High strength extrusion alloy

Abstract

The present disclosure provides an aging treatment or method for aging an aluminum alloy. For example, an aging process may be performed on a 6xxx Al-Si-Mg-Cu aluminum alloy to produce a 6xxx Al-Si-Mg-Cu aluminum alloy with improved intergranular corrosion resistance (IGC). The disclosed aging process includes exposing the solution heat treated and quenched 6xxx aluminum alloy to a temperature above the age hardening temperature of the alloy but below the solution heat treatment temperature for a short period of time, and then exposing the alloy to an aging heat treatment at the age hardening temperature.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Non-provisional Application No. 18 / 139,465, filed April 26, 2023, and U.S. Provisional Application No. 63 / 334,765, filed April 26, 2022, the entireties of which are incorporated by reference herein.

[0002] The present disclosure relates to alloys, more particularly aluminum alloys, and even more particularly aluminum extrusion alloys. [Background technology]

[0003] Aluminum alloys are widely used in various industries due to their advantageous properties such as low density, high strength-to-weight ratio, and good corrosion resistance. Some aluminum extrusion alloys are used in the automotive industry because of their ability to achieve very complex shapes and contours. One such alloy is the 6xxx series. The 6xxx series aluminum alloys, which include the aluminum-magnesium-silicon (Al-Mg-Si) alloy system, are favored due to their excellent combination of strength, formability, and weldability. The 6xxx series alloys can be used in automotive body structures, suspensions, and driveline components. Aluminum extrusion alloys such as the 6xxx extrusion alloys can enable innovative lightweight designs with integrated functions. There is a general demand for better extrusion alloys. Summary of the Invention

[0004] The following summary is a high-level overview of various aspects and introduces some of the concepts that are further described in the Detailed Description below. This summary is not intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification, any or all of the drawings, and appropriate portions of each claim.

[0005] The present disclosure provides improved methods of manufacture and improved 6xxx series aluminum alloys that are superior to conventional alloys, the alloy compositions including aluminum (Al), magnesium (Mg), silicon (Si) and one or more additional elements such as copper (Cu), zinc (Zn), and / or manganese (Mn).

[0006] In some aspects, the technology described herein relates to a method that includes exposing an alloy to a first temperature for a first duration, where the first temperature is greater than an age hardening temperature and less than a solution heat treatment temperature of the alloy, and exposing the alloy to a second temperature for a second duration.

[0007] In some embodiments, the technology described herein relates to a method further comprising solution heat treating the alloy at a solution heat treatment temperature prior to exposing the alloy to the first temperature.

[0008] In some embodiments, the technology described herein relates to methods where the second temperature is an age hardening temperature.

[0009] In some aspects, the technology described herein relates to methods, wherein the alloy comprises an alloy that has been solution heat treated and quenched.

[0010] In some embodiments, the technology described herein relates to methods, wherein the alloy comprises a 6xxx aluminum alloy.

[0011] In some embodiments, the technology described herein relates to a method, wherein the alloy comprises a 6xxx Al-Si-Mg-Cu aluminum alloy.

[0012] In some embodiments, the techniques described herein further include obtaining the resulting alloy in methods 1-6, wherein the resulting alloy has improved intergranular corrosion (IGC) resistance.

[0013] In some embodiments, the technology described herein relates to methods where the first temperature is between 200°C and 210°C.

[0014] In some embodiments, the technology described herein relates to methods where the first duration is between 5 minutes and 20 minutes.

[0015] In some embodiments, the technology described herein relates to methods in which the second temperature is between 150°C and 200°C.

[0016] In some embodiments, the technology described herein relates to methods where the second duration is between 30 minutes and 3 hours.

[0017] In some embodiments, the technology described herein relates to a method that includes exposing an aluminum alloy to a first temperature for a first duration and exposing the aluminum alloy to a second temperature for a second duration, where the first temperature is greater than the second temperature and the first duration is between 5 minutes and 20 minutes. [Brief description of the drawings]

[0018] Reference is made to the accompanying drawings, which form a part of this disclosure and which illustrate embodiments in which the systems and methods described herein may be practiced, in which like reference characters refer to the same or similar parts throughout.

[0019] [Figure 1] FIG. 1 is an exemplary flow chart according to an embodiment of the method disclosed herein.

[0020] [Diagram 2] FIG. 2 is a schematic comparison graph illustrating an exemplary treatment step according to an embodiment of the method disclosed herein and a conventional aging step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The 6xxx series aluminum alloys are extremely difficult to improve. The embodiments disclosed herein improve various properties and / or manufacturing processes.

[0022] The present disclosure provides improved methods of manufacture and improved 6xxx series aluminum alloys that are superior to conventional alloys. The alloy compositions include aluminum (Al), magnesium (Mg), silicon (Si) and one or more additional elements such as copper (Cu), zinc (Zn), and / or manganese (Mn).

[0023] Alloys such as aluminum alloys, particularly 6xxx series aluminum alloys, can be subjected to solution heat treatment. Solution heat treatment is performed in the hope of increasing the practical solid solution concentration of hardening solutes such as Cu, Mg, Si, Zn, etc. The solubility of these elements increases with temperature, and is particularly marked at temperatures slightly lower than the eutectic melting temperature. Therefore, the most preferred temperature for solution treatment is a temperature close to the eutectic temperature (e.g., about 5°C to 8°C lower than the eutectic temperature).

[0024] FIG. 1 shows a flow chart according to an embodiment of a method 100 disclosed herein. The method 100 includes subjecting an alloy (e.g., an aluminum alloy, a 6xxx aluminum alloy) to a solution heat treatment 102 at a specific solution heat treatment temperature. The alloy then undergoes a two-stage artificial aging treatment. The artificial aging treatment includes a first temperature treatment 104 for a first duration and a second temperature treatment 106 for a second duration. In the first temperature treatment 104, a first temperature is applied. The first temperature of the first temperature treatment 104 is higher than the age hardening temperature of the alloy, but lower than the solution heat treatment temperature used in the solution heat treatment 102. During the aging treatment 106, the second temperature may be an age hardening temperature.

[0025] In some embodiments, the solution heat treatment 102 includes or is followed by a quenching step. In some embodiments, a quench is performed after the solution heat treatment 102. In some embodiments, a quench is not performed after the solution heat treatment 102.

[0026] In some embodiments, the aging treatment does not include natural aging treatment. In some embodiments, the aging treatment includes natural aging treatment. In some embodiments, the natural aging treatment is after a first temperature treatment. In some embodiments, the natural aging treatment is before a second temperature treatment. In some embodiments, the natural aging treatment is after a first temperature treatment and before a second temperature treatment. In some embodiments, the natural aging treatment is for 1 hour to 24 hours. In some embodiments, the aging treatment does not include other conventional artificial aging treatments.

[0027] In some aspects, embodiments of the methods described herein may include any combination of the following first temperatures, first durations, second temperatures, and / or second durations. Thus, in some embodiments, the first temperature is 205°C. Thus, in some embodiments, the first temperature is 200°C to 205°C. Thus, in some embodiments, the first temperature is 205°C to 210°C. Thus, in some embodiments, the first temperature is 200°C to 202°C, 200°C to 204°C, 200°C to 206°C, 200°C to 208°C, or 200°C to 210°C. Thus, in some embodiments, the first temperature is 202°C to 204°C, 202°C to 206°C, 202°C to 208°C, or 202°C to 210°C. Thus, in some embodiments, the first temperature is 204°C to 206°C, 204°C to 208°C, or 204°C to 210°C. Thus, in some embodiments, the first temperature is 206°C to 208°C, or 206°C to 210°C. Thus, in some embodiments, the first temperature is 208°C to 210°C. Thus, in some embodiments, the first duration is 5 minutes to 15 minutes. Thus, in some embodiments, the first duration is 15 minutes to 20 minutes. Thus, in some embodiments, the first duration is 5 minutes to 8 minutes, 5 minutes to 10 minutes, 5 minutes to 12 minutes, 5 minutes to 14 minutes, 5 minutes to 16 minutes, 5 minutes to 18 minutes, or 5 minutes to 20 minutes. Thus, in some embodiments, the first duration is 8 minutes to 10 minutes, 8 minutes to 12 minutes, 8 minutes to 14 minutes, 8 minutes to 16 minutes, 8 minutes to 18 minutes, or 8 minutes to 20 minutes. Thus, in some embodiments, the first duration is 10 minutes to 12 minutes, 10 minutes to 14 minutes, 10 minutes to 16 minutes, 10 minutes to 18 minutes, or 10 minutes to 20 minutes. Thus, in some embodiments, the first duration is 12 minutes to 14 minutes, 12 minutes to 16 minutes, 12 minutes to 18 minutes, or 12 minutes to 20 minutes. Thus, in some embodiments, the first duration is 14 minutes to 16 minutes, 14 minutes to 18 minutes, or 14 minutes to 20 minutes. Thus, in some embodiments, the first duration is 16 minutes to 18 minutes, or 16 minutes to 20 minutes. Thus, in some embodiments, the first duration is 18 minutes to 20 minutes. Thus, in some embodiments, the second temperature is 175°C.Thus, in some embodiments, the second temperature is 150°C to 175°C. Thus, in some embodiments, the second temperature is 175°C to 200°C. Thus, in some embodiments, the second temperature is 150°C to 160°C, 150°C to 170°C, 150°C to 180°C, or 150°C to 200°C. Thus, in some embodiments, the second temperature is 150°C to 160°C, 150°C to 170°C, 150°C to 180°C, or 150°C to 200°C. Thus, in some embodiments, the second temperature is 160°C to 170°C, 160°C to 180°C, or 160°C to 200°C. Thus, in some embodiments, the second temperature is 170°C to 180°C, or 170°C to 200°C. Thus, in some embodiments, the second temperature is 180°C to 200°C. Thus, in some embodiments, the second duration is 1 hour. Thus, in some embodiments, the second duration is 2 hours. Thus, in some embodiments, the second duration is 3 hours. Thus, in some embodiments, the second duration is 30 minutes to 2 hours. Thus, in some embodiments, the second duration is 2 hours to 3 hours. Thus, in some embodiments, the second duration is 30 minutes to 40 minutes, 30 minutes to 50 minutes, 30 minutes to 60 minutes, 30 minutes to 70 minutes, 30 minutes to 80 minutes, 30 minutes to 90 minutes, 30 minutes to 100 minutes, 30 minutes to 110 minutes, 30 minutes to 120 minutes, 30 minutes to 130 minutes, 30 minutes to 140 minutes, 30 minutes to 150 minutes, 30 minutes to 160 minutes, 30 minutes to 170 minutes, or 30 minutes to 180 minutes. Thus, in some embodiments, the second duration is between 40 minutes and 50 minutes, between 40 minutes and 60 minutes, between 40 minutes and 70 minutes, between 40 minutes and 80 minutes, between 40 minutes and 90 minutes, between 40 minutes and 100 minutes, between 40 minutes and 110 minutes, between 40 minutes and 120 minutes, between 40 minutes and 130 minutes, between 40 minutes and 140 minutes, between 40 minutes and 150 minutes, between 40 minutes and 160 minutes, between 40 minutes and 170 minutes, or between 40 minutes and 180 minutes. Thus, in some embodiments, the second duration is 50 minutes to 60 minutes, 50 minutes to 70 minutes, 50 minutes to 80 minutes, 50 minutes to 90 minutes, 50 minutes to 100 minutes, 50 minutes to 110 minutes, 50 minutes to 120 minutes, 50 minutes to 130 minutes, 50 minutes to 140 minutes, 50 minutes to 150 minutes, 50 minutes to 160 minutes, 50 minutes to 170 minutes, or 50 minutes to 180 minutes.Thus, in some embodiments, the second duration is 60 to 70 minutes, 60 to 80 minutes, 60 to 90 minutes, 60 to 100 minutes, 60 to 110 minutes, 60 to 120 minutes, 60 to 130 minutes, 60 to 140 minutes, 60 to 150 minutes, 60 to 160 minutes, 60 to 170 minutes, or 60 to 180 minutes. Thus, in some embodiments, the second duration is 70 to 80 minutes, 70 to 90 minutes, 70 to 100 minutes, 70 to 110 minutes, 70 to 120 minutes, 70 to 130 minutes, 70 to 140 minutes, 70 to 150 minutes, 70 to 160 minutes, 70 to 170 minutes, or 70 to 180 minutes. Thus, in some embodiments, the second duration is 80 minutes to 90 minutes, 80 minutes to 100 minutes, 80 minutes to 110 minutes, 80 minutes to 120 minutes, 80 minutes to 130 minutes, 80 minutes to 140 minutes, 80 minutes to 150 minutes, 80 minutes to 160 minutes, 80 minutes to 170 minutes, or 80 minutes to 180 minutes. Thus, in some embodiments, the second duration is 90 minutes to 100 minutes, 90 minutes to 110 minutes, 90 minutes to 120 minutes, 90 minutes to 130 minutes, 90 minutes to 140 minutes, 90 minutes to 150 minutes, 90 minutes to 160 minutes, 90 minutes to 170 minutes, or 90 minutes to 180 minutes. Thus, in some embodiments, the second duration is 100 minutes to 110 minutes, 100 minutes to 120 minutes, 100 minutes to 130 minutes, 100 minutes to 140 minutes, 100 minutes to 150 minutes, 100 minutes to 160 minutes, 100 minutes to 170 minutes, or 100 minutes to 180 minutes. Thus, in some embodiments, the second duration is 110 minutes to 120 minutes, 110 minutes to 130 minutes, 110 minutes to 140 minutes, 110 minutes to 150 minutes, 110 minutes to 160 minutes, 110 minutes to 170 minutes, or 110 minutes to 180 minutes. Thus, in some embodiments, the second duration is 120 minutes to 130 minutes, 120 minutes to 140 minutes, 120 minutes to 150 minutes, 120 minutes to 160 minutes, 120 minutes to 170 minutes, or 120 minutes to 180 minutes. Thus, in some embodiments, the second duration is 130 minutes to 140 minutes, 130 minutes to 150 minutes, 130 minutes to 160 minutes, 130 minutes to 170 minutes, or 130 minutes to 180 minutes. Thus, in some embodiments, the second duration is 140 minutes to 150 minutes, 140 minutes to 160 minutes, 140 minutes to 170 minutes, or 140 minutes to 180 minutes.Thus, in some embodiments, the second duration is between 150 minutes and 160 minutes, between 150 minutes and 170 minutes, or between 150 minutes and 180 minutes.

[0028] Thus, in some embodiments, the second duration is between 160 minutes and 170 minutes, or between 160 minutes and 180 minutes. Thus, in some embodiments, the second duration is between 170 minutes and 180 minutes.

[0029] After the second temperature treatment 106, the method 100 includes obtaining a resultant alloy 108. Examples of resultant alloys include, for example, 6xxx Al-Si-Mg-Cu aluminum alloys with improved intergranular corrosion (IGC) resistance that may be produced using embodiments of these methods.

[0030] In some embodiments, improved IGC resistance as described herein means a maximum IGC depth of less than 250 μm, an average IGC depth of less than 150 μm, or both.

[0031] Thus, some embodiments of the aging process include the following steps. 1. Exposing the solution heat treated and quenched 6xxx aluminum alloy to a temperature above the age hardening temperature of the alloy but below the solution heat treatment temperature for a short period of time (e.g., 205°C for 16 minutes). 2. Thereafter, the alloy is subjected to an extended age-hardening heat treatment at an age-hardening temperature (e.g., 175°C) for approximately 2 hours.

[0032] Advantages of the method embodiments disclosed herein include significant cost savings and improved properties of the resulting alloy. For example, for A210 extrusion alloy, the method embodiments disclosed herein can reduce the aging time from over 8 hours (conventional aging) to approximately 3 hours (embodiments of the disclosed method). FIG. 2 shows a schematic of the difference between the method 100 and a conventional single-step aging process for a 6xxx A210 alloy. The dashed line represents a conventional single-step aging process, which involves a 45 minute ramp to 175° C. and an 8 hour soak at 175° C. The solid line shows an exemplary method 100 used for a 6xxx A210 alloy. In this example, the method 100 involves a 45 minute ramp to 205° C., a 16 minute soak at 205° C. (first duration at first temperature), a 1 minute cool to 175° C., and a 2 hour soak at 175° C. (second duration at second temperature). The total aging time is approximately 3 hours for method 100 applied in this example, compared to over 8.5 hours for conventional aging.

[0033] Obviously, this significantly reduces the manufacturing time and cost of A210 extrusion products, thus making A210 alloy more competitive than other extrusion alloys. Also, the method embodiments can significantly improve the IG corrosion performance of A210 extrusion alloy without compromising other properties such as bendability and yield strength. Thus, the embodiments disclosed herein can provide an economical and effective solution to the IG corrosion problem and promote the application of A210 alloy.

[0034] Figure 2 summarizes some advantages of the disclosed embodiments over conventional aging treatments. Embodiments of the disclosed method can be used for many 6xxx alloys. Exemplary results are shown below.

[0035] Example 1: A210 alloy

[0036] Alcoa 6xxx high strength extruded alloy A210 was used to study the effectiveness of the methods disclosed herein. The wall thickness of the A210 extrusions varied from 2.5 mm to 4 mm. Extrusion was performed in a 2500 ton extruder with an extrusion speed of about 10 m / min. The exit temperature was controlled at about 555°C to 565°C. The extrusion profile was water quenched with a quench rate of 50°C / sec to 75°C / sec. Table 1 shows the actual composition of the A210 alloys evaluated. [Table 1]

[0037] The A210 alloy samples were processed through eight different aging processes. The details of the eight steps are shown in Table 2. Process 1 is a conventional aging process commonly used for A210 alloy, which involved an aging temperature of 175°C and a duration of 8 hours. Processes 2-8 are artificial aging processes according to embodiments of the methods disclosed herein, which involve a first temperature treatment for a first duration and then a second temperature treatment for a second duration. The total duration of the first duration and the second duration can be substantially shorter than the conventional duration (e.g., 8 hours). [Table 2]

[0038] The alloys obtained from the above eight processes were evaluated. Characterization included IG corrosion and tensile properties. Three tensile and two IG corrosion specimens were used for each condition. Tensile tests were performed at Westmoreland Mechanical Testing and Research Lab according to ASTM E8 / E8M specifications. Intergranular corrosion tests were performed according to ISO 11846 Method B. Measurement and inspection of IG corrosion depth (not explicitly stated in ISO 11846 Method B) was performed as follows: After immersion tests, the specimens were inspected under a stereoscope with 20x magnification. For each specimen, two sections containing the most severely corroded areas were marked. After mounting and polishing, the sections were observed under an optical microscope. Photographs were taken consecutively on both sides of all sections. Approximately 18 photographs cover the entire length (one side) of the section. The maximum corrosion depth for each photograph was measured. A normal distribution plot can be obtained to determine the maximum and average corrosion depths. The effects of eight aging treatments on the mechanical properties and IG corrosion depth of A210 alloy are shown in Table 3. [Table 3]

[0039] The average tensile test results for A210 alloy for each of the eight different aging treatments are shown in Table 3. The conventional aging process, Process 1, was expected to result in an alloy that met the target properties of having a tensile strength (UTS) greater than 380 MPa, a yield strength (YS) greater than 350 MPa, and an elongation (E) greater than 8%.

[0040] Surprisingly, Processes 2-8 can also produce resultant alloys that meet the target properties of having a tensile strength (UTS) of greater than 380 MPa, a yield strength (YS) of greater than 350 MPa, and an elongation (E) of greater than 8%.

[0041] The maximum and average corrosion depths for each aging condition are also shown in Table 3. These results are surprising, and all of the two-step aging processes with the first step aging treatment at 205°C for 16 min showed better IG corrosion performance than the conventional aging treatment. In particular, the samples aged with Process 6 and Process 8 can meet both the maximum and average corrosion depth requirements. In particular, the alloy obtained with Process 6 (16 min at the first temperature of 205°C and 2 h at the second temperature of 175°C) is commercially preferred because the total time of the aging cycle is only 3 h.

[0042] Example 2: A210 alloy with 3.5% prestrain

[0043] To investigate the effectiveness of the methods disclosed herein, Alcoa 6xxx high strength extrusion alloy A210 was used. The wall thickness of the A210 extrusion sections varied from 2.5 mm to 4 mm. Extrusion was performed in a 2500 ton extruder with an extrusion speed of about 10 m / min. The exit temperature was controlled at about 555°C to 565°C. The extrusion profile was water quenched with a quench rate of 50°C / sec to 75°C / sec. Table 1 shows the actual composition of the A210 alloy evaluated. All samples were prestrained by 3.5% in the extrusion direction prior to aging treatment.

[0044] A210 alloy with a 3.5% prestrain was processed through four different aging processes. Details of the four processes are shown in Table 4. Process 1 is a conventional aging process commonly used for A210 alloy, which involves aging at an aging temperature of 175°C for 8 hours. Processes 2-4 are aging processes according to embodiments of the methods disclosed herein, which involve a first temperature treatment for a first duration, followed by a second temperature treatment for a second duration. Process 4 included 24 hours of natural aging between the first and second temperature treatments. In processes 2 and 3, the total duration of the first and second durations is substantially shorter than the conventional duration (e.g., 8 hours). [Table 4]

[0045] The alloys obtained from the above four processes were evaluated. Characterization included IG corrosion, tensile properties, and three-point bend tests. The three-point bend tests were performed according to VDA 238-100 specifications. The three-point bend test parameters were as follows: 100% Cr content, ... Sample length: ~60mm Sample width: ~25mm Distance between rollers: 6mm Knife radius: 0.4mm Roller diameter: 30mm Speed ​​to reserve: 10mm / min Reserve force: 100N Test speed: 20mm / min Test end criteria: Maximum load -4%

[0046] Table 5 shows surprising results. Clearly, the disclosed method embodiments (Processes 2-4) can significantly improve the IG corrosion performance of the resulting alloys without obvious adverse effects on mechanical properties and bend angle. Compared with the traditional aging process (Process 1), Processes 3 and 4 can significantly improve the IG corrosion performance of the resulting A210 alloy (pre-strained 3.5% before aging). Process 2 can also improve the IG corrosion performance, but Process 2 did not show better results than Processes 3 and 4. [Table 5]

[0047] Among the disclosed advantages and improvements, other objects and advantages of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings. Although detailed embodiments of the present disclosure are disclosed herein, it should be understood that the disclosed embodiments are merely exemplary of the present disclosure, which may be embodied in various forms. Moreover, the examples given in connection with the various embodiments of the present disclosure are intended to be illustrative and not limiting.

[0048] Various embodiments are provided below. It will be understood that any of the features described in the following embodiments may be combined with any other embodiment. Aspect 1. Exposing an alloy to a first temperature for a first duration; exposing the alloy to a second temperature for a second duration, The method, wherein the first temperature is greater than the age hardening temperature and less than the solution heat treatment temperature of the alloy. Embodiment 2. The method of embodiment 1, further comprising solution heat treating the alloy at a solution heat treatment temperature prior to exposing the alloy to the first temperature. Aspect 3. The method of any one of Aspects 1-2, wherein the second temperature is an age hardening temperature. Aspect 4. The method of any of Aspects 1-3, wherein the alloy comprises a solution heat treated and quenched alloy. Embodiment 5. The method of any one of embodiments 1-4, wherein the alloy comprises a 6xxx aluminum alloy. Aspect 6. The method of any one of Aspects 1-5, wherein the alloy comprises a 6xxx Al-Si-Mg-Cu based aluminum alloy. Embodiment 7. The method of any of embodiments 1-6, further comprising obtaining the resulting alloy, wherein the resulting alloy has improved resistance to intergranular corrosion (IGC). Aspect 8. The method according to any one of aspects 1 to 7, wherein the first temperature is 200°C to 210°C. Aspect 9. The method of any one of aspects 1 to 8, wherein the first duration is 5 minutes to 20 minutes. Aspect 10. The method according to any one of aspects 1 to 9, wherein the second temperature is 150°C to 200°C. Aspect 11. The method of any one of aspects 1 to 10, wherein the second duration is from 30 minutes to 3 hours. Embodiment 12. A method comprising exposing an aluminum alloy to a first temperature for a first duration and exposing the aluminum alloy to a second temperature for a second duration, The first temperature is greater than the second temperature; The method, wherein the first time period is 5 minutes to 20 minutes. Aspect 13. The method of aspect 12, wherein the first temperature is 200°C to 210°C. Aspect 14. The method of any one of aspects 12 to 13, wherein the second temperature is 150°C to 200°C. Aspect 15. The method of any of aspects 12 to 14, wherein the second duration is from 30 minutes to 3 hours.

[0049] The terms used herein are intended to describe the embodiments and are not intended to be limiting. The terms "a / an" and "the" include the plural unless expressly indicated otherwise. As used herein, the terms "comprises" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components. As used herein, the term "based on" is not exclusive and allows for the basis of additional unstated factors unless the context clearly dictates otherwise. Additionally, the meaning of "in" includes "in" and "on."

[0050] It being understood that changes may be made in details, particularly in matters relating to the materials of construction used and the shape, size and arrangement of parts without departing from the scope of the present disclosure. The specification and described embodiments are exemplary, the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims

1. exposing the alloy to a first temperature for a first duration; exposing the alloy to a second temperature for a second duration; and A method comprising: The method of claim 1, wherein the first temperature is greater than the age hardening temperature of the alloy and less than the solution heat treatment temperature.

2. 10. The method of claim 1, further comprising solution heat treating the alloy at the solution heat treatment temperature prior to exposing the alloy to the first temperature.

3. The method of claim 1 , wherein the second temperature is an age hardening temperature.

4. The method of claim 1 , wherein the alloy comprises a solution heat treated and quenched alloy.

5. The method of claim 1 , wherein the alloy comprises a 6xxx aluminum alloy.

6. The method of claim 1 , wherein the alloy comprises a 6xxx Al-Si-Mg-Cu aluminum alloy.

7. 7. The method of claim 1, further comprising obtaining a resulting alloy, the resulting alloy having improved intergranular corrosion (IGC) resistance.

8. The method of claim 1, wherein the first temperature is between 200°C and 210°C.

9. The method of claim 1 , wherein the first duration is between 5 minutes and 20 minutes.

10. The method of claim 1, wherein the second temperature is between 150°C and 200°C.

11. The method of claim 1, wherein the second duration is between 30 minutes and 3 hours.

12. exposing the aluminum alloy to a first temperature for a first duration; exposing the aluminum alloy to a second temperature for a second duration; A method comprising: the first temperature is greater than the second temperature; The method wherein the first period of time is between 5 minutes and 20 minutes.

13. The method of claim 12, wherein the first temperature is between 200°C and 210°C.

14. The method of claim 12, wherein the second temperature is between 150°C and 200°C.

15. The method of claim 12, wherein the second period of time is between 30 minutes and 3 hours.

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