WO2025080531A1 - Method of making thick aluminum alloy products - Google Patents

Abstract

New methods of producing thick plate heat treatable aluminum alloy products are described. The new methods may include hot rolling a heat treatable aluminum alloy ingot to a final gauge product, wherein the hot rolling comprises hot rolling in at least two different hot rolling directions and to achieve a final gauge plate product having a thickness of from 6.00 to 12.0 inches. The final gauge plate product may be then processed to a T temper. Due to the material being hot rolled in at least two different directions, the final gauge product may realize an improved combination of properties, such as an improved combination of two or more of strength, ductility, fracture toughness, fatigue crack growth resistance, and isotropy, among others.

Description

METHOD OF MAKING THICK ALUMINUM ALLOY PRODUCTS

CROSS-REFERENCE TO RELATED APPLICATION

[001] This patent application claims priority to U.S. Provisional Patent Application No. 63/543,398, entitled, “METHOD OF MAKING THICK ALUMINUM ALLOY PRODUCTS,” filed October 10, 2023, which application is incorporated herein by reference in its entirety.

BACKGROUND

[002] Aluminum alloys are useful in a variety of applications. However, improving one property of an aluminum alloy without degrading another property is elusive. For example, it is difficult to increase the strength of a wrought aluminum alloy without affecting other properties such as fracture toughness or corrosion resistance.

SUMMARY OF THE DISCLOSURE

[003] Broadly, the present patent application relates to new methods of producing thick plate heat treatable aluminum alloy products. The new methods may include hot rolling a heat treatable aluminum alloy ingot to a final gauge product, wherein the hot rolling comprises hot rolling in at least two different hot rolling directions and to achieve a final gauge plate product having a thickness of from 6.00 to 12.0 inches. The final gauge plate product may be then processed to a T temper. At least partially due to the material being hot rolled in at least two different directions, the final gauge product may realize an improved combination of properties, such as an improved combination of two or more of strength, ductility, fracture toughness, fatigue crack growth resistance, and isotropy, among others. Additional details are provided below. i. Methods of Production a. Hot Rollins

[004] As noted above, the new methods described herein relate to hot rolling a heat treatable aluminum alloy ingot to a final gauge product, wherein the hot rolling step comprises hot rolling in at least two different hot rolling directions. In one embodiment, the hot rolling step comprises first hot rolling a heat treatable aluminum alloy ingot in a first rolling direction and second hot rolling the heat treatable aluminum alloy ingot in a second rolling direction, different than the first rolling direction. In one embodiment, the second rolling direction is transverse to the first rolling direction. In one embodiment, the second rolling direction is generally perpendicular to the second first rolling direction.

[005] The first hot rolling step can include one or more hot rolling passes. In one embodiment, the first hot rolling step includes multiple hot rolling passes. In one embodiment, the first hot rolling step comprises hot rolling the ingot to an intermediate gauge product.

[006] The second hot rolling step can include one or more hot rolling passes. In one embodiment, the second hot rolling step includes multiple hot rolling passes. In one embodiment, the second hot rolling step comprises hot rolling an intermediate gauge product to a final gauge product.

[007] Generally, all of the hot rolling passes of the first hot rolling step are completed, after which all of the hot rolling passes of the second hot rolling step are completed. However, in other embodiments, a subset of the hot rolling passes of the first hot rolling step may be completed, after which all or a subset of the hot rolling passes of the second hot rolling step may be completed. Thus, the hot rolling passes of the first and second hot rolling steps may be alternated, as needed, until the final gauge product is realized.

[008] In one embodiment, the first rolling direction is associated with the long-transverse direction and the second rolling direction is associated with the longitudinal direction. In another embodiment, the first rolling direction is associated with the longitudinal direction and the second rolling direction is associated with the long-transverse direction.

[009] Other rolling directions may be utilized. In one embodiment, a method comprised third hot rolling in a third rolling direction, different than the first or second rolling directions. In one embodiment, the third rolling direction is associated with the 45° direction. The third hot rolling step may include one or more hot rolling passes. The third hot rolling step may be completed before, after, or iteratively in conjunction with the first and/or second hot rolling steps.

[0010] As noted above, the hot rolling generally results in a final gauge plate product. The final gauge plate product generally has a thickness of from 6.00 inches to 12.0 inches and is suited for use in aerospace structural applications, as described in further detail below. Final gauge dimensions are determined in accordance with ANSI H35.2 (2001). In one embodiment, the final gauge product has a thickness of not greater than 11.5 inches. In another embodiment, the final gauge product has a thickness of not greater than 11.0 inches. In yet another embodiment, the final gauge product has a thickness of not greater than 10.5 inches. In another embodiment, the final gauge product has a thickness of not greater than 10.0 inches.

[0011] In one approach, the final gauge product has a thickness of 6.01 to 6.50 inches, and the as-rolled (completed) width of the final gauge plate product is at least 60% larger than a width of the heat treatable aluminum alloy ingot. The width of the heat treatable aluminum alloy ingot is the width of the ingot just prior to initiation of the hot rolling step. In one embodiment, the as- rolled width of the rolled plate is at least 65% larger than the width of the heat treatable aluminum alloy ingot. In another embodiment, the as-rolled width of the rolled plate is at least 70% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 75% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 80% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 85% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 90% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 95% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 100% larger than the width of the heat treatable aluminum alloy.

[0012] In another approach, the final gauge product has a thickness of 6.51 to 7.00 inches, and the as-rolled width of the final gauge plate product is at least 50% larger than a width of the heat treatable aluminum alloy ingot. The width of the heat treatable aluminum alloy ingot is the width of the ingot just prior to initiation of the hot rolling step. In one embodiment, the as-rolled width of the rolled plate is at least 55% larger than the width of the heat treatable aluminum alloy ingot. In another embodiment, the as-rolled width of the rolled plate is at least 60% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 65% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 70% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 75% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 80% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 85% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 90% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 95% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 100% larger than the width of the heat treatable aluminum alloy.

[0013] In yet another approach, the final gauge product has a thickness of 7.01 to 7.50 inches, and the as-rolled width of the final gauge plate product is at least 40% larger than a width of the heat treatable aluminum alloy ingot. The width of the heat treatable aluminum alloy ingot is the width of the ingot just prior to initiation of the hot rolling step. In one embodiment, the as-rolled width of the rolled plate is at least 45% larger than the width of the heat treatable aluminum alloy ingot. In another embodiment, the as-rolled width of the rolled plate is at least 50% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 55% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 60% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 65% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 70% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 75% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 80% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 85% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 90% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 95% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 100% larger than the width of the heat treatable aluminum alloy.

[0014] In another approach, final gauge product has a thickness of 7.51 to 8.00 inches, and the as-rolled width of the final gauge plate product is at least 30% larger than a width of the heat treatable aluminum alloy ingot. The width of the heat treatable aluminum alloy ingot is the width of the ingot just prior to initiation of the hot rolling step. In one embodiment, the as-rolled width of the rolled plate is at least 35% larger than the width of the heat treatable aluminum alloy ingot. In another embodiment, the as-rolled width of the rolled plate is at least 40% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 45% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 50% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 55% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 60% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 65% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 70% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 75% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 80% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 85% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 90% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 95% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 100% larger than the width of the heat treatable aluminum alloy.

[0015] In yet another approach, the final gauge product has a thickness of at 8.01 to 12.00 inches, and the as-rolled width of the final gauge plate product is at least 25% larger than a width of the heat treatable aluminum alloy ingot. The width of the heat treatable aluminum alloy ingot is the width of the ingot just prior to initiation of the hot rolling step. In one embodiment, the as- rolled width of the rolled plate is at least 30% larger than the width of the heat treatable aluminum alloy ingot. In another embodiment, the as-rolled width of the rolled plate is at least 35% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 40% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 45% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 50% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 55% larger than the width of the heat treatable aluminum alloy. Tn another embodiment, the as-rolled width of the rolled plate is at least 60% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as- rolled width of the rolled plate is at least 70% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 75% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 80% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 85% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 90% larger than the width of the heat treatable aluminum alloy. In yet another embodiment, the as-rolled width of the rolled plate is at least 95% larger than the width of the heat treatable aluminum alloy. In another embodiment, the as-rolled width of the rolled plate is at least 100% larger than the width of the heat treatable aluminum alloy. b. Post-Hot Rollins Processins

[0016] As noted above, after hot rolling, the method may include processing the final gauge aluminum alloy product to a T temper, as defined by ANSI H35.1 (2009). In one embodiment, after hot rolling, the final gauge plate product may be cooled to room temperature and stored. In one embodiment, after hot rolling (and with or without cooling to room temperature), the final gauge plate product is solution heat treated and then quenched. In one embodiment, the method is absent of cold rolling of the plate prior to solution heat treatment, i.e., no cold rolling is completed during hot rolling, or after hot rolling, prior to solution heat treatment. The quenching may be cold water quenching, such as by immersion of the final gauge product in a cold water bath or by spraying of cold water, or other suitable quenching media. After solution heat treating and quenching, the final gauge aluminum alloy product may be naturally aged for 24-48 hours and nominally stretched (e.g., 1-5%) for flatness, or otherwise stress relieved in manners known to those skilled in the art. After natural aging and stretching (if any), the final gauge product may be artificially aged to a suitable temper, such as any of the T6 or T7 tempers. In one embodiment, the temper is a T7X temper, such as any of a T73, T74, T76, T77 or T79 temper. In one embodiment, the T7X temper is a T7X51 temper, as defined by ANSI H35.1 (2009). ii. Microstructure

[0017] As noted above, the new methods described herein may result in improved properties in thick, final gauge aluminum alloy plate products, such as an improved combination of two or more of strength, ductility, fracture toughness, fatigue crack growth resistance, and isotropy, among others. The microstructural features of the new thick plate heat treatable aluminum alloy products may at least partially facilitate such improved properties.

[0018] In one approach, a final gauge product realizes an ARprojAwt of not greater than 2.75 as determined in accordance with the Microstructure Assessment Procedure, described below. As explained in the Microstructure Assessment Procedure, ARprojAwtis a ratio of the L_Proj:LT_proj, and is a quantitative manner of determining an average grain aspect ratio of the grains of the final gauge product in the L-LT plane at the T/4 location of the product. In one embodiment, a final gauge product realizes a ARprojAwt of not greater than 2.5. In another embodiment, a final gauge product realizes a ARprojAwt of not greater than 2.4. In yet another embodiment, a final gauge product realizes a ARproj Awt of not greater than 2.3. In another embodiment, a final gauge product realizes a ARprojAwt of not greater than 2.2. In yet another embodiment, a final gauge product realizes a ARproj Awt of not greater than 2.1. In another embodiment, a final gauge product realizes a ARproj Awt of not greater than 2.0. In yet another embodiment, a final gauge product realizes a ARprojAwt of not greater than 1.9. In another embodiment, a final gauge product realizes a ARprojAwt of not greater than 1.8. In another embodiment, a final gauge product realizes a ARprojAwt of not greater than 1.7. In yet another embodiment, a final gauge product realizes a ARprojAwt of not greater than 1.6. In another embodiment, a final gauge product realizes a ARproj Awt of not greater than 1.5. In yet another embodiment, a final gauge product realizes a ARprojAwt of not greater than 1.4. In another embodiment, a final gauge product realizes a ARprojAwt of not greater than 1.3. In yet another embodiment, a final gauge product realizes a ARproj Awt of not greater than 1.2.

Hi. Properties

[0019] As noted above, the new methods described herein may result in improved properties in thick, final gauge aluminum alloy plate products, such as an improved combination of two or more of strength, ductility, fracture toughness, fatigue crack growth resistance, and isotropy, among others.

[0020] In one approach, the final gauge products realize improved strength isotropy. For instance, a final gauge product may realize a longitudinal tensile yield strength (TYS-L) and a long-transverse tensile yield strength (TYS-LT), wherein the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 5%. Because the longitudinal and long- transverse yield strengths are generally similar, the product may be considered strength isotropic. In one embodiment, the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 4.5%. In another embodiment, the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 4.0%. In yet another embodiment, the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 3.5%. In another embodiment, the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 3.0%. In yet another embodiment, the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 2.5%. In another embodiment, the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 2.0%.

[0021] In one approach, the final gauge products have improved elongation isotropy. For instance, a final gauge product may realize a longitudinal elongation (Elong. -L) and a long- transverse elongation (Elong. -LT). In one embodiment, the final gauge plate product is elongation isotropic, wherein the absolute value of [(Elong. -L) minus (Elong. -LT)] divided by (Elong. -L) is not greater than 25%. Because the longitudinal and long-transverse elongations are generally similar, the product may be considered elongation isotropic. In one embodiment, the absolute value of [(Elong. -L) minus (Elong. -LT)] divided by (Elong.-L) is not greater than 20%. In another embodiment, the absolute value of [(Elong.-L) minus (Elong. -LT)] divided by (Elong.-L) is not greater than 15%. In yet another embodiment, the absolute value of [(Elong.-L) minus (Elong. - LT)] divided by (Elong.-L) is not greater than 10%. In another embodiment, the absolute value of [(Elong.-L) minus (Elong. -LT)] divided by (Elong.-L) is not greater than 8%. In yet another embodiment, the absolute value of [(Elong.-L) minus (Elong. -LT)] divided by (Elong.-L) is not greater than 6%.

[0022] In one approach, the final gauge products have improved fracture toughness isotropy. For instance, a final gauge product may realize a L-T Kic fracture toughness and a T-L Kic fracture toughness. In one embodiment, the final gauge plate product is fracture toughness isotropic, wherein the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 20%. Because the longitudinal and long-transverse fracture toughness values are generally similar, the product may be considered fracture toughness isotropic. In one embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 18%. In another embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 16%. In yet another embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 14%. In another embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 12%. In yet another embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 10%. In another embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 8%. In yet another embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 6%. In another embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 4%. In yet another embodiment, the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 2%.

[0023] In another approach, improved damage tolerance is realized. In one embodiment, the final gauge product realizes at least 2% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 20, wherein the baseline product is of equivalent composition, temper and gauge, and wherein the baseline product is produced by hot rolling in the longitudinal direction only. In another embodiment, the final gauge product realizes at least 4% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 20. In yet another embodiment, the final gauge product realizes at least 6% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 20. In another embodiment, the final gauge product realizes at least 8% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 20. In yet another embodiment, the final gauge product realizes at least 10% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 20. In another embodiment, the final gauge product realizes at least 12% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 20. In yet another embodiment, the final gauge product realizes at least 14% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 20. In another embodiment, the final gauge product realizes at least 16% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 20.

[0024] In one embodiment, the final gauge product realizes at least 5% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 25, wherein the baseline product is of equivalent composition, temper and gauge, and wherein the baseline product is produced by hot rolling in the longitudinal direction only. In another embodiment, the final gauge product realizes at least 10% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In yet another embodiment, the final gauge product realizes at least 15% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In another embodiment, the final gauge product realizes at least 20% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In yet another embodiment, the final gauge product realizes at least 22% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In another embodiment, the final gauge product realizes at least 24% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In yet another embodiment, the final gauge product realizes at least 26% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In another embodiment, the final gauge product realizes at least 28% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In yet another embodiment, the final gauge product realizes at least 30% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In another embodiment, the final gauge product realizes at least 32% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25. In yet another embodiment, the final gauge product realizes at least 34% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 25.

[0025] In one embodiment, the final gauge product realizes at least 5% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 30, wherein the baseline product is of equivalent composition, temper and gauge, and wherein the baseline product is produced by hot rolling in the longitudinal direction only. In another embodiment, the final gauge product realizes at least 10% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In yet another embodiment, the final gauge product realizes at least 15% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In another embodiment, the final gauge product realizes at least 20% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In yet another embodiment, the final gauge product realizes at least 22% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In another embodiment, the final gauge product realizes at least 24% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In yet another embodiment, the final gauge product realizes at least 26% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In another embodiment, the final gauge product realizes at least 28% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In yet another embodiment, the final gauge product realizes at least 30% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In another embodiment, the final gauge product realizes at least 32% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In yet another embodiment, the final gauge product realizes at least 34% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In another embodiment, the final gauge product realizes at least 36% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In another embodiment, the final gauge product realizes at least 38% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In yet another embodiment, the final gauge product realizes at least 40% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In another embodiment, the final gauge product realizes at least 42% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. In yet another embodiment, the final gauge product realizes at least 44% better fatigue crack growth resistance as compared to the baseline product at a Delta K of 30. iv. Compositions

[0026] As noted above, the new methods generally are applicable to heat treatable aluminum alloy products. Heat treatable aluminum alloy products are those products that may be artificially aged to achieve precipitation hardening. Suitable heat treatable aluminum alloy products include 2xxx aluminum alloy products, 6xxx aluminum alloy products, and 7xxx aluminum alloy products. In one embodiment, the heat treatable aluminum alloy product is a 2xxx aluminum alloy product, with or without lithium. A 2xxx aluminum alloy product is considered as having lithium when it contains more than 0.05 wt. % Li. In another embodiment, the heat treatable aluminum alloy product is a 6xxx aluminum alloy product. In yet another embodiment, the heat treatable aluminum alloy product is a 7xxx aluminum alloy product. Suitable thick plate 7xxx aluminum alloys include, for instance, the following known 7xxx aluminum alloys: 7050, 7150, 7050A, 7040, 7140, 7085, 7185, 7065, 7036, 7136, 7081, and 7181, which alloys are compositionally defined by the Aluminum Association in the document ''International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys f January 2015. In one embodiment, a thick plate 2xxx aluminum alloy product is a 2050 or 2195 aluminum alloy product. v. Product Applications

[0027] The new aluminum alloys described herein may be used in a variety of product applications, such as in aerospace applications. For instance, the new alloys may be used as ribs, spars, frames (thick), side of body fittings/attachments, bulky fittings/lugs, bulkheads, monolithic/built-up cargo floor structures, and landing gear/pylon/engine support structures for airplanes/aerospace vehicles. The new alloys may also be used as armor products, such as in armored vehicles and the like. vi. Definitions

[0028] “Wrought aluminum alloy product” means an aluminum alloy product that is hot worked after casting, and includes rolled products (sheet or plate), forged products, and extruded products.

[0029] “Hot working” such as by hot rolling means working the aluminum alloy product at elevated temperature, and generally at least 121.1°C (250°F). Strain-hardening is restricted / avoided during hot working, which generally differentiates hot working from cold working.

[0030] “Cold working” such as by cold rolling means working the aluminum alloy product at temperatures that are not considered hot working temperatures, generally below about 121.1°C (250°F) (e.g., at ambient).

[0031] Temper definitions are per ANSI H35.1 (2009), entitled “American National Standard Alloy and Temper Designation Systems for Aluminum,” published by The Aluminum Association.

[0032] Strength and elongation are measured in accordance with ASTM E8/E8M-21 and B557-15. Fracture toughness is measured in accordance with ASTM E399-20a and B645-21. vii. Microstructure Assessment Procedure

[0033] The following procedures and definitions apply to measuring microstructure features (e.g., grain major and minor axes, projection distances, aspect ratios) for products made in accordance with present patent application.

[0034] An EBSD (electron backscatter diffraction) analysis is to be completed using the EBSD sample procedure, below. Prior to measurement, the EBSD samples are prepared by standard metallographic sample preparation methods. For example, the EBSD samples are metallographically prepared and then polished (e.g., using 0.05 micron colloidal silica). The samples are then etched by immersing in a solution of 0.5% hydrofluoric acid HF solution for 5 seconds, and then rinsed and dried.

[0035] The “EBSD sample procedure” is as follows:

• The software used is APEX EBSD Collection Software, Version 2 (EDAX Inc., New Jersey, U.S.A.), or equivalent, which is connected to a Velocity Super EBSD camera (EDAX Inc., New Jersey, U.S.A.), or equivalent. The scanning electron microscope (SEM) is an APREO S Field Emission Gun (Thermo Fisher Scientific. Waltham, MA, U.S.A.), or equivalent.

• SEM operating parameters for the EBSD scans are: accelerating voltage of 20 kV, beam current of 51 nA (nanoamps), 18 mm working distance, 68° stage tilt, and dynamic focusing implemented. The mode of collection is a composite scan, consisting of multiple maps offset in x and y axes by the individual map dimensions, such that there is no overlap; points are collected using a square grid. A selection is made such that orientations are collected in the analysis (i.e., Hough peaks information is not collected). The collected data is output in an *.osc file. This data may be used to calculate the aspect ratio parameter, as described below.

[0036] EBSD scans are to be performed on the rolling plane (i.e., L-LT) to characterize the microstructures at one-quarter thickness (T/4) of the final plate product. Scanned area dimensions should be at least 20.0 mm horizontally and at least 15.0 mm vertically. The scanned area should preferably be at least 400 mm². Using a 4.0 pm step size results in greater than 25 million data points.

[0037] The term “grain” has the meaning defined in ASTM E267-13 (2019) §3.1.6, i.e. “a group of similarly oriented neighboring points on the scan grid. The group is surrounded by a perimeter where misorientation across that perimeter exceeds a specified tolerance value.” For each measured grain, the commercial software (OIM Analysis version 8.5.1 or equivalent) reports several statistics in the ‘Grain File’, including:

• Edge grain: value = 1 if a grain has at least one point that intersects the perimeter of the composite scan. An “internal grain” has a value = 0, indicating that all points are contained within the interior of the map; • Area of grain in square microns, Ai;

• Length of major axis of ellipse fit to grain in microns, e_maj;

• Length of minor axis of ellipse fit to grain in microns, e_min; and

• Orientation of major axis relative to the horizontal in degrees, 9, with range of 0-180°.

[0038] Calculations are to be made of each grain’s projection to the longitudinal (L) direction and the long-transverse (LT) direction, L_proj and LT_proj, respectively. The longitudinal (L) direction generally corresponds to the primary rolling direction and the long-transverse (LT) direction generally corresponds to a direction transverse (e.g., perpendicular) to the primary rolling direction.

[0039] Various non-limiting examples of Lproj and LTproj are shown in FIG. 1, which is a nonlimiting example EBSD map of an L-LT plane that overlays grain boundaries with best-fit ellipses. As illustrated:

• Lproj is calculated by taking the maximum value of either abs [(e_maj)*(cos 9)] or abs [(emin)*(sin 9)]; and

• LTproj is calculated by taking the maximum value of either abs [(e_min)*(cos 9)] or abs [(e_maj)*(sin 9)]; wherein abs [ ] is the absolute value of the calculation to ensure the projection is positive.

[0040] The ratio of these two projections (Lproj : LTproj) is the aspect ratio parameter (AR_proj), i.e. :

ARproj Lproj / LTproj

[0041] An “area- weighted average aspect ratio” may also be calculated using the following equation for all internal grains:

The “area- weighted average aspect ratio” may be indicative of the degree of isotropy of the final gauge products.

[0042] While a number of embodiments of the present disclosure have been described, it is understood that these embodiments are illustrative only, and not restrictive, and that many modifications may become apparent to those of ordinary skill in the art. Further still, unless the context clearly requires otherwise, the various steps may be carried out in any desired order, and any applicable steps may be added and/or eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 is an illustrative EBSD map in the L-LT plane with grain boundary overlays based on best-fit ellipses.

[0044] FIG. 2a is an illustrative EBSD-generated map at T/4 of the rolling plane (L-LT) for a conventional plate product showing boundaries > 15° misorientation.

[0045] FIG. 2b is an illustrative EBSD-generated map at T/4 of the rolling plane (L-LT) for a new plate product showing boundaries > 15° misorientation.

[0046] FIG. 3a is an illustrative EBSD-generated map at T/4 of the L-ST plane for a conventional plate product showing boundaries > 15° misorientation.

[0047] FIG. 3b is an illustrative EBSD-generated map at T/4 of the L-ST plane for a new plate product showing boundaries > 15° misorientation.

DETAILED DESCRIPTION

[0048] Example 1

[0049] Ten lots of aluminum alloy 7050 were produced as thick plate products from industrial size ingots. Prior to rolling, the ingots had a width of 66 inches (1676 mm). Six of the lots were conventionally hot rolled, where <10% of the total reduction occurred from hot rolling passes conducted in the long-transverse (LT) direction, followed by rolling in the longitudinal (L) direction. Four other lots were produced with a significant number of hot rolling passes being conducted in a first rolling direction, followed by several hot rolling passes being conducted in a second direction, the second direction being generally transverse (e.g., perpendicular) to the first rolling direction. In this case, the first rolling direction corresponds to the long-transverse direction and the second direction corresponds to the longitudinal direction, but it is to be appreciated that the first rolling direction may be the longitudinal direction and the second direction may be the long-transverse direction. Table 1, below, provides the dimensions of the plates after rolling.

Table 1 -As-Rolled Data^1,2

1 : The as-rolled gauge is reported in Table 1; final gauge will vary minimally from the as- rolled gauge due to subsequent processing (e.g., conventional stretching after solution heat treatment and quench).

2: Percent broadening is calculated by subtracting the starting ingot size (66 inches or 1676 mm in this case) from the as-rolled plate width and then dividing by the original ingot width.

[0050] After rolling, the thick gauge plates were processed to a T7451 temper, after which the mechanical properties were then tested, the result of which are shown in Tables 2-4 below. The reported strength and elongation values are the average of at least duplicate specimens. The reported fracture toughness values are based on a single specimen. Strength and elongation are measured in accordance with ASTM E8/E8M-21 and B557-15. Fracture toughness was measured in accordance with ASTM E399-20a and B645-21.

Table 2a - Longitudinal (L) Properties (English Units)

Table 2b - Longitudinal (L) Properties (Metric Units)

Table 3a - Long-transverse (LT) Properties (English Units)

Table 3b - Long-transverse (LT) Properties (Metric Units)

Table 4a - Short Transverse (ST) Properties (English Units)

Table 4b - Short Transverse (ST) Properties (Metric Units)

[0051] Table 5, below, shows the strength, elongation, and fracture toughness differential of the conventional alloys versus the new alloys. As shown, the new alloys having been hot rolled a significant amount in both the L and LT directions achieve more isotropic strength, elongation, and fracture toughness properties, i.e. percent difference values are closer to 0%.

Table 5 - Percent Difference in L v. LT Properties³

3 : The percent difference is calculated by subtracting the LT or T-L property from the L or

L-T property and then dividing by the L or L-T property.

[0052] Electrical conductivity and fatigue crack growth rates (FCGR) were also measured for the Example 1 plates, the results of which are shown in Table 6, below. Fatigue crack growth testing was conducted in accordance with ASTM E647-15el, on middle tension, M(T), specimen geometries with a specimen width = 6.3 in. (160 mm) and specimen thickness = 0.197 in. (5 mm). The specimens were tested in the T-L orientation and centered at the T/4 thickness location in the plate. The tests were conducted with a K-increasing test procedure using a constant-force- amplitude or K-Gradient (C = 1.75 /in. [0.069 / mm]), at a force ratio ofR = 0.1, a frequency of2- 15 Hz, at room temperature and in a laboratory air environment.

Table 6 - Electrical Conductivity and Fatigue Crack Growth Rate (FCGR) Properties

• da/dN units are in mm/cycle;

• AK (Delta K) units are MPaA/m.

[0053] As shown, the electrical conductivities of the new alloys are consistent with the conventional alloys. The FCGR properties of the new alloys are significantly improved, especially at higher Delta K. Table 7, below, shows the improved FCGR properties of the new alloys as compared to the highest performing conventional alloy at Delta K values of 20, 25, and 30. Table 7 - Comparison of Fatigue Crack Growth Rate Properties

• da/dN units are in mm/cycle;

• AK (Delta K) units are MPa^/m.

[0054] The improvement is even more magnified when considering the average crack growth resistance of the conventional alloys versus the new alloys, as illustrated in Table 8, below.

Table 8 - Comparison of Fatigue Crack Growth Rate Properties

• da/dN units are in mm/cycle;

• AK (Delta K) units are MPa m.

[0055] Microstructures for some of the thick gauge plates were obtained in accordance with the Microstructure Assessment Procedure described above. As shown by FIGS. 2a-2b and FIGS. 3a-3b, the new alloys realize more equiaxed grains in the L-LT plane while still realizing high aspect ratio grains in the L-ST plane. The calculation of L-LT ARprojAwt confirms that the grains are more isotropic in the L-LT plane. As shown in Table 9, below, the conventional plates realized a L-LT ARproj Awt of from 3.11 to 3.57, while the new plates realize a L-LT ARprojAwt of from 1.18 to 1.98, indicating that the new plates realize a more-equiaxed grain structure in the rolling plane. Table 9 - L:LT Projection Properties

[0056] While various embodiments of the present disclosure have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present disclosure.

Claims

CLAIMS What is claimed is:

1. A method comprising:

(a) hot rolling a heat treatable aluminum alloy ingot to a final gauge product, wherein the hot rolling comprises:

(i) first hot rolling the heat treatable aluminum alloy ingot in a first rolling direction; and

(ii) second hot rolling the heat treatable aluminum alloy ingot in a second direction, wherein the second direction is different than the first direction;

(iii) optionally repeating step (a)(i), step (a)(ii), or both steps (a)(i) and (a)(ii); and

(b) processing the final gauge product to a T temper; wherein the final gauge plate product has a thickness of from 6.00 inches to 12.0 inches, and wherein:

(i) when the final gauge product has a thickness of 6.01 to 6.50 inches, the as- rolled width of the final gauge plate product is at least 60% larger than a width of the heat treatable aluminum alloy ingot;

(ii) when the final gauge product has a thickness of 6.51 to 7.00 inches, the as- rolled width of the final gauge plate product is at least 50% larger than a width of the heat treatable aluminum alloy ingot;

(iii) when the final gauge product has a thickness of 7.01 to 7.50 inches, the as- rolled width of the final gauge plate product is at least 40% larger than a width of the heat treatable aluminum alloy ingot;

(iv) when the final gauge product has a thickness of 7.51 to 8.00 inches, the as- rolled width of the final gauge plate product is at least 30% larger than a width of the heat treatable aluminum alloy ingot;

(iv) when the final gauge product has a thickness of at 8.01 to 12.00 inches, the as-rolled width of the final gauge plate product is at least 25% larger than a width of the heat treatable aluminum alloy ingot; wherein the final gauge is determined in accordance with ANSI H35.2.

2. The method of claim 1, wherein the second hot rolling step occurs after the first hot rolling step.

3. The method of claim 1, wherein the second hot rolling step occurs before the first hot rolling step.

4. The method of any of the preceding claims, wherein the second rolling direction is transverse to the first rolling direction.

5. The method of any of the preceding claims, wherein the second rolling direction is perpendicular to the second rolling direction.

6. The method of any of the preceding claims, wherein the first hot rolling step includes multiple hot rolling passes.

7. The method of any of the preceding claims, wherein the first hot rolling step comprises hot rolling the heat treatable aluminum alloy ingot to an intermediate gauge.

8. The method of any of the preceding claims, wherein the second hot rolling step comprises multiple hot rolling passes.

9. The method of any of the preceding claims, wherein the second hot rolling step comprises hot rolling an intermediate gauge product to a final gauge product.

10. The method of any of the preceding claims, comprising completing all hot rolling passes of the first hot rolling step and then completing all hot rolling passes of the second hot rolling step.

11. The method of any of claims 1-9, comprising completing a subset of the hot rolling passes of the first hot rolling step and then completing all or a subset of the second hot rolling step.

12. The method of claim 11, comprising, after the second hot rolling step, completing additional hot rolling passes of the first hot rolling step.

13. The method of claim 11, comprising after the second hot rolling step, completing all remaining hot rolling passes of the first hot rolling step.

14. The method of any of the preceding claims wherein the first rolling direction corresponds to the long-transverse direction of the final gauge product and wherein the second rolling direction corresponds to the longitudinal direction of the final gauge product.

15. The method of any claims 1-13, wherein the first rolling direction corresponds to the longitudinal direction of the final gauge product and wherein the second rolling direction corresponds to the long-transverse direction of the final gauge product.

16. The method of any of the preceding claims, wherein the hot rolling step comprises: third hot rolling in a third hot rolling direction, wherein the third hot rolling direction is different than both the first hot rolling direction and the second hot rolling direction.

17. The method of claim 16, wherein the third hot rolling direction corresponds to the 45° direction of the final gauge product.

18. The method of any of claims 16-17, wherein the third hot rolling direction is completed before or after the first hot rolling step.

19. The method of any of claims 16-18, wherein the third hot rolling direction is completed before or after the second hot rolling step.

20. The method of any of claims 1-19, wherein the final gauge product has a thickness of at 6.01 to 6.50 inches, and wherein the as-rolled width of the rolled plate is at least 65% larger than the width of the heat treatable aluminum alloy ingot, or at least 70% larger than the width of the heat treatable aluminum alloy ingot, or at least 75% larger than the width of the heat treatable aluminum alloy ingot, or at least 80% larger than the width of the heat treatable aluminum alloy ingot, or at least 85% larger than the width of the heat treatable aluminum alloy ingot, or at least 90% larger than the width of the heat treatable aluminum alloy ingot, or at least 95% larger than the width of the heat treatable aluminum alloy ingot, or at least 100% larger than the width of the heat treatable aluminum alloy ingot.

21. The method of any of claims 1-19, wherein the final gauge product has a thickness of at 6.51 to 7.00 inches, and wherein the as-rolled width of the rolled plate is at least 55% larger than the width of the heat treatable aluminum alloy ingot, or at least 60% larger than the width of the heat treatable aluminum alloy ingot, or at least 65% larger than the width of the heat treatable aluminum alloy ingot, or at least 70% larger than the width of the heat treatable aluminum alloy ingot, or at least 75% larger than the width of the heat treatable aluminum alloy ingot, or at least 80% larger than the width of the heat treatable aluminum alloy ingot, or at least 85% larger than the width of the heat treatable aluminum alloy ingot, or at least 90% larger than the width of the heat treatable aluminum alloy ingot, or at least 95% larger than the width of the heat treatable aluminum alloy ingot, or at least 100% larger than the width of the heat treatable aluminum alloy ingot.

22. The method of any of claims 1-19, wherein the final gauge product has a thickness of at 7.01 to 7.50 inches, and wherein the as-rolled width of the rolled plate is at least 45% larger than the width of the heat treatable aluminum alloy ingot, or at least 50% larger than the width of the heat treatable aluminum alloy ingot, or at least 55% larger than the width of the heat treatable aluminum alloy ingot, or at least 60% larger than the width of the heat treatable aluminum alloy ingot, or at least 65% larger than the width of the heat treatable aluminum alloy ingot, or at least 70% larger than the width of the heat treatable aluminum alloy ingot, or at least 75% larger than the width of the heat treatable aluminum alloy ingot, or at least 80% larger than the width of the heat treatable aluminum alloy ingot, or at least 85% larger than the width of the heat treatable aluminum alloy ingot, or at least 90% larger than the width of the heat treatable aluminum alloy ingot, or at least 95% larger than the width of the heat treatable aluminum alloy ingot, or at least 100% larger than the width of the heat treatable aluminum alloy ingot.

23. The method of any of claims 1-19, wherein the final gauge product has a thickness of at 7.51 to 8.00 inches, and wherein the as-rolled width of the rolled plate is at least 35% larger than the width of the heat treatable aluminum alloy ingot, or at least 40% larger than the width of the heat treatable aluminum alloy ingot, or at least 45% larger than the width of the heat treatable aluminum alloy ingot, or at least 50% larger than the width of the heat treatable aluminum alloy ingot, or at least 55% larger than the width of the heat treatable aluminum alloy ingot, or at least 60% larger than the width of the heat treatable aluminum alloy ingot, or at least 65% larger than the width of the heat treatable aluminum alloy ingot, or at least 70% larger than the width of the heat treatable aluminum alloy ingot, or at least 75% larger than the width of the heat treatable aluminum alloy ingot, or at least 80% larger than the width of the heat treatable aluminum alloy ingot, or at least 85% larger than the width of the heat treatable aluminum alloy ingot, or at least 90% larger than the width of the heat treatable aluminum alloy ingot, or at least 95% larger than the width of the heat treatable aluminum alloy ingot, or at least 100% larger than the width of the heat treatable aluminum alloy ingot.

24. The method of any of claims 1-19, wherein the final gauge product has a thickness of at 8.01 to 12.00 inches, and wherein the as-rolled width of the rolled plate is at least 30% larger than the width of the heat treatable aluminum alloy ingot, or at least 35% larger than the width of the heat treatable aluminum alloy ingot, or at least 40% larger than the width of the heat treatable aluminum alloy ingot, or at least 45% larger than the width of the heat treatable aluminum alloy ingot, or at least 50% larger than the width of the heat treatable aluminum alloy ingot, or at least 55% larger than the width of the heat treatable aluminum alloy ingot, or at least 60% larger than the width of the heat treatable aluminum alloy ingot, or at least 65% larger than the width of the heat treatable aluminum alloy ingot, or at least 70% larger than the width of the heat treatable aluminum alloy ingot, or at least 75% larger than the width of the heat treatable aluminum alloy ingot, or at least 80% larger than the width of the heat treatable aluminum alloy ingot, or at least 85% larger than the width of the heat treatable aluminum alloy ingot, or at least 90% larger than the width of the heat treatable aluminum alloy ingot, or at least 95% larger than the width of the heat treatable aluminum alloy ingot, or at least 100% larger than the width of the heat treatable aluminum alloy ingot.

25. The method of claim 24, wherein the final gauge product has a thickness of not greater than 11.5 inches (292.1 mm), or not greater than l l.O inches (279.4 mm), or not greater than 10.5 inches (266.7 mm), or not greater than 10.0 inches (254 mm).

26. The method of any of the preceding claims, wherein the final gauge product realizes an ARprojAwt of not greater than 2.75.

27. The method of claim 26, wherein the final gauge product realizes an ARprojAwt of not greater than 2.5, or not greater than 2.4, or not greater than 2.3 or not greater than 2.2, or not greater than 2.1, or not greater than 2.0, or not greater than 1.9, or not greater than 1.8, or not greater than 1.7, or not greater than 1.6, or not greater than 1.5, or not greater than 1.4, or not greater than 1.3, or not greater than 1.2.

28. The method of any of the preceding claims, wherein the final gauge product realizes a longitudinal tensile yield strength (TYS-L) and a long-transverse tensile yield strength (TYS- LT), and wherein the final gauge plate product is strength isotropic, wherein the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 5%.

29. The method of claim 28, wherein the absolute value of [(TYS-L) minus (TYS-LT)] divided by (TYS-L) is not greater than 4.5%, or not greater than 4.0%, or not greater than 3.5% or not greater than 3.0% or not greater than 2.5% or not greater than 2.0%.

30. The method of any of the preceding claims, wherein the final gauge product realizes a longitudinal elongation (Elong. -L) and a long-transverse elongation (Elong.-LT), and wherein the final gauge plate product is elongation isotropic, wherein the absolute value of [(Elong. -L) minus (Elong.-LT)] divided by (Elong.-L) is not greater than 25%.

31. The method of claim 30, wherein the absolute value of [(Elong.-L) minus (Elong.-LT)] divided by (Elong.-L) is not greater than 20%, or not greater than 15%, or not greater than 10%, or not greater than 8%, or not greater than 6%.

32. The method of any of the preceding claims, wherein the final gauge product realizes a L-T Kic fracture toughness and a T-L Kic fracture toughness, and wherein the final gauge plate product is fracture toughness isotropic, wherein the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 20%.

33. The method of claim 32, wherein the absolute value of [(L-T Kic) minus (T-L Kic)] divided by (L-T Kic) is not greater than 18%, or not greater than 16%, or not greater than 14%, or not greater than 12%, or not greater than 10%, or not greater than 8%, or not greater than 6%, or not greater than 4%, or not greater than 2%.

34. The method of any of the preceding claims, wherein the final gauge product realizes at least 2% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 20, wherein the baseline product is of equivalent composition, temper and gauge, and wherein the baseline product is produced by hot rolling in the longitudinal direction only.

35. The method of claim 34, wherein the final gauge product realizes at least 4% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 20, or at least 6% better fatigue crack growth resistance, or at least 8% better fatigue crack growth resistance, or at least 10% better fatigue crack growth resistance, or at least 12% better fatigue crack growth resistance, or at least 14% better fatigue crack growth resistance, or at least 16% better fatigue crack growth resistance.

36. The method of any of the preceding claims, wherein the final gauge product realizes at least 5% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 25, wherein the baseline product is of equivalent composition, temper and gauge, and wherein the baseline product is produced by hot rolling in the longitudinal direction only.

37. The method of claim 36, wherein the final gauge product realizes at least 10% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 25, or at least 15% better fatigue crack growth resistance, or at least 20% better fatigue crack growth resistance, or at least 22% better fatigue crack growth resistance, or at least 24% better fatigue crack growth resistance, or at least 26% better fatigue crack growth resistance, or at least 28% better fatigue crack growth resistance, or at least 30% better fatigue crack growth resistance, or at least 32% better fatigue crack growth resistance, or at least 34% better fatigue crack growth resistance.

38. The method of any of the preceding claims, wherein the final gauge product realizes at least 5% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 30, wherein the baseline product is of equivalent composition, temper and gauge, and wherein the baseline product is produced by hot rolling in the longitudinal direction only.

39. The method of claim 38, wherein the final gauge product realizes at least 10% better fatigue crack growth resistance as compared to a baseline product at a Delta K of 30, or at least 15% better fatigue crack growth resistance, or at least 20% better fatigue crack growth resistance, or at least 22% better fatigue crack growth resistance, or at least 24% better fatigue crack growth resistance, or at least 26% better fatigue crack growth resistance, or at least 28% better fatigue crack growth resistance, or at least 30% better fatigue crack growth resistance, or at least 32% better fatigue crack growth resistance, or at least 34% better fatigue crack growth resistance, or at least 36% better fatigue crack growth resistance, or at least 38% better fatigue crack growth resistance, or at least 40% better fatigue crack growth resistance, or at least 42% better fatigue crack growth resistance, or at least 44% better fatigue crack growth resistance.

40. The method of any of the preceding claims, wherein the heat treatable aluminum alloy is selected from the group consisting of 2xxx, 6xxx, 7xxx, and 8xxx aluminum alloys.

41. The method of any of the preceding claims, wherein the heat treatable aluminum alloy is a 7xxx aluminum alloy.

42. The method of claim 41, wherein the 7xxx aluminum alloy is selected from the group consisting of 7050, 7150, 7050A, 7040, 7140, 7085, 7185, 7065, 7036, 7136, 7081, and 7181.

43. The method of claim 41, wherein the 7xxx aluminum alloy is a 7050.

44. The method of claim 40, wherein the 2xxx aluminum alloy is a lithium-containing 2xxx aluminum alloy.

45. The method of claim 44, wherein the 2xxx aluminum alloy is 2050 or 2195.