HIGH STRENGTH AND THERMALLY STABLE 5000-SERIES ALUMINUM ALLOYS

TECHNICAL FIELD

The present disclosure relates to a family of 5000-series aluminum alloys with high strength, high formability, and high thermal stability during stabilization treatment and/or paint-bake cycle. The alloy can be fabricated through processing methods used for rolled products such as continuous casting, including, but not limited to twin-roll, belt casting, and block casting, as well as all forms of direct chill casting. The alloys disclosed herein can be solid-solution-hardened, age-hardened, dispersion-hardened, and or hardened via grain refinement.

BACKGROUND

Aluminum alloys have a wide range of applications in light weight structures in aerospace, automotive, marine, wire and cable, electronics, nuclear, and consumer products industries. Among them, aluminum 5000 series alloys are commonly used due to a combination of good mechanical properties, formability, and corrosion resistance. These alloys are produced in the form of rolled sheets and plates. The disclosed alloys are especially advantageous for, among other things, improving performance of food and beverage can lids and tabs, and automotive parts and panels. Additionally, the disclosed alloys are, for example, advantageous for improving performance of roofing and siding materials, chemical and food equipment, storage tanks, home appliances, sheet-metal work, marine parts, transportation parts, heavy duty cooking utensils, hydraulic tubes, fuel tanks, pressure vessels, heavy-duty truck and trailer bodies and assemblies, drilling rigs, missile components, and railroad cars.

Aluminum 5000-series alloys are typically hardened through two main strengthening mechanisms: a) solid-solution strengthening by magnesium and/or manganese, and b) strain-hardening by working (H tempers). Consequently, these alloys soften upon exposure to elevated temperatures, due to loss of strain hardening and due to grain growth. This significantly reduces their maximum achievable strength after exposure to elevated temperatures.

5000-series alloys are especially susceptible to ‘age softening’, even at room or moderate temperatures, in the strain-hardened condition due to the accelerated diffusion of magnesium in the Al matrix. A stabilization treatment at moderate temperatures (e.g., 100-250° C.) is typically performed on Al alloys with high Mg content. For example, the stabilization treatment is typically performed on AA5182 sheet, after cold rolling, which is used for food and beverage can lids and tabs. The treatment improves ductility, but is followed by a reduction in strength. A similar behavior occurs in processing automotive 5000-series sheets. The fully annealed (O-temper) AA5182 sheet, achieves an increase in strength via strain-hardening during the forming process. However, the strength increase is typically nearly deleted during the paint-bake cycle (i.e., annealing at moderate temperatures of 100-250° C. for a few minutes to a few hours).

Accordingly, disclosed herein is a new family of 5000-series alloys that can resist strength softening during stabilization and/or annealing treatment, after cold rolling, working and strain hardening. Such alloys are expected to be highly advantageous in multiple applications.

SUMMARY

The embodiments described herein relate to new heat-treatable aluminum-magnesium-based (5000-series) alloys (i.e., disclosed alloys).

In some embodiments, the alloys include about 3 to 6.2% by weight magnesium, 0.01 to 1.8% by weight manganese, 0.01-0.6% by weight iron, 0.01-0.5% by weight silicon, 0.08-0.6% by weight copper, and aluminum as the remainder. In some embodiments, the alloys comprise an α-Al(Mn,Fe)Si nanoscale precipitate. In some embodiments, the alloys comprise a Cu-containing precipitate. In some embodiments, the Cu-containing precipitate comprises Al₂CuMg. The alloys exhibit high strength and high thermal stability during annealing processes such as stabilization and/or a paint-bake cycle.

In some embodiments, the alloys include about 3 to 6.2% by weight magnesium, 0.01 to 1.8% by weight manganese, 0.01-0.6% by weight iron, 0.01-0.5% by weight silicon, 0.1-0.5% by weight zirconium, 0.01-0.2% by weight inoculant (e.g., tin); 0.08-0.6% by weight copper, and aluminum as the remainder. In some embodiments, the alloys comprise an Al₃Zr nanoscale precipitate, wherein the nanoscale precipitate has an average diameter of about 20 nm or less and has an Ll₂ structure in an α-Al face centered cubic matrix, wherein the average number density of the nanoscale precipitate is about 20²¹ m^-3 or more. In some embodiments, the alloys comprise an α-Al(Mn,Fe)Si nanoscale precipitate. In some embodiments, the alloys comprise a Cu-containing precipitate. In some embodiments, the Cu-containing precipitate comprises Al₂CuMg. The alloys exhibit high strength and high thermal stability during annealing processes such as stabilization and/or a paint-bake cycle.

The disclosed alloys can be fabricated via traditional casting methods known in the art, such as direct-chill casting, squeeze casting, twin-belt casting, twin-roll casting, strip casting, and block casting.

The high strength at room temperature for the disclosed alloys stems from three main approaches: i) maximizing the matrix strength through solid solution strengthening utilizing alloying elements such as magnesium and manganese, ii) further strengthening the matrix through precipitation hardening, and (iii) further strengthening through strain hardening (plastic deformation). In some embodiments, the precipitation hardening in the disclosed alloys is associated with: a) the precipitation of coherent Al₃Zr with Ll₂ crystal structure, wherein the nanoscale precipitate has an average radius in the range of 6-20 nm, b) the precipitation of incoherent Al₆Mn dispersoids with an average radius in the range of 50-200 nm, c) the precipitation of semi-coherent α-Al(MnFe)Si dispersoids, d) the precipitation of coherent Al₂CuMg G. P. zones and intermediate so called S′phase in alloys with Cu content, and/or e) the formation of Al₁₂Mn intermetallic phases in the range of 50-800 nm. The presence of intermetallic phases and nano-precipitates within the grains creates a strong pinning force against dislocation motions at ambient temperature.

In some embodiments, the high thermal stability at elevated annealing temperatures (e.g. 250-500° C.) for the disclosed alloys is associated with the presence of a) coherent heat- and coarsening-resistant Al₃Zr with Ll₂ crystal structure and an average radius in the range of 6-20 nm, b) incoherent coarsening-resistant Al6Mn dispersoids with an average radius in the range of 50-200 nm, and c) semi-coherent heat- and coarsening- resistant α-Al(Mn,Fe)Si dispersoids, and/or d) heat-resistant Al₁₂Mn intermetallic phases in the range of 50-800 nm. The presence of thermally stable intermetallic phases and nano-precipitates within the grains create a strong pinning force against dislocation motions at elevated temperatures, which translates into strength retention during annealing processes.

The thermal stability at moderate annealing temperatures (e.g., 100-250° C.) during processes such as stabilization treatment and/or paint-bake cycles for the disclosed alloys in pre-deformed condition is partly associated with the precipitation of coherent Al₂CuMg G. P. zones and intermediate S′ phase. The deformed alloy contains a high number density of dislocations which provide heterogeneous nucleation sites for the Al₂CuMg to precipitate. These precipitates help offset strength loss during the recovery process and slow dislocation motion, thus helping mitigate rapid strength drop during annealing.

Methods of manufacturing of the alloys are also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B: Tensile strength (1A) and yield strength (1B) as result of various processing paths for example alloys including: Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si wt.% (AA5182, reference alloy) compared to Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Cu wt.% (AA5182-I, disclosed alloy 1).

FIGS. 2A and 2B: Tensile strength (2A) and yield strength (2B) versus annealing time at various stabilization and coat cure temperatures of example peak-aged, cold-rolled alloys that include: Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si wt.% (AA5182, reference alloy) compared to Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Cu wt.% (AA5182-I, disclosed alloy 1), Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Zr-0.1Sn wt.% (AA5182-nano-I, reference patent application US 2019/0390306A1) and Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Zr-0.1Sn-0.3Cu wt.% (AA5182-nano-II, disclosed alloy 2).

FIGS. 3A and 3B: Tensile strength (3A) and yield strength (3B), both as a function of elongation at break, of example peak-aged, cold-rolled and stabilized alloys including: Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si wt.% (AA5182, reference alloy) compared to Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Cu wt.% (AA5182-I, disclosed alloy 1), Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Zr-0.1Sn wt.% (AA5182-nano-I, reference patent application US 2019/0390306A1) and Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Zr-0.1Sn-0.3Cu wt.% (AA5182-nano-II, disclosed alloy 2).

FIG. 4: Yield strength evolution through various processing steps including mechanical stretching (forming) and annealing (paint-bake) of example cold-rolled, fully-annealed alloys (soft-temper): Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si wt.% (AA5182, reference alloy) compared to 4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Zr-0.1Sn-0.3Cu wt.% (AA5182-nano-II, disclosed alloy 2).

FIG. 5: Yield strength evolution at various processing steps including mechanical stretching (forming) and annealing (paint-bake) of example cold-rolled, fully-annealed alloys (soft-temper) produced at manufacturing scale (continuous casting) via two processing routes (traditional and modified): Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si wt.% (AA5182, reference alloy) compared to 4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Zr-0.1Sn wt.% (AA5182-nano-I, reference patent application US 2019/0390306A1)

FIGS. 6A, 6B and 6C: Physical properties including tensile strength (6A and 6B) and elongation values; and corrosion potential (6C), as a function of Cu concentration for example peak-aged, cold-rolled, and stabilized alloys: (6A) Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si wt.% (AA5182, reference alloy) and (6B) Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Cu wt.% (AA5182-nano-I, reference patent application US 2019/0390306A1).

DETAILED DESCRIPTION

Traditionally 5000-series alloys are understood to be strain-hardenable, but not heat-treatable. They contain magnesium as the main alloying element, optionally manganese, and typically have good strength, formability, and corrosion resistance. AA5182 aluminum alloy, containing 4-5 Mg and 0.2-0.5Mn (wt.%), is currently being utilized for food and beverage can lids. It is also being used in automotive applications. For can lid, the AA5182 production is finalized by cold rolling down to a specified thickness (e.g. 0.25 mm), which produces microstructural changes that increase the total strength, but significantly reduce ductility/formability of the alloy. A moderate temperature treatment (stabilization) can be employed to recover ductility, though it also reduces the strength gained through cold rolling of the alloy. Much of the strength gain stems from the generation a high number density of dislocations, which can diminish at elevated temperatures. In some embodiments, stabilization can be used to increase ductility, but it can also be strategically used as an artificial aging step with additions of specific elements. The dislocation forests are a key part of the aging process since they create a high number of precipitate nucleation sites. The effect of a micro-addition of Cu in AA5182 is investigated during the stabilization stage of the fabrication process.

Accordingly, in some embodiments, the present disclosure provides an aluminum alloy comprising about 3 to 6.2% by weight magnesium, 0.01 to 1.8% by weight manganese, 0.01-0.6% by weight iron, 0.01-0.5% by weight silicon, 0.08-0.6% by weight copper, and aluminum as the remainder. In some embodiments, the amount of copper in the aluminum alloy is about 0.10 to about 0.6% by weight copper, about 0.12 to about 0.6% by weight copper, about 0.14 to about 0.6% by weight copper, about 0.16 to about 0.6% by weight copper, about 0.18 to about 0.6% by weight copper, about 0.2 to about 0.6% by weight copper, 0.25 to about 0.6% by weight copper, about 0.3 to about 0.6% by weight copper, 0.35 to about 0.6% by weight copper, about 0.4 to about 0.6% by weight copper, or about 0.45 to about 0.6% by weight copper, including all ranges and values therebetween.

The disclosed aluminum alloys include an inoculant, wherein the inoculant comprises one or more of tin, strontium, zinc, gallium, germanium, arsenic, indium, antimony, lead, and bismuth. Presence of an inoculant accelerates precipitation kinetics of Al₃Zr nano-precipitates, thus these precipitates can be formed within a practical amount of time during heat-treatment. In the other words, the beneficial Al₃Zr nano-precipitates can be formed within a few hours of heat treatment, with the presence of inoculant, compared to a few weeks of heat treatment, without the presence of inoculant. In some embodiments, the inoculant is tin. In some embodiments, tin accelerates the precipitation kinetics of Al₃Zr nano-precipitates most effectively compared to other inoculants. This behavior is described in U.S. Pat. No. 9,453,272.

In one embodiment, an aluminum alloy comprises aluminum, magnesium, zirconium, copper, an inoculant, unavoidable impurity limits, and a nanoscale precipitate comprising Al₃Zr, wherein the nanoscale precipitate has an average diameter of about 20 nm or less and has an Ll₂ structure in an α-Al face centered cubic matrix, wherein the average number density of the nanoscale precipitate is about 20²¹ m^-3 or more, and wherein the inoculant comprises tin.

In some embodiments, the aluminum alloys of the present disclosure comprise a Cu-containing precipitate. In some embodiments, the Cu-containing precipitate comprises a coherent Al₂CuMg G. P. zone and an intermediate S′phase. Without being bound by any particular theory, the copper is believed to enhance thermal stability during moderate annealing treatments during processes such as stabilization treatment and/or paint-bake cycles.

In some embodiments, the aluminum alloy comprises about 2.5 to about 6.2% by weight magnesium; about 0.01 to about 1.8% by weight manganese; about 0.01 to about 0.5% by weight silicon; about 0.01-0.6% by weight iron; about 0.1 to about 0.5% by weight zirconium; about 0.01 to about 0.2% by weight tin; 0-0.6% by weight copper; and aluminum as the remainder.

In some embodiments, the aluminum alloy comprises about 2.5 to about 6.2% by weight magnesium; about 0.01 to about 1.8% by weight manganese; about 0.01 to about 0.5% by weight silicon; about 0.01-0.6% by weight iron; about 0.1 to about 0.5% by weight zirconium; about 0.01 to about 0.2% by weight tin; 0-1% by weight copper; and aluminum as the remainder.

In some embodiments, the aluminum alloy comprises about 2.5 to about 6.2% by weight magnesium; about 0.01 to about 1.8% by weight manganese; about 0.01 to about 0.6% by weight iron; about 0.01 to about 0.5% by weight silicon; about 0.1 to about 0.5% by weight zirconium; about 0.01 to about 0.2% by weight tin; about 0.08 to about 1% by weight copper; and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 3 to about 6.2% by weight magnesium; about 0.01 to about 1.8% by weight manganese; about 0.01 to about 0.5% by weight silicon; 0.01-0.6% by weight iron; about 0.1 to about 0.5% by weight zirconium; about 0.01 to about 0.2% by weight tin; about 0.08 to about 1% by weight copper; and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 3 to about 6.2% by weight magnesium; about 0.01 to about 1.8% by weight manganese; about 0.01 to about 0.5% by weight silicon; 0.01-0.6% by weight iron; about 0.1 to about 0.5% by weight zirconium; about 0.01 to about 0.2% by weight tin; about 0.08 to about 0.6% by weight copper; and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 3 to about 6.2% by weight magnesium; about 0.01 to about 1.8% by weight manganese; about 0.01 to about 0.5% by weight silicon; 0.01-0.6% by weight iron; about 0.1 to about 0.5% by weight zirconium; about 0.01 to about 0.2% by weight tin; about 0.2 to about 0.6% by weight copper; and aluminum as the remainder.

In some embodiments, the aluminum alloy comprises about 3 to about 6.2% by weight magnesium, about 3.2 to about 6.2% by weight magnesium, about 3.4 to about 6.2% by weight magnesium, about 3.6 to about 6.2% by weight magnesium, about 3.8 to about 6.2% by weight magnesium, about 4 to about 6.2% by weight magnesium, or about 4.2 to about 6.2% by weight magnesium. In some embodiments, the aluminum alloy comprises about 3 to about 6.2% by weight magnesium. In some embodiments, the aluminum alloy comprises about 3.2 to about 6.2% by weight magnesium. In some embodiments, the aluminum alloy comprises about 3.4 to about 6.2% by weight magnesium. In some embodiments, the aluminum alloy comprises about 3.6 to about 6.2% by weight magnesium. In some embodiments, the aluminum alloy comprises about 3.8 to about 6.2% by weight magnesium. In some embodiments, the aluminum alloy comprises about 4 to about 6.2% by weight magnesium. In some embodiments, the aluminum alloy comprises about 4.2 to about 6.2% by weight magnesium.

In some embodiments, the aluminum alloy comprises about 0.05 to about 1.8% by weight manganese. In some embodiments, the aluminum alloy comprises about 0.05 to about 1.5% by weight manganese. In some embodiments, the aluminum alloy comprises about 0.05 to about 1.2% by weight manganese. In some embodiments, the aluminum alloy comprises about 0.05 to about 1% by weight manganese. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.8% by weight manganese. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.6% by weight manganese. In some embodiments, the aluminum alloy comprises about 0.1 to about 1.8% by weight manganese, about 0.1 to about 1.6% by weight manganese, about 0.1 to about 1.4% by weight manganese, about 0.1 to about 1.2% by weight manganese, about 0.1 to about 1% by weight manganese, about 0.1 to about 0.8% by weight manganese, about 0.1 to about 0.6% by weight manganese or about 0.1 to about 0.5% by weight manganese. In some embodiments, the aluminum alloy comprises about 0.1 to about 0.5% by weight manganese.

In some embodiments, the aluminum alloy comprises about 0.05 to about 0.6% by weight iron, about 0.1 to about 0.6% by weight iron, about 0.15 to about 0.6% by weight iron, or about 0.2 to about 0.6% by weight iron. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.6% by weight iron. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.55% by weight iron. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.5% by weight iron. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.45% by weight iron. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.40% by weight iron. In some embodiments, the aluminum alloy comprises about 0.1 to about 0.6% by weight iron. In some embodiments, the aluminum alloy comprises about 0.1 to about 0.55% by weight iron. In some embodiments, the aluminum alloy comprises about 0.1 to about 0.50% by weight iron. In some embodiments, the aluminum alloy comprises about 0.1 to about 0.45% by weight iron. In some embodiments, the aluminum alloy comprises about 0.1 to about 0.4% by weight iron.

In some embodiments, the aluminum alloy comprises about 0.05 to about 0.5% by weight silicon, about 0.1 to about 0.5% by weight silicon, about 0.15 to about 0.5% by weight silicon, or about 0.2 to about 0.5% by weight silicon. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.5% by weight silicon. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.5% by weight silicon. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.45% by weight silicon. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.40% by weight silicon. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.35% by weight silicon. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.3% by weight silicon.

In some embodiments, the aluminum alloy comprises about 0.1 to about 0.5% by weight zirconium, about 0.15 to about 0.5% by weight zirconium, or about 0.2 to about 0.5% by weight zirconium. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.5% by weight zirconium. In some embodiments, the aluminum alloy comprises about 0.1 to about 0.5% by weight zirconium. In some embodiments, the aluminum alloy comprises about 0.15 to about 0.5% by weight zirconium. In some embodiments, the aluminum alloy comprises about 0.2 to about 0.5% by weight zirconium. In some embodiments, the aluminum alloy comprises about 0.25 to about 0.5% by weight zirconium. In some embodiments, the aluminum alloy comprises about 0.2 to about 0.4% by weight zirconium.

In some embodiments, the aluminum alloy comprises about 0.01 to about 0.2% by weight tin, about 0.05 to about 0.2% by weight tin, or about 0.1 to about 0.2% by weight tin. In some embodiments, the aluminum alloy comprises about 0.01 to about 0.2% by weight tin. In some embodiments, the aluminum alloy comprises about 0.05 to about 0.2% by weight tin. In some embodiments, the aluminum alloy comprises about 0.10 to about 0.2% by weight tin.

In some embodiments, the aluminum alloy comprises about 0.08 to about 1% by weight copper, including about 0.10 to about 1% by weight copper, about 0.12 to about 1% by weight copper, about 0.14 to about 1% by weight copper, about 0.16 to about 1% by weight copper, about 0.18 to about 1% by weight copper, about 0.2 to about 1% by weight copper, 0.25 to about 1% by weight copper, about 0.3 to about 1% by weight copper, 0.35 to about 1% by weight copper, about 0.4 to about 1% by weight copper, about 0.45 to about 1% by weight copper, about 0.5 to about 1% by weight copper, 0.55 to about 1% by weight copper, about 0.6 to about 1% by weight copper, 0.65 to about 1% by weight copper, about 0.7 to about 1% by weight copper, or about 0.75 to about 1% by weight copper. In some embodiments, the aluminum alloy comprises about 0.08 to about 0.6% by weight copper, about 0.10 to about 0.6% by weight copper, about 0.12 to about 0.6% by weight copper, about 0.14 to about 0.6% by weight copper, about 0.16 to about 0.6% by weight copper, about 0.18 to about 0.6% by weight copper, about 0.2 to about 0.6% by weight copper, 0.25 to about 0.6% by weight copper, about 0.3 to about 0.6% by weight copper, 0.35 to about 0.6% by weight copper, about 0.4 to about 0.6% by weight copper, or about 0.45 to about 0.6% by weight copper. In some embodiments, the aluminum alloy comprises about 0.08 to about 0.6% by weight copper. In some embodiments, the aluminum alloy comprises about 0.10 to about 0.6% by weight copper. In some embodiments, the aluminum alloy comprises about 0.15 to about 0.6% by weight copper. In some embodiments, the aluminum alloy comprises about 0.20 to about 0.6% by weight copper. In some embodiments, the aluminum alloy comprises about 0.25 to about 0.6% by weight copper. In some embodiments, the aluminum alloy comprises about 0.30 to about 0.6% by weight copper.

In one embodiment, the aluminum alloy comprises about 3 to about 6.2% by weight magnesium, about 0.1 to about 0.5% by weight manganese, about 0.01 to about 0.3% by weight silicon, about 0.05 to about 0.4% by weight iron, 0-0.5% by weight zirconium, 0- 0.2% by weight tin, about 0.08 to about 1% by weight copper; and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.08 to about 1% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.08 to about 0.6% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.08 to about 0.3% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.15% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.45% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.60% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight zirconium, about 0.1% by weight tin, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight zirconium, about 0.1% by weight tin, about 0.15% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight zirconium, about 0.1% by weight tin, about 0.3% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight zirconium, about 0.1% by weight tin, about 0.45% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight zirconium, about 0.1% by weight tin, about 0.60% by weight copper, and aluminum as the remainder.

In one embodiment, the aluminum alloy comprises about 0.01% to about 0.5% iron, e.g., as an impurity element.

In some embodiments of the present disclosure, the aluminum alloy comprises:

a base composition that is substantially similar (i.e., within about 5-10% by weight for each component) to an aluminum alloy selected from the group consisting of: AA5042, AA5052, AA5056, AA5083, AA5086, AA5182, AA5352, and AA5754;
about 0.1 to about 0.5% by weight zirconium;
about 0.01 to about 0.2% by weight tin;
about 0.15 to about 1% by weight intentionally added copper;
and aluminum as the reminder.

In some embodiments of the present disclosure, the aluminum alloy comprises:

a base composition that is substantially similar (i.e., within about 5-10% by weight for each component) to an aluminum alloy selected from the group consisting of: AA5042, AA5052, AA5056, AA5083, AA5086, AA5182, AA5352, and AA5754;
about 0.15 to about 1% by weight intentionally added copper;
and aluminum as the reminder.

In some embodiments of the present disclosure, the aluminum alloy comprises a composition selected from the group consisting of:

Mg (wt.%)
Mn (wt.%)
Fe (wt.%)
Si (wt.%)
Zr (wt.%)
Cu (wt.%)
Sn (wt.%)
Cr (wt.%)
Ti (wt.%)
Zn (wt.%)
Impurities (wt.%)

a)
3-4
0.2-0.5
0-0.35
0-0.2
0.1-0.5
0.15-1
0.01-0.2
0-0.1
0-0.1
0-0.25
up to 0.015

b)
2.2-2.8
0-0.1
0-0.4
0-0.25
0.1-0.5
0.15-1
0.01-0.2
0.15-0.35
-
0-0.1
up to 0.015

c)
4.5-5.6
0.05-0.2
0-0.4
0-0.3
0.1-0.5
0.15-1
0.01-0.2
0.05-0.2
-
0-0.1
up to 0.015

d)
4.4-4.9
0.4-1
0-0.4
0-0.4
0.1-0.5
0.15-1
0.01-0.2
0.05-0.25
0-0.15
0-0.25
up to 0.015

e)
3.5-4.5
0.2-0.7
0-0.5
0-0.4
0.1-0.5
0.15-1
0.01-0.2
0.05-0.25
0-0.15
0-0.25
up to 0.015

f)
4-5
0.2-0.5
0-0.35
0-0.2
0.1-0.5
0.15-1
0.01-0.2
0-0.1
0-0.1
0-0.25
up to 0.015

g)
2.6-3.6
0-0.5
0-0.4
0-0.4
0.1-0.5
0.15-1
0.01-0.2
0-0.3
0-0.15
0-0.20
up to 0.015

h)
3.6-6.2
0-0.5
0-0.4
0-0.4
0.1-0.5
0.15-1
0.01-0.2
0-0.3
0-0.15
0-0.20
up to 0.015

In some embodiments of the present disclosure, the aluminum alloy comprises a composition selected from the group consisting of:

Mg (wt.%)
Mn (wt.%)
Fe (wt.%)
Si (wt.%)
Cu (wt.%)
Cr (wt.%)
Ti (wt.%)
Zn (wt.%)
Impurities (wt.%)

a)
3-4
0.2-0.5
0-0.35
0-0.2
0.15-1
0-0.1
0-0.1
0-0.25
up to 0.015

b)
2.2-2.8
0-0.1
0-0.4
0-0.25
0.15-1
0.15-0.35
-
0-0.1
up to 0.015

c)
4.5-5.6
0.05-0.2
0-0.4
0-0.3
0.15-1
0.05-0.2
-
0-0.1
up to 0.015

d)
4.4-4.9
0.4-1
0-0.4
0-0.4
0.15-1
0.05-0.25
0-0.15
0-0.25
up to 0.015

e)
3.5-4.5
0.2-0.7
0-0.5
0-0.4
0.15-1
0.05-0.25
0-0.15
0-0.25
up to 0.015

f)
4-5
0.2-0.5
0-0.35
0-0.2
0.15-1
0-0.1
0-0.1
0-0.25
up to 0.015

g)
2.6-3.6
0-0.5
0-0.4
0-0.4
0.15-1
0-0.3
0-0.15
0-0.20
up to 0.015

h)
3.6-6.2
0-0.5
0-0.4
0-0.4
0.15-1
0-0.3
0-0.15
0-0.20
up to 0.015

In some embodiments, zinc is unintentionally added.

In some embodiments, the chromium and/or titanium are intentionally added for grain refinement purposes for good casting characteristics. In one embodiment, the aluminum alloys comprise about 0-0.35% by weight chromium, and/or 0-0.15% by weight titanium for grain refinement purposes for good casting characteristics.

In some embodiments, the aluminum alloys of the present disclosure are essentially free of scandium. In some embodiments, if scandium is present, it is unintentionally added and present in less than about 0.5%, less than about 0.4%, less than about 0.3%, less than about 0.2%, less than about 0.1%, less than about 0.09%, less than about 0.08%, less than about 0.07%, less than about 0.06%, less than about 0.05%, less than about 0.04%, less than about 0.03%, or less than about 0.02% by weight, including any range of value therebetween.

In some embodiments, the aluminum alloys comprise about 0 to about 0.5% by weight unavoidable impurities, e.g., about 0.01%, about 0.05%, about 0.1%, about 0.15%, about 0.2%, about 0.25%, about 0.3%, about 0.35%, about 0.4%, about 0.45%, or about 0.5% by weight unavoidable impurities. In some embodiments, the aluminum alloys comprise less than about 0.5%, less than about 0.4%, less than about 0.3%, less than about 0.2%, or less than about 0.1% by weight unavoidable impurities.

As would be understood by one of skill in the art, unavoidable impurities present in the disclosed alloys have no measurable impact on the properties of the alloy, for example its tensile strength, yield strength, elongation at break, or any other property described herein.

In some embodiments, the alloys of the present disclosure comprise greater than about 90% aluminum by weight, greater than about 91% aluminum by weight, greater than about 92% aluminum by weight, greater than about 93% aluminum by weight, greater than about 94% aluminum by weight, greater than about 95% aluminum by weight, greater than about 96% aluminum by weight, greater than about 97% aluminum by weight, or greater than about 98% aluminum by weight. In some embodiments, the alloys of the present disclosure about 90% aluminum by weight, about 91% aluminum by weight, about 92% aluminum by weight, about 93% aluminum by weight, about 94% aluminum by weight, about 95% aluminum by weight, about 96% aluminum by weight, about 97% aluminum by weight, or about 98% aluminum by weight.

In some embodiments of the present disclosure, the alloy possesses a yield strength of at least 400 MPa, a tensile strength of at least 450 MPa, and an elongation of at least 5% in the hard-temper condition. In some embodiments, the alloy possesses a yield strength of at least 405 MPa, at least 400 MPa, at least 395 MPa, at least 390 MPa, or at least 385 MPa in the hard-temper condition. In some embodiments, the alloy possesses a tensile strength of at least 470 MPa, at least 465 MPa, at least 460 MPa, at least 455 MPa, or at least 450 MPa in the hard-temper condition. In some embodiments, the alloy possesses an elongation of at least 5%, at least 5.5%, at least 6%, at least 6.5%, at least 7%, or at least 7.5% in the hard-temper condition.

In some embodiments of the present disclosure, the alloy possesses a yield strength of at least 170 MPa, a tensile strength of at least 320 MPa, and an elongation of at least 10% in the soft-temper condition. In some embodiments, the alloy possesses a yield strength of at least 210 MPa, at least 205 MPa, at least 200 MPa, at least 195 MPa, at least 190 MPa, at least 185 MPa, or at least 180 MPa in the soft-temper condition. In some embodiments, the alloy possesses a tensile strength of at least 470 MPa, at least 465 MPa, at least 460 MPa, at least 455 MPa, or at least 450 MPa in the soft-temper condition. In some embodiments, the alloy possesses an elongation of at least 10%, at least 11%, at least 12%, at least 13%, at least 14%, or at least 15% in the soft-temper condition.

One method for manufacturing a component from a disclosed aluminum alloy comprises: a) melting the alloy at a temperature about 700 to 900° C.; b) casting the alloy into casting molds; c) using a cooling medium to cool the cast ingot (the cooling rate needs to be high enough to allow increased content of solute atoms in the solid solution, which is crucial to obtain optimal mechanical properties after precipitation); d) hot rolling the ingot into plates or sheets at temperatures between 300° C. and 600° C.; e) heat aging the sheet at a temperature about 350° C. to about 550° C. for a time of about 2 to about 48 hours. In some embodiments, the method further comprises f) cold rolling the hot rolled and heat treated sheet or plate, to form thin sheet or foil products. In some embodiments, the method further comprises g) the final stabilizing heat treatment (100-250° C. for 1 min to 8 h) of the thin sheet or foil products.

Another method for manufacturing a component from a disclosed aluminum alloy comprises: a) melting the alloy at a temperature about 700 to 900° C.; b) casting the alloy into casting molds; c) using a cooling medium to cool the cast ingot (the cooling rate needs to be high enough to allow increased content of solute atoms in the solid solution, which is crucial to obtain optimal mechanical properties after precipitation); d) hot rolling the alloy into plates or sheets at temperatures between 300° C. and 600° C. In some embodiments, the method further comprises e) cold rolling the hot rolled sheet or plate, to form thick sheet, thin sheet, or foil products; and f) heat aging the sheet at a temperature about 300° C. to about 550° C. for a time of about 2 to about 48 hours.

In some embodiments of the present method, after cold rolling, the alloy (e.g., a sheet or foil product) resists strength softening during stabilization treatment and shows improved ductility. In some embodiments, after cold rolling, the alloy resists strength softening during coat cure treatment and shows improved ductility. In some embodiments, the ductility is improved by about 5%, about 20%, about 50%, about 100%, about 150%, about 200%, about 250%, about 300%, about 350%, about 400%, about 450%, or about 500%, including all ranges and values therebetween, compared to the cold-rolled state without any stabilization or coat cure treatment

Some applications for the disclosed alloys include, for example, food and beverage can lids, food and beverage can tabs, roofing materials, siding materials, chemical manufacturing equipment, food manufacturing equipment, storage tanks, home appliances, sheet-metal work, marine parts, transportation parts, heavy duty cooking utensils, hydraulic tubes, fuel tanks, pressure vessels, truck bodies, truck assemblies, trailer bodies, trailer assemblies, drilling rigs, missile components, and railroad cars. Some fabricated forms of the disclosed aluminum alloys include, for example, wires, sheets, plates and foils.

INCORPORATION BY REFERENCE

The entire disclosure of each of the patent documents and scientific articles referred to herein is incorporated by reference for all purposes.

EQUIVALENTS

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and the range of equivalency of the claims are intended to be embraced therein.

Thus, from the foregoing, it will be understood that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present disclosure. It is to be understood that no limitation with respect to the specific embodiments illustrated and described is intended or should be inferred. For example, even though the exemplified alloys of the present disclosure use AA5182 aluminum alloy as the reference material, a skilled artisan would instantly understand that the same improvements achieved with the disclosed alloys can be applied to other traditional 5000-series aluminum alloys, including, but not limited to AA5052, AA5056, AA5352, AA5754, AA5083, AA5086 and AA5042, containing magnesium, manganese and other minor alloying elements and impurity elements.

EXAMPLES

The present disclosure is further illustrated by reference to the following Examples. However, it is noted that these Examples are illustrative and are not to be construed as restricting the scope of the disclosure in any way.

Example 1: Fabrication and Evaluation of Disclosed Alloys

Two alloys were fabricated: AA5182 (reference alloy) and AA5182-I (disclosed alloy 1). The nominal compositions of the alloys are listed in Table 1. Both alloys were fabricated via the same processing path; casting, hot rolling, cold rolling, and a stabilizing treatment (Path-I). Additionally, one AA5182 sample and several AA5182-I samples were heat treated at 445° C. (solutionization heat treatment of Cu) and cooled to room temperature at different cooling rates before cold rolling. Effects of the various cooling rates were investigated to determine age-hardening dependence on quench rate (Path II-water quench ~100° C./s, Path III- furnace cool ~1° C./min, and Path IV- furnace cool ~0.5° C./min).

TABLE 1

Nominal compositions (wt. %) of AA5182 and AA5182-I

Al
Mg
Mn
Fe
Si
Cu

AA5182 (reference alloy)
Bal
4.5
0.25
0.2
0.1
0.05

AA5182-I (disclosed alloy 1)
Bal
4.5
0.25
0.2
0.1
0.3

FIG. 1 displays the tensile strength of AA5182-I (disclosed alloy 1) resulting from each processing path (I-IV). The tensile strength of the reference alloy (referred to as AA5182 hereafter) processed via paths I (casting, hot rolling, cold rolling, stabilizing) and II (casting, hot rolling, solutionizing and water quenching, cold rolling, stabilizing) are also displayed. The disclosed alloys, with higher Cu content than commercially available AA5182 alloys, are designed to maximize the strengthening effects of Cu through formation of Al₂CuMg precipitates, together with solid solution strengthening. When the alloys are processed via path I (non-solutionized), only a minor increase in tensile strength (~10 MPa) of AA5182-I is displayed when compared to AA5182, but a clear increase in tensile strength of ~30 MPa is displayed when both alloys are processed via path II. Tensile strength for AA5182-I on paths II, III, and IV are similar, indicating that cooling rates (solutionizing temperature to room temperature) within this range has insignificant effect on the effectiveness of Cu addition. AA5182 was not processed through paths III and IV since no significant difference is expected for the alloy if cooled at slower rates than that of path II. Thus, in some embodiments, the Cu is solutionized before cold rolling and subjected to stabilization treatment to maximize the strengthening effects of Cu.

Example 2: Fabrication and Evaluation of Disclosed Alloys Comprising Zirconium

The addition of Zr and inoculant elements in the disclosed alloys can introduce a high number density of thermally stable, coherent Al₃Zr nano-precipitates. The effect of small additions of Cu in combination with Al₃Zr nano-precipitates on the tensile strength of AA5182 is investigated. Four alloys were fabricated: AA5182, AA5182-I, AA5182-nano-I, and AA5182-nano-II. The nominal compositions of the alloys are listed in Table 2. All alloys were fabricated via the same processing path: casting, hot rolling, high temperature heat treatment (445° C./5 h), cold rolling, and a stabilizing treatment. The high temperature heat treatment in the fabrication process serves two purposes; 1) aging treatment to generate Al₃Zr nano-precipitates, 2) solution heat treatment for the Cu and other alloying elements. Several temperatures (160, 180, and 200° C.) were chosen for the stabilizing treatment of AA5182-nano-II (disclosed alloy 2) to demonstrate strength retention after the stabilization treatment. A stabilizing temperature (160° C./3 h) was chosen for AA5182 and AA5182-nano-I (reference patent application US 2019/0390306A1) that yielded standard hard-temper properties for the reference alloy AA5182. All alloys went through a 60 second oil bath at 224° C., to simulate a coat curing process required for various food and packaging applications.

TABLE 2

Nominal compositions (wt. %) of AA5182, AA5182-I, AA5182-nano-I, and AA5182-nano-II

Al
Mg
Mn
Fe′
Si
Cu
Zr
Sn

AA5182 (reference alloy)
Bal
4.5
0.25
0.2
0.1
0.05 1
-
-

AA5182-I (disclosed alloy 1)
Bal
4.5
0.25
0.2
0.1
0.3
-
-

AA5182-nano-I (reference patent application US 2019/0390306A1)
Bal
4.5
0.25
0.2
0.1
0.05
0.3
0.1

AA5182-nano-II (disclosed alloy 2)
Bal
4.5
0.25
0.2
0.1
0.3
0.3
0.1

FIGS. 2A and 2B display the tensile and yield strength, respectively, as a function of annealing time at various stabilization and coat cure temperatures for the disclosed alloy with the existence of the Al₃Zr nano-precipitates coupled with the micro-addition of Cu. Tensile and yield strengths of AA5182 and AA5182-nano-I stabilized at 160° C. for 3 h (typical for H39-temper) are included in the figures. The initial points (zero hour) represent the as-cold-rolled properties before stabilization or oil bath treatment. It is apparent from FIG. 2A that both tensile and yield strength of AA5182-nano-II shows much higher values after stabilizing at a temperature of 160° C. for 3 h, compared to AA5182 and AA5182-nano-I. Additional stabilizing temperatures are shown for AA5182-nano-II to further demonstrate its thermal stability. At a temperature of 180° C., tensile and yield strength remain relatively stable for at least 8 hours. At 200° C. both tensile and yield strength curves still lie above the AA5182-nano-I (160° C./3 h) value until 8 hours. For AA5182-I alloy, even though strength at as-cold-rolled condition is comparable to that of reference AA5182 alloy, it is significantly higher after stabilizing treatment (160° C./3 h) compared to that of reference AA5182 alloy. It is shown that thermal stability of the reference AA5182 alloy during moderate annealing treatment is also improved with the micro-addition of Cu. Results from a 60 second oil bath at 224° C. are included for all alloys. Both tensile and yield strength of AA5182-nano-II are significantly higher compared to the other alloys.

FIGS. 3A and 3B display tensile and yield strengths, respectively, as a function of elongation at break for the same alloys in FIG. 2. It is evident that elongation values for all investigated AA5182, AA5182-I, AA5182-nano-I, and AA5182-nano-II, after stabilization treatment, are similar, approximately between 5.5-7.5%, while strength are significantly different. Strength of both AA5182-I and AA5182-nano-I are higher than that of reference AA5182 alloy, and strength of AA5182-nano-II is the highest, showing the strength increases in the disclosed alloys, with no sacrifice of ductility.

Accordingly, the improvement in strength without sacrificing ductility in the disclosed alloys in sheet form is highly advantageous for food and beverage can industry. Disclosed alloys help downgauge food and beverage can sheet thickness, while maintaining the same function, resulting in reduction of aluminum usage and cost saving for food and beverage companies and end users.

Example 3: Mechanical Properties of Disclosed Alloys After a Paint-Bake Cycle

Automotive manufacturers that use AA5182 for production typically receive the alloy as O-temper/soft-temper (fully annealed) sheet, which has high formability. When the sheet is formed into a desired shape (e.g. stamping), its strength increases via working or strain-hardening. However, after a typical paint-bake cycle for an assembled vehicle (i.e. moderate temperature annealing treatment), the increased strength from working is diminished. The effects on mechanical properties during and after the paint-bake cycle are studied for AA5182 and AA5182-nano-II alloys. The nominal compositions of these alloys are listed in Table 2. Sheets fabricated from these alloys are via the same processing path: casting, hot rolling, cold rolling, and a final anneal treatment (270° C./4 h for AA5182, 420° C./4 h for AA5182-nano-II). To simulate the forming and paint-bake cycle, the sheets were stretched (in tension) to about 5% strain, then annealed at 205° C. for 20 min and 2 h.

FIG. 4 displays the yield strength for each alloy at each stage of forming and paint-bake cycle: soft-temper, 5% stretch, annealed at 205° C. for 20 min, and annealed at 205° C. for 2 h. In the 5% stretch, both alloys have an increase in yield strength of about 55 MPa. When annealed at 205° C., yield strength of AA5182 drops back down by 55 MPa within 20 min, while AA5182-nano-II drops by only 30 MPa in 20 min and increases by about 10 MPa after 2 h compared to 20 min. In the annealed state (post paint-bake) AA5182-nano-II shows an increased yield strength > 30% compared to the reference AA5182 alloy.

Processing parameters for these alloys can be changed to further improve their response during the paint bake cycle. Two alloys were produced via continuous casting to show scalability of the technology and to further explore processing parameters. The nominal compositions of the alloys are those of AA5182 and AA5182-nano-I as listed in Table 2. The alloys were both processed via two slightly different processing paths: a traditional O-temper path consisting of casting, hot rolling, cold rolling, and an annealing treatment; and a modified O-temper path consisting of casting, hot rolling, high temperature heat treatment (445° C./5 h), cold rolling, and an annealing treatment. The high temperature heat treatment in the fabrication process serves as an aging step to generate Al₃Zr nano-precipitates prior to cold rolling as opposed to being generated during the final annealing treatment. This change in the order of precipitate formation can lead to changes in thermal stability due to precipitate and dislocation interactions during alloy recovery. Effects of the two processing paths on paint bake response were investigated. To simulate the forming and paint-bake cycle, the sheets were stretched (in tension) to about 5% strain, then annealed at 205° C. for 20, 60, and 120 min.

FIG. 5 displays the yield strength for each alloy, processed via traditional and modified paths, at every stage of the forming and paint-bake cycle: soft-temper, 5% stretch, annealed at 205° C. for 20, 60, and 120 min. For alloy AA5182, both processing paths generate about the same result. When compared to the traditional path, alloy AA5182-nano-I processed via a modified path displays greater yield strength during the stretching stage and annealing stages (~6 % increase). The modified processing path is applicable to AA5182-nano-II; thus, the same strength increase is expected.

Example 4: Evaluation of Disclosed Alloys Comprising Varying Amounts of Copper

An increased amount of Cu can provide additional benefits to the mechanical properties of the disclosed alloys. The effects were studied using eight alloys with various Cu concentrations including: AA5182 (0.05, 0.15, 0.3, 0.45, 0.6 wt. %) and AA5182-nano-I (0.05, 0.3, 0.6 wt. %). Nominal compositions of the alloys are listed in Table 3. All alloys were fabricated via the same processing path; casting, hot rolling, heat treating, cold rolling, and a stabilizing treatment. Effects of increasing levels of Cu alloying concentrations were investigated to determine age-hardening response during the stabilization heat treatment. Additionally, the effect of Cu on corrosion potential in the alloys was measured using ASTM G69 standards.

TABLE 3

Nominal compositions (wt. %) of AA5182 and AA5182-nano-I, with increasing levels of Cu alloying

Al
Mg
Mn
Fe
Si
Cu
Zr
Sn

AA5182
Bal
4.5
0.25
0.2
0.1
0.05
-
-

AA5182 + 0.15 (disclosed alloy 1)
Bal
4.5
0.25
0.2
0.1
0.15
-
-

AA5182 + 0.3 (disclosed alloy 1)
Bal
4.5
0.25
0.2
0.1
0.3
-
-

AA5182 + 0.45 (disclosed alloy 1)
Bal
4.5<
0.25
0.2
0.1
0.45
-
-

AA5182 + 0.6 (disclosed alloy 1)
Bal
4.5
0.25
0.2
0.1
0.6
-
-

AA5182-nano-I (reference patent application US 2019/0390306A1)
Bal
4.5
0.25
0.2
0.1
0.05
0.3
0.1

AA5182-nano-I + 0.3 (disclosed alloy 2)
Bal
4.5
0.25
0.2
0.1
0.3
0.3
0.1

AA5182-nano-I + 0.6 (disclosed alloy 2)
Bal
4.51
0.25
0.2
0.1
0.6
0.3
0.1

FIG. 6A displays tensile strength and elongation values of AA5182 as a function of Cu concentration from 0.05 to 0.6 wt.%. The alloy shows enhanced strength with increasing Cu content, initially starting at about 410 MPa at a level of 0.05 wt.% Cu, rising to 475 MPa at 0.6 wt.% Cu. The largest jump in strength occurs after the first 0.15 wt.% Cu increase (~25 MPa), after which the incremental increase at every 0.15 wt.% Cu addition is less (from 0.45 to 0.6 wt.% Cu strength is improved by 5 MPa). There is no significant change in elongation with increasing Cu content (all at ~9%). Similarly, FIG. 6B shows tensile strength and elongation values of AA5182-nano-I as a function of Cu concentration from 0.05 to 0.6 wt.%. There is a 35 MPa increase in strength with the addition of 0.3 wt.% Cu, and an increase of 50 MPa at 0.6 wt.% Cu. The increased Cu concentration does not show any detriment to elongation values. FIG. 6C summarizes the measured corrosion potential values of AA5182 and A5182-nano-I as a function of Cu concentration from 0.05 to 0.6 wt.%. There is no significant difference in corrosion potential between AA5182 and AA5182-nano-I at the same Cu alloying concentrations. Values suggest a more noble alloy at higher Cu concentrations, with the total decrease in corrosion potential being about 40 mV with the addition of 0.6 wt.% Cu.

Example 5: Mechanical Properties of Disclosed Alloys in Hard- or Soft-Temper

Table 4 lists mechanical properties of thin sheet (0.25 mm in thickness) including Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si wt.% (AA5182) in hard-temper and soft-temper, Al-4.5 Mg-0.25Mn-0.2Fe-0.1Si-0.3Zr-0.1Sn-0.3Cu wt.% (AA5182-nano-II) in hard-temper and soft-temper (stretched and annealed condition to simulate post paint-bake cycle properties). AA5182 hard-temper is a common aluminum alloy for food and beverage can tab and lid, whereas AA5182 soft-temper is commonly used in automotive applications. The AA5182-nano-II alloy, in both hard-and soft-temper achieve higher yield strength, tensile strength, while maintaining essentially the same elongation at break, compared to the AA5182 alloy with the respective temper.

TABLE 4

Mechanical properties of AA5182 and AA5182-nano-II sheet (0.25 mm in thickness) both in hard- and soft-temper, fabricated by the following steps: casting, hot rolling, annealing, cold rolling, and stabilizing heat treatment for hard-temper; and casting, hot rolling, cold rolling, and annealing for soft-temper. Additionally, soft-temper sheets are stretched and annealed to simulate the post paint-bake cycle properties

Yield strength (MPa)
Tensile strength (MPa)
Elongation at break (%)

AA5182 - hard temper (reference alloy)
355 ± 5
412 ± 5
6-8

AA5182-nano-II - hard temper (disclosed alloy 2)
420 ± 5
490 ± 5
6-8

AA5182 - soft-temper, stretched and annealed (reference alloy)
160 ± 5
300 ± 5
15-20

AA5182-nano-II - soft-temper, stretched and annealed (disclosed alloy 2)
220 ± 5
345 ± 5
15-20

Numbered Embodiments of the Disclosure

Other subject matter contemplated by the present disclosure is set out in the following numbered embodiments:

1. An aluminum alloy comprising:

about 3 to about 6.2% by weight magnesium;
about 0.01 to about 1.8% by weight manganese;
about 0.01 to about 0.6% by weight iron;
about 0.01 to about 0.5% by weight silicon;
about 0.1 to about 0.5% by weight zirconium;
about 0.01 to about 0.2% by weight tin;
about 0.08 to about 1% by weight copper; and
aluminum as the remainder.

2. The aluminum alloy of embodiment 1, comprising about 0.05 to about 0.6% by weight manganese.

2a. The aluminum alloy of embodiment 1 or 2, comprising about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight zirconium, about 0.1% by weight tin, about 0.15% by weight copper, and aluminum as the remainder.

3. The aluminum alloy of embodiment 1 or 2, comprising about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight zirconium, about 0.1% by weight tin, about 0.3% by weight copper, and aluminum as the remainder.

4. The aluminum alloy of embodiment 1 or 2, comprising about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight zirconium, about 0.1% by weight tin, about 0.6% by weight copper, and aluminum as the remainder.

5. The aluminum alloy of embodiment 1-4, wherein the alloy is essentially free of scandium.

6. The aluminum alloy of any one of embodiments 1-5, wherein the alloy possesses a yield strength of at least 400 MPa, a tensile strength of at least 450 MPa, and an elongation of at least 5% in the hard-temper condition.

7. The aluminum alloy of any one of embodiments 1-6, wherein after cold rolling, the alloy resists strength softening during stabilization treatment and shows improved ductility.

7a. The aluminum alloy of any one of embodiments 1-6, wherein after cold rolling, the alloy resists strength softening during coat cure treatment and shows improved ductility.

8. The aluminum alloy of any one of embodiments 1-7, wherein after forming or stretching, the alloy resists strength softening during paint-bake cycle.

9. The aluminum alloy of any one of embodiments 1-8, wherein the alloy possesses a yield strength of at least 170 MPa after forming and stretching, following by a paint-bake cycle.

10. The aluminum alloy of any one of embodiments 1-9, wherein the alloy comprises an Al₃Zr nanoscale precipitate, wherein the nanoscale precipitate has an average diameter of about 20 nm or less and has an Ll₂ structure in an α-Al face centered cubic matrix, and wherein the average number density of the nanoscale precipitate is about 20²¹ m^-3 or more.

11. The aluminum alloy of any one of embodiments 1-10, wherein the alloy comprises Cu-containing phases.

12. The aluminum alloy of embodiment 11, wherein the Cu-containing phases enhance thermal stability during moderate aging treatment, after cold rolling, forming or stretching (e.g. stabilization treatment and/or a paint-bake cycle).

13. The aluminum alloy of embodiment 11 or 12, wherein the Cu-containing phases comprise Al₂CuMg precipitates and/or S′phase.

14. The aluminum alloy of embodiment 13, wherein the formation of Al₂CuMg precipitates results in an increase in tensile strength compared to a reference AA5182 alloy without intentionally added copper.

15. A method for manufacturing a component from the aluminum alloy of any one of embodiments 1-14, the method comprising:

a) melting the alloy at a temperature of about 700° C. to about 900° C.;
b) casting the alloy into casting molds;
c) using a cooling medium to cool the cast ingot; and
d) hot rolling the cast ingot into plates or sheet at temperatures between 300° C. and 600° C.

16. The method of embodiment 15, wherein to generate a hard-temper condition, the method further comprises:

e) heat aging the plate or sheet at a temperature of about 350° C. to about 550° C. for a time of about 2 hours to about 48 hours;
f) cold rolling the hot rolled and heat treated sheet or plate to form thin sheet or foil products; and
g) stabilizing heat treatment and/or coat cure treatment at temperatures between 100° C. and 250° C. for 1 min to 8 h of the sheet products.

17. The method of embodiment 15, wherein to generate a soft-temper condition, the method further comprises:

e) cold rolling the hot rolled sheet or plate to form thin sheet or foil products; and
f) heat aging the sheet or foil at a temperature about 300° C. to about 550° C. for a time of about 2 h to about 48 h.

17a. The method of embodiment 16 or 17, wherein after cold rolling, the alloy resists strength softening during stabilization treatment and shows improved ductility.

17b. The method of embodiment 16 or 17, wherein after cold rolling, the alloy resists strength softening during coat cure treatment and shows improved ductility.

18. An aluminum alloy comprising:

about 2.5 to about 6.2% by weight magnesium;
about 0.01 to about 1.8% by weight manganese;
about 0.01 to about 0.6% by weight iron;
about 0.01 to about 0.5% by weight silicon;
about 0.01 to about 1% by weight copper; and
aluminum as the remainder.

19. The aluminum alloy of any one of embodiments 1-14 and 18, comprising about 0.1% by weight copper, about 0.15% by weight copper, about 0.2% by weight copper, 0.25% by weight copper, 0.3% by weight copper, 0.35% by weight copper, 0.4% by weight copper, 0.45% by weight copper, 0.5% by weight copper, 0.55% by weight copper, 0.6% by weight copper, 0.65% by weight copper, 0.7% by weight copper, 0.75% by weight copper, 0.8% by weight copper, 0.85% by weight copper, 0.9% by weight copper, 0.95% by weight copper, or 1% by weight copper.

20. The aluminum alloy of embodiment 18, comprising about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.15% by weight copper, and aluminum as the remainder.

20a. The aluminum alloy of embodiment 18, comprising about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.3% by weight copper, and aluminum as the remainder.

20b. The aluminum alloy of embodiment 18, comprising about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.45% by weight copper, and aluminum as the remainder.

21. The aluminum alloy of embodiment 18, comprising about 4.5% by weight magnesium, about 0.25% by weight manganese, about 0.2% by weight iron, about 0.1% by weight silicon, about 0.6% by weight copper, and aluminum as the remainder.

22. The aluminum alloy of any one of embodiments 18-21, wherein the alloy possesses a yield strength of at least 370 MPa, a tensile strength of at least 430 MPa, and an elongation of at least 5% in a hard-temper condition.

23. The aluminum alloy of any one of embodiments 18-22, wherein after cold rolling, the alloy resists strength softening during stabilization treatment, and shows improved ductility.

24. The aluminum alloy of any one of embodiments 18-23, wherein after cold rolling, the alloy resists strength softening during coat cure treatment, and shows improved ductility.

25. The aluminum alloy of any one of embodiments 18-24, wherein the alloy comprises Cu-containing phases.

26. The aluminum alloy of embodiment 25, wherein the Cu-containing phases enhance thermal stability during moderate aging treatment and/or coat cure treatment, performed after cold rolling, forming or stretching (e.g. stabilization treatment and/or a paint-bake cycle).

27. The aluminum alloy of embodiment 25 or 26, wherein the Cu-containing phases comprise Al₂CuMg precipitates and/or S′phase.

28. The aluminum alloy of embodiment 27, wherein the formation of Al₂CuMg precipitates results in an increase in tensile strength compared to a reference AA5182 alloy without intentionally added copper.

29. A method for manufacturing a component from the aluminum alloy of any one of embodiments 18-28, the method comprising:

a) melting the alloy at a temperature of about 700° C. to about 900° C.;
b) casting the alloy into casting molds;
c) using a cooling medium to cool the cast ingot;
d) hot rolling the cast ingot into plates or sheet at temperatures between 300° C. and 600° C.;
e) optionally heat aging the sheet at a temperature of about 350° C. to about 550° C. for a time of about 1 min to about 48 h;
f) cold rolling the hot rolled and heat treated sheet or plate to form thin sheet or foil products; and
g) stabilizing treatment and/or coat cure treatment at temperatures between 100° C. and 250° C. for 1 min to 8 h of the sheet products.

30. A food and/or beverage can lid and/or tab comprising the aluminum alloy of any one of embodiments 1-14 or any one of embodiments 18-28.

31. An aluminum alloy component comprising the aluminum alloy of any one of embodiments 1-14 or any one of embodiments 18-28, wherein the aluminum alloy component is selected from the group consisting of roofing materials, siding materials, chemical manufacturing equipment, food manufacturing equipment, storage tanks, home appliances, sheet-metal work, marine parts, transportation parts, heavy duty cooking utensils, hydraulic tubes, fuel tanks, pressure vessels, truck bodies, truck assemblies, trailer bodies, trailer assemblies, drilling rigs, missile components, and railroad cars.

32. A fabricated form of the aluminum alloy of any one of embodiments 1-14 or any one of embodiments 18-28, the fabricated form selected from a group consisting of wires, sheets, plates, and foils.

33. A food and/or beverage can lid and/or tab, that are color-coated for decoration, comprising the aluminum alloy of any one of embodiments 1-14 or any one of embodiments 18-28.

34. The aluminum alloy of any one of embodiments 1-14 or any one of embodiments 18-28, formed by:

a) melting the alloy at a temperature of about 700° C. to about 900° C.;
b) casting the alloy into casting molds;
c) using a cooling medium to cool the cast ingot;
d) hot rolling the cast ingot into plates or sheet at temperatures between 300° C. and 600° C.;
e) optionally heat aging the sheet at a temperature of about 350° C. to about 550° C. for a time of about 1 min to about 48 h;
f) cold rolling the hot rolled and heat treated sheet or plate to form thin sheet or foil products; and
g) stabilizing treatment and/or coat cure treatment at temperatures between 100° C. and 250° C. for 1 min to 8 h of the sheet products.

35. The aluminum alloy of embodiment 34, wherein after cold rolling, the alloy resists strength softening during stabilization treatment and/or cure coat treatment, and shows improved ductility.

	Number	Date	Country
Parent	PCT/US2021/030676	May 2021	WO
Child	17979580		US

HIGH STRENGTH AND THERMALLY STABLE 5000-SERIES ALUMINUM ALLOYS

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