Classifications

• • 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
  • 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
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/10—Alloys based on aluminium with zinc 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
• • 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
  • C22C21/02—Alloys based on aluminium with silicon 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
  • C22C21/12—Alloys based on aluminium with copper as the next major constituent
  • C22C21/14—Alloys based on aluminium with copper as the next major constituent with silicon
• • 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
  • C22C21/12—Alloys based on aluminium with copper as the next major constituent
  • C22C21/16—Alloys based on aluminium with copper as the next major constituent with magnesium
• • 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
  • C22F1/053—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 zinc as the next major constituent
• • 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
  • C22F1/057—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 copper as the next major constituent
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L9/00—Rigid pipes
  • F16L9/02—Rigid pipes of metal
• • 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
  • C22F1/05—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 of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
  • F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
  • F24S23/82—Arrangements for concentrating solar-rays for solar heat collectors with reflectors characterised by the material or the construction of the reflector
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B10/00—Integration of renewable energy sources in buildings
  • Y02B10/20—Solar thermal

Definitions

• 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 an alloy without decreasing the toughness of an alloy. Other properties of interest for aluminum alloys include corrosion resistance and fatigue crack growth rate resistance, to name two.
• FIG. 2 One embodiment of a new process for producing new 7xxx aluminum alloy products is illustrated in FIG. 2.
• a 7xxx aluminum alloy body is prepared for post-solutionizing cold work (100), after which it is cold worked (200), and then thermally treated (300).
• the new process may also include optional final treatment(s) (400), as described in further detail below.
• Post-so !utionizing cold work and the like means cold working of an aluminum alloy body after solutionizing.
• the amount of post-solutionizing cold work applied to the 7xxx aluminum alloy body is generally at least 25%, such as more than 50% cold work.
• the preparing step (100) comprises a continuous casting method, such as belt casting, rod casting, twin roll casting, twin belt casting (e.g., Hazelett casting), drag casting, and block casting, among others.
• a continuous casting methodology is illustrated in FIG. 6.
• the aluminum alloy body is cast and solutionized at about the same time (142), i.e., concomitant to one another.
• the casting places the aluminum alloy body in a form sufficient to cold work.
• the casting / solutionizing step (142) may include quenching of the aluminum alloy body after casting (not illustrated).
• This embodiment may be applicable to twin-roll casting processes, among other casting processes.
• the cold working (200) and thermal treatment step (300) are completed continuously.
• a solutionized aluminum alloy body may enter the cold working operation at ambient conditions.
• the cold worked aluminum alloy body could be immediately thermally treated (300) after cold working (e.g., in-line). Conceivably, such thermal treatments could occur proximal the outlet of the cold working apparatus, or in a separate heating apparatus connected to the cold working apparatus. This could increase productivity.
• the new process includes cold working (200) the aluminum alloy body a high amount.
• Cold working and the like means deforming an aluminum alloy body in at least one direction and at temperatures below hot working temperatures (e.g., not greater than 400°F).
• Cold working may be imparted by one or more of rolling, extruding, forging, drawing, ironing, spinning, flow-forming, and combinations thereof, among other types of cold working methods. These cold working methods may at least partially assist in producing various 7xxx aluminum alloy products (see, Product Applications, below).
• the aluminum alloy body enters the rolling equipment at ambient conditions, i.e., the cold rolling step (220) is initiated at ambient conditions in this embodiment.
• the cold rolling step (220) reduces the thickness of a 7xxx aluminum alloy body by at least 25%.
• the cold rolling step (220) may be completed in one or more rolling passes.
• the cold rolling step (220) rolls the aluminum alloy body from an intermediate gauge to a final gauge.
• the cold rolling step (220) may produce a sheet, plate, or foil product.
• a foil product is a rolled product having a thickness of less than 0.006 inch.
• a sheet product is a rolled product having a thickness of from 0.006 inch to 0.249 inch.
• a plate product is a rolled product having a thickness of 0.250 inch or greater.
• Cold rolled XX% and the like means XX CR %, where XX CR % is the amount of thickness reduction achieved when the aluminum alloy body is reduced from a first thickness of i to a second thickness of T 2 by cold rolling, where Ti is the thickness prior to the cold rolling step (200) (e.g., after solutionizing) and T 2 is the thickness after the cold rolling step (200).
• XX C R% is equal to:
• the aluminum alloy body is cold rolled (220) at least 30% (XX C R% > 30%), i.e., is reduced in thickness by at least 30%.
• the aluminum alloy body is cold rolled (220) at least 35% (XX CR % > 35%), or at least 40% (XXCR% > 40%), or at least 45% (XX C R% > 45%), or at least 50% (XX CR % > 50%), or at least 55% (XX C R% > 55%), or at least 60% (XX C R% > 60%), or at least 65% (XX C R% > 65%), or at least 70% (XX C R% > 70%), or at least 75% (XX CR % > 75%), or at least 80% (XXCR% > 80%), or at least 85% (XX CR % > 85%), or at least 90% (XX C R% > 90%), or more.
• the aluminum alloy body may be cold rolled (220) by not greater than 87% (XX C R% ⁇ 87%), such as cold rolled (220) not more than 85% (XX C R% ⁇ 85%), or not greater than 83% ( XX CR % ⁇ 83%), or not greater than 80% ( X CR % ⁇ 80%).
• optional pre-cold rolling may be completed.
• This pre-cold rolling step (128) may further reduce the intermediate gauge of the aluminum alloy body (due to the hot rolling 126) to a secondary intermediate gauge before solutionizing ( 140).
• the optional cold rolling step ( 128) may be used to produce a secondary intermediate gauge that facilitates production of a final cold rolled gauge during the cold rolling step (220).
• Cold working by XX% (“XX CW %") and the like means cold working the aluminum alloy body an amount sufficient to achieve an equivalent plastic strain (described below) that is at least as large as the amount of equivalent plastic strain that would have been achieved if the aluminum alloy body had been cold rolled XX% (XX C R%).
• cold working 68.2% means cold working the aluminum alloy body an amount sufficient to achieve an equivalent plastic strain that is at least as large as the amount of equivalent plastic strain that would have been achieved if the aluminum alloy body had been cold rolled 68.2%.
• Equivalent plastic strain is related to true strain.
• cold rolling XX% i.e., XX C R%
• true strain values where true strain (8 true ) is given by the formula:
• true strain values may be converted to equivalent plastic strain values.
• the estimated equivalent plastic strain will be 1.155 times greater than the true strain value (2 divided by the 3 equals 1.155).
• Biaxial strain is representative of the type of plastic strain imparted during cold rolling operations.
• the loading is proportional.
• the above and/or other principles may be used to determine an equivalent plastic strain for various cold working operations.
• the equivalent plastic strain due to cold working may be determined using the formula:
• the cold working step (200) may include deforming the aluminum alloy body in a first manner (e.g., compressing) and then deforming the aluminum alloy body in a second manner (e.g., stretching), and that the equivalent plastic strain described herein refers to the accumulated strain due to all deformation operations completed as a part of the cold working step (200). Furthermore, those skilled in the art appreciate that the cold working step (200) will result in inducement of strain, but not necessarily a change in the final dimensions of the aluminum alloy body.
• a first manner e.g., compressing
• a second manner e.g., stretching
• an aluminum alloy body may be cold deformed in a first manner (e.g., compressing) after which it is cold deformed in a second manner (e.g., stretching), the accumulated results of which provide an aluminum alloy body having about the same final dimensions as the aluminum alloy body before the cold working step (200), but with an increased strain due to the various cold deformation operations of the cold working step (200).
• high accumulated strains can be achieved through sequential bending and reverse bending operations.
• the accumulated equivalent plastic strain, and thus XXCR%, may be determined for any given cold working operation, or series of cold working operations, by computing the equivalent plastic strain imparted by those cold working operations and then determining its corresponding XX C R% value, via the methodologies shown above, and other methodologies known to those skilled in the art.
• an aluminum alloy body may be cold drawn, and those skilled in the art may compute the amount of equivalent plastic strain imparted to the aluminum alloy body based on the operation parameters of the cold drawing.
• XX CW % cold working by XX%
• XX CW % cold working by XX%
• the cold working (200) is accomplished such that the aluminum alloy body realizes an XX C w% or XXCR% ⁇ 25%, i.e., > 0.3322 equivalent plastic strain.
• Cold working XX% and the like means XX C w%- Phrases such as “cold working 80%” and “cold worked 80%” are equivalent to the expression XXcw% - 80.
• the amount of equivalent plastic strain, and thus the amount of XXcw or XXCR is determined on the portion(s) of the aluminum alloy body receiving the cold work (200).
• the aluminum alloy body is cold worked (200) sufficiently to achieve, and realizes, an equivalent plastic strain ("EPS") of at least 0.41 19 (i.e., XXcw% ⁇ 30%).
• EPS equivalent plastic strain
• the aluminum alloy body is cold worked (200) sufficiently to achieve, and realizes, an EPS of at least 0.4974 (XX CW % > 35%), or at least 0.5899 (XX c w% > 40%), or at least 0.6903 (XX C w% > 45%), or at least 0.8004, (XX C w% > 50%), or at least 0.9220 (XXcw% > 55%), or at least 1.0583 (XX CW % ⁇ 60%), or at least 1.2120 (XX C w% > 65%), or at least 1.3902 (XX CW % 70%), or at least 1.6008 (XX CW % > 75%), or at least 1.8584 (XX CW % > 80%), or at least 2.1906 (XXX CW
• the aluminum alloy body may be cold worked (200) not more than 87% (XX C w% ⁇ 87% and EPS ⁇ 2.3564), such as cold worked (200) not more than 85% (XX C w% ⁇ 85% and EPS ⁇ 2.1906), or not more than 83% (XX CW % ⁇ 83% and EPS ⁇ 2.0466), or not more than 80% (XX C w% ⁇ 80% and EPS ⁇ 1.8584).
• the aluminum alloy body is cold worked (200) in the range of from more than 50% to not greater than 85% (50% ⁇ XX C w% ⁇ 85%). This amount of cold working (200) may produce an aluminum alloy body having preferred properties.
• the aluminum alloy body is cold worked (200) in the range of from 55% to 85% (55% ⁇ XX C w% ⁇ 85%).
• the aluminum alloy body is cold worked (200) in the range of from 60% to 85% (60% ⁇ XX CW % ⁇ 85%).
• the aluminum alloy body is cold worked (200) in the range of from 65% to 85% (65% ⁇ XX CW % ⁇ 85%).
• the aluminum alloy body is cold worked (200) in the range of from 70% to 80% (70% ⁇ XX CW % ⁇ 80%).
• the cold working step (200) may be tailored to deform the aluminum alloy body in a generally uniform manner, such as via rolling, described above, or conventional extruding processes, among others.
• the cold working step may be tailored to deform the aluminum alloy body in a generally non-uniform manner.
• the process may produce an aluminum alloy body having tailored cold working gradients, i.e., a first portion of the aluminum alloy body receives a first tailored amount of cold work and a second portion of the aluminum alloy body receives a second tailored amount of cold work, where the first tailored amount is different than the second tailored amount.
• cold working operations (200) that may be completed, alone or in combination, to achieve tailored non-uniform cold work include forging, burnishing, shot peening, flow forming, and spin-forming, among others. Such cold working operations may also be utilized in combination with generally uniform cold working operations, such as cold rolling and/or extruding, among others. As mentioned above, for tailored non-uniform cold working operations, the amount of equivalent plastic strain is determined on the portion(s) of the aluminum alloy body receiving the cold work (200).
• the cold working step (200) may be initiated at temperatures below hot working temperatures (e.g., not greater than 400°F). In one approach, the cold working step (200) is initiated when the aluminum alloy body reaches a sufficiently low temperature after solutionizing (140). In one embodiment, the cold working step (200) may be initiated when the temperature of the aluminum alloy body is not greater than 250°F. In other embodiments, the cold working step (200) may be initiated when the temperature of the aluminum alloy body is not greater than 200°F, or not greater than 175°F, or not greater than 150°F, or not greater than 125°F, or less. In one embodiment, a cold working step (200) may be initiated when the temperature of the aluminum alloy body is around ambient. In other embodiments, a cold working step (200) may be initiated at higher temperatures, such as when the temperature of the aluminum alloy body is in the range of from 250°F to less than hot working temperatures (e.g., less than 400°F).
• the cold working step (200) is initiated and/or completed in the absence of any purposeful / meaningful heating (e.g., purposeful heating that produces a material change in the microstructure and/or properties of the aluminum alloy body).
• purposeful heating e.g., purposeful heating that produces a material change in the microstructure and/or properties of the aluminum alloy body.
• an aluminum alloy body may realize an increase in temperature due to the cold working step (200), but that such cold working steps (200) are still considered cold working (200) because the working operation began at temperatures below those considered to be hot working temperatures.
• each one of these operations may employ any of the above-described temperature(s), which may be the same as or different from the temperatures employed by a prior or later cold working operation.
• the cold working (200) is generally initiated when the aluminum alloy body reaches a sufficiently low temperature after solutionizing (140).
• no purposeful / meaningful thermal treatments are applied to the aluminum alloy body between the end of the solutionizing step (140) and the beginning of the cold working step (200), i.e., the process may be absent of thermal treatments between the completion of the solutionizing step (140) and the initiation of the cold working step (200).
• the cold working step (200) is initiated soon after the end of the solutionizing step (140) (e.g., to facilitate cold working). In one embodiment, the cold working step (200) is initiated not more than 72 hours after the completion of the solutionizing step (140).
• the cold working step (200) is initiated in not greater than 60 hours, or not greater than 48 hours, or not greater than 36 hours, or not greater than 24 hours, or not greater than 20 hours, or not greater than 16 hours, or not greater than 12 hours, or less, after the completion of the solutionizing step (140). In one embodiment, the cold working step (200) is initiated within a few minutes, or less, of completion of the solutionizing step (140) (e.g., for continuous casting processes). In another embodiment, the cold working step (200) is initiated concomitant to completion of the solutionizing step (140) (e.g., for continuous casting processes).
• the cold working step (200) may be completed one or more weeks or months after the completion of the solutionizing step (140).
• a thermally treating step (300) is completed after the cold working step (200).
• "Thermally treating” and the like means purposeful heating of an aluminum alloy body such that the aluminum alloy body reaches an elevated temperature.
• the thermal treatment step (300) may include heating the aluminum alloy body for a time and at a temperature sufficient to achieve a condition or property (e.g., a selected strength, a selected ductility, among others).
• the thermally treating step (300) heats the aluminum alloy body to a temperature within a selected temperature range.
• this temperature refers to the average temperature of the aluminum alloy body during the thermally treating step (300).
• the thermally treating step (300) may include a plurality of treatment steps, such as treating at a first temperature for a first period of time, and treating at a second temperature for a second period of time.
• the first temperature may be higher or lower than the second temperature, and the first period of time may be shorter or longer than the second period of time.
• the thermally treating step (300) is generally completed such that the aluminum alloy body achieves / maintains a predominately unrecrystallized microstructure, as defined below.
• a predominately unrecrystallized microstructure may achieve improved properties.
• the thermally treating step (300) generally comprises heating the aluminum alloy body to an elevated temperature, but below the recrystallization temperature of the aluminum alloy body, i.e., the temperature at which the aluminum alloy body would not achieve a predominately unrecrystallized microstructure.
• the thermally treating step (300) may comprise heating the 7xxx aluminum alloy body to a temperature in the range of from 150°F to 400°F (or higher), but below the recrystallization temperature of the aluminum alloy body.
• the thermally treating step (300) may be completed in any suitable manner that maintains the aluminum alloy body at one or more selected temperature(s) for one or more selected period(s) of time (e.g., in order to achieve a desired / selected property or combination of properties).
• the thermally treating step (300) is completed in an aging furnace, or the like.
• the thermally treating step (300) is completed during a paint-bake cycle. Paint-bake cycles are used in the automotive and other industries to cure an applied paint by baking it for a short period of time (e.g., 5-30 minutes).
• thermally treating step (300) may be used to complete the thermally treating step (300), thereby obviating the need for separate thermal treatment and paint-bake steps.
• the thermally treating step (300) may be completed during a coating cure step, or the like.
• the combination of the cold working step (200) and the thermally treating step (300) are capable of producing aluminum alloy bodies having improved properties. It is believed that the combination of the high deformation of the cold working step (200) in combination with the appropriate thermally treatment conditions (300) produce a unique microstructure (see, Microstructure, below) capable of achieving combinations of strength and ductility that have been heretofore unrealized.
• the cold working step (200) facilitates production of a severely deformed microstructure while the thermally treating step (300) facilitates precipitation hardening.
• the cold working (200) is at least 25%, and preferably more than 50%, and when an appropriate thermal treatment step (300) is applied, improved properties may be realized.
• the cold working (200) and thermally treating (300) steps are accomplished such that the aluminum alloy body achieves an increase in strength (e.g., tensile yield strength (R0.2) or ultimate tensile strength (R m )).
• the strength increase may be realized in one or more of the L, LT or ST directions.
• the cold working (200) and thermally treating (300) steps are accomplished such that the aluminum alloy body achieves an increase in strength as compared to a reference-version of the aluminum alloy body in the "as-cold worked condition".
• the cold working (200) and thermally treating (300) steps are accomplished such that the aluminum alloy body achieves an increase in strength as compared to a reference-version of the aluminum alloy body in the T6 temper.
• the cold working (200) and thermally treating (300) steps are accomplished such that the aluminum alloy body achieves an increase a higher R-value as compared to a reference-version of the aluminum alloy body in the T4 temper.
• the "as-cold worked condition" means: (i) the aluminum alloy body is prepared for post-solutionizing cold work, (ii) the aluminum alloy body is cold worked, (iii) not greater than 4 hours elapse between the completion of the solutionizing step (140) and the initiation of the cold working step (200), and (iv) the aluminum alloy body is not thermally treated.
• the mechanical properties of the aluminum alloy body in the as-cold worked condition should be measured within 4 - 14 days of completion of the cold working step (200).
• the reference-version of the aluminum alloy body in the "as-cold worked condition” one would generally prepare an aluminum alloy body for post-solutionizing cold work (100), and then cold work the aluminum alloy body (200) according to the practices described herein, after which a portion of the aluminum alloy body is removed to determine its properties in the as-cold worked condition per the requirements described above. Another portion of the aluminum alloy body would be processed in accordance with the new processes described herein, after which its properties would be measured, thus facilitating a comparison between the properties of the reference-version of the aluminum alloy body in the as-cold worked condition and the properties of an aluminum alloy body processed in accordance with the new processes described herein (e.g., to compare strength, ductility, fracture toughness). Since the reference-version of the aluminum alloy body is produced from a portion of the aluminum alloy body, it would have the same composition as the aluminum alloy body.
• the "T6 temper” and the like means an aluminum alloy body that has been solutionized and then thermally treated to a maximum strength condition (within 1 ksi of peak strength); applies to bodies that are not cold worked after solutionizing, or in which the effect of cold work in flattening or straightening may not be recognized in mechanical property limits.
• a maximum strength condition within 1 ksi of peak strength
• aluminum alloy bodies produced in accordance with the new processes described herein may achieve superior as compared to the aluminum alloy body in a T6 temper.
• a reference-version of the aluminum alloy body in a T6 temper one would prepare an aluminum alloy body for post-solutionizing cold work (100), after which a portion of the aluminum alloy body would be processed to a T6 temper (i.e., a referenced aluminum alloy body in the T6 temper). Another portion of the aluminum alloy body would be processed in accordance with the new processes described herein, thus facilitating a comparison between the properties of the reference-version of the aluminum alloy body in the T6 temper and the properties of an aluminum alloy body processed in accordance with the new processes described herein (e.g., to compare strength, ductility, fracture toughness).
• the reference-version of the aiuminum alloy body is produced from a portion of the aluminum alloy body, it would have the same composition as the aluminum alloy body.
• the reference-version of the aluminum alloy body may require work (hot and/or cold) before the solutionizing step (140) to place the reference-version of the aluminum alloy body in a comparable product form to the new aluminum alloy body (e.g., to achieve the same final thickness for rolled products).
• the "T4 temper” and the like means an aluminum alloy body that has been solutionized and then naturally aged to a substantially stable condition; applies to bodies that are not cold worked after solutionizing, or in which the effect of cold work in flattening or straightening may not be recognized in mechanical property limits.
• To produce a reference- version of the aluminum alloy body in a T4 temper one would prepare an aluminum alloy body for post-solutionizing cold work (100), after which a portion of the aluminum alloy body would be allowed to naturally age to a T4 temper (i.e., a referenced aluminum alloy body in the T4 temper).
• Another portion of the aluminum alloy body would be processed in accordance with the new processes described herein, thus facilitating a comparison between the properties of the reference-version of the aluminum alloy body in the T4 temper and the properties of an aluminum alloy body processed in accordance with the new processes described herein (e.g., to compare strength, ductility, fracture toughness). Since the reference-version of the aluminum alloy body is produced from a portion of the aluminum alloy body, it would have the same composition as the aluminum alloy body.
• the reference- version of the aluminum alloy body may require work (hot and/or cold) before the solutionizing step (140) to place the reference-version of the aluminum alloy body in a comparable product form to the new aluminum alloy body (e.g., to achieve the same thickness for rolled products).
• the cold working (200) and thermally treating (300) steps may be accomplished such that the aluminum alloy body achieves / maintains a predominately unrecrystallized microstructure.
• a predominately unrecrystallized microstructure means that the aluminum alloy body contains less than 50% of first type grains (by volume fraction), as defined below.
• An aluminum alloy body has a crystalline microstructure.
• a "crystalline microstructure” is the structure of a polycrystalline material.
• a crystalline microstructure has crystals, referred to herein as grains. "Grains" are crystals of a polycrystalline material.
• First type grains means those grains of a crystalline microstructure that meet the "first grain criteria”, defined below, and as measured using the OIM (Orientation Imaging Microscopy) sampling procedure, described below. Due to the unique microstructure of the aluminum alloy body, the present application is not using the traditional terms “recrystallized grains” or “unrecrystallized grains”, which can be ambiguous and the subject of debate, in certain circumstances. Instead, the terms “first type grains” and “second type grains” are being used where the amount of these types of grains is accurately and precisely determined by the use of computerized methods detailed in the OIM sampling procedure. Thus, the term “first type grains” includes any grains that meet the first grain criteria, and irrespective of whether those skilled in the art would consider such grains to be unrecrystallized or recrystallized.
• the OIM analysis is to be completed from the T/4 (quarter-plane) location to surface of the L-ST plane.
• the size of the sample to be analyzed will generally vary by gauge.
• the OIM samples Prior to measurement, the OIM samples are prepared by standard metallographic sample preparation methods. For example, the OIM samples are generally polished with Buehler Si-C paper by hand for 3 minutes, followed by polishing by hand with a Buehler diamond liquid polish having an average particle size of about 3 microns. The samples are anodized in an aqueous fluoric-boric solution for 30-45 seconds. The samples are then stripped using an aqueous phosphoric acid solution containing chromium trioxide, and then rinsed and dried.
• the software used is TexSEM Lab OIM Data Collection Software version 5.31 (EDAX Inc., New Jersey, U.S.A.), which is connected via FIRE WIRE (Apple, Inc., California, U.S.A.) to a DigiView 1612 CCD camera (TSL/EDAX, Utah, U.S.A.).
• the SEM is a JEOL JSM6510 (JEOL Ltd. Tokyo, Japan).
• OIM run conditions are 70° tilt with a 18 mm working distance and an accelerating voltage of 20 kV with dynamic focusing and spot size of 1 times 10 "7 amp.
• the mode of collection is a square grid. A selection is made such that orientations are collected in the analysis (i.e., Hough peaks information is not collected).
• the area size per scan (i.e., the frame) is 2.0 mm by 0.5 mm for 2 mm gauge samples and 2.0 mm by 1.2 mm for 5 mm gauge samples at 3 micron steps at 80X. Different frame sizes can be used depending upon gauge.
• the collected data is output in an *.osc file. This data may be used to calculate the volume fraction of first type grains, as described below.
• First grain criteria Calculated via grain orientation spread (GOS) with a grain tolerance angle of 5°, minimum grain size is three (3) data points, and confidence index is zero (0). All of “apply partition before calculation”, “include edge grains”, and “ignore twin boundary definitions” should be required, and the calculation should be completed using "grain average orientation”. Any grain whose GOS is ⁇ 3° is a first type grain. If multiple frames are used, the GOS data are averaged.
• GOS grain orientation spread
• First grain volume means the volume fraction of first type grains of the crystalline material.
• the aluminum alloy body generally comprises a predominately unrecrystallized microstructure, i.e., FGV ⁇ 0.50 and URX% > 50%.
• the aluminum alloy body contains (by volume fraction) not greater than 0.45 first type grains (i.e., the aluminum alloy body is at least 55% unrecrystallized (U R x% > 55%), per the definitions provided above).
• the aluminum alloy body may contain (by volume fraction) not greater than 0.40 first type grains (URX% > 60%), or not greater than 0.35 first type grains (URX% > 65%), or not greater than 0.30 first type grains (URX% > 70%), or not greater than 0.25 first type grains (U RX % > 75%), or not greater than 0.20 first type grains (URX% > 80%), or not greater than 0.15 first type grains (URX% > 85%), or not greater than 0.10 first type grains (URX% > 90%), or less.
• the aluminum alloy body may achieve a unique microstructure. This unique microstructure may be illustrated by the R-values of the aluminum alloy body derived from crystallographic texture data.
• the microstructure of an aluminum alloy body relates to its properties (e.g., strength, ductility, toughness, corrosion resistance, among others).
• R-values are generated according to the R-value generation procedure, described below.
• An x-ray generator with a computer-controlled pole figure unit e.g., Rigaku Ultima III diffractometer (Rigaku USA, The Woodlands, TX) and data collection software and ODF software for processing pole figure data (e.g., Rigaku software included with the Rigaku diffractometer) is used.
• the reflection pole figures are captured in accordance with "Elements of X-ray Diffraction" by B.D. Cullity, 2 nd edition 1978 (Addison- Wesley Series in Meta!iurgy and Materials) and the Rigaku User Manual for the Ultima III Diffractometer and Multipurpose Attachment (or other suitable manual of other comparable diffractometer equipment).
• sample preparation The pole figures are to be measured from the T/4 location to surface.
• the sample used for R-value generation is (preferably) 7/8 inch (LT) by 1 1 ⁇ 4 inches (L). Sample size may vary based on measurement equipment.
• the sample Prior to measurement of the R-value, the sample may be prepared by:
• the sample should be oscillated 2 cm per second to achieve a larger sampling area for improved sampling statistics
• the output data are usually converted to a format for input into ODF software.
• the ODF software normalizes the data, calculates the ODF, and recalculates normalized pole figures. From this information, R-vaiues are calculated using the Taylor-Bishop-Hill model (see, Kuroda, M. et al., Texture optimization of rolled aluminum alloy sheets using a genetic algorithm, Materials Science and Engineering A 385 (2004) 235-244 and Man, Chi-Sing, On the r-value of textured sheet metals, International Journal of Plasticity 18 (2002) 1683-1706).
• Normalized R-value and the like means the R-value as normalized by the R- value of the RV-control sample at an angle of 0° relative to the rolling direction. For example, if the RV-control sample achieves an R-value of 0.300 at an angle of 0° relative to the rolling direction, this and all other R-values would be normalized by dividing by 0.300.
• RV-control sample and the like means a control sample taken from a reference- version aluminum alloy body in a T4 temper (defined above).
• Rolling direction and the like means the L-direction for rolled products (see, FIG. 13).
• Rolling direction and in the context of R-values "rolling direction” and the like means the principle direction of extension (e.g., the extrusion direction).
• the various R-values of a material are calculated from an angle of 0° to an angle of 90° relative to the rolling direction, and in increments of 5°.
• orientation angle is sometimes used to refer to the phrase "angle relative to the rolling direction”.
• Maximum normalized R-value and the like means the maximum normalized R- value achieved at any angle relative to the rolling direction.
• Max RV angle and the like means the angle at which the maximum normalized R-value is achieved.
• FIG. 10 also contains the normalized R- values for aluminum alloy bodies with 25%, 50% and 85% cold work.
• the example aluminum alloy bodies achieve much higher R-values than the RV-control sample, especially between orientation angles of 20° and 70° relative to the rolling direction.
• a maximum normalized R- value of 8.192 is achieved at a max RV angle of 50°.
• the RV-control sample achieves a maximum normalized R-value of 1.415 at a max RV angle of 45°.
• an aluminum alloy body processed in accordance with the new methods described herein may achieve a maximum normalized R-value of at least 2.0.
• the new aluminum alloy body may achieve a maximum normalized R-value of at least 2.5.
• the new aluminum alloy body may achieve a maximum normalized R-value of at least 3.0, or at least 3.5, or at least 4.0, or at least 4.5, or at least 5.0, at least 5.5, or at least 6.0, or at least 6.5, or at least 7.0, or at least 7.5, or at least 8.0, or at least 8.25, or higher.
• the maximum normalized R-value may be achieved at an orientation angle of from 20° to 70°.
• the maximum normalized R-value may be achieved at an orientation angle of from 30° to 70°. In other embodiments, the maximum normalized R-value may be achieved at an orientation angle of from 35° to 65°. In yet other embodiments, the maximum normalized R-value may be achieved at an orientation angle of from 40° to 65°. In yet other embodiments, the maximum normalized R-value may be achieved at an orientation angle of from 45° to 60°. In other embodiments, the maximum normalized R-value may be achieved at an orientation angle of from 45° to 55°.
• an aluminum alloy body processed in accordance with the new methods described herein may achieve a maximum normalized R-value that is at least 200% higher than the RV-control sample at the max RV angle of the new aluminum alloy body.
• the normalized R-value of the new aluminum alloy body is compared to the normalized R-value of the RV-control sample at the angle where the max RV angle of the new aluminum alloy body occurs.
• an aluminum alloy body may achieve a maximum normalized R-value that is at least 250% higher than the RV-control sample at the max RV angle of the new aluminum alloy body. In other embodiments, the aluminum alloy body may achieve a maximum normalized R-value that is at least 300% higher, or at least 350% higher, or at least 400% higher, or at least 450% higher, or at least 500% higher, or at least 550% higher, or at least 600% higher, or more, than the RV-control sample at the max RV angle of the aluminum alloy body.
• an aluminum alloy body processed in accordance with the new methods described herein may achieve a maximum normalized R-value that is at least 200% higher than the maximum normalized R-value of the RV-control sample.
• the maximum normalized R-value of the new aluminum alloy body is compared to the maximum normalized R-value of the RV-control sample, irrespective of the angle at which the maximum normalized R-values occur.
• the 75% cold worked aluminum alloy body alloy realizes a maximum normalized R-value of 8.192 at an orientation angle of 50°.
• the maximum normalized R- value of the RV-control sample is 1.415 at an orientation angle of 45°.
• an aluminum alloy body may achieve a maximum normalized R-value that is at least 250%) higher than the maximum normalized R-value of the RV-control sample. In other embodiments, the aluminum alloy body may achieve a maximum normalized R-value that is at least 300%> higher, or at least 350%) higher, or at least 400% higher, or at least 450% higher, or at least 500% higher, or at least 550% higher, or at least 600% higher, or more, than the maximum normalized R-value of the RV-control sample.
• FIGS, l lb-l le Optical micrographs of some 7xxx aluminum alloys bodies produced in accordance with the new processes described herein are illustrated in FIGS, l lb-l le.
• FIG. 1 l a is a microstructure of a reference- vers ion of the aluminum alloy body in the T6 temper.
• FIGS, l lb-l le are microstructures of new aluminum alloy bodies having 25%, 50%, 75% and 85% cold work, respectively.
• These micrographs illustrate some aspects of the unique microstructures that may be attained using the new processes described herein.
• the grains of the new aluminum alloy bodies appear to be non-equiaxed (elongated) grains.
• the grain structure appears fibrous / rope-like, and with a plurality of shear bands.
• These unique microstructures may contribute to the improved properties of the new aluminum alloy bodies.
• the 7xxx aluminum alloy body may be subjected to various optional final treatment(s) (400).
• the 7xxx aluminum alloy body may be subjected to various additional working or finishing operations (e.g., forming operations, flattening or straightening operations that do not substantially affect mechanical properties, such as stretching, and/or other operations, such as machining, anodizing, painting, polishing, buffing).
• the optional final treatment(s) step (400) may be absent of any purposeful / meaningful thermal treatment(s) that would materially affect the microstructure of the aluminum alloy body (e.g., absent of any anneal steps).
• the microstructure achieved by the combination of the cold working (200) and thermally treating (300) steps may be retained.
• one or more of the optional final treatment(s) (400) may be completed concomitant to the thermal treatment step (300).
• the optional final treatment(s) step (400) may include forming, and this forming step may be completed concomitant to (e.g., contemporaneous to) the thermal treatment step (300).
• the aluminum alloy body may be in a substantially final form due to concomitant forming and thermal treatment operations (e.g., forming automotive door outer and/or inner panels during the thermal treatment step).
• the 7xxx aluminum alloy body is made from a 7xxx aluminum alloy.
• 7xxx aluminum alloys are aluminum alloys containing zinc as the predominate alloying ingredient other than aluminum.
• 7xxx aluminum alloys are aluminum alloys having at least 2.0 wt. % Zn, and up to 22 wt. % Zn, with the zinc being the predominate alloying element other than aluminum.
• the 7xxx aluminum alloy may also include secondary elements, tertiary elements and/or other elements, as defined below.
• the zinc, secondary elements and/or tertiaiy elements may promote a strain hardening response, a precipitation hardening response, and combinations thereof. In one embodiment, at least some of the alloying elements promote both a strain hardening response and a precipitation hardening response. In turn, improved properties may be realized.
• the 7xxx aluminum alloy includes at least 3.0 wt. % Zn. In another embodiment, the 7xxx aluminum alloy includes at least 4.0 wt. % Zn. In yet another embodiment, the 7xxx aluminum alloy body includes at least 5.0 wt. % Zn.
• the 7xxx aluminum alloy includes not greater than 18 wt. % Zn. In another embodiment, the 7xxx aluminum alloy includes not greater than 15.0 wt. % Zn. In another embodiment, the 7xxx aluminum alloy includes not greater than 12.0 wt. % Zn. In yet another embodiment, the 7xxx aluminum alloy includes not greater than 10.0 wt. % Zn. In another embodiment, the 7xxx aluminum alloy includes not greater than 9.0 wt. % Zn.
• the 7xxx aluminum alloy may include secondary elements.
• the secondary elements are selected from the group consisting of magnesium, copper and combinations thereof.
• the 7xxx aluminum alloy includes magnesium.
• the 7xxx aluminum alloy includes copper.
• the 7xxx aluminum alloy includes both magnesium and copper.
• the 7xxx aluminum alloy generally includes at least 0.25 wt. % Mg. in one embodiment, the 7xxx aluminum alloy includes at least 0.5 wt. % Mg. In another embodiment, the 7xxx alloy includes at least 1.0 wt. % Mg. The 7xxx aluminum alloy generally includes not greater than 6.0 wt. % Mg, such as not greater than 5.0 wt. % Mg. In one embodiment, the 7xxx aluminum alloy includes not greater than 4.0 wt. % Mg. In another embodiment, the 7xxx aluminum alloy includes not greater than 3.0 wt. % Mg. In other embodiments, magnesium may be present as an impurity, and in these embodiments is present at levels of 0.24 wt. % or less.
• the 7xxx aluminum alloy generally includes at least 0.25 wt. % Cu. In one embodiment, the 7xxx aluminum alloy includes 0.5 wt. % Cu. In yet another embodiment, the 7xxx aluminum alloy includes at least 1.0 wt. % Cu. The 7xxx aluminum alloy generally includes not greater than 6.0 wt. % Cu. In one embodiment, the 7xxx aluminum alloy includes not greater than 5.0 wt. % Cu. In other embodiments, the 7xxx aluminum alloy includes not greater than 4.0 wt. % Cu, or not greater than 3.5 wt. % Cu. In one embodiment, the 7xxx aluminum alloy includes not greater than 3.0 wt. % Cu. In other embodiments, copper may be present as an impurity, and in these embodiments is present at levels of 0.24 wt. % or less.
• the 7xxx aluminum alloy may include a variety of tertiary elements for various purposes, such as to enhance mechanical, physical or corrosion properties (i.e., strength, toughness, fatigue resistance, corrosion resistance), to enhance properties at elevated temperatures, to facilitate casting, to control cast or wrought grain structure, and/or to enhance machinability, among other purposes.
• these tertiary elements may include one or more of: (i) up to 5.0 wt. % Li, (ii) up to 2.0 wt. % each of one or more of Mn, Si, Ag, Sn, Bi, and Pb, (iii) up to 1.0 wt.
• a tertiary element is usually contained in the alloy by an amount of at least 0.01 wt. %.
• the 7xxx aluminum alloy may include at least one grain structure control element, such as any of Zr, Sc and Hf.
• Mn, Cr, Ni and/or V may be used for grain structure control.
• the grain structure control element is Zr and the alloy includes 0.05 to 0.25 wt. % Zr.
• the 7xxx aluminum alloy may contain less than 0.25 wt. % of each of Cr, Ni, V, and Mn, such as not greater than 0.15 wt. % of each of Cr, Ni, V, and Mn, or not greater than 0.10 wt. % of each of Cr, Ni, V, and Mn.
• the 7xxx aluminum alloy includes Cr, Ni, V, and Mn as impurities, i.e., not more than 0.05 wt. % of each of Cr, Ni, V, and Mn.
• the 7xxx aluminum alloy includes at least one grain refiner, such as titanium, usually with either boron or carbon (e.g., when using semi-continuous casting processes).
• the 7xxx aluminum alloy may include from 0.01 to 0.06 wt. % Ti.
• the 7xxx aluminum alloy may include impurities, such as iron and silicon. When silicon and/or iron are not included in the alloy as a tertiary element, silicon and/or iron may be included in the 7xxx aluminum alloy as an impurity.
• the 7xxx aluminum alloy generally includes not greater than 0.50 wt. % of either silicon and iron. In one embodiment, the 7xxx aluminum alloy includes not greater than 0.25 wt. % of either silicon and iron. In another embodiment, the 7xxx aluminum alloy includes not greater than 0.15 wt. % of either silicon and iron. In yet another embodiment, the 7xxx aluminum alloy includes not greater than 0.10 wt. % of either silicon and iron. In another embodiment, the 7xxx aluminum alloy includes not greater than 0.05 wt. % of at least one of silicon and iron.
• the aluminum alloy body contains not more than 0.25 wt. % each of any element of the other elements, with the total combined amount of these other elements not exceeding 0.50 wt. %.
• each one of these other elements individually, does not exceed 0.10 wt. % in the 7xxx aluminum alloy, and the total combined amount of these other elements does not exceed 0.35 wt. %, in the 7xxx aluminum alloy.
• each one of these other elements individually, does not exceed 0.05 wt. % in the 7xxx aluminum alloy, and the total combined amount of these other elements does not exceed 0.15 wt. % in the 7xxx aluminum alloy.
• each one of these other elements individually, does not exceed 0.03 wt. % in the 7xxx aluminum alloy, and the total combined amount of these other elements does not exceed 0.1 wt. % in the 7xxx aluminum alloy.
• the new 7xxx aluminum alloy bodies produced by the new processes described herein may achieve (realize) an improved combination of properties.
• a new 7xxx aluminum alloy body realizes a typical tensile yield strength in the LT direction of at least 61 ksi. In other embodiments, a new 7xxx aluminum alloy body realizes a typical tensile yield strength in the LT direction of at least 62 ksi, or at least 63 ksi, or at least 64 ksi, or at least 65 ksi, or at least 66 ksi, or at least 67 ksi, or at least 68 ksi, or at least 69 ksi, or at least 70 ksi, or at least 71 ksi, or at least 72 ksi, or at least 73 ksi, or at least 74 ksi, or at least 75 ksi, or at least 76 ksi, or at least 77 ksi, or at least 78 ksi, or at least 79 ksi, or at least 80 ks
• a product made by the new processes described herein is used in a reflector, such as for lighting, mirrors, and concentrated solar power, among others.
• a reflector such as for lighting, mirrors, and concentrated solar power, among others.
• the products could provide better reflective qualities in the bare, coated or anodized condition at a given strength level.
• a product made by the new processes described herein is used in an electrical application, such as for connectors, terminals, cables, bus bars, and wires, among others.
• the product could offer reduced tendency for sag for a given current carrying capability.
• Connectors made from the product could have enhanced capability to maintain high integrity connections over time.
• the product could provide improved fatigue performance at a given level of current carrying capability.
• a product made by the new processes described herein is used in an industrial engineering application, such as for tread-plate, tool boxes, bolting decks, bridge decks, and ramps, among others where enhanced properties could allow down- gauging and reduced weight or material usage.
• a product made by the new processes described herein is used in a fluid container (tank), such as for rings, domes, and barrels, among others.
• a fluid container such as for rings, domes, and barrels, among others.
• the tanks could be used for static storage.
• the tanks could be parts of launch vehicles or aircraft. Benefits in these applications could include down-gauging or enhanced compatibility with the products to be contained.
• the new process is applied to a cold hole expansion process, such as for treating holes to improve fatigue resistance, among others, which may result in a cold work gradient and tailored properties, as described above.
• This cold hole expansion process may be applicable to forged wheels and aircraft structures, among others.
• the new process is applied to cold indirect extrusion processes, such as for producing cans, bottles, aerosol cans, and gas cylinders, among others.
• the product could provide higher strength which could provide reduced material usage.
• improved compatibility with the contents could result in greater shelf life.
• the new process is applied to a conforming processes, such as for producing heat-exchanger components, e.g., tubing where higher strength can be translated into reduced material usage. Improved durability and longer life could also be realized.
• a conforming processes such as for producing heat-exchanger components, e.g., tubing where higher strength can be translated into reduced material usage. Improved durability and longer life could also be realized.
• the new 7xxx aluminum alloy products may find use in multi-layer applications.
• a multi-layer product may be formed using a 7xxx aluminum alloy body as a first layer and any of the lxxx-8xxx alloys being used as a second layer.
• FIG 12 illustrates one embodiment of a method for producing multi-layered products.
• a multi-layered product may be produced (107), after which it is homogenized (122), hot rolled (126), solutionized (140) and then cold rolled (220), as described above relative to FIG. 9.
• the multi-layered products may be produced via multi- alloy casting, roll bonding, and metallurgical bonding, among others. Multi-alloy casting techniques include those described in U.S. Patent Application Publication No.
• FIGS, l la-l le are optical micrographs illustrating aluminum alloy body microstructures; the optical micrographs were obtained by anodizing the samples and viewing them in polarized light.
• FIG. 12 is a flow chart illustrating one method of producing multi-layered aluminum alloy products.
• FIG. 13 is a schematic view illustrating the L, LT and ST directions of a rolled product.
• FIGS. 14-16 are graphs illustrating the thermal treatment response of various 7xxx aluminum alloy bodies for a first 7xxx aluminum alloy composition.
• FIGS. 17-19 are graphs illustrating the strength-toughness performance of various 7xxx aluminum alloy bodies for the first 7xxx aluminum alloy composition.
• FIGS. 20-23 are graphs illustrating various properties of various 7xxx aluminum alloy bodies for a second 7xxx aluminum alloy composition.
• a first 7xxx aluminum alloy having the composition listed in Table 3, below, is cast, homogenized, and hot rolled into plate/sheet having intermediate gauges of about 0.53 inch, 0.32 inch, 0.16 inch (x2), and 0.106 inch, respectively.
• One of the 0.16 inch samples (the control) is then cold rolled to a final sheet gauge of about 0.08 in, solution heat treated by soaking at about 885°F for about 30 minutes, followed by a cold water quench, and then stretching of 1-2% for stress relief.
• the control is naturally aged for about four days, and then thermally treated to a T6-style temper.
• the other ones of the samples are first solution heat treated (by the same process) and then cold rolled to a final sheet gauge of 0.08 inch, representing about 85%, 75%, 50%, and 25% cold work, respectively.
• Sheets B-E made by the new process realize increases in strength over Sheet A. Indeed, new Sheet B made by the new process realizes a peak tensile yield strength of 91.3 ksi with only about 4 hours of thermal treatment at 250°F.
• the conventionally produced Sheet A achieves a peak tensile yield strength of about 78-79 ksi, as shown by the data of Tables 5-6.
• new Sheet B achieves about a 15.6% increase in tensile yield strength over the conventionally prepared material. It also takes over 36 hours for conventional Sheet A to achieve its peak strength at 250°F.
• Sheets B-E also realize good electrical conductivity as shown in Tables 8-10, below. All electrical conductivity values are in percent IACS (International Annealed Copper Standard).
• KQ, K APP and R25 typically increase as the test specimen width increases.
• KQ, K A P and KR2 are also influenced by specimen thickness, initial crack length and test coupon geometry.
• KQ, K APP and KR25 values usually can be reliably compared only from test specimens of equivalent geometry, width, thickness and initial crack length.
• the 7xxx aluminum alloy body realizes good toughness. Despite the significant increase in strength over the control, the new 7xxx aluminum alloy bodies realize the same strength-toughness trend as the control bodies. This is illustrated in FIGS. 17-19. Thus, the new 7xxx aluminum alloy bodies achieve at least equivalent toughness, and generally a better strength-toughness trend as compared to the conventionally processed aluminum alloy bodies.
• the new 7xxx aluminum alloy bodies have a predominately unrecrystallized microstructure, having a volume fraction of not greater than 0.34 first type grains (i.e., 66% unrecrystallized) in all instances. Conversely, the control body is nearly fully recrystallized having a volume fraction of 0.96 first type grains (i.e., 4% unrecrystallized).
• the R-values of the 7xxx aluminum alloy bodies are also tested as per the R-value generation procedure, described above. The results are illustrated in FIG. 10, described above.
• the new 7xxx aluminum alloy bodies have high normalized R-values, achieving a peak (maximum) normalized R-value at an orientation angle of 45-50°. These high R-values are indicative of the unique texture, and thus microstructure, of the new 7xxx aluminum alloy bodies described herein.
• the new 7xxx aluminum alloy bodies realize about 450% to 600% higher maximum R-values as compared to the R-value of the control body (for the purpose of measuring R-values, the control is in the T4 temper, not the T6 temper).
• Two additional 7xxx aluminum alloy bodies are prepared as per Example 1. Both are known Russian alloys. One alloy is a copper-free 7xxx aluminum alloy (alloy 1980), and the other alloy is a low copper 7xxx aluminum alloy (alloy 1953). The compositions of these aluminum alloys are provided in Tables 16-17, below. The alloys contain the listed ingredients, the balance being aluminum and not greater than 0.05 wt. % each of other elements, and not greater than 0.15 wt. % in total of these other elements.
• Example 3 The results of Example 3 illustrate that the cold working and thermal treatment steps must be appropriately accomplished to achieve improved properties (e.g., strength). As shown in FIGS. 20-21 and 24-25, alloys that are thermally treated for an insufficient period of time may not realize the improved properties, as illustrated by the reduction in strength as compared to the as-cold worked condition. As shown in FIGS. 20-21 , alloys that are thermally treated for an excessive period may also not realize the improved properties, as illustrated by the reduction in strength as compared to the as-cold worked condition.
• improved properties e.g., strength

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• 2011
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• 2012
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