℃ to about 565 ℃, about 540 ℃ to about 560 ℃, about 560 ℃ to about 580 ℃, or about 550 ℃ to about 575 ℃). The final gauge aluminum alloy may be soaked at the temperature for a period of time. In certain aspects, the final gauge aluminum alloy is allowed to soak for up to about 2 hours (e.g., about 10 seconds to about 120 minutes, inclusive). For example, the final gauge aluminum alloy may be soaked at a temperature of about 525 ℃ to about 590 ℃ 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 any time therebetween.

Quenching

In certain aspects, the final gauge aluminum alloy may then be cooled to a temperature of about 35 ℃ in a quenching step based on the selected gauge at a quenching rate that may vary between about 50 degrees celsius/second to 400 degrees celsius/second. For example, the quenching rate can be about 50 degrees celsius/second to about 375 degrees celsius/second, about 60 degrees celsius/second to about 375 degrees celsius/second, about 70 degrees celsius/second to about 350 degrees celsius/second, about 80 degrees celsius/second to about 325 degrees celsius/second, about 90 degrees celsius/second to about 300 degrees celsius/second, about 100 degrees celsius/second to about 275 degrees celsius/second, about 125 degrees celsius/second to about 250 degrees celsius/second, about 150 degrees celsius/second to about 225 degrees celsius/second, or about 175 degrees celsius/second to about 200 degrees celsius/second.

In the quenching step, the final gauge aluminum alloy is rapidly quenched with a liquid (e.g., water) and/or a gas or another selected quenching medium. In certain aspects, the final gauge aluminum alloy may be rapidly quenched with water.

Pre-ageing

Optionally, a pre-aging step may be performed. The pre-aging step can include heating the final gauge aluminum alloy to a temperature of about 100 ℃ to about 160 ℃ (e.g., about 105 ℃ to about 155 ℃, about 110 ℃ to about 150 ℃, about 115 ℃ to about 145 ℃, about 120 ℃ to about 140 ℃, or about 125 ℃ to about 135 ℃) after the quenching step. In certain aspects, the aluminum alloy sheet, plate, or sheet is allowed to soak for up to about three hours (e.g., up to about 10 minutes, up to about 20 minutes, up to about 30 minutes, up to about 40 minutes, up to about 45 minutes, up to about 60 minutes, up to about 90 minutes, up to about two hours, or up to about three hours).

Aging

The final gauge aluminum alloy may be naturally aged or artificially aged. In some examples, the final gauge aluminum alloy may be naturally aged for a period of time to produce a T4 temper. In certain aspects, the final gauge aluminum alloy in the T4 temper may be Artificially Aged (AA) for a period of time at about 180 ℃ to 225 ℃ (e.g., 185 ℃, 190 ℃, 195 ℃, 200 ℃, 205 ℃, 210 ℃, 215 ℃, 220 ℃, or 225 ℃). Optionally, the final gauge aluminum alloy is artificially aged for a period of time from about 15 minutes to about 8 hours (e.g., 15 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, or 8 hours, or any time in between) to produce a T6 temper.

Application method

The alloys and methods described herein may be used in automotive, electronics, and transportation applications, such as commercial vehicle, aircraft, or railroad applications, or other applications. For example, the alloy may be used for the chassis, cross-members, and chassis internals (including but not limited to all components between two C-channels in a commercial vehicle chassis) to obtain strength, as a full or partial replacement for high strength steel. In certain examples, the alloys may be used in T4 and T6 tempers.

In certain aspects, the alloys and methods can be used to prepare automotive body part products. For example, the disclosed alloys and methods can be used to prepare automotive body parts such as bumpers, side rails, roof rails, cross beams, pillar reinforcements (e.g., a-pillars, B-pillars, and C-pillars), inner panels, side panels, flooring, pipes, structural panels, gusset panels, inner covers, or trunk lids. The disclosed aluminum alloys and methods may also be used in aircraft or railway vehicle applications to make, for example, exterior and interior panels. In certain aspects, the disclosed alloys may be used in other specific applications, such as automotive battery plates/sheets.

The described alloys and methods may also be used to prepare housings for electronic devices, including mobile phones and tablet computers. For example, the alloys may be used to prepare the housing of the outer casing of a mobile phone (e.g., a smartphone) and a tablet chassis, with or without anodization. The alloys can also be used to make other consumer electronics and product parts. Exemplary consumer electronics include mobile phones, audio devices, video devices, cameras, laptop computers, desktop computers, tablet computers, televisions, displays, home appliances, video playback and recording devices, and the like. Exemplary consumer electronic parts include housings (e.g., exterior walls) and interior linings for consumer electronics.

However, the following examples will serve to additionally illustrate the invention without constituting any limitation thereof. On the contrary, it is to be clearly understood that resort may be had to various embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the present invention. Unless otherwise indicated, during the study described in the examples below, conventional procedures were followed. For illustrative purposes, some of the procedures are described below.

Examples of the invention

Example 1: aluminum alloy composition

Tables 4A and 4B below summarize exemplary aluminum alloys, and table 5 provides the properties of the alloys, including Yield Strength (YS), intergranular corrosion pit depth (IGC), and 90 ° bendability (bend).

TABLE 4A

All expressed in wt%; total impurities up to 0.15 wt%; the balance being Al.

TABLE 4B

TABLE 5

Alloy (I)	YS(MPa)	IGC(μm)	Bending (90 degree)
				1	380	300	Failure of
2	370	250	Failure of
				3	340	0	By passing
4	360	200	Failure of
				5	370	120	By passing

The properties of the alloy are achieved by controlling the ratio of the alloying elements. Alloy 1 represents a comparative AA6 xxx-series aluminum alloy, due to Mg₂Si strengthens precipitates in the aluminum alloy to exhibit high strength. Alloy 2 represents a comparative aluminum alloy that exhibits improved corrosion resistance and a slight decrease in strength upon addition of Zn.

Alloys

1 and 2, wherein Cu/[ Zn/(Mg/Si)]Does not fall within the range of about 0.7 to about 1.4, exhibits significant IGC and failure in the 90 ° bend test. Alloy 3 represents an exemplary aluminum alloy, where Cu/[ Zn/(Mg/Si)]Closer to the range of about 0.7 to about 1.4 than alloy 2, which exhibits reduced strength and excellent formability and IGC resistance. Alloy 4 represents an exemplary aluminum alloy, where Cu/[ Zn/(Mg/Si)]Falls within the range of about 0.7 to about 1.4, but the Zn/(Mg/Si) ratio does not fall within the range of about 0.75 to about 14, which exhibits significant IGC and poor formability and increased strength when compared to alloy 3. Alloy 5 represents an exemplary aluminum alloy, with Mg/Si, Zn/(Mg/Si), and Cu/[ Zn/(Mg/Si)]Fall within respective ranges, which exhibit high strength, good formability, and good corrosion resistance.

Additionally, exemplary alloys are manufactured according to the direct chill casting method described herein. The alloy compositions are summarized in table 6 below:

TABLE 6

Alloy (I)	Si	Fe	Cu	Mn	Mg	Cr	Zn	Ti
									A	0.65	0.20	1.10	0.15	1.50	0.05	2.0	0.02
B	0.65	0.20	1.10	0.15	1.50	0.05	2.5	0.02
									C	0.65	0.20	1.10	0.15	1.50	0.05	3.0	0.02

All expressed in wt%; the balance being Al.

Example 2: microstructure of aluminum alloy

Exemplary alloys are manufactured by direct chill casting and processed according to the methods described herein. As described above, the Mg and Cu content may provide an M phase (e.g., MgZn)₂/Mg(Zn,Cu)₂) Providing precipitates that increase the strength of the aluminum alloy. M phase (e.g., MgZn) as a function of Mg content in exemplary alloys₂) Evaluation of the precipitate. FIG. 1 is a graph showing that the Mg content increases from 1.0 wt% to 3.0 wt%. As is apparent from the figure, the mass fraction of M-phase precipitates (i) increases proportionally with the increase in Mg content from 1.0 wt% to 1.5 wt%, (ii) when the Mg content increases from 1.5 wt%, (ii) is increasedRemains constant when added to 2.0 wt.%, (iii) increases proportionally with Mg content increasing from 2.0 wt.% to 2.5 wt.%, and (iv) plateaus with Mg content greater than 2.5 wt.%. The increase in M-phase precipitates provides increased strength in the exemplary alloys.

Fig. 2 is a graph showing Differential Scanning Calorimetry (DSC) analysis of samples of exemplary alloy 3 described above (referred to as "H1", "H2", and "H3"). Exothermic peak a indicates the formation of a precipitate in the exemplary alloy, and endothermic peak B indicates the melting point of the exemplary alloy 3 sample.

Fig. 3 is a graph showing DSC analysis of samples of the exemplary alloy 5 described above (referred to as "H5", "H6", and "H7"). Exothermic peak a indicated M-phase precipitate. Exothermic peak B indicating beta' (Mg)₂Si) precipitates, showing the formation of strengthening precipitates during the artificial aging step, and corresponding to the strength increase of the exemplary aluminum alloys. Endothermic peak C indicates the melting point of the exemplary alloy 5 sample.

FIG. 4A is a graph showing three different strengthening precipitation phases, namely M (MgZn)₂)410、β”(Mg₂Si)420 and L (Al)₄Mg₈Si₇Cu₂)430, respectively, in a Transmission Electron Microscope (TEM) micrograph. For a 10mm gauge aluminum alloy (e.g., alloy 5), the combination of the three precipitation phases produces a yield strength of about 370MPa in the T6 temper. Fig. 4B is a TEM micrograph showing Zr-containing precipitate particles 440. Excess Zr in the exemplary alloys can lead to the formation of coarse acicular particles. The coarse acicular Zr-containing precipitate particles 440 may reduce the formability of the exemplary alloy. Likewise, too little Zr in exemplary alloys may not provide the desired Al₃Zr and/or (Al, Si)₃Zr dispersion.

FIG. 5 is a graph showing the number (#/mm) of precipitated particles per square millimeter²) Each different strengthening precipitation phase, i.e. M (MgZn), in units and as a function of the analyzed area of the occupation (%) of each different precipitation phase in alloy C (see table 6)₂)、L(Al₄Mg₈Si₇Cu₂) And beta' (Mg)₂Si) density. The β "precipitates are dominant in both density and footprint due to their shape. Thus, the smaller M and L precipitate occupied areaThe volume is small and is present in a density comparable to the β "precipitate.

Fig. 6 shows an optical micrograph of a sample of alloy 3 as described above. The as-cast samples (top row), homogenized samples (middle row) and hot rolled samples reduced to 10mm gauge (bottom row) were analyzed for precipitates. Eutectic phase precipitates were evident in the as-cast samples. The precipitate was not completely dissolved after homogenization, as shown in the middle row of the micrograph. Coarse (e.g., greater than about 5 microns) precipitates are evident in the hot rolled samples.

Fig. 7 shows an optical micrograph of a sample of alloy 3 described above after casting, homogenization, hot rolling to 10mm gauge and various solution heat treatment procedures to achieve maximum dissolution of strengthening precipitates during solution heat treatment. Plot a of fig. 7 shows alloy 3 samples solutionized at a temperature of 555 ℃ for 45 minutes. Panel B of FIG. 7 shows alloy 3 samples solutionized at a temperature of 350℃ for 45 minutes, then at a temperature of 500℃ for 30 minutes, and finally at a temperature of 565℃ for 30 minutes. Panel C of FIG. 7 shows alloy 3 samples solutionized at a temperature of 350℃ for 45 minutes, then at a temperature of 500℃ for 30 minutes, and finally at a temperature of 565℃ for 60 minutes. Plot D of fig. 7 shows alloy 3 samples solutionized at a temperature of 560 ℃ for 120 minutes. Panel E of FIG. 7 shows alloy 3 samples solutionized at a temperature of 500 ℃ for 30 minutes, and then at a temperature of 570 ℃ for 30 minutes. Panel F of FIG. 7 shows alloy 3 samples solutionized at a temperature of 500 ℃ for 30 minutes, and then at a temperature of 570 ℃ for 60 minutes.

Fig. 8 shows an optical micrograph of a sample of alloy 5 as described above. The as-cast samples (top row) and the homogenized samples (bottom row) were analyzed for precipitates. Eutectic phase precipitates were evident in the as-cast samples. The precipitate was not completely dissolved after homogenization, as seen in the bottom row of the micrograph. However, alloy 5 exhibited less undissolved precipitate than homogenized alloy 3 due to changes in solute levels (e.g., Mg levels, Si levels, and Mg/Si ratios).

Fig. 9 shows an optical micrograph of a sample of alloy 5 described above after hot rolling to 10mm gauge. Plots A, B and C of FIG. 9 show precipitated particles (seen as black dots) in the exemplary alloy sample after hot rolling to 10mm gauge. Plots D, E and F of FIG. 9 show the grain structure after hot rolling an exemplary alloy 5 sample to 10mm gauge. The grains are not completely recrystallized due to the low hot rolling exit temperature of about 280 ℃ to about 300 ℃.

FIG. 10 shows an optical micrograph of a sample of alloy 5 described above after hot rolling to 10mm gauge, solution heat treatment and natural aging to T4 temper. Regions A, B and C of FIG. 10 show very few precipitated particles in the exemplary alloy sample in the T4 temper. Regions D, E and F of FIG. 10 show the fully recrystallized grain structure of the exemplary alloy 5 sample in a T4 temper.

Fig. 11 is a graph showing the electrical conductivity of samples of alloy 3 after casting, homogenization, hot rolling, various solution heat treatment procedures, and Artificial Aging (AA). The conductivity data (i.e. the conductivity as a percentage of international annealed copper standard (% IACS)) shows that there is a large amount of precipitation after hot rolling. Various solution heat treatment procedures were evaluated in an attempt to dissolve the precipitate. Solution heat treatment is not effective in dissolving the precipitates. Furthermore, there is not enough strengthening precipitate formation during artificial aging to provide optimal strength.

Fig. 12 is a graph showing the electrical conductivity of samples of alloy 5 (referred to as "HR 5", "HR 6", and "HR 7") after casting, homogenization, hot rolling, solution heat treatment, and artificial aging. Electrochemical test data showed a large amount of precipitation after hot rolling. Various solution heat treatment procedures were evaluated in an attempt to dissolve the precipitate. The solution heat treatment is effective to dissolve the precipitate. Furthermore, artificial aging provides enhanced precipitate formation, thereby providing optimal strength.

Example 3: mechanical Properties of aluminum alloy

Fig. 13 is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of the exemplary alloys A, B and C described above. The alloy was solutionized at 565 ℃ for 45 minutes, pre-aged at 125 ℃ for 2 hours, and artificially aged at 200 ℃ for 4 hours to produce a T6 temper. Each alloy exhibits a yield strength greater than 370MPa, an ultimate tensile strength greater than 425MPa, a uniform elongation greater than 10% and a total elongation greater than 17%. The increase in Zn content did not significantly affect the strength of the exemplary aluminum alloys, but did improve the intergranular corrosion resistance and formability.

Fig. 14A is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) for samples of exemplary alloy 3 (designated "H1T 4", "H2T 4", and "H3T 4") in a T4 temper. Fig. 14B is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) for samples of exemplary alloy 3 (designated "H1T 6", "H2T 6", and "H3T 6") in a T6 temper.

Fig. 15 is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of samples of exemplary alloy 3 in a T6 temper (referred to as "H1", "H2", and "H3") after various aging procedures as indicated by the x-axis of the graph. As is evident in the figure, the three-step aging procedure is capable of producing high strength (e.g., 348MPa) aluminum alloys. It is also apparent in the figure that aging at low temperatures (e.g., below 250 ℃) is not sufficient to produce strengthening precipitates in the alloy samples.

Fig. 16A is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) for samples of exemplary alloy 4 (referred to as "HR 1", "HR 2", "HR 3", and "HR 4") in a T4 temper. Fig. 16B is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) after various aging procedures for samples of exemplary alloy 4 in a T6 temper (referred to as "HR 1", "HR 2", "HR 3", and "HR 4"). As is evident in the figure, a maximum strength of 360MPa is reached. It is also apparent in the figure that aging at low temperatures (e.g., below 250 ℃) is not sufficient to produce strengthening precipitates in the alloy samples.

Fig. 17A is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of samples of exemplary alloy 5 in T4 temper (referred to as "HR 5", "HR 6", and "HR 7") after casting, homogenization, hot rolling to 10mm gauge, solution heat treatment, and various quenching techniques. After hot rolling, the air-cooled sample was referred to as "AC" and the water-quenched sample was referred to as "WQ". Fig. 17B is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of samples of exemplary alloy 5 in T6 temper (referred to as "HR 5", "HR 6", and "HR 7") after casting, homogenization, hot rolling to 10mm gauge, solution heat treatment, various quenching techniques, and various aging procedures. After hot rolling, the air-cooled sample was referred to as "AC" and the water-quenched sample was referred to as "WQ". Artificially aging to a T6 temper provides a high strength aluminum alloy having a yield strength of about 360MPa to about 370 MPa.

Fig. 18A is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of samples of exemplary alloy 5 in T4 temper (referred to as "HR 5", "HR 6", and "HR 7") after casting, homogenization, hot rolling to a gauge of 10mm, and solution heat treatment. Fig. 18B is a graph showing the yield strength (left histogram in each group), ultimate tensile strength (right histogram in each group), uniform elongation (open circles), and total elongation (open diamonds) of samples of exemplary alloy 5 in T6 temper (referred to as "HR 5", "HR 6", and "HR 7") after casting, homogenization, hot rolling to 10mm gauge, solution heat treatment, and various aging procedures as indicated in the graph. Artificially aging to a T6 temper provides a high strength aluminum alloy having a yield strength of about 360MPa to about 370 MPa.

Fig. 19 is a graph of load displacement data showing 90 ° bend test formability of samples of exemplary alloy 5 (referred to as "HR 5", "HR 6", and "HR 7") as described above. The samples tested in the direction longitudinal to the rolling direction are indicated by "-L" and the samples tested in the direction transverse to the rolling direction are indicated by "-T". Alloy 5 was cast, homogenized, hot rolled to 10mm gauge, solution heat treated and naturally aged for one week to provide alloy 5 samples in a T4 temper. The samples were subjected to a 90 ° bend test and the load displacement (left axis) and maximum load (right axis) were recorded.

Fig. 20 is a graph of load displacement data showing 90 ° bend test formability of samples of exemplary alloy 5 (referred to as "HR 5", "HR 6", and "HR 7") as described above. The samples tested in the direction longitudinal to the rolling direction are indicated by "-L" and the samples tested in the direction transverse to the rolling direction are indicated by "-T". Alloy 5 was cast, homogenized, hot rolled to 10mm gauge, solution heat treated, pre-aged at 125 ℃ for 2 hours (referred to as "PX") and naturally aged for one week to provide alloy 5 samples in a T4 temper. The samples were subjected to a 90 ° bend test and the load displacement (left axis) and maximum load (right axis) were recorded.

Fig. 21 is a graph of load displacement data showing 90 ° bend test formability of a sample of exemplary alloy 5 as described above. The samples tested in the direction longitudinal to the rolling direction are indicated by "-L" and the samples tested in the direction transverse to the rolling direction are indicated by "-T". The samples were cast, homogenized, hot rolled to 10mm gauge, solution heat treated, pre-aged at a temperature of 125 ℃ for 2 hours and naturally aged for one month to provide alloy 5 samples in a T4 temper. The samples were subjected to a 90 ° bend test and the load displacement (left axis) and maximum load (right axis) were recorded. In the case of pre-aging during manufacturing, the formability does not change significantly from one week of natural aging to one month of natural aging.

Fig. 22 shows an optical micrograph showing the effect of corrosion testing on the alloy described above. The alloy is subjected to corrosion testing according to ISO standard 11846B (e.g., immersion in a solution containing 3.0 wt% sodium chloride (NaCl) and 1.0 vol% hydrochloric acid (HCl) in water for 24 hours). Plot a of fig. 22 and plot B of fig. 22 show the effect of the corrosion test in comparative alloy 2 described above. The corrosion morphology is intergranular corrosion (IGC) attack. Plots C, D and E of FIG. 22 illustrate the effect of the corrosion test in exemplary alloy 3 as described above. The corrosion morphology is pitting. Point erosion is a more desirable corrosion morphology with less damage to the alloy and indicates that the exemplary alloy has corrosion resistance.

Fig. 23 shows an optical micrograph illustrating the effect of corrosion testing on a sample of exemplary alloy 4 as described above. It is apparent in the micrograph that significant IGC erosion is caused by the composition of alloy 4, with the ratio of Cu/[ Zn/(Mg/Si) ] being in the range of about 0.7 to about 1.4, but not in the range of about 0.75 to about 1.4, resulting in significant IGC erosion.

24A, 24B, and 24C are optical micrographs illustrating the results of corrosion testing on the exemplary alloys described above. FIG. 24A shows intergranular corrosion (IGC) attack in alloy A. FIG. 24B shows intergranular corrosion attack in alloy B. FIG. 24C shows intergranular corrosion attack in alloy C. It is apparent in fig. 24A, 24B, and 24C that increasing Zn content changes the corrosion morphology from IGC to pitting and that the corrosion attack depth decreases from about 150 μm (alloy a, fig. 24A) to less than 100 μm (alloy C, fig. 24C).

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

Claims

1. An aluminum alloy comprising 0.25 to 1.3 wt.% Si, 1.0 to 2.5 wt.% Mg, 0.5 to 1.5 wt.% Cu, at most 0.2 wt.% Fe, at most 3.0 wt.% Zn, at most 0.15 wt.% impurities, and Al, wherein the ratio of Mg to Si (Mg/Si ratio) is 1.5 to 1 to 3.5 to 1, wherein the ratio of Zn to the Mg/Si ratio (Zn/(Mg/Si) ratio) is 0.75 to 1 to 1.4 to 1, and wherein the ratio of Cu to the Zn/(Mg/Si) ratio (Cu/[ Zn/(Mg/Si) ] ratio) is 0.7 to 1 to 1.4 to 1.

2. The aluminum alloy of claim 1, comprising 0.55 to 1.1 wt.% Si, 1.25 to 2.25 wt.% Mg, 0.6 to 1.0 wt.% Cu, 0.05 to 0.17 wt.% Fe, 1.5 to 3.0 wt.% Zn, up to 0.15 wt.% impurities, and Al.

3. The aluminum alloy of claim 1 or 2, comprising 0.65 to 1.0 wt.% Si, 1.5 to 2.25 wt.% Mg, 0.6 to 1.0 wt.% Cu, 0.12 to 0.17 wt.% Fe, 2.0 to 3.0 wt.% Zn, up to 0.15 wt.% of impurities, and Al.

4. The aluminum alloy of claim 1 or 2, further comprising Zr.

5. The aluminum alloy of claim 4, wherein Zr is present in an amount up to 0.15 wt.%.

6. The aluminum alloy of claim 4, wherein Zr is present in an amount of 0.09 to 0.12 wt.%.

7. The aluminum alloy of claim 1 or 2, further comprising Mn.

8. The aluminum alloy of claim 7, wherein Mn is present in an amount up to 0.5 wt.%.

9. The aluminum alloy of claim 7, wherein Mn is present in an amount of 0.05 to 0.3 wt.%.

10. The aluminum alloy of claim 1, wherein the Mg/Si ratio is 2.0 to 1 to 3.0 to 1.

11. The aluminum alloy of claim 1, wherein the Zn/(Mg/Si) ratio is from 0.8 to 1 to 1.1 to 1.

12. The aluminum alloy of claim 1, wherein the Cu/[ Zn/(Mg/Si) ] ratio is from 0.8 to 1 to 1.1 to 1.

13. An aluminum alloy product comprising the aluminum alloy of any of claims 1-12.

14. The aluminum alloy product of claim 13, wherein the aluminum alloy product comprises a yield strength of at least 340MPa in a T6 temper.

15. The aluminum alloy product of claim 14, wherein the yield strength in a T6 temper is 360MPa to 380 MPa.

16. The aluminum alloy product of any of claims 13-15, wherein the aluminum alloy product comprises an average intergranular corrosion pit depth of less than 100 μ ι η in a T6 temper.

17. The aluminum alloy product of any of claims 13-15, wherein the aluminum alloy product comprises an r/T (bendability) ratio of 0.5 or less in a T4 temper.

18. The aluminum alloy product of any of claims 13-15, wherein the aluminum alloy product comprises an aluminum alloy selected from the group consisting of MgZn₂/Mg(Zn,Cu)₂、Mg₂Si and Al₄Mg₈Si₇Cu₂One or more precipitates of the group.

19. The aluminum alloy product of claim 18, wherein the aluminum alloy product comprises an average amount of at least 300,000,000 particles per millimeter²MgZn of₂/Mg(Zn,Cu)₂。

20. The aluminum alloy product of claim 18, wherein the aluminum alloy productThe product comprises an average amount of at least 600,000,000 particles/mm²Mg of (2)₂Si。

21. The aluminum alloy product of claim 18, wherein the aluminum alloy product comprises an average amount of at least 600,000,000 particles/mm²Al of (2)₄Mg₈Si₇Cu₂。

22. The aluminum alloy product of claim 18, wherein the aluminum alloy product comprises MgZn₂/Mg(Zn,Cu)₂、Mg₂Si and Al₄Mg₈Si₇Cu₂。

23. The aluminum alloy product of claim 22, wherein Mg₂Si and Al₄Mg₈Si₇Cu₂In a ratio of 1:1 to 1.5: 1.

24. The aluminum alloy product of claim 22, wherein Mg₂Si and MgZn₂/Mg(Zn,Cu)₂Is 1.5:1 to 3: 1.

25. The aluminum alloy product of claim 22, wherein Al₄Mg₈Si₇Cu₂With MgZn₂/Mg(Zn,Cu)₂Is 1.5:1 to 3: 1.

26. An aluminum alloy comprising 0.25 to 1.3 wt.% Si, 1.0 to 2.5 wt.% Mg, 0.5 to 1.5 wt.% Cu, at most 0.2 wt.% Fe, 0.3 to 3.0 wt.% Zn, at most 0.15 wt.% impurities, and Al, wherein the ratio of Mg to Si (Mg/Si ratio) is 1.5 to 1 to 3.5 to 1, wherein the ratio of Zn to the Mg/Si ratio (Zn/(Mg/Si) ratio) is 0.75 to 1 to 1.4 to 1, and wherein the ratio of Cu to the Zn/(Mg/Si) ratio (Cu/[ Zn/(Mg/Si) ] ratio) is 0.7 to 1 to 1.4 to 1.