Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/003—Alloys based on aluminium containing at least 2.6% of one or more of the elements: tin, lead, antimony, bismuth, cadmium, and titanium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
  • C22C21/08—Alloys based on aluminium with magnesium as the next major constituent with silicon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
  • C22F1/047—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with magnesium as the next major constituent

Definitions

• the present disclosure relates to the fields of metallurgy, aluminum alloys, aluminum fabrication, and related fields.
• the present disclosure provides novel 5xxx series aluminum alloy variants having improved strength and formability and methods for preparing the same.
• 5xxx series aluminum alloys i.e., aluminum alloys containing magnesium as its main alloying ingredient
• it is difficult to improve the performance of one property of a 5xxx series aluminum e.g., strength
• another property e.g., formability
• the composition of the AA5182 alloy is strictly controlled to have a magnesium (Mg) content between 4.0 wt. % and 5.0 wt. %, a manganese (Mn) content between 0.2 wt. % and 0.5 wt. %, a maximum iron (Fe) content of 0.35 wt. %, a maximum silicon (Si) content of 0.2 wt. %, a maximum copper (Cu) content of 0.15 wt.
• Mg magnesium
• Mn manganese
• Fe maximum iron
• Si maximum silicon
• Cu maximum copper
• the aluminum alloy will be highly susceptible to cracking during the production process. Thus, it is extremely difficult to produce 5xxx series aluminum alloys with higher strength and/or formability using conventional aluminum alloys or methods of production.
• the present disclosure relates to an aluminum alloy comprising about 0 - 0.30 wt. % Si, 0.01 - 0.40 wt. % Fe, 0 - 1.0 wt. % Cu, 0.01 - 0.50 wt. % Mn, 5.0 - 6.0 wt. % Mg, 0 - 0.20 wt. % Cr, 0 - 0.30 wt. % Zn, 0 - 0.25 wt. % Ti, up to 0.15 wt. % of impurities, and Al.
• the aluminum alloy comprises 0.01 - 0.20 wt. % Si, 0.01 - 0.30 wt. % Fe, 0.01 - 0.90 wt. % Cu, 0.01 - 0.40 wt. % Mn, 5.1 - 6.0 wt. % Mg, 0 - 0.10 wt. % Cr, 0 - 0.20 wt. % Zn, 0 - 0.10 wt. % Ti, up to 0.15 wt. % of impurities, and Al.
• the aluminum alloy comprises 0.01 - 0.15 wt. % Si, 0.01 - 0.20 wt. % Fe, 0.05 - 0.80 wt.
• the aluminum alloy comprises 0.01 - 0.06 wt. % Si, 0.02 - 0.15 wt. % Fe, 0.20 - 0.80 wt. % Cu, 0.05 - 0.20 wt. % Mn, 5.3 - 6.0 wt. % Mg, 0.001 - 0.02 wt.
• the aluminum alloy comprises 0.01 - 0.05 wt. % Si, 0.05 - 0.11 wt. % Fe, 0.30 - 0.80 wt. % Cu, 0.05 - 0.10 wt. % Mn, 5.5 - 5.9 wt. % Mg, 0.001 - 0.02 wt. % Cr, 0 - 0.01 wt. % Zn, 0.001 - 0.03 wt. % Ti, up to 0.15 wt.
• the aluminum alloy comprises at least one of: Mg in an amount from 5.5 wt. % to 6.0 wt. %; and Cu in an amount from 0.30 wt. % to 1.0 wt. %.
• the aluminum alloy comprises Fe-containing constituents having a particle size of less than 5 microns.
• a number density of Mg 2 Si particles in the aluminum alloy microstructure is at least 500/mm 2 .
• the aluminum alloy has a yield strength of at least 130 MPa.
• the aluminum alloy has an ultimate tensile strength of at least 300 MPa.
• the aluminum alloy has a total elongation of at least 5%.
• the present disclosure relates to a method of producing an aluminum alloy product, comprising: continuously casting an aluminum alloy to form a cast product, wherein the aluminum alloy comprises 0 - 0.30 wt. % Si, 0.01 - 0.40 wt. % Fe, 0 - 1.0 wt. % Cu, 0.01 - 0.50 wt. % Mn, 5.0 - 6.0 wt. % Mg, 0 - 0.20 wt. % Cr, 0 - 0.30 wt. % Zn, 0 - 0.25 wt. % Ti, up to 0.15 wt.
• the aluminum alloy comprises at least one of: Mg in an amount from 5.5 wt. % to 6.0 wt. %; and Cu in an amount from 0.30 wt. % to 1.0 wt. %.
• continuously casting comprises a solidification rate of at least 1 °C/s to produce the cast product.
• annealing comprises batch annealing or continuous annealing.
• flash homogenizing comprises heating the cast product from 400 °C to 600 °C for less than 10 minutes.
• the method comprises paint baking the cold rolled product after annealing to produce an aluminum alloy product.
• the yield strength of the aluminum alloy product increases by 5 MPa or greater after paint baking.
• Figure 1 shows a method of producing aluminum alloys according to some embodiments of the present disclosure.
• Figure 2 shows a graph of the yield strength of sample aluminum alloys measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• Figure 3 shows a graph of the ultimate tensile strength of sample aluminum alloys measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• Figure 4 shows a graph of the change in tensile properties of sample aluminum alloys after a paint bake simulation measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• Figure 5 shows a graph of the uniform elongation (Ag) of sample aluminum alloys measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• Figure 6 shows a graph of the total elongation (A80) of sample aluminum alloys measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• Figure 7 shows a graph of the r-value (r (10-15)) of sample aluminum alloys measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• Figure 8 shows a graph of the average n-value of sample aluminum alloys measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• Figures 9A and 9B show graphs of the instantaneous average n-value at different strain rates of sample aluminum alloys measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction, in a process for producing aluminum alloys that includes batch annealing or continuous annealing, respectively.
• Figure 10 shows the area percent of Fe-containing constituents in the aluminum alloy microstructure for the sample aluminum alloys.
• Figure 11 shows the number density of Fe-containing constituents in the aluminum alloy microstructure for the sample aluminum alloys.
• Figure 12 shows the area percent of Mg 2 Si constituents in the aluminum alloy microstructure for the sample aluminum alloys.
• Figure 13 shows the number density of Mg 2 Si constituents in the aluminum alloy microstructure for the sample aluminum alloys.
• Figures 14A-E show photographs of the grain structure of the sample aluminum alloys that were produced in a process including batch annealing after cold rolling.
• Figures 15A-E show photographs of the grain structure of the sample aluminum alloys that were produced in a process including continuous annealing after cold rolling.
• Described herein are novel 5xxx series aluminum alloy variants which exhibit high strength and formability, and methods for preparing the same. Surprisingly, the aluminum alloys described herein exhibit high strength and formability and do not have the same processing issues as conventional 5xxx series aluminum alloys (e.g., cracking during hot rolling), despite having a greater Mg content than conventional 5xxx series aluminum alloys.
• the aluminum alloys described herein can be produced using a continuous casting process described herein which allows higher amounts of Mg (e.g., greater than 5 wt. %) than other processes for producing 5xxx series aluminum alloys. By incorporating higher levels of Mg and utilizing continuous casting, the aluminum alloys described herein exhibit higher levels of strength and formability without the risk of cracking during the production process.
• the aluminum alloys and methods of producing aluminum alloys described herein provide superior properties compared to conventional 5xxx series aluminum alloys.
• AA5182 aluminum alloys for producing automotive parts require a strictly controlled composition to meet the minimum strength requirements while still maintaining formability to produce complex geometries.
• greater strength is required for aluminum alloys used to produce automotive parts, which has dictated that such automotive parts be fabricated from an aluminum alloy including high amounts of Mg, such as an AA5182 aluminum alloy.
• aluminum alloys having high Mg content are susceptible to cracking.
• Traditional approaches to reduce cracking mainly focus on b-phase morphology modification (e.g., continuous to discontinuous) at the grain boundaries by adding some alloying elements which can provide more nucleation sites or form additional particles to interrupt b-phase formation.
• higher quantities of Mg exacerbate cracking and results in an aluminum alloy with significant formability loss.
• the novel 5xxx series aluminum alloy variants described herein have an increased amount of Mg content in the aluminum alloy composition, but avoid the cracking problems associated with high Mg aluminum alloys.
• the aluminum alloys described herein include a higher amount of Mg, as compared to AA5182 aluminum alloys, and achieve higher strength and formability properties.
• increasing the Mg content and incorporating other alloying elements e.g., Mn, Cu, Si, etc.
• 5xxx series aluminum alloys e.g., AA5182 aluminum alloys.
• a synergistic combination of alloying elements, as further described herein produces a 5xxx series aluminum alloy variant that exhibits little or no cracking during the production process.
• the high Mg content aluminum alloys have higher solidification rates that prevent cracking during the production process. Although increasing the Mg content leads to very high work hardening rates and pile up of dislocations, which can result in edge cracking during cold rolling, this can be controlled by either performing an interannealing step during cold rolling or managing a gentle pass schedule during cold rolling.
• the high Mg content aluminum alloys described herein have enhanced strength and formability and could replace many existing materials (steels, A A5182 alloys, etc.) in automotive applications.
• invention As used herein, the terms “invention,” “the invention,” “this invention” and “the present invention” are intended to refer broadly to all of the subject matter of this patent application and the claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below.
• alloys identified by aluminum industry designations such as “series” or “5xxx.”
• series or “5xxx.”
• a plate generally has a thickness of greater than about 15 mm.
• a plate may refer to an aluminum product having a thickness of greater than about 15 mm, greater than about 20 mm, greater than about 25 mm, greater than about 30 mm, greater than about 35 mm, greater than about 40 mm, greater than about 45 mm, greater than about 50 mm, or greater than about 100 mm.
• a shate (also referred to as a sheet plate) generally has a thickness of from about 4 mm to about 15 mm.
• a shate may have a thickness of about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, or about 15 mm.
• a sheet generally refers to an aluminum product having a thickness of less than about 4 mm (e.g., less than 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, less than 0.3 mm, or less than 0.1 mm).
• a sheet may have a thickness of about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5, about 0.6 mm about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm, about 1.6 mm, about 1.7 mm, about 1.8 mm, about 1.9 mm, about 2 mm, about 2.1 mm, about 2.2 mm, about 2.3 mm, about 2.4 mm, about 2.5 mm, about 2.6 mm about 2.7 mm, about 2.8 mm, about 2.9 mm, about 3 mm, about 3.1 mm, about 3.2 mm, about 3.3 mm, about 3.4 mm, about 3.5 mm, about 3.6 mm, about 3.7 mm, about 3.8 mm, about 3.9 mm, or about 4 mm.
• formability refers to the ability of a material to undergo deformation into a desired shape without fracturing, tearing-off, necking, earing, or shaping errors such as wrinkling, spring-back, or galling occurring.
• formability may be classified according to deformation modes. Examples of deformation modes include drawing, stretching, bending, and stretch-flanging.
• An F condition or temper refers to an aluminum alloy as fabricated.
• An O condition or temper refers to an aluminum alloy after annealing.
• An Hxx condition or temper also referred to herein as an H temper, refers to a non-heat treatable aluminum alloy after cold rolling with or without thermal treatment (e.g., annealing). Suitable H tempers include HX1, HX2, HX3 HX4, HX5, HX6, HX7, HX8, or HX9 tempers.
• a TI condition or temper refers to an aluminum alloy cooled from hot working and naturally aged (e.g., at room temperature).
• a T2 condition or temper refers to an aluminum alloy cooled from hot working, cold worked and naturally aged.
• a T3 condition or temper refers to an aluminum alloy solution heat treated, cold worked, and naturally aged.
• a T4 condition or temper refers to an aluminum alloy solution heat treated and naturally aged.
• a T5 condition or temper refers to an aluminum alloy cooled from hot working and artificially aged (at elevated temperatures).
• a T6 condition or temper refers to an aluminum alloy solution heat treated and artificially aged.
• a T7 condition or temper refers to an aluminum alloy solution heat treated and artificially overaged.
• a T8x condition or temper refers to an aluminum alloy solution heat treated, cold worked, and artificially aged.
• a T9 condition or temper refers to an aluminum alloy solution heat treated, artificially aged, and cold worked.
• a W condition or temper refers to an aluminum alloy after solution heat treatment.
• room temperature can include a temperature of from about 15 °C to about 30 °C, for example about 15 °C, about 16 °C, about 17 °C, about 18 °C, about 19 °C, about 20 °C, about 21 °C, about 22 °C, about 23 °C, about 24 °C, about 25 °C, about 26 °C, about 27 °C, about 28 °C, about 29 °C, or about 30 °C. All ranges disclosed herein are to be understood to encompass both endpoints and any and all subranges subsumed therein.
• a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all 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 percentage (wt. %) based on the total weight of the alloy. In certain examples of each alloy, the remainder is aluminum, with a maximum wt. % of 0.15 % for the sum of the impurities.
• Aluminum alloy properties are partially determined by the composition of the aluminum alloys.
• the alloy composition may influence or even determine whether the alloy will have properties adequate for a desired application.
• the alloys described herein are novel 5xxx series aluminum alloy variants.
• the alloys exhibit high strength, high formability (e.g., excellent elongation and forming properties), and resistance to cracking during the production process.
• the properties of the alloy are achieved at least in part due to the elemental composition of the alloy.
• the novel 5xxx series aluminum alloy variants described herein can include a Mg content that is higher than the Mg content of a conventional 5xxx series aluminum alloy and, among other elements, can include one or more of Cu, Mn, and Si in certain amounts, as further described below.
• an aluminum alloy as described herein can have the following elemental composition as provided in Table 1.
• the aluminum alloy as described herein can have the following elemental composition as provided in Table 2.
• the aluminum alloy as described herein can have the following elemental composition as provided in Table 3.
• the aluminum alloy can have the following elemental composition as provided in Table 4.
• the aluminum alloy can have the following elemental composition as provided in Table 5.
• the aluminum alloy described herein includes Si in an amount of from 0 % to 0.30 % (e.g., from 0 % to 0.25 %, from 0.01 % to 0.20 %, from 0.01 % to 0.15 %, from 0.01 % to 0.10 %, from 0.01 % to 0.06 %, or from 0.01 % to 0.05 %) based on the total weight of the alloy.
• the alloy can include 0 %, 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08 %, 0.09 %, 0.10 %, 0.11 %, 0.12 %, 0.13 %, 0.14 %, 0.15 %, 0.16 %, 0.17 %, 0.18 %, 0.19 %, 0.20 %, 0.21 %, 0.22 %, 0.23 %, 0.24 %, 0.25 %, 0.26 %, 0.27 %, 0.28 %, 0.29 %, or 0.30 % Si. All expressed in wt. %.
• the aluminum alloy described herein also includes Fe in an amount of from 0.01 % to 0.40 % (e.g., from 0.01 % to 0.25 %, from 0.01 % to 0.20 %, from 0.01 % to 0.15 %, from 0.02 % to 0.11 %, or from 0.05 % to 0.11 %) based on the total weight of the alloy.
• the alloy can include 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08 %, 0.09 %, 0.10 %, 0.11 %, 0.12 %, 0.13 %, 0.14 %, 0.15 %, 0.16 %, 0.17 %, 0.18 %, 0.19 %, 0.20 %, 0.21 %, 0.22 %, 0.23 %, 0.24 %, 0.25 %, 0.26 %, 0.27 %, 0.28 %, 0.29 %, 0.30 %, 0.31 %, 0.32 %, 0.33 %, 0.34 %, 0.35 %, 0.36 %, 0.37 %, 0.38 %, 0.39 %, or 0.40 % Fe. All expressed in wt. %.
• the aluminum alloy can include up to 0.40 % Fe, and thus can be produced from higher amounts of recycled aluminum alloy.
• the aluminum alloy described herein includes Cu in an amount of up to 1.0 % (e.g., from 0 % to 1.0 %, from 0.01 % to 0.90 %, from 0.05 % to 0.80 %, from 0.20 % to 0.80 %, or from 0.30 % to 0.80 %) based on the total weight of the alloy.
• the alloy can include 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08 %, 0.09 %, 0.10 %, 0.11 %, 0.12 %, 0.13 %, 0.14 %, 0.15 %, 0.16 %, 0.17 %, 0.18 %, 0.19 %, 0.20 %, 0.21 %, 0.22 %, 0.23 %, 0.24 %, 0.25 %, 0.26 %, 0.27 %, 0.28 %, 0.29 %, 0.30 %, 0.31 %, 0.32 %, 0.33 %, 0.34 %, 0.35 %, 0.36 %, 0.37 %, 0.38 %, 0.39 %, 0.40 %, 0.41 %, 0.42 %, 0.43 %, 0.44 %, 0.45 %, 0.46 %, 0.47 %, 0.48 %, 0.49 %, 0.50
• an aluminum composition including Cu in the amounts described herein improves the paint bake response of the aluminum alloy.
• an aluminum with the amounts of Cu described herein exhibits improved strength and formability after paint bake when the aluminum alloy is subjected to continuous annealing. Additionally, the high Cu content increases the ultimate tensile strength which provides a higher work hardening range compared to low Cu content alloys.
• adding Cu to the aluminum alloy composition in amounts greater than 1.0 wt. % may cause cracking during the casting or hot rolling process.
• the aluminum alloy described herein also includes Mn in an amount of from 0.01 % to 0.50 % (e.g., 0.01 % to 0.40 %, from 0.01 % to 0.30 %, from 0.01 % to 0.15 %, from 0.05 % to 0.30 %, from 0.05 % to 0.20 %, from 0.05 % to 0.15 %, or from 0.05 % to 0.10 %) based on the total weight of the alloy.
• the alloy can include 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08 %, 0.09 %, 0.10 %, 0.11 %,
• an aluminum composition including Mn in the amounts described herein results in excellent n-values (hardening exponent).
• aluminum alloys having a Mn content greater than 0.40 wt. % reduces the n-value due to the solute drag effect and also increases the volume fraction of constituent particles with Fe and Si that results in reduced formability.
• the amounts of Mn in the aluminum alloys described herein are finely controlled to prevent loss in formability.
• the aluminum alloy described herein can include Mg in an amount of from 5.0 % to 6.0 % (e.g., from 5.1 % to 6.0 %, from 5.2 % to 6.0 %, from 5.3 % to 6.0 %, from 5.4 % to 6.0 %, from 5.5 % to 6.0 %, from 5.5 % to 5.9 %, from 5.6 % to 5.9 %, or from 5.6 % to 5.8 %).
• the alloy can include 5.0 %, 5.1 %, 5.2 %, 5.3 %, 5.4 %, 5.5 %, 5.6 %, 5.7 %, 5.8 %, 5.9 %, or 6.0 % Mg.
• the inclusion of the aforementioned amounts of Mg in the alloys described herein serve as a solid solution strengthening element.
• aluminum alloys including an Mg content in the amount described herein surprisingly produces an aluminum alloy having excellent strength and formability.
• an aluminum composition including less than 5.0 wt. % Mg cannot achieve high strength and/or formability.
• an aluminum composition including greater than 6.0 wt. % Mg results in an aluminum alloy that is very difficult to cold roll and requires multiple inter-annealing steps for rolling, which often results in large amounts of edge cracking during rolling.
• the aluminum alloy described herein includes Cr in an amount of up to 0.20 % (e.g., from 0 % to 0.20 %, from 0 % to 0.10 %, from 0 % to 0.05 %, from 0.001 % to 0.05 %, from 0.001 % to 0.02 %, from 0.005 % to 0.05 %, or from 0.01 % to 0.05 %) based on the total weight of the alloy.
• up to 0.20 % e.g., from 0 % to 0.20 %, from 0 % to 0.10 %, from 0 % to 0.05 %, from 0.001 % to 0.05 %, from 0.001 % to 0.02 %, from 0.005 % to 0.05 %, or from 0.01 % to 0.05 %
• the alloy can include 0.001 %, 0.002 %, 0.003 %, 0.004 %, 0.005 %, 0.006 %, 0.007 %, 0.008 %, 0.009 %, 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08 %, 0.09 %, 0.10 %, 0.11 %, 0.12 %, 0.13 %, 0.14 %,
• adding Cr in the aforementioned amounts reduces pitting corrosion and increases strength by solid solution hardening. In some cases, Cr is not present in the alloy (i.e., 0 %). All expressed in wt. %.
• the aluminum alloy described herein includes Zn in an amount of up to 0.30 % (e.g., from 0 % to 0.25 %, from 0 % to 0.20 %, from 0 % to 0.10 %, from 0 % to 0.05 %, from 0.001 % to 0.05 %, from 0.001 % to 0.02 %, from 0.005 % to 0.05 %, or from 0.01 % to 0.05 %) based on the total weight of the alloy.
• the alloy can include 0.001 %, 0.002 %, 0.003 %, 0.004 %, 0.005 %, 0.006 %, 0.007 %, 0.008 %, 0.009 %,
• Zn is not present in the alloy (i.e., 0 %). In some cases, excess Zn addition (e.g., above 0.30 wt. %) deteriorates corrosion properties. Thus, the amounts of Zn in the aluminum alloys described herein is limited. All expressed in wt. %.
• the aluminum alloy described herein can include titanium (Ti) in an amount up to 0.20 % (e.g., from 0 % to 0.20 %, from 0 % to 0.10 %, from 0 % to 0.05 %, from 0.001 % to 0.05 %, from 0.001 % to 0.02 %, or from 0.005 % to 0.05 %) based on the total weight of the alloy.
• Ti titanium
• the alloy can include 0.001 %, 0.002 %, 0.003 %, 0.004 %, 0.005 %, 0.006 %, 0.007 %, 0.008 %, 0.009 %, 0.01 %, 0.02 %, 0.03 %, 0.04 %, 0.05 %, 0.06 %, 0.07 %, 0.08 %, 0.09 %, 0.10 %, 0.11 %, 0.12 %, 0.13 %, 0.14 %, 0.15 %,
• Ti is not present in the alloy (i.e., 0 %). All expressed in wt. %.
• the aluminum alloys described herein can further include other minor elements, sometimes referred to as impurities, in amounts of 0.05 % or below, 0.04 % or below, 0.03 % or below, 0.02 % or below, or 0.01 % or below.
• impurities may include, but are not limited to V, Ni, Hf, Zr, Sc, Sn, Ga, Ca, Bi, Na, Pb, or combinations thereof. Accordingly, V, Ni, Hf, Zr, Sc, Sn, Ga, Ca, Bi, Na, or Pb may be present in alloys in amounts of 0.05 % or below, 0.04 % or below, 0.03 % or below, 0.02 % or below, or 0.01 % or below.
• the aluminum alloy can include up to 0.15 wt. % to improve corrosion resistance. All expressed in wt. %. The remaining percentage of each alloy can be aluminum.
• the aluminum alloys described herein exhibit excellent properties when produced according to the methods described herein. In some embodiments, the aluminum alloys described herein exhibit improved properties compared to conventional 5xxx series aluminum alloys when produced according to a continuous casting process described herein in combination with batch annealing after cold rolling. In some embodiments, the aluminum alloys described herein exhibit improved properties compared to conventional 5xxx series aluminum alloys when produced according to a continuous casting process described herein in combination with continuous annealing after cold rolling. The processing steps significantly improve the strength and formability properties of the aluminum alloy.
• an aluminum alloy product produced from the aluminum alloys described herein can have a yield strength of about 130 MPa or greater.
• an aluminum alloy product produced from the aluminum alloys described herein can have a yield strength of 130 MPa or greater, 135 MPa or greater, 140 MPa or greater, 145 MPa or greater, 150 MPa or greater, 155 MPa or greater, 160 MPa or greater, 165 MPa or greater,
• the yield strength is from about 130 MPa to about 250 MPa (e.g., from about 135 MPa to about 200 MPa, from about 140 MPa to 190 MPa, or from about 145 MPa to about 180 MPa), or anywhere in between.
• the aluminum alloy products described herein can exhibit the yield strengths as described herein when measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• an aluminum alloy product produced from the aluminum alloys described herein can have an ultimate tensile strength of about 300 MPa or greater.
• an aluminum alloy product produced from the aluminum alloys described herein can have a yield strength of 300 MPa or greater, 305 MPa or greater, 310 MPa or greater, 315 MPa or greater, 320 MPa or greater, 325 MPa or greater, 330 MPa or greater, 335 MPa or greater, 340 MPa or greater, 345 MPa or greater, or 350 MPa or greater.
• the ultimate tensile strength is from about 300 MPa to about 500 MPa (e.g., from about 305 MPa to about 450 MPa, from about 310 MPa to about 400 MPa, or from about 315 MPa to about 350 MPa), or anywhere in between.
• the aluminum alloy products described herein can exhibit the ultimate tensile strength as described herein when measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the aluminum alloy products produced from the aluminum alloys described herein also exhibit an increase in yield strength after paint baking.
• an aluminum alloy product produced from the aluminum alloys described herein, after a simulated paint bake cycle exhibit an increased yield strength of 2 MPa or greater, 4 MPa or greater, 5 MPa or greater, 10 MPa or greater, 15 MPa or greater, 20 MPa or greater, or 25 MPa or greater.
• an aluminum alloy product produced from the aluminum alloys described herein exhibit an increased yield strength from 2 MPa to 100 MPa, e.g., from 5 MPa to 90 MPa, from 10 MPa to 80 MPa, from 20 MPa to 75 MPa, from 25 MPa to 60 MPa, from 30 MPa to 50 MPa, or from 35 MPa to 45 MPa.
• the aluminum alloy products described herein can exhibit the improved yield strength as described herein when measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the simulated paint bake cycle may include heating the aluminum alloy product to 185 °C for about 20 minutes.
• the aluminum alloys described herein produced according to the methods described herein also exhibit high formability.
• the high formability can be measured, for example, by measuring total elongation or uniform elongation.
• ISO/EN A80 is one standard that can be used for testing the total elongation.
• ISO/EN Ag is one standard that can be used for testing the uniform elongation.
• an aluminum alloy product produced from the aluminum alloys described herein can have a total elongation (A80) of at least about 5% and up to about 30%.
• an aluminum alloy product produced from the aluminum alloys described herein can have a total elongation of about 5 %, 6 %, 7 %, 8 %, 9 %, 10 %,
• the aluminum alloy products described herein can exhibit the total elongations as described herein when measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• an aluminum alloy product produced from the aluminum alloys described herein can have a uniform elongation (Ag) of at least about 5% and up to about 30%.
• an aluminum alloy product produced from the aluminum alloys described herein can have a uniform elongation of about 5 %, 6 %, 7 %, 8 %, 9 %, 10 %, 11 %, 12 %,
• the aluminum alloy products described herein can exhibit the uniform elongation as described herein when measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the r-value also known as the Lankford coefficient
• the r-value is a measurement of the deep-drawability of a sheet metal (i.e., the resistance of a material to thinning or thickening when put into tension or compression).
• the r-value can be measured according to ASTM E517 (2020).
• an aluminum alloy product produced from the aluminum alloys described herein can have an r-value in any direction or all directions (longitudinal (L), diagonal (D), and/or transverse (T)) of at least about 0.45, e.g., at least about 0.50, at least about 0.55, at least about 0.60, at least about 0.65, at least about 0.70, or at least about 0.75.
• an aluminum alloy product produced from the aluminum alloys described herein can have an r-value in any direction or all directions from 0.45 to 0.95, e.g., from 0.50 to 0.95, from 0.55 to 0.90, from 0.60 to 0.90, from 0.65 to 0.85, or from 0.70 to 0.85.
• n value or the strain hardening exponent
• the n-value can be measured according to ASTM E646 (2020).
• the n-value measured over a strain range from 10% to 20% is indicated as n (10-20).
• an aluminum alloy product produced from the aluminum alloys described herein can have an n (10-20) value in any individual direction or in all directions (longitudinal (L), diagonal (D), and/or transverse (T)) of at least about 0.10, e.g., at least about 0.15, at least about 0.20, at least about 0.25, or at least about 0.30.
• an aluminum alloy product produced from the aluminum alloys described herein can have an n-value in any direction or all directions from 0.10 to 0.50, e.g., from 0.15 to 0.45, from 0.20 to 0.40, from 0.25 to 0.40, from 0.30 to 0.40, or from 0.30 to 0.35.
• the aluminum alloys described herein when produced according to the methods described herein possess a particle distribution that results in improved mechanical properties.
• the aluminum alloys described herein include higher amounts of Mg (e.g., from 5.0 wt. % to 6.0 wt. %) and/or Cu (e.g., from 0.3 wt. % up to 1.0 wt. %) than conventional 5xxx series aluminum alloys.
• Mg e.g., from 5.0 wt. % to 6.0 wt.
• Cu e.g., from 0.3 wt. % up to 1.0 wt. %
• the constituents formed with Fe did not substantially increase compared to AA5182 alloys.
• the particle size distribution of the Fe constituents remains effectively the same.
• the area fraction of Al x (Fe,Mn) and Al(Fe,Mn)Si particles in the aluminum alloy microstructure for aluminum alloys with 5.0 wt. % to 6.0 % Mg were similar to AA5182 alloy.
• the particle size of the Fe-containing constituent particles had a small particle size (e.g., less than 5 microns) with predominantly Al x (Fe,Mn) particles in the aluminum alloy microstructure, which is similar to AA5182 alloy. Therefore, the higher amounts of Mg and Cu in the aluminum alloys described herein did not negatively affectively the microstructure of the aluminum alloy.
• the aluminum alloys described herein when produced according to the methods described herein include Fe-containing constituents having a particle size less than 10 microns, e.g., less than 9 microns, less than 8 microns, less than 7 microns, less than 6 microns, less than 5 microns, or less than 4 microns.
• the aluminum alloys described herein when produced according to the methods described herein include Fe-containing constituents having a particle size from 0.01 to 10 microns, e.g., from 0.01 to 10 microns, from 0.01 to 10 microns, from 0.05 to 8 microns, from 0.1 to 6 microns, from 0.2 to 5 microns, or from 0.2 to 4.5 microns.
• Fe-containing constituent particles in the aluminum alloys described herein result in improved formability and corrosion resistance properties.
• Fe- containing constituent particles typically serve as crack initiation sites, which results in damage to the aluminum alloys when subjected to deformation. Additionally, large Fe- containing constituent particles result in higher corrosion potential and poor corrosion performance.
• the low amounts and small size of the Fe-containing constituent particles of the aluminum alloys described herein are favorable for both forming and corrosion resistance.
• FIGS. 12 and 13 show graphs of the Mg 2 Si particle distribution in the aluminum alloy and provides the number density, percent area, and average size of Mg 2 Si particles of the example alloys. As shown in FIGS. 12 and 13, the particle size distribution of the Mg 2 Si particles for the aluminum alloys described herein was greater than the AA5182 alloy. For example, FIG. 12 shows that the area percent of Mg 2 Si of the aluminum alloys was greater than 0.01 % and the particle size was from 0.2 microns to 5 microns. The number density and area fraction of Mg 2 Si of the aluminum alloys described herein was greater than the AA5182 alloy.
• the aluminum alloys described herein when produced according to the methods described herein include Mg 2 Si particles having a particle size less than 10 microns, e.g., less than 9 microns, less than 8 microns, less than 7 microns, less than 6 microns, less than 5 microns, or less than 4 microns.
• the aluminum alloys described herein when produced according to the methods described herein include Mg 2 Si particles having a particle size from 0.01 to 10 microns, e.g., from 0.01 to 10 microns, from 0.01 to 10 microns, from 0.05 to 8 microns, from 0.1 to 6 microns, from 0.2 to 5 microns, or from 0.2 to 4.5 microns.
• the aluminum alloys described herein when produced according to the methods described herein includes a peak area fraction of Mg 2 Si particles greater than 0.013 %, e.g., greater than 0.013 %, greaterthan 0.015 %, greater than 0.018 %, greater than 0.020 %, greater than 0.021 %, or greater than 0.025 %.
• the aluminum alloys described herein when produced according to the methods described herein includes a peak area fraction of Mg 2 Si particles from 0.013 % to 0.030 %, e.g., from 0.014 % to 0.028 %, from 0.015 % to 0.025 %, from 0.018 % to 0.024 %, or from 0.020 % to 0.024 %.
• the aluminum alloys described herein when produced according to the methods described herein includes a number density of Mg 2 Si particles greater than 300/mm 2 %, e.g., greater than 325/mm 2 , greater than 350/mm 2 , greater than 375/mm 2 , greater than 400/mm 2 , greater than 425/mm 2 , greater than 450/mm 2 , greater than 475/mm 2 , or greater than 500/mm 2 .
• the aluminum alloys described herein when produced according to the methods described herein includes a number density ofMg2Si particles from 300/mm 2 to 600/mm 2 , e.g., from 325/mm 2 to 575/mm 2 , from 350/mm 2 to 550/mm 2 , from 375/mm 2 to 525/mm 2 , or from 400/mm 2 to 525/mm 2 .
• the total number density (overall number density) of Mg 2 Si particles is less than 3000/mm 2 .
• the Mg 2 Si particles dissolve during high temperature annealing (e.g., continuous annealing) for solid solution strengthening.
• the Mg 2 Si particles will form strengthening precipitates during paint bake for extra strength improvement.
• the Fe-containing constituent particles and the Mg 2 Si particles act as heterogeneous nucleation sites during annealing and produce fine grain orientation/random texture for better formability.
• the disclosed alloy composition is a product of a disclosed method.
• aluminum alloy properties are partially determined by the formation of microstructures during the alloy’s preparation.
• the method of preparation for an alloy composition may influence or even determine whether the alloy will have properties adequate for a desired application.
• the aluminum alloys described herein can be produced by continuous casting, optional flash homogenization, hot rolling, coiling, cold rolling, and annealing.
• the method may include continuously casting a metal strip.
• the method for casting the metal strip can be any suitable continuous casting process.
• a continuous casting process such as the continuous casting process described in U.S. PatentNo. 10,913,107 entitled “METAL CASTING AND ROLLING LINE,” the disclosure of which is hereby incorporated by reference in its entirety.
• the method comprises flash homogenizing the metal strip prior to hot rolling.
• the flash homogenization temperature and duration of hot rolling are finely controlled to preserve a large grain size and high strength for the aluminum alloy.
• the metal strip can be flash homogenized at a temperature from 400 °C to 500 °C in a furnace at a suitable heating rate, followed by maintaining the temperature (“soak” or “soaking”) for short period of time (e.g., up to 10 minutes).
• the metal strip is hot rolled at a hot rolling temperature from 300 °C to 500 °C to produce a hot rolled product.
• the hot rolled product can be coil cooled.
• the hot rolled product is cold rolled in a number of cold rolling passes to produce a cold rolled product.
• the cold rolled product can optionally be coiled.
• the cold rolled product is batch annealed or continuously annealed to produce an aluminum alloy product.
• FIG. 1 provides one exemplary system 100 for producing the aluminum alloys described herein.
• the system 100 can include a continuous caster 105, a furnace 110 (e.g., a tunnel furnace), a hot roll stand 115, a first coiler 120, a cold mill stand 125, and a second coiler 130.
• the system 100 comprises a decoupled or partially-decoupled continuous casting and rolling lines for casting, rolling, and otherwise preparing metal articles (e.g., metal strip) suitable for providing a distributable coil of metal strip.
• the term decoupled refers to removing the speed link between the casting device and the rolling stand(s).
• the continuous caster 105 may be decoupled from the hot roll stand 115.
• the hot roll stand 115 can provide a reduction in thickness of the metal strip between 40% to 80%.
• a quench before the hot rolling stand may be optional, however it may beneficially break up Fe- containing particles and improve precipitation characteristics.
• the metal strip cast from the continuous caster 105 can be rolled (e.g., hot rolled) prior to coiling.
• the metal strip can be coiled in the first coiler 120.
• the metal strip can be cooled before, or simultaneously with, coiling in the first coiler 120.
• the metal strip can be uncoiled and cold rolled in the cold mill stand 125.
• the cold mill stand 125 can provide a reduction in thickness of the metal strip greater than 50%.
• the metal strip optionally be coiled, and then batch annealed or continuously annealed.
• the alloys described herein can be cast into a metal article (e.g., metal strip) using a continuous casting (CC) process.
• Continuous casting involves continuously injecting molten metal into a casting cavity defined between a pair of moving opposed casting surfaces and withdrawing a cast metal form (e.g., a metal strip) from the exit of the casting cavity.
• beneficial results can be achieved by intentionally decoupling the casting process from the hot rolling process in a continuous casting and rolling system.
• the casting speed and the rolling speed no longer need to be closely matched. Rather, the casting speed can be selected to produce desired characteristics in the metal strip, and the rolling speed can be selected based on the requirements and limitations of the rolling equipment.
• the continuous casting device can cast a metal strip that is immediately or shortly thereafter coiled into an intermediate, or transfer, coil.
• the intermediate coil can be stored or immediately brought to the rolling equipment.
• the intermediate coil can be uncoiled, allowing the metal strip to pass through the rolling equipment to be hot rolled and otherwise processed.
• the end result of the hot rolling process is a metal strip that can have the characteristics desired for a particular customer.
• the metal strip can be coiled and distributed, such as to an automotive plant capable of forming automotive parts from the metal strip.
• the metal strip can be heated at various points after being initially cast in the continuous casting process (e.g., by the continuous caster), however the metal strip will remain below a solidus temperature of the metal strip.
• the casting device can be any suitable continuous casting device.
• a belt casting device such as the belt casting device described in U.S. Patent No. 6,755,236 entitled “BELT-COOLING AND GUIDING MEANS FOR CONTINUOUS BELT CASTING OF METAL STRIP,” the disclosure of which is hereby incorporated by reference in its entirety.
• especially desirable results can be achieved by using a belt casting device having belts made from a metal having a high thermal conductivity, such as copper.
• the belt casting device can include belts made from a metal having a thermal conductivity of at least 250, 300, 325, 350, 375, or 400 watts per meter per Kelvin at casting temperatures, although metals having other values of thermal conductivity may be used.
• the casting device can cast a metal strip at any suitable thickness, however desirable results have been achieved at thicknesses of approximately 5 mm to 50 mm.
• the casting device can be configured to provide fast solidification (e.g., quickly solidifying at rates of at or more than about 10 times faster than standard DC casting solidification, such as at least at or about 1 °C/s, at least at or about 10 °C/s, or at least at or about 100 °C/s) and fast cooling (e.g., quickly cooling at rates of at least at or about 1 °C/s, at least at or about 10 °C/s, or at least at or about 100 °C/s) of the metal strip, which can facilitate improved microstructure in the final metal strip.
• the solidification rate can be at or above 100 times the solidification rate of traditional DC casting.
• Fast solidification can result in a unique microstructure, including a unique distribution of dispersoid-forming elements very evenly distributed throughout the solidified aluminum matrix.
• Fast cooling this metal strip such as immediately quenching the metal strip as it exits the casting device, or shortly thereafter, can facilitate locking the dispersoid-forming elements in solid solution.
• the resultant metal strip can be then supersaturated with dispersoid-forming elements.
• the supersaturated metal strip can then be coiled into an intermediate coil for further processing in the decoupled casting and rolling system.
• the desired dispersoid-forming elements include Mn, Cr, V, and/or Zr. This metal strip that is supersaturated with dispersoid-forming elements can, when reheated, very quickly induce the precipitation of evenly distributed and desirably-sized dispersoids.
• fast solidification and fast cooling can be performed singularly by a casting device.
• the casting device can be of sufficient length and have sufficient heat removal characteristics to produce a metal strip supersaturated in dispersoid-forming elements.
• the casting device can be of sufficient length and have sufficient heat removal characteristics to reduce the temperature of the cast metal strip to at or below 250 °C, 240 °C, 230 °C, 220 °C, 210 °C, or 200 °C, although other values may be used.
• such a casting device would have to either occupy significant space or operate at slow casting speeds.
• the metal strip can be quenched immediately after exiting the casting device or soon thereafter.
• One or more nozzles can be positioned downstream of the casting device to reduce the temperature of the metal strip to at or below 250 °C, 240 °C, 230 °C, 220 °C, 210 °C, 200 °C, 175 °C, 150 °C, 125 °C, or 100 °C, although other values may be used.
• the quench can occur sufficiently fast or quickly to lock the dispersoid-forming elements in a supersaturated metal strip.
• the metal strip can then be subjected to further processing steps.
• the further processing steps can be used to prepare sheets.
• processing steps include, but are not limited to, an optional flash homogenization step, a hot rolling step, a cold rolling step, and an annealing step.
• the processing steps are described below in relation to a metal strip. However, the processing steps can also be used for a cast slab or strip, using modifications as known to those of skill in the art. Homogenization
• a metal strip prepared from the alloy compositions described herein may be heated to a homogenization temperature, such as a temperature ranging from about 400 °C to 600 °C.
• a homogenization temperature such as a temperature ranging from about 400 °C to 600 °C.
• the metal strip can be heated to a temperature of about 400 °C, 410 °C, 420 °C, 430 °C, 440 °C, 450 °C, 460 °C, 470 °C, 480 °C, 490 °C, 500 °C, 510 °C, 520 °C, 530 °C, 540 °C, or 550 °C.
• the metal strip can be flash homogenized.
• Flash homogenization can include heating the metal strip to a temperature above 500 °C (e.g., from 500 °C to 570 °C, from 520 °C to 560 °C, or at or approximately 560 °C) for a relatively short period of time (e.g., approximately 1 minute to 10 minutes, such as 30 second, 45 seconds, 1 minutes, 1.5 minutes, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, or 10 minutes, or any range in between).
• This heating can occur between the continuous caster and the optional initial coiling, and more specifically between the continuous caster and the hot rolling stand prior to coiling, or between that hot rolling stand and coiling.
• flash homogenization can help reduce the aspect ratio of the Fe-containing particles and can also reduce the size of these particles.
• flash homogenization e.g., at 570 °C for about 2 minutes
• an optional soaking furnace e.g., a tunnel furnace
• a soaking furnace can be positioned downstream of the continuous belt caster near the exit of the continuous belt caster to perform flash homogenization.
• the use of a soaking furnace can facilitate achieving a uniform temperature profile across the lateral width of the metal strip.
• the soaking furnace can flash homogenize the metal strip, which can prepare the metal strip for improved breakup of Fe-containing particles during hot rolling.
• the metal strip or optionally the homogenized metal strip if a homogenization step is performed, can be subjected to a hot rolling step to produce a hot rolled product.
• the metal strip cast from the continuous caster can be rolled (e.g., hot rolled) prior to coiling.
• the rolling prior to coiling can be at a large reduction of thickness, such as at least 30% or more typically between 50% and 75%. Especially useful results have been found when the continuously cast metal strip is rolled with a single hot rolling stand prior to coiling, although additional stands can be used in some cases.
• this high-reduction e.g., greater than 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or 75% reduction in thickness
• hot rolling after continuous casting can help break up Fe-containing particles in the metal strip, among other benefits.
• hot rolling can be performed at a temperature of from about 300 °C to about 500 °C (e.g., about 300 °C, about 310 °C, about 320 °C, about 330 °C, about 340 °C, about 350 °C, about 360 °C, about 370 °C, about 380 °C, about 390 °C, about 400 °C, about 410 °C, about 420 °C, about 430 °C, about 440 °C, about 450 °C, about 460 °C, about 470 °C, about 480 °C, about 490 °C, or about 500 °C).
• about 300 °C to about 500 °C e.g., about 300 °C, about 310 °C, about 320 °C, about 330 °C, about 340 °C, about 350 °C, about 360 °C, about 370 °C, about 380 °C, about 390
• the combination of flash homogenization and hot rolling after continuous casting, as described herein, can be especially useful for refining (e.g., breaking up) Fe-containing particles.
• the hot rolled product can be cool coiled after hot rolling.
• the hot rolled product can be cool coiled at a temperature ranging from about 200 °C to 400 °C.
• the hot rolled product is coil cooled for ease of cold rolling as well as to modify grain and crystallographic texture of the aluminum alloy.
• the hot rolled product can be coiled at a temperature of about 200 °C (e.g., about 210 °C, about 220 °C, about 230 °C, about 240 °C, about 250 °C, about 260 °C, about 270 °C, about 280 °C, about 290 °C, about 300 °C, about 310 °C, about 320 °C, about 330 °C, about 340 °C, about 350 °C, about 360 °C, about 370 °C, about 380 °C, about 390 °C, or about 400 °C).
• one or more cold rolling steps can then be performed to result in a cold rolled product.
• the hot rolled product can be uncoiled using an uncoiler.
• the uncoiled hot rolled product can be cold rolled in a cold rolling stand.
• the hot rolled product can be cold rolled using cold rolling mills into thinner products, such as a cold rolled sheet.
• the cold rolling can be performed to result in a final gauge thickness that represents a gauge reduction of greater than 50 % (e.g., greater than 55 %, greater than 60 %, greater than 65 %, greater than 70 %, greater than 75 %, greater than 80 %, greater than 85 %, or greater than 90 % reduction) as compared to a gauge prior to the start of cold rolling.
• the cold rolling step may include one or more cold rolling steps to achieve the desired gauge thickness reduction.
• the process for producing the aluminum alloy can include an interannealing step (e.g., between one or more cold rolling steps).
• the cold rolled product can be coiled after cold rolling. Annealing
• the cold rolled product can be annealed after cold rolling.
• the annealing process can be batch annealing or continuous annealing.
• batch annealing can be performed after cold rolling.
• the batch-annealing step can be performed at a peak metal temperature of from about 300 °C to about 450 °C (e.g., about 310 °C, about 320 °C, about 330 °C, about 340 °C, about 350 °C, about 360 °C, about 370 °C, about 380 °C, about 390 °C, about 400 °C, about 410 °C, about 420 °C, about 430 °C, about 440 °C, or about 450 °C).
• the heating rate in the batch-annealing step can be about 10 °C/h to about 100 °C/h (e.g., from about 20 °C/h to about 90 °C/h, from about 30 °C/h to about 85 °C/h, from about 40 °C/h to about 80 °C/h, from about 50 °C/h to about 75 °C/h, from about 30 °C/h to about 80 °C/h, from about 40 °C/h to about 70 °C/h, or from about 50 °C/h to about 60 °C/h).
• the cold rolled product is allowed to soak for up to about 5 hours during the the batch-annealing step (e.g., from about 30 minutes to about 4 hours, from about 45 minutes to about 3 hours, or from about 1 hour to about 2 hours, inclusively).
• the cold rolled product can be soaked at a temperature of from about 300 °C to about 450 °C for about 20 minutes, about 30 minutes, about 45 minutes, about 1 hour, about 1.5 hours, about 2 hours, about 3 hours, about 4 hours, about 5 hours, or anywhere in between.
• the cold rolling product is heated to a temperature from about 350 °C to about 400 °C at a heating rate from about 50 °C/h to about 75 °C/h, soaked from about 1 hour seconds to about 2 hours, and is cooled at a cooling rate from about 5 °C/h to about 30 °C/h.
• continuous annealing can be performed after cold rolling.
• the continuous-annealing step can be performed at a peak metal temperature of from about 400 °C to about 600 °C (e.g., about 410 °C, about 420 °C, about 430 °C, about 440 °C, about 450 °C, about 460 °C, about 470 °C, about 480 °C, about 490 °C, about 500 °C, about 510 °C, about 520 °C, about 530 °C, about 540 °C, about 550 °C, about 560 °C, about 570 °C, about 580 °C, about 590 °C, or about 600 °C).
• the heating rate in the continuous-annealing step can be about 0.1 °C/s to about 30 °C/s (e.g., from about 0.2 °C/s to about 28 °C/s, from about 0.3 °C/s to about 28 °C/s, from about 0.4 °C/s to about 25 °C/s, from about 0.5 °C/s to about 20 °C/s, from about 0.8 °C/s to about 18 °C/s, from about 1 °C/s to about 15 °C/s, or from about 2 °C/s to about 10 °C/s).
• the cold rolled product is allowed to soak for up to about 1 minute during the the continuous-annealing step (e.g., 0 seconds, 5 seconds, 10 seconds, or 30 seconds).
• the cold rolling product is heated to a temperature from about 400 °C to about 600 °C at a heating rate from about 0.5 °C/s to about 20 °C/s, soaked from about 0 seconds to about 5 seconds, and is cooled at a cooling rate from about 5 °C/s to about 200 °C/s.
• the aluminum alloy products described herein can be used in automotive applications and other transportation applications, including aircraft and railway applications.
• the disclosed aluminum alloy products can be used to prepare automotive structural parts, such as bumpers, side beams, roof beams, cross beams, pillar reinforcements (e.g., A- pillars, B-pillars, and C-pillars), inner panels, outer panels, side panels, inner hoods, outer hoods, or trunk lid panels.
• pillar reinforcements e.g., A- pillars, B-pillars, and C-pillars
• inner panels outer panels
• side panels inner hoods
• outer hoods outer hoods
• trunk lid panels trunk lid panels.
• the aluminum alloy products and methods described herein can also be used in aircraft or railway vehicle applications, to prepare, for example, external and internal panels.
• the aluminum alloy products and methods described herein can also be used in electronics applications.
• the aluminum alloy products and methods described herein can be used to prepare housings for electronic devices, including mobile phones and tablet computers.
• the aluminum alloy products can be used to prepare housings for the outer casing of mobile phones (e.g., smart phones), tablet bottom chassis, and other portable electronics.
• Alloys 1-3 are exemplary alloys produced according to methods described below.
• Alloy A is a conventional AA5182 aluminum alloy which is currently employed in automotive body parts.
• Alloys 1-3 were continuously cast into metal strips based on the methods described herein.
• the metal strips were flash homogenized in a tunnel furnace operating at a temperature from 400 °C to 500 °C.
• the metal strips were hot rolled in a hot mill stand resulting in hot rolled products having a gauge thickness reduction from 40% to 80%.
• the hot rolled products were coil cooled to a temperature of about 350 °C.
• the hot rolled products were uncoiled and cold rolled in a cold mill stand resulting in cold rolled products having a gauge thickness reduction greater than 50%.
• the cold rolled products were coiled.
• the cold rolled products were subjected to batch annealing or continuous annealing to produce a final aluminum alloy product. Alloy A was direct chill cast or continuously cast.
• the strength properties of the exemplary alloys and comparative alloy were determined. Specifically, the alloys were subjected to yield strength and ultimate tensile strength tests.
• FIG. 2 shows the results of yield strength tests for Alloys 1-3 and Alloy A measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the yield strength values for Alloy A when produced using direct chill casting and continuous casting are shown in the first two columns.
• yield strength values are provided for the alloys after batch annealing (BA) and continuous annealing (CAL).
• BA batch annealing
• CAL continuous annealing
• the left bar shows the yield strength after continuous annealing
• the right bar shows the yield strength after batch annealing.
• the yield strength was slightly higher for aluminum alloys obtained after batch annealing compared to continuous annealing.
• the examples of Alloy A that were continuously cast exhibited a yield strength increase of about 15 MPa to 20 MPa compared to direct chill cast examples.
• Alloys 1-3 exhibited a higher yield strength in the L, T, and D directions compared to both examples of Alloy A.
• the higher Mg content of Alloys 1-3 in combination with producing the aluminums according to the continuous casting process described herein, resulted in higher strength compared to aluminum alloys produced by direct chill casting due to higher amounts of retained solute in solution. Additionally, Alloys 1-3 exhibited higher strength values with increased amounts of Mg and Cu.
• FIG. 3 shows the result of ultimate tensile strength tests for Alloys 1-3 and Alloy A measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the ultimate tensile strength values for Alloy A when produced using direct chill casting and continuous casting are shown in the first two columns.
• ultimate tensile strength values are provided for the alloys after batch annealing (BA) and continuous annealing (CAL).
• the left bar shows the ultimate tensile strength after continuous annealing and the right bar shows the ultimate tensile strength after batch annealing.
• the ultimate tensile strength was slightly higher for aluminum alloys obtained after batch annealing compared to continuous annealing.
• Alloys 1-3 exhibited a higher ultimate tensile strength in the L, T, and D directions compared to both examples of Alloy A. Alloys 1-3 produced according the continuous casting process described herein resulted in higher tensile strength compared to direct chill casting and conventional continuous casting.
• FIG. 4 shows the result of tensile strength tests for Alloys 1-3 and Alloy A measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction, after a paint bake simulation.
• Each of the alloys were heated to 185 °C and maintained at this temperature for about 20 minutes in the paint bake simulation.
• the change in tensile strength values for Alloy A when produced using direct chill casting and continuous casting are shown in the first two columns.
• Alloys 1-3 and Alloy A change in tensile strength values are provided for the alloys after batch annealing (BA) and continuous annealing (CAL). For each pair of bars representing the change in tensile strength values in the L, T, and D directions, the left bar shows the change in tensile strength values after continuous annealing and the right bar shows the change in tensile strength values after batch annealing. Alloy A did not exhibit any increase in strength after the paint bake cycle, regardless of how it was produced. Alloys 1-3 exhibited higher strength gains as the Cu content in the alloy increased. For example, Alloy 3 which contained 0.8 wt. % Cu, had the greatest increase in tensile strength after the paint bake simulation. Additionally, the variants that were produced using a continuous annealing process showed good response to paint bake due to high annealing temperature.
• the formability properties of the exemplary alloys and comparative alloy were determined. Specifically, the alloys were subjected to uniform elongation, total elongation, r- value, and n- value tests to determine the formability of the exemplary alloys and comparative alloy.
• FIG. 5 shows the results of uniform elongation tests for Alloys 1-3 and Alloy A measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the uniform elongation values for Alloy A produced according to direct chill casting and continuous casting methods are shown in the first two columns.
• Alloys 1-3 and Alloy A uniform elongation values are provided for the alloys after batch annealing (BA) and continuous annealing (CAL). For each pair of bars representing the uniform elongation in the L, T, and D directions, the left bar shows the uniform elongation after continuous annealing and the right bar shows the uniform elongation after batch annealing.
• the uniform elongation was higher for aluminum alloys obtained after continuous annealing compared to batch annealing. Alloys 1-3 exhibited a higher uniform elongation in the L, T, and D directions compared to both examples of Alloy A. Alloys 1-3 had higher uniform elongation with increased amounts of Mg.
• FIG. 6 shows the results of total elongation tests for Alloys 1-3 and Alloy A measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the total elongation values for Alloy A produced according to direct chill casting and continuous casting methods are shown in the first two columns.
• total elongation values are provided for the alloys after batch annealing (BA) and continuous annealing (CAL).
• the left bar shows the total elongation after continuous annealing and the right bar shows the total elongation after batch annealing.
• the total elongation was higher for aluminum alloys obtained after continuous annealing compared to batch annealing.
• Alloys 1-3 exhibited a higher total elongation in the L, T, and D directions compared to both examples of Alloy A. Alloys 1-3 had higher total elongation with increased amounts of Mg.
• FIG. 7 shows the r-values for Alloys 1-3 and Alloy A measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the r-value for Alloy A produced according to direct chill casting and continuous casting methods are shown in the first two columns.
• r-values are provided for the alloys after batch annealing (BA) and continuous annealing (CAL).
• BA batch annealing
• CAL continuous annealing
• the left bar shows the r-value after continuous annealing
• the right bar shows the r-value after batch annealing.
• the r-value was slightly higher for aluminum alloys obtained after batch annealing compared to continuous annealing.
• Alloys 1-3 exhibited a lower r-value in the L, T, and D directions compared to Alloy A.
• FIG. 8 shows the n-values for Alloys 1-3 and Alloy A measured in a longitudinal (L) direction, a transverse (T) direction, and/or in a diagonal (D) direction, each respective to the rolling direction.
• the n-value for Alloy A produced according to direct chill casting and continuous casting methods are shown in the first two columns.
• n-values are provided for the alloys after batch annealing (BA) and continuous annealing (CAL).
• BA batch annealing
• CAL continuous annealing
• the left bar shows the n-value after continuous annealing
• the right bar shows the n-value after batch annealing.
• n-value was similar for aluminum alloys obtained after batch annealing and continuous annealing. Alloys 1-3 exhibited a higher n-value in the L, T, and D directions compared to both examples of Alloy A. Alloys 1-3 exhibited an increase of about 10 % in n-value compared to Alloy A. The increased Mg content in Alloys 1-3 contributed to an improved n-value.
• FIGS. 9A and 9B show the instantaneous n-values for Alloys 1-3 and Alloy A over a range of strain rates after batch annealing and continuous annealing, respectively. Alloys 1-3 exhibited a higher retention of n-value at higher strain rates compared to Alloy A.
• FIGS. 10 and 11 show the particle distribution of the Fe-containing constituents in the aluminum alloy microstructure for Alloy 2 (dashed lines) and Alloy A (solid line).
• the Fe-constituent particle distribution of Alloy 2 having a Mg content of 5.8 wt. % was similar to the Fe-constituent particle distribution of Alloy A.
• FIG. 10 shows that the area fraction of Al x (Fe,Mn) of Alloy 2 was substantially the same as Alloy A. Both Alloy 2 and Alloy A had less than 0.06 % area fraction of Al x (Fe,Mn).
• FIG. 11 shows that the number density of Al x (Fe,Mn) and Al(Fe,Mn)Si particles in the aluminum alloy microstructure were also similar for Alloy 2 and Alloy A.
• Both Alloy 2 and Alloy A had Fe-constituent particles having a particle size less than 5 microns with predominantly Al x (Fe,Mn) particles in the aluminum alloy microstructure.
• Alloy 2 had a greater concentration of Mg and Cu, the alloy composition did not substantially alter the Fe-constituent particle distribution.
• FIGS. 12 and 13 show graphs of the Mg 2 Si particle distribution in the aluminum alloy microstructure for Alloy 2 (dashed line) and Alloy A (solid line).
• FIG. 12 shows the area % of Mg 2 Si particles in the aluminum alloy microstructure
• FIG. 13 shows the number of Mg 2 Si particles in the aluminum alloy microstructure.
• Alloy 2 exhibited a higher area fraction and number density of Mg 2 Si particles compared to Alloy A. Specifically, Alloy A had an area % of Mg 2 Si particles of 0.129 and a number density of Mg 2 Si particles of 1186.33/mm 2 , whereas Alloy 2 had an area % of Mg 2 Si particles of 0.212 and a number density of Mg 2 Si particles of 2125.31/mm 2 .
• Alloy 2 exhibited substantial strength advantages over Alloy A.
• the carefully balanced composition of the aluminum alloys plays an important role in controlling the strength and formability of the aluminum alloy.
• the Alloy A which utilizes direct chill casting, will result in coarse intermetallic particles for both Fe-containing constituents and Mg 2 Si particles due to the slow cooling rate (e.g., 4 °C/s - 6 °C/s) compared to continuous casting (e.g., 100 °C/s - 200 °C/s).
• the slow chill casting is difficult for high solute alloys due to longer freezing range, which results in hot cracking.
• Figures 14A-E show photographs of the grain structure for Alloy A and Alloys 1-3 after batch annealing and Figures 15 A-E show photographs of the grain structure for Alloy A and Alloys 1-3 after continuous annealing.
• Alloys 1-3 produced using batch annealing had elongated grains, whereas Alloys 1-3 produced using continuous annealing exhibited equiaxed grains.
• the addition of Mg in the aluminum alloy composition of Alloys 1-3 slightly refined the grains compared to Alloy A.
• Illustration 1 is an aluminum alloy comprising 0 - 0.30 wt. % Si, 0.01 - 0.40 wt. % Fe, 0 - 1.0 wt. % Cu, 0.01 - 0.50 wt. % Mn, 5.0 - 6.0 wt. % Mg, 0 - 0.20 wt. % Cr, 0 - 0.30 wt. % Zn, 0 - 0.25 wt. % Ti, up to 0.15 wt. % of impurities, and Al.
• Illustration 2 is the aluminum alloy of any preceding or subsequent illustration, wherein the aluminum alloy comprises 0.01 - 0.20 wt. % Si, 0.01 - 0.30 wt. % Fe, 0.01 - 0.90 wt. % Cu, 0.01 - 0.40 wt. % Mn, 5.1 - 6.0 wt. % Mg, 0 - 0.10 wt. % Cr, 0 - 0.20 wt. % Zn, 0 - 0.20 wt. % Ti, up to 0.15 wt. % of impurities, and Al.
• the aluminum alloy comprises 0.01 - 0.20 wt. % Si, 0.01 - 0.30 wt. % Fe, 0.01 - 0.90 wt. % Cu, 0.01 - 0.40 wt. % Mn, 5.1 - 6.0 wt. % Mg, 0 - 0.10 wt. % Cr, 0 - 0.20 wt
• Illustration 3 is the aluminum alloy of any preceding or subsequent illustration, wherein the aluminum alloy comprises 0.01 - 0.15 wt. % Si, 0.01 - 0.20 wt. % Fe, 0.05 - 0.80 wt. % Cu, 0.05 - 0.30 wt. % Mn, 5.2 - 6.0 wt. % Mg, 0 - 0.05 wt. % Cr, 0 - 0.10 wt. % Zn, 0 - 0.10 wt. % Ti, up to 0.15 wt. % of impurities, and Al.
• Illustration 4 is the aluminum alloy of any preceding or subsequent illustration, wherein the aluminum alloy comprises 0.01 - 0.06 wt. % Si, 0.02 - 0.15 wt. % Fe, 0.20 - 0.80 wt. % Cu, 0.05 - 0.20 wt. % Mn, 5.3 - 6.0 wt. % Mg, 0.001 - 0.02 wt. % Cr, 0 - 0.05 wt. % Zn, 0 - 0.03 wt. % Ti, up to 0.15 wt. % of impurities, and Al.
• Illustration 5 is the aluminum alloy of any preceding or subsequent illustration, wherein the aluminum alloy comprises 0.01 - 0.05 wt. % Si, 0.05 - 0.11 wt. % Fe, 0.30 - 0.80 wt. % Cu, 0.05 - 0.10 wt. % Mn, 5.5 - 5.9 wt. % Mg, 0.001 - 0.02 wt. % Cr, 0 - 0.01 wt. % Zn, 0.001 - 0.03 wt. % Ti, up to 0.15 wt. % of impurities, and Al.
• the aluminum alloy comprises 0.01 - 0.05 wt. % Si, 0.05 - 0.11 wt. % Fe, 0.30 - 0.80 wt. % Cu, 0.05 - 0.10 wt. % Mn, 5.5 - 5.9 wt. % Mg, 0.001 - 0.02 wt. % Cr, 0 - 0.01
• Illustration 6 is the aluminum alloy of any preceding or subsequent illustration, wherein the aluminum alloy comprises at least one of: Mg in an amount from 5.5 wt. % to 6.0 wt. %; and Cu in an amount from 0.30 wt. % to 1.0 wt. %.
• Illustration 7 is the aluminum alloy of any preceding or subsequent illustration, wherein a particle size of Fe-containing constituents is less than 5 microns.
• Illustration 8 is the aluminum alloy of any preceding or subsequent illustration, wherein a number density of Mg 2 Si particles in the aluminum alloy microstructure is at least 500/mm 2 .
• Illustration 9 is the aluminum alloy of any preceding or subsequent illustration, wherein the aluminum alloy has a yield strength of at least 130 MPa.
• Illustration 10 is the aluminum alloy of any preceding or subsequent illustration, wherein the aluminum alloy has an ultimate tensile strength of at least 300 MPa.
• Illustration 11 is the aluminum alloy of any preceding or subsequent illustration, wherein the aluminum alloy has a total elongation of at least 5%.
• Illustration 12 is an aluminum alloy product comprising an aluminum alloy of any preceding or subsequent illustration.
• Illustration 13 is the aluminum alloy product of any preceding or subsequent illustration, wherein the aluminum alloy product is produced by continuous casting, flash homogenization, hot rolling, and cold rolling.
• Illustration 14 is a method of producing an aluminum alloy product, comprising: continuously casting an aluminum alloy to form a cast product, wherein the aluminum alloy comprises 0 - 0.30 wt. % Si, 0.01 - 0.40 wt. % Fe, 0 - 1.0 wt. % Cu, 0.01 - 0.50 wt. % Mn, 5.0 - 6.0 wt. % Mg, 0 - 0.20 wt. % Cr, 0 - 0.30 wt. % Zn, 0 - 0.25 wt.
• % Ti up to 0.15 wt. % of impurities, and Al; optionally flash homogenizing the cast product; hot rolling the cast product to produce a hot rolled product; coiling the hot rolled product; cold rolling the hot rolled product to produce a cold rolled product; and annealing the cold rolled product.
• Illustration 15 is the method of any preceding or subsequent illustration, wherein the aluminum alloy comprises at least one of: Mg in an amount from 5.5 wt. % to 6.0 wt. %; and Cu in an amount from 0.30 wt. % to 1.0 wt. %.
• Illustration 16 is the method of any preceding or subsequent illustration, wherein continuously casting comprises a solidification rate of at least 1 °C/s to produce the cast product.
• Illustration 17 is the method of any preceding or subsequent illustration, wherein annealing comprises batch annealing or continuous annealing.
• Illustration 18 is the method of any preceding or subsequent illustration, wherein flash homogenizing comprises heating the cast product from 400 °C to 600 °C for less than 10 minutes.
• Illustration 19 is the method of any preceding or subsequent illustration, further comprising paint baking the cold rolled product after annealing to produce an aluminum alloy product.
• Illustration 20 is the method of any preceding or subsequent illustration, wherein the yield strength of the aluminum alloy product increases by 5 MPa or greater after paint baking.

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