U.S. patent application number 16/518446 was filed with the patent office on 2020-01-23 for highly formable, recycled aluminum alloys and methods of making the same.
This patent application is currently assigned to Novelis Inc.. The applicant listed for this patent is Novelis Inc.. Invention is credited to Martin Beech, Cyrille Bezencon, Sazol Kumar Das, Peter Evans, David Scott Fisher, Guillaume Florey, David Fryatt, Matthew Heyen, Rajeev G. Kamat, Rainer Kossak, Mark Marsh, ChangOok Son, Juergen Timm.
Application Number | 20200024713 16/518446 |
Document ID | / |
Family ID | 67515213 |
Filed Date | 2020-01-23 |
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United States Patent
Application |
20200024713 |
Kind Code |
A1 |
Das; Sazol Kumar ; et
al. |
January 23, 2020 |
HIGHLY FORMABLE, RECYCLED ALUMINUM ALLOYS AND METHODS OF MAKING THE
SAME
Abstract
Provided herein are highly formable aluminum alloys and methods
of making the same. The highly formable aluminum alloys described
herein can be prepared from recycled materials without significant
addition of primary aluminum alloy material. The aluminum alloys
are prepared by casting an aluminum alloy that can include such
recycled materials and processing the resulting cast aluminum alloy
article. Also described herein are methods of using the aluminum
alloys and alloy products.
Inventors: |
Das; Sazol Kumar; (Acworth,
GA) ; Heyen; Matthew; (Kennesaw, GA) ; Evans;
Peter; (Belleville, MI) ; Beech; Martin;
(Warrington, GB) ; Son; ChangOok; (Marietta,
GA) ; Marsh; Mark; (Marietta, GA) ; Kamat;
Rajeev G.; (Marietta, GA) ; Kossak; Rainer;
(South Lyon, MI) ; Fryatt; David; (Brownstown
Township, MI) ; Fisher; David Scott; (Baldwinsville,
NY) ; Florey; Guillaume; (Veyras, CH) ;
Bezencon; Cyrille; (Chermignon, CH) ; Timm;
Juergen; (Steissilingen, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Novelis Inc. |
Atlanta |
GA |
US |
|
|
Assignee: |
Novelis Inc.
Atlanta
GA
|
Family ID: |
67515213 |
Appl. No.: |
16/518446 |
Filed: |
July 22, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62701977 |
Jul 23, 2018 |
|
|
|
62810585 |
Feb 26, 2019 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21B 1/22 20130101; B21B
3/00 20130101; C22C 21/02 20130101; B21B 2001/225 20130101; C22F
1/043 20130101; B21B 2003/001 20130101; C22F 1/002 20130101 |
International
Class: |
C22F 1/043 20060101
C22F001/043; C22C 21/02 20060101 C22C021/02 |
Claims
1. An aluminum alloy, comprising about 0.5 to 2.0 wt. % Si, 0.2 to
0.4 wt. % Fe, up to 0.4 wt. % Cu, up to 0.5 wt. % Mg, 0.02 to 0.1
wt. % Mn, 0.01 to 0.1 wt. % Cr, up to 0.15 wt. % Sr, up to 0.15 wt.
% impurities, and Al.
2. The aluminum alloy of claim 1, comprising about 0.7 to 1.4 wt. %
Si, 0.2 to 0.3 wt. % Fe, up to 0.2 wt. % Cu, up to 0.4 wt. % Mg,
0.02 to 0.08 wt. % Mn, 0.02 to 0.05 wt. % Cr, 0.01 to 0.12 wt. %
Sr, up to 0.15 wt. % impurities, and Al.
3. The aluminum alloy of claim 1, comprising about 1.0 to 1.4 wt. %
Si, 0.22 to 0.28 wt. % Fe, up to 0.15 wt. % Cu, up to 0.35 wt. %
Mg, 0.02 to 0.06 wt. % Mn, 0.02 to 0.04 wt. % Cr, 0.02 to 0.10 wt.
% Sr, up to 0.15 wt. % impurities, and Al.
4. The aluminum alloy of claim 1, wherein a combined content of Fe
and Cr is from about 0.22 wt. % to 0.5 wt. %.
5. An aluminum alloy product, comprising an aluminum alloy
comprising about 0.5 to 2.0 wt. % Si, 0.2 to 0.4 wt. % Fe, up to
0.4 wt. % Cu, up to 0.5 wt. % Mg, 0.02 to 0.1 wt. % Mn, 0.01 to 0.1
wt. % Cr, up to 0.15 wt. % Sr, up to 0.15 wt. % impurities, and Al,
wherein a combined content of Fe and Cr is from about 0.22 wt. % to
0.5 wt. %.
6. The aluminum alloy product of claim 5, wherein the aluminum
alloy product comprises a grain size of up to about 35 .mu.m.
7. The aluminum alloy product of claim 6, wherein the grain size is
from about 25 .mu.m to about 35 .mu.m.
8. The aluminum alloy product of claim 5, comprising
iron-containing intermetallic particles.
9. The aluminum alloy product of claim 8, wherein at least about
36% of the iron-containing intermetallic particles are
spherical.
10. The aluminum alloy product of claim 8, wherein at least about
36% of the iron-containing intermetallic particles present in the
aluminum alloy product have an equivalent circular diameter of
about 3 .mu.m or less.
11. The aluminum alloy product of claim 8, wherein at least about
50% of the iron-containing intermetallic particles present in the
aluminum alloy product have an equivalent circular diameter of
about 3 .mu.m or less.
12. The aluminum alloy product of claim 8, wherein at least about
75% of the iron-containing intermetallic particles present in the
aluminum alloy product have an equivalent circular diameter of
about 3 .mu.m or less.
13. The aluminum alloy product of claim 8, wherein at least about
36% of the iron-containing intermetallic particles comprise
.alpha.-AlFe(Mn,Cr)Si intermetallic particles.
14. The aluminum alloy product of claim 8, wherein at least about
50% of the iron-containing intermetallic particles comprise
.alpha.-AlFe(Mn,Cr)Si intermetallic particles.
15. The aluminum alloy product of claim 8, wherein at least about
80% of the iron-containing intermetallic particles comprise
.alpha.-AlFe(Mn,Cr)Si intermetallic particles.
16. The aluminum alloy product of claim 8, wherein a volume
fraction of a cube textural component in the aluminum alloy product
comprises at least about 12%.
17. The aluminum alloy product of claim 8, wherein the aluminum
alloy product comprises a total elongation of at least about
32%.
18. The aluminum alloy product of claim 8, wherein the aluminum
alloy product comprises an automobile body part.
19. A method of producing an aluminum alloy product, comprising:
casting the aluminum alloy of claim 1 to produce a cast aluminum
alloy article; homogenizing the cast aluminum alloy article to
produce a homogenized cast aluminum alloy article; hot rolling and
cold rolling the homogenized cast aluminum alloy article to produce
a final gauge aluminum alloy product; and solution heat treating
the final gauge aluminum alloy product.
20. The method of claim 19, wherein the homogenizing is performed
at a homogenization temperature of from about 530.degree. C. to
about 570.degree. C.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to and filing
benefit of U.S. Provisional Patent Application No. 62/701,977,
filed on Jul. 23, 2018, and U.S. Provisional Patent Application No.
62/810,585, filed on Feb. 26, 2019, which are incorporated herein
by reference in their entireties.
FIELD
[0002] The present disclosure relates to metallurgy generally and
more specifically to producing aluminum alloys, optionally from
recycled scrap, manufacturing aluminum alloy products, and
recycling aluminum alloys.
BACKGROUND
[0003] Due to the costs and time associated with producing primary
aluminum, many original equipment manufacturers rely on existing
aluminum-containing scrap to prepare aluminum alloy materials.
However, recyclable scrap can be unsuitable for use in preparing
high performance aluminum alloys, as the recyclable scrap can
contain high levels of certain undesirable elements. For example,
the recyclable scrap can include certain elements in amounts that
affect the mechanical properties of the aluminum alloys, such as
formability and strength.
SUMMARY
[0004] Covered embodiments of the invention are defined by the
claims, not this summary. This summary is a high-level overview of
various aspects of the invention and introduces some of the
concepts that are further described in the Detailed Description
section below. This summary is not intended to identify key or
essential features of the claimed subject matter, nor is it
intended to be used in isolation to determine the scope of the
claimed subject matter. The subject matter should be understood by
reference to appropriate portions of the entire specification, any
or all drawings, and each claim.
[0005] Described herein are highly formable, recycled aluminum
alloys and methods of producing the aluminum alloys. The aluminum
alloys described herein comprise about 0.5 to 2.0 wt. % Si, 0.2 to
0.4 wt. % Fe, up to 0.4 wt. % Cu, up to 0.5 wt. % Mg, 0.02 to 0.1
wt. % Mn, 0.01 to 0.1 wt. % Cr, up to 0.15 wt. % Sr, up to 0.15 wt.
% total impurities, wherein each impurity is present in an amount
of up to about 0.05 wt. %, and Al. In some non-limiting examples,
the aluminum alloys comprise about 0.7 to 1.4 wt. % Si, 0.2 to 0.3
wt. % Fe, up to 0.2 wt. % Cu, up to 0.4 wt. % Mg, 0.02 to 0.08 wt.
% Mn, 0.02 to 0.05 wt. % Cr, 0.01 to 0.12 wt. % Sr, up to 0.15 wt.
% impurities, and Al. In some non-limiting examples, the aluminum
alloys comprise about 1.0 to 1.4 wt. % Si, 0.22 to 0.28 wt. % Fe,
up to 0.15 wt. % Cu, up to 0.35 wt. % Mg, 0.02 to 0.06 wt. % Mn,
0.02 to 0.04 wt. % Cr, 0.02 to 0.10 wt. % Sr, up to 0.15 wt. %
impurities, and Al. Optionally, a combined content of Fe and Cr in
the aluminum alloy is from about 0.22 wt. % to about 0.5 wt. %.
Also described herein are aluminum alloy products comprising the
aluminum alloys as described herein. In some examples, the aluminum
alloy products comprise a grain size up to about 35 .mu.m (e.g.,
from about 25 .mu.m to about 35 .mu.m or from about 28 .mu.m to
about 32 .mu.m). Optionally, the aluminum alloy products comprise
iron-containing intermetallic particles. In some cases, at least
about 36% of the iron-containing intermetallic particles can be
spherical. In some non-limiting examples, at least about 36% (e.g.,
at least about 50% or at least about 75%) of the iron-containing
intermetallic particles present in the aluminum alloy products have
an equivalent circular diameter (i.e., "ECD") of about 3 .mu.m or
less. Optionally, at least about 36% (e.g., at least about 50%, at
least about 70%, or at least about 80%) of the iron-containing
intermetallic particles comprise .alpha.-AlFe(Mn,Cr)Si
intermetallic particles. In some cases, a volume fraction of a cube
textural component in the aluminum alloy product comprises at least
about 12%. In some cases, the aluminum alloy products comprise a
total elongation of at least about 32%. The aluminum alloy product
can comprise an automobile body part, among others.
[0006] Further described herein are methods of producing an
aluminum alloy product. The methods comprise casting an aluminum
alloy as described herein to produce a cast aluminum alloy article,
homogenizing the cast aluminum alloy article to produce a
homogenized cast aluminum alloy article, hot rolling, and cold
rolling the homogenized cast aluminum alloy article to produce a
final gauge aluminum alloy product, and solution heat treating the
final gauge aluminum alloy product. Optionally, the homogenizing is
performed at a homogenization temperature of from about 530.degree.
C. to about 570.degree. C. Optionally, the aluminum alloy in the
casting step comprises a recycled content in an amount of at least
about 40 wt. %.
BRIEF DESCRIPTION OF THE FIGURES
[0007] FIG. 1A is a schematic depicting a processing method as
described herein.
[0008] FIG. 1B is a schematic depicting a processing method as
described herein.
[0009] FIG. 1C is a schematic depicting a processing method as
described herein.
[0010] FIG. 2 is a graph showing the yield strength of aluminum
alloys as described herein.
[0011] FIG. 3 is a graph showing the ultimate tensile strength of
aluminum alloys as described herein.
[0012] FIG. 4 is a graph showing the uniform elongation of aluminum
alloys as described herein.
[0013] FIG. 5 is a graph showing the total elongation of aluminum
alloys as described herein.
[0014] FIG. 6 is a graph showing the n-value (i.e., increase in
strength after deformation) of aluminum alloys as described
herein.
[0015] FIG. 7 is a graph showing the r-value (i.e., anisotropy) of
aluminum alloys as described herein.
[0016] FIG. 8 is a graph showing the average r-value (i.e.,
anisotropy) of aluminum alloys as described herein.
[0017] FIG. 9 is a graph showing the change in yield strength after
paint baking of aluminum alloys as described herein.
[0018] FIG. 10 is a graph showing the bendability of aluminum
alloys as described herein.
[0019] FIG. 11 is a graph showing the bendability of aluminum
alloys as described herein.
[0020] FIG. 12 is a graph showing cupping test results of aluminum
alloys as described herein.
[0021] FIG. 13A is a scanning electron microscope (SEM) micrograph
depicting the particle distribution of an aluminum alloy product as
described herein.
[0022] FIG. 13B is a SEM micrograph depicting the particle
distribution of a comparative aluminum alloy product.
[0023] FIG. 13C is a SEM micrograph depicting the particle
distribution of an aluminum alloy product as described herein.
[0024] FIG. 13D is a SEM micrograph depicting the particle
distribution of a comparative aluminum alloy product.
[0025] FIG. 13E is a SEM micrograph depicting the particle
distribution of a comparative aluminum alloy product.
[0026] FIG. 14 is a graph showing the particle size distribution
based on an equivalent circular diameter (ECD) measurement of
non-spherical particles in an aluminum alloy as described
herein.
[0027] FIG. 15 is a graph showing the particle size distribution
based on an aspect ratio measurement of the particles in an
aluminum alloy as described herein.
[0028] FIG. 16 is a graph showing the volume fraction of
iron-containing constituent particles in aluminum alloys as
described herein.
[0029] FIG. 17 is a graph showing the number density of
iron-containing constituent particles in aluminum alloys as
described herein.
[0030] FIG. 18A is an optical microscope (OM) micrograph depicting
the grain structure of an aluminum alloy product as described
herein.
[0031] FIG. 18B is an OM micrograph depicting the grain structure
of a comparative aluminum alloy product.
[0032] FIG. 18C is an OM micrograph depicting the grain structure
of an aluminum alloy product as described herein.
[0033] FIG. 18D is an OM micrograph depicting the grain structure
of a comparative aluminum alloy product.
[0034] FIG. 18E is an OM micrograph depicting the grain structure
of a comparative aluminum alloy product.
[0035] FIG. 19 is a graph showing the average grain size of
aluminum alloys as described herein.
[0036] FIG. 20 is a graph showing the texture component content of
aluminum alloys as described herein.
DETAILED DESCRIPTION
[0037] Provided herein are aluminum alloy products having desirable
mechanical properties and methods of casting and processing the
same. The aluminum alloy products can be recycled as well as
produced from recycled material (e.g., post-consumer scrap) and
still exhibit desirable mechanical properties, such as good
formability without cracking and/or fracture, high elongation
before fracture, and good durability.
[0038] The aluminum alloy products described herein contain
intermetallic particles that have a low aspect ratio (e.g., width
to height ratio). In some cases, a low aspect ratio is a ratio of
about 4 or less (e.g., about 3 or less, about 2 or less, or about
1.5 or less). In particular, the intermetallic particles are
circular or spherical in shape. An aspect ratio of 1 (e.g., close
to a circular cross section, i.e., spherical particles) is a
preferable Fe-containing intermetallic particle shape for
mechanical properties, for example bending, forming, crushing,
and/or crash-testing. These intermetallic particles enhance the
desirable mechanical properties of the products and result in
products exhibiting superior results as compared to aluminum alloy
products having intermetallic particles that are elliptical or
needle-like in shape.
Definitions and Descriptions
[0039] As used herein, the terms "invention," "the invention,"
"this invention" and "the present invention" are intended to refer
broadly to all of the subject matter of this patent application and
the claims below. Statements containing these terms should be
understood not to limit the subject matter described herein or to
limit the meaning or scope of the patent claims below.
[0040] In this description, reference is made to alloys identified
by aluminum industry designations, such as "series" or "6xxx." For
an understanding of the number designation system most commonly
used in naming and identifying aluminum and its alloys, see
"International Alloy Designations and Chemical Composition Limits
for Wrought Aluminum and Wrought Aluminum Alloys," or "Registration
Record of Aluminum Association Alloy Designations and Chemical
Compositions Limits for Aluminum Alloys in the Form of Castings and
Ingot," both published by The Aluminum Association.
[0041] As used herein, the meaning of "a," "an," or "the" includes
singular and plural references unless the context clearly dictates
otherwise.
[0042] As used herein, a plate generally has a thickness of greater
than about 15 mm. For example, a plate may refer to an aluminum
product having a thickness of greater than about 15 mm, greater
than about 20 mm, greater than about 25 mm, greater than about 30
mm, greater than about 35 mm, greater than about 40 mm, greater
than about 45 mm, greater than about 50 mm, greater than about 100
mm, or up to about 300 mm.
[0043] As used herein, a shate (also referred to as a sheet plate)
generally has a thickness of from about 4 mm to about 15 mm. For
example, a shate may have a thickness of about 4 mm, about 5 mm,
about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about
11 mm, about 12 mm, about 13 mm, about 14 mm, or about 15 mm.
[0044] As used herein, a sheet generally refers to an aluminum
product having a thickness of less than about 4 mm. For example, a
sheet may have a thickness of less than about 4 mm, less than about
3 mm, less than about 2 mm, less than about 1 mm, less than about
0.5 mm, less than about 0.3 mm, or less than about 0.1 mm.
[0045] Reference is made in this application to alloy temper or
condition. For an understanding of the alloy temper descriptions
most commonly used, see "American National Standards (ANSI) H35 on
Alloy and Temper Designation Systems." An F condition or temper
refers to an aluminum alloy as fabricated. An O condition or temper
refers to an aluminum alloy after annealing. A T1 condition or
temper refers to an aluminum alloy cooled from hot working and
naturally aged (e.g., at room temperature). A T2 condition or
temper refers to an aluminum alloy cooled from hot working, cold
worked and naturally aged. A T3 condition or temper refers to an
aluminum alloy solution heat treated, cold worked, and naturally
aged. A T4 condition or temper refers to an aluminum alloy solution
heat treated and naturally aged. A T5 condition or temper refers to
an aluminum alloy cooled from hot working and artificially aged (at
elevated temperatures). A T6 condition or temper refers to an
aluminum alloy solution heat treated and artificially aged. A T7
condition or temper refers to an aluminum alloy solution heat
treated and artificially overaged. A T8x condition or temper refers
to an aluminum alloy solution heat treated, cold worked, and
artificially aged. A T9 condition or temper refers to an aluminum
alloy solution heat treated, artificially aged, and cold
worked.
[0046] As used herein, the meaning of "room temperature" can
include a temperature of from about 15.degree. C. to about
30.degree. C., for example about 15.degree. C., about 16.degree.
C., about 17.degree. C., about 18.degree. C., about 19.degree. C.,
about 20.degree. C., about 21.degree. C., about 22.degree. C.,
about 23.degree. C., about 24.degree. C., about 25.degree. C.,
about 26.degree. C., about 27.degree. C., about 28.degree. C.,
about 29.degree. C., or about 30.degree. C.
[0047] As used herein, terms such as "cast aluminum alloy article,"
"cast metal article," "cast article," and the like are
interchangeable and refer to a product produced by direct chill
casting (including direct chill co-casting) or semi-continuous
casting, continuous casting (including, for example, by use of a
twin belt caster, a twin roll caster, a block caster, or any other
continuous caster), electromagnetic casting, hot top casting, or
any other casting method, or any combination thereof.
[0048] All ranges disclosed herein are to be understood to
encompass any endpoints and any and all subranges subsumed therein.
For example, a stated range of "1 to 10" should be considered to
include any and all subranges between (and inclusive of) the
minimum value of 1 and the maximum value of 10; that is, all
subranges beginning with a minimum value of 1 or more, e.g., 1 to
6.1, and ending with a maximum value of 10 or less, e.g., 5.5 to
10.
[0049] The following aluminum alloys are described in terms of
their elemental composition in weight percentage (wt. %) based on
the total weight of the alloy. In certain examples of each alloy,
the remainder is aluminum, with a maximum wt. % of 0.15% for the
sum of the impurities.
Alloy Compositions
[0050] Described herein are novel aluminum alloys and products that
exhibit desirable mechanical properties. Among other properties,
the aluminum alloys and products described herein display excellent
elongation and forming properties and exceptional durability. In
some cases, the mechanical properties can be achieved due to the
elemental composition of the alloys. For example, the alloys
described herein include iron (Fe), manganese (Mn), and chromium
(Cr). The presence of at least two of these components, for example
Fe and Mn, Fe and Cr, or Fe, Mn, and Cr, in the described amounts
results in desirable intermetallic particles. As described below,
an Fe content of at least about 0.50 wt. % provides an increased
number of intermetallic particles during the casting process. In
addition, other elements, such as Mn and/or Cr, influence the size
and aspect ratio of the intermetallic particles and result in
small, spherical particles having a low aspect ratio. The
intermetallic particles, in turn, serve as nucleation sites for new
grains, thus resulting in an aluminum alloy product containing
small, equiaxial grains rather than coarse, elongated grains. Such
aluminum alloy products exhibit desired forming properties. The
properties displayed by the aluminum alloy products described
herein are unexpected, as a high Fe content of about 0.20 wt. % and
greater typically results in a decrease in formability and
bendability.
[0051] In some cases, an aluminum alloy as described herein can
have the following elemental composition as provided in Table
1.
TABLE-US-00001 TABLE 1 Element Weight Percentage (wt. %) Si 0.5-2.0
Fe 0.2-0.4 Cu 0.0-0.4 Mg 0.0-0.5 Mn 0.02-0.1 Cr 0.01-0.1 Sr
0.0-0.15 Others 0-0.05 (each) 0-0.15 (total) Al
[0052] In some examples, the aluminum alloy as described herein can
have the following elemental composition as provided in Table
2.
TABLE-US-00002 TABLE 2 Element Weight Percentage (wt. %) Si 0.7-1.4
Fe 0.2-0.3 Cu 0.0-0.2 Mg 0.0-0.4 Mn 0.02-0.08 Cr 0.02-0.05 Sr
0.01-0.12 Others 0-0.05 (each) 0-0.15 (total) Al
[0053] In some examples, the aluminum alloy as described herein can
have the following elemental composition as provided in Table
3.
TABLE-US-00003 TABLE 3 Element Weight Percentage (wt. %) Si 1.0-1.4
Fe 0.22-0.28 Cu 0.0-0.15 Mg 0.0-0.35 Mn 0.02-0.06 Cr 0.02-0.04 Sr
0.02-0.1 Others 0-0.05 (each) 0-0.15 (total) Al
[0054] In some examples, the aluminum alloy described herein
includes silicon (Si) in an amount of from about 0.5% to about 2.0%
(e.g., from about 0.7 to about 1.5% or from about 1.0 to about
1.4%) based on the total weight of the alloy. For example, the
alloy can include 0.5%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%,
0.57%, 0.58%, 0.59%, 0.6%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%,
0.66%, 0.67%, 0.68%, 0.69%, 0.7%, 0.71%, 0.72%, 0.73%, 0.74%,
0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.8%, 0.81%, 0.82%, 0.83%,
0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.9%, 0.91%, 0.92%,
0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.0%, 1.01%,
1.02%, 1.03%, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, 1.09%, 1.1%,
1.11%, 1.12%, 1.13%, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%,
1.2%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%,
1.29%, 1.3%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%,
1.36%1.37%1.38%1.39%, 1.4%, 1.41%, 1.42%, 1.43%, 1.44%, 1.45%,
1.46%, 1.47%, 1.48%, 1.49%, 1.5%, 1.51%, 1.52%, 1.53%, 1.54%,
1.55%, 1.56%, 1.57%, 1.58%, 1.59%, 1.6%, 1.61%, 1.62%, 1.63%,
1.64%, 1.65%, 1.66%, 1.67%, 1.68%, 1.69%, 1.7%, 1.71%, 1.72%,
1.73%, 1.74%, 1.75%, 1.76%, 1.77%, 1.78%, 1.79%, 1.8%, 1.81%,
1.82%, 1.83%, 1.84%, 1.85%, 1.86%, 1.87%, 1.88%, 1.89%, 1.9%,
1.91%, 1.92%, 1.93%, 1.94%, 1.95%, 1.96%, 1.97%, 1.98%, 1.99%, or
2.0% Si. All expressed in wt. %.
[0055] In some examples, the aluminum alloy described herein
includes iron (Fe) in an amount of from about 0.2% to about 0.4%
(e.g., from about 0.2% to about 0.35%, from about 0.2% to about
0.3%, from about 0.2% to about 0.28%, or from about 0.22% to about
0.28%) based on the total weight of the alloy. For example, the
alloy can include 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%,
0.27%, 0.28%, 0.29%, 0.3%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%,
0.36%, 0.37%, 0.38%, 0.39%, or 0.4% Fe. All expressed in wt. %.
[0056] In some examples, the aluminum alloy described herein
includes copper (Cu) in an amount of up to about 0.4% (e.g., from
0.0% to about 0.35% or from 0.0% to about 0.15%) based on the total
weight of the alloy. For example, the alloy can include 0.01%,
0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%,
0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%,
0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%,
0.29%, 0.3%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%,
0.38%, 0.39%, or 0.4% Cu. In some cases, Cu is not present in the
alloy (i.e., 0%). All expressed in wt. %.
[0057] In some examples, the aluminum alloy described herein
includes magnesium (Mg) in an amount of up to about 0.5% (e.g.,
from 0.0% to about 0.5%, from 0.0% to about 0.4%, from 0.0% to
about 0.35%, from about 0.1% to about 0.5%, or from about 0.2% to
about 0.35%) based on the total weight of the alloy. For example,
the alloy can include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%,
0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%,
0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%,
0.25%, 0.26%, 0.27%, 0.28%0.29%, 0.3%, 0.31%, 0.32%, 0.33%, 0.34%,
0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.4%, 0.41%, 0.42%, 0.43%,
0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, or 0.5% Mg. In some
cases, Mg is not present in the alloy (i.e., 0%). All expressed in
wt. %.
[0058] In some examples, the aluminum alloy described herein
includes manganese (Mn) in an amount of from about 0.02% to about
0.1% (e.g., from about 0.02% to about 0.08% or from about 0.02% to
about 0.06%) based on the total weight of the alloy. For example,
the alloy can include 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%,
0.08%, 0.09%, or 0.1% Mn. All expressed in wt. %.
[0059] In some examples, the aluminum alloy described herein
includes chromium (Cr) in an amount of from about 0.01% to about
0.1% (e.g., from about 0.02 to about 0.1%, from about 0.02% to
about 0.08%, or from about 0.02% to about 0.06%) based on the total
weight of the alloy. For example, the alloy can include 0.01%,
0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1% Cr.
All expressed in wt. %.
[0060] In some examples, the aluminum alloy described herein
includes strontium (Sr) in an amount of up to about 0.15% (e.g.,
from 0.0% to about 0.15%, from about 0.02% to about 0.15%, from
about 0.02% to about 0.10%, or from about 0.02% to about 0.14%)
based on the total weight of the alloy. For example, the alloy can
include 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%,
0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, or 0.15% Sr. In some
cases, Sr is not present in the alloy (i.e., 0%). All expressed in
wt. %. In some cases, adding Sr to the aluminum alloy described
herein can further increase the formability and ductility of the
material. Not to be bound by theory, the increase in formability
can be due to the eutectic modification of the intermetallic
particles that can reduce the lamellar spacing within the eutectic
component during casting and solidification of the aluminum alloy.
Thus, Sr modification of the eutectic component can allow the
intermetallic particles to break apart into smaller and/or finer
intermetallic particles during, for example, a hot rolling process.
Finally, the finer intermetallic particles can reduce the tendency
of the aluminum alloy to undergo internal damage during deformation
(e.g., forming), thereby improving the formability of the aluminum
alloy.
[0061] Optionally, the aluminum alloy described herein can include
one or both of titanium (Ti) and zinc (Zn). In some examples, the
aluminum alloy described herein includes Ti in an amount up to
about 0.1% (e.g., from about 0.001% to about 0.08% or from about
0.005% to about 0.06%) based on the total weight of the alloy. For
example, the alloy can include 0.001%, 0.002%, 0.003%, 0.004%,
0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%,
0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1% Ti. In some cases, Ti is
not present in the alloy (i.e., 0%). In some examples, the aluminum
alloy described herein includes Zn in an amount up to about 0.1%
(e.g., from about 0.001% to about 0.08% or from about 0.005% to
about 0.06%) based on the total weight of the alloy. For example,
the alloy can include 0.001%, 0.002%, 0.003%, 0.004%, 0.005%,
0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%,
0.06%, 0.07%, 0.08%, 0.09%, or 0.1% Zn. In some cases, Zn is not
present in the alloy (i.e., 0%). All expressed in wt. %.
[0062] As described above, the presence of Fe in an amount of at
least about 0.2 wt. % and in combination with Cr is a factor that
results in the desirable properties exhibited by aluminum alloy
products described herein. Optionally, the combined content of Fe
and Cr is at least about 0.22 wt. %. In some cases, the combined
content of Fe and Cr can be from about 0.22 wt. % to about 0.5 wt.
%, from about 0.22 wt. % to about 0.4 wt. %, or from about 0.25 wt.
% to about 0.35 wt. %. For example, the combined content of Fe and
Cr can be 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%0.28%0.29%, 0.3%,
0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%,
0.4%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%,
0.49%, or 0.5%. All expressed in wt. %.
[0063] Optionally, the aluminum alloys described herein can further
include other minor elements, sometimes referred to as impurities,
in amounts of 0.05% or below, 0.04% or below, 0.03% or below, 0.02%
or below, or 0.01% or below. These impurities may include, but are
not limited to V, Ni, Sc, Hf, Zr, Sn, Ga, Ca, Bi, Na, Pb, or
combinations thereof. Accordingly, V, Ni, Sc, Hf, Zr, Sn, Ga, Ca,
Bi, Na, or Pb may be present in alloys in amounts of 0.05% or
below, 0.04% or below, 0.03% or below, 0.02% or below, or 0.01% or
below. The sum of all impurities does not exceed 0.15% (e.g.,
0.1%). All expressed in wt. %. The remaining percentage of each
alloy is aluminum.
[0064] The aluminum alloy products described herein include
iron-containing intermetallic particles. In some cases, the
iron-containing intermetallic particles are spherical. For example,
at least about 36% of the iron-containing intermetallic particles
are spherical (e.g., at least about 40%, at least about 50%, at
least about 60%, at least about 70%, at least about 80%, or at
least about 90% of the iron-containing intermetallic particles are
spherical). At least about 36% of the particles present in the
aluminum alloy products have a particle size, measured by
equivalent circular diameter (i.e., "ECD"), of about 3 .mu.m or
less (e.g., about 2.5 .mu.m or less, about 2.0 .mu.m or less, about
1.5 .mu.m or less, or about 1.2 .mu.m or less). The ECD can be
determined by imposing an estimated circular cross-section on a
non-spherical measured object. For example, the iron-containing
intermetallic particles present in the aluminum alloy products can
have an ECD of 3 .mu.m or less, 2.9 .mu.m or less, 2.8 .mu.m or
less, 2.7 .mu.m or less, 2.6 .mu.m or less, 2.5 .mu.m or less, 2.4
.mu.m or less, 2.3 .mu.m or less, 2.2 .mu.m or less, 2.1 .mu.m or
less, 2 .mu.m or less, 1.9 .mu.m or less, 1.8 .mu.m or less, 1.7
.mu.m or less, 1.6 .mu.m or less, 1.5 .mu.m or less, 1.4 .mu.m or
less, 1.3 .mu.m or less, 1.2 .mu.m or less, 1.1 .mu.m or less, 1
.mu.m or less, 0.9 .mu.m or less, 0.8 .mu.m or less, 0.7 .mu.m or
less, 0.6 .mu.m or less, 0.5 .mu.m or less, 0.4 .mu.m or less, 0.3
.mu.m or less, 0.2 .mu.m or less, 0.1 .mu.m or less, or anywhere in
between. In some cases, at least 45%, at least 50%, at least 55%,
at least 60%, at least 65%, at least 70%, at least 75%, at least
80%, at least 85%, at least 90%, at least 95%, or at least 99% of
the particles present in the aluminum alloy products have an ECD of
3 .mu.m or less.
[0065] In some non-limiting examples, the iron-containing
intermetallic particles described herein comprise
.alpha.-AlFe(Mn,Cr)Si intermetallic particles. The a-AlFe(Mn,Cr)Si
intermetallic particles can be spherical particles. The aluminum
alloys described herein having such spherical type intermetallic
particles are amenable to forming (e.g., bending, shaping,
stamping, or any suitable forming method) when compared to aluminum
alloys that predominantly include .beta.-AlFeSi intermetallic
particles. The .beta.-AlFeSi intermetallic particles typically have
an elongated, needle-like shape. Such needle-like intermetallic
particles are detrimental to forming and thus problematic when
creating aluminum alloy parts from recycled aluminum alloys.
[0066] Introducing Cr in the concentrations described above (e.g.,
from about 0.01 wt. % to about 0.1 wt. %) into the aluminum alloy
in a molten stage during production of a primary aluminum alloy)
and/or recycling (e.g., by melting scrap aluminum alloys and
optionally adding primary aluminum alloys) can allow the Cr to
interact with any excess Fe found in the aluminum alloy (e.g., the
molten alloy containing the primary aluminum alloy and the molten
scrap) and provide the .alpha.-AlFe(Mn,Cr)Si intermetallic
particles, thus replacing the .beta.-AlFeSi intermetallic
particles. Accordingly, replacing .beta.-AlFeSi intermetallic
particles with .alpha.-AlFe(Mn,Cr)Si intermetallic particles
provides aluminum alloys that demonstrate high formability and
durability. In some cases, at least about 36% of the
iron-containing intermetallic particles in the aluminum alloys
described herein are .alpha.-AlFe(Mn,Cr)Si intermetallic particles.
For example, at least 36%, at least 40%, at least 45%, at least
50%, at least 55%, at least 60%, at least 65%, at least 70%, at
least 75%, at least 80%, at least 85%, at least 90%, at least 95%,
or at least 99% of the iron-containing intermetallic particles in
the aluminum alloys described herein are .alpha.-AlFe(Mn,Cr)Si
intermetallic particles.
[0067] In some cases, adding Cr as described herein can increase an
amount of recycled content when providing the aluminum alloys. The
aluminum alloys described herein can contain at least about 40 wt.
% recycled content. For example, the aluminum alloys can contain at
least about 45 wt. %, at least about 50 wt. %, at least about 60
wt. %, at least about 70 wt. %, at least about 80 wt. %, at least
about 90 wt. %, or at least about 95 wt. % recycled content.
[0068] In some examples, the iron-containing intermetallic
particles can be present in the aluminum alloy in an average amount
of at least about 2000 to about 3000 particles per square
millimeter (mm.sup.2). For example, the average amount of
iron-containing intermetallic particles can be about 2000
particles/mm.sup.2, 2100 particles/mm.sup.2, 2200
particles/mm.sup.2, 2300 particles/mm.sup.2, 2400
particles/mm.sup.2, 2500 particles/mm.sup.2, 2600
particles/mm.sup.2, 2700 particles/mm.sup.2, 2800
particles/mm.sup.2, 2900 particles/mm.sup.2, 3000
particles/mm.sup.2, or anywhere in between.
[0069] As described above, the intermetallic particles in the
aluminum alloys can serve as nucleation sites for grains. The
aluminum alloys and products including the aluminum alloys can
include grains having an average grain size of up to about 35 .mu.m
(e.g., from about 5 .mu.m to about 35 .mu.m, from about 25 .mu.m to
about 35 .mu.m, or from about 28 .mu.m to about 32 .mu.m). For
example, the average grain size can be about 1 .mu.m, 5 .mu.m, 10
.mu.m, 15 .mu.m, 20 .mu.m, 25 .mu.m, 30 .mu.m, 35 .mu.m, or
anywhere in between.
[0070] In some cases, the aluminum alloy products can have a total
elongation of at least about 27% and up to about 40% when in, for
example, a T4 temper. For example, the aluminum alloy products can
have a total elongation of about 27%, 28%, 29%, 30%, 31%, 32%, 33%,
34%, 35%, 36%, 37%, 38%, 39%, or 40%, or anywhere in between.
[0071] In some cases, the aluminum alloy products can have a
uniform elongation of at least about 20% and up to about 30% when
in, for example, a T4 temper. For example, the aluminum alloy
products can have a uniform elongation of about 20%, 21%, 22%, 23%,
24%, 25%, 26%, 27%, 28%, 29%, or 30%, or anywhere in between.
[0072] In some examples, the aluminum alloy products have a yield
strength of about 100 MPa or greater when in, for example, a T4
temper. For example, the aluminum alloy products can have a yield
strength of 105 MPa or greater, 110 MPa or greater, 115 MPa or
greater, 120 MPa or greater, 125 MPa or greater, 130 MPa or
greater, 135 MPa or greater, 140 MPa or greater, 145 MPa or
greater, or 150 MPa or greater. In some cases, the yield strength
is from about 100 MPa to about 150 MPa (e.g., from about 105 MPa to
about 145 MPa, from about 110 MPa to about 140 MPa, or from about
115 MPa to about 135 MPa).
[0073] In some examples, the aluminum alloy products have an
ultimate tensile strength of about 200 MPa or greater when in, for
example, a T4 temper. For example, the aluminum alloy products can
have an ultimate tensile strength of 205 MPa or greater, 210 MPa or
greater, 215 MPa or greater, 220 MPa or greater, 225 MPa or
greater, 230 MPa or greater, 235 MPa or greater, 240 MPa or
greater, 245 MPa or greater, or 250 MPa or greater. In some cases,
the ultimate tensile strength is from about 200 MPa to about 250
MPa (e.g., from about 205 MPa to about 245 MPa, from about 210 MPa
to about 240 MPa, or from about 215 MPa to about 235 MPa).
[0074] The aluminum alloy products include at least a first surface
portion having a plurality of crystallographic texture components.
The crystallographic texture components can include
recrystallization texture components (e.g., a G.sub.OSS component,
a Cube component, and Rotated Cube (RC) components including an
RC.sub.RD1 component, an RC.sub.RD2 component, an RC.sub.RN1
component, and an RC.sub.RN2 component). The crystallographic
texture components can also include deformation texture components
(e.g., a Brass (Bs) component, an S component, a Copper component,
a Shear 1 component, a Shear 2 component, a Shear 3 component, a P
component, a Q component, and an R component).
[0075] In some examples, the aluminum alloy products can include a
Cube component. Optionally, a volume fraction of the Cube component
in the aluminum alloy products can be at least about 12% (e.g., at
least about 13%, at least about 14%, at least about 15%, at least
about 16%, at least about 17%, or at least about 18%). In some
examples, the volume fraction of the Cube component in the aluminum
alloy products is up to about 20% (e.g., up to about 15% or up to
about 10%). For example, the volume fraction of the Cube component
in the aluminum alloy products can range from about 12% to about
20% (e.g., from about 13% to about 20% or from about 16% to about
18%).
[0076] In some examples, the aluminum alloy products can include a
Brass component, an S component, a Copper component, and a
G.sub.OSS component. Optionally, a volume fraction of any one of
the Brass, S, Copper, or G.sub.OSS components in the aluminum alloy
products can be lower than about 5% (e.g., lower than about 4%,
lower than about 3%, lower than about 2%, or lower than about 1%).
For example, the volume fraction of any one of the Brass, S,
Copper, or G.sub.OSS components in the aluminum alloy products can
be from about 1% to about 5%, from about 1.5% to about 4.5%, or
from about 2% to about 4%.
Methods for Preparing the Aluminum Alloys
[0077] Aluminum alloy properties are partially determined by the
formation of microstructures during the alloy's preparation. In
certain aspects, the method of preparation for an alloy composition
may influence or even determine whether the alloy will have
properties adequate for a desired application.
[0078] Casting
[0079] The aluminum alloys as described herein can be cast into a
cast aluminum alloy article using any suitable casting method. For
example, the casting process can include a direct chill (DC)
casting process or a continuous casting (CC) process. In some
non-limiting examples, the aluminum alloys for use in the casting
step can be a primary material produced from raw materials (e.g.,
purified aluminum and additional alloying elements). In some
further examples, the aluminum alloys for use in the casting step
can be a recycled material, produced at least in part by aluminum
scrap and optionally in combination with a primary material. In
some cases, aluminum alloys for use in the casting step can contain
at least about 40% of recycled content. For example, the aluminum
alloy for use in the casting step can contain at least about 45%,
at least about 50%, at least about 60%, at least about 70%, at
least about 80%, at least about 90%, or at least about 95% of
recycled content.
[0080] The cast aluminum alloy article can then be subjected to
further processing steps. For example, the processing methods as
described herein can include the steps of homogenizing, hot
rolling, cold rolling, and/or solution heat treating to form an
aluminum alloy product.
[0081] Homogenization
[0082] The homogenization step as described herein was designed for
the aluminum alloys described above. The aluminum alloys described
herein have a high Si content (i.e., from 0.5 to 2.0 wt. %), which
can lead to localized melting within the aluminum alloy matrix when
homogenized at temperatures greater than about 550.degree. C.
(e.g., 560.degree. C. and greater). Such localized melting can
cause fracturing during downstream thermal processing steps. The
homogenization step described herein is effective in dissolving any
elemental Si and concurrently avoiding localized melting.
[0083] The homogenization step can include heating the cast
aluminum alloy article to attain a temperature of about, or up to
about, 570.degree. C. (e.g., up to about 560.degree. C., up to
about 550.degree. C., up to about 540.degree. C., up to about
530.degree. C., up to about 520.degree. C., up to about 510.degree.
C., up to about 500.degree. C., up to about 490.degree. C., up to
about 480.degree. C., up to about 470.degree. C., or up to about
460.degree. C.). For example, the cast aluminum alloy article can
be heated to a temperature of from about 460.degree. C. to about
570.degree. C. (e.g., from about 465.degree. C. to about
570.degree. C., from about 470.degree. C. to about 570.degree. C.,
from about 480.degree. C. to about 570.degree. C., from about
490.degree. C. to about 570.degree. C., from about 500.degree. C.
to about 570.degree. C., from about 510.degree. C. to about
570.degree. C., from about 520.degree. C. to about 570.degree. C.,
from about 530.degree. C. to about 570.degree. C., from about
540.degree. C. to about 570.degree. C., or from about 550.degree.
C. to about 570.degree. C.). In some cases, the heating rate can be
about 100.degree. C./hour or less, 75.degree. C./hour or less,
50.degree. C./hour or less, 40.degree. C./hour or less, 30.degree.
C./hour or less, 25.degree. C./hour or less, 20.degree. C./hour or
less, or 15.degree. C./hour or less. In other cases, the heating
rate can be from about 10.degree. C./min to about 100.degree.
C./min (e.g., from about 10.degree. C./min to about 90.degree.
C./min, from about 10.degree. C./min to about 70.degree. C./min,
from about 10.degree. C./min to about 60.degree. C./min, from about
20.degree. C./min to about 90.degree. C./min, from about 30.degree.
C./min to about 80.degree. C./min, from about 40.degree. C./min to
about 70.degree. C./min, or from about 50.degree. C./min to about
60.degree. C./min).
[0084] The cast aluminum alloy article is then allowed to soak for
a period of time. According to one non-limiting example, the cast
aluminum alloy article is allowed to soak for up to about 15 hours
(e.g., from about 20 minutes to about 15 hours or from about 5
hours to about 10 hours, inclusively). For example, the cast
aluminum alloy article can be soaked at a temperature of from about
500.degree. C. to about 550.degree. C. for about 20 minutes, about
30 minutes, about 45 minutes, about 1 hour, about 1.5 hours, about
2 hours, about 3 hours, about 4 hours, about 5 hours, about 6
hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours,
about 11 hours, about 12 hours, about 13 hours, about 14 hours,
about 15 hours, or anywhere in between.
[0085] Hot Rolling
[0086] Following the homogenization step, a hot rolling step can be
performed. In certain cases, the cast aluminum alloy articles are
laid down and hot-rolled with an entry temperature range of about
500.degree. C. to 560.degree. C. (e.g., from about 510.degree. C.
to about 550.degree. C. or from about 520.degree. C. to about
540.degree. C.). The entry temperature can be, for example, about
505.degree. C., 510.degree. C., 515.degree. C., 520.degree. C.,
525.degree. C., 530.degree. C., 535.degree. C., 540.degree. C.,
545.degree. C., 550.degree. C., 555.degree. C., 560.degree. C., or
anywhere in between. In certain cases, the hot roll exit
temperature can range from about 200.degree. C. to about
290.degree. C. (e.g., from about 210.degree. C. to about
280.degree. C. or from about 220.degree. C. to about 270.degree.
C.). For example, the hot roll exit temperature can be about
200.degree. C., 205.degree. C., 210.degree. C., 215.degree. C.,
220.degree. C., 225.degree. C., 230.degree. C., 235.degree. C.,
240.degree. C., 245.degree. C., 250.degree. C., 255.degree. C.,
260.degree. C., 265.degree. C., 270.degree. C., 275.degree. C.,
280.degree. C., 285.degree. C., 290.degree. C., or anywhere in
between.
[0087] In certain cases, the cast aluminum alloy article is hot
rolled to an about 4 mm to about 15 mm gauge (e.g., from about 5 mm
to about 12 mm gauge), which is referred to as a hot band. For
example, the cast article can be hot rolled to a 15 mm gauge, a 14
mm gauge, a 13 mm gauge, a 12 mm gauge, a 11 mm gauge, a 10 mm
gauge, a 9 mm gauge, an 8 mm gauge, a 7 mm gauge, a 6 mm gauge, a 5
mm gauge, or a 4 mm gauge. The temper of the as-rolled hot band is
referred to as F-temper.
[0088] Coil Cooling
[0089] Optionally, the hot band can be coiled into a hot band coil
(i.e., an intermediate gauge aluminum alloy product coil) upon exit
from the hot mill. In some examples, the hot band is coiled into a
hot band coil upon exit from the hot mill resulting in F-temper. In
some further examples, the hot band coil is cooled in air. The air
cooling step can be performed at a rate of about 12.5.degree.
C./hour (.degree. C./h) to about 3600.degree. C./h. For example,
the coil cooling step can be performed at a rate of about
12.5.degree. C./h, 25.degree. C./h, 50.degree. C./h, 100.degree.
C./h, 200.degree. C./h, 400.degree. C./h, 800.degree. C./h,
1600.degree. C./h, 3200.degree. C./h, 3600.degree. C./h, or
anywhere in between. In some still further examples, the air cooled
coil is stored for a period of time. In some examples, the
intermediate coils are maintained at a temperature of about
100.degree. C. to about 350.degree. C. (for example, about
200.degree. C. or about 300.degree. C.).
[0090] Cold Rolling
[0091] A cold rolling step can optionally be performed before the
solution heat treating step. In certain aspects, the hot band is
cold rolled to a final gauge aluminum alloy product (e.g., a
sheet). In some examples, the final gauge aluminum alloy sheet has
a thickness of 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or
less, 0.9 mm or less, 0.8 mm or less, 0.7 mm or less, 0.6 mm or
less, 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or
less, or 0.1 mm.
[0092] Optional Inter-Annealing
[0093] In some non-limiting examples, an optional inter-annealing
step can be performed during cold rolling. For example, the hot
band can be cold rolled to an intermediate cold roll gauge,
annealed, and subsequently cold rolled to a final gauge. In some
aspects, the optional inter-annealing can be performed in a batch
process (i.e., a batch inter-annealing step). The inter-annealing
step can be performed at a temperature of from about 300.degree. C.
to about 450.degree. C. (e.g., about 310.degree. C., about
320.degree. C., about 330.degree. C., about 340.degree. C., about
350.degree. C., about 360.degree. C., about 370.degree. C., about
380.degree. C., about 390.degree. C., about 400.degree. C., about
410.degree. C., about 420.degree. C., about 430.degree. C., about
440.degree. C., or about 450.degree. C.).
[0094] Solution Heat Treating
[0095] The solution heat treating step can include heating the
final gauge aluminum alloy product from room temperature to a peak
metal temperature. Optionally, the peak metal temperature can be
from about 530.degree. C. to about 570.degree. C. (e.g., from about
535.degree. C. to about 560.degree. C., from about 545.degree. C.
to about 555.degree. C., or about 540.degree. C.). The final gauge
aluminum alloy product can soak at the peak metal temperature for a
period of time. In certain aspects, the final gauge aluminum alloy
product is allowed to soak for up to approximately 2 minutes (e.g.,
from about 10 seconds to about 120 seconds inclusively). For
example, the final gauge aluminum alloy product can be soaked at
the temperature of from about 530.degree. C. to about 570.degree.
C. for 10 seconds, 15 seconds, 20 seconds, 25 seconds, 30 seconds,
35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60
seconds, 65 seconds, 70 seconds, 75 seconds, 80 seconds, 85
seconds, 90 seconds, 95 seconds, 100 seconds, 105 seconds, 110
seconds, 115 seconds, 120 seconds, or anywhere in between. After
solution heat treating, the final gauge aluminum alloy product can
be quenched from the peak metal temperature at a rate of at least
about 75.degree. C. per second (.degree. C./s). For example, the
final gauge aluminum alloy product can be quenched at a rate of
about 75.degree. C./s, 100.degree. C./s, 125.degree. C./s,
150.degree. C./s, 175.degree. C./s, 200.degree. C./s, or anywhere
in between.
[0096] Optionally, the aluminum alloy product can then be naturally
aged and/or artificially aged. In some non-limiting examples, the
aluminum alloy product can be naturally aged to a T4 temper by
storing at room temperature (e.g., about 15.degree. C., about
20.degree. C., about 25.degree. C., or about 30.degree. C.) for at
least 72 hours. For example, the aluminum alloy product can be
naturally aged for 72 hours, 84 hours, 96 hours, 108 hours, 120
hours, 132 hours, 144 hours, 156 hours, 168 hours, 180 hours, 192
hours, 204 hours, 216 hours, 240 hours, 264 hours, 288 hours, 312
hours, 336 hours, 360 hours, 384 hours, 408 hours, 432 hours, 456
hours, 480 hours, 504 hours, 528 hours, 552 hours, 576 hours, 600
hours, 624 hours, 648 hours, 672 hours, or anywhere in between.
Methods of Using
[0097] The alloys and methods described herein can be used in
automotive and/or transportation applications, including motor
vehicle, aircraft, and railway applications, or any other desired
application. In some examples, the alloys and methods can be used
to prepare motor vehicle body part products, such as safety cages,
bodies-in-white, crash rails, bumpers, side beams, roof beams,
cross beams, pillar reinforcements (e.g., A-pillars, B-pillars, and
C-pillars), inner panels, outer panels, side panels, inner hoods,
outer hoods, or trunk lid panels. The aluminum alloys and methods
described herein can also be used in aircraft or railway vehicle
applications, to prepare, for example, external and internal
panels.
[0098] The alloys and methods described herein can also be used in
electronics applications, to prepare, for example, external and
internal encasements. For example, the alloys and methods described
herein can also be used to prepare housings for electronic devices,
including mobile phones and tablet computers. In some examples, the
alloys can be used to prepare housings for the outer casing of
mobile phones (e.g., smart phones) and tablet bottom chassis.
Illustrations of Suitable Alloys, Products, and Methods
[0099] Illustration 1 is an aluminum alloy, comprising about 0.5 to
2.0 wt. % Si, 0.2 to 0.4 wt. % Fe, up to 0.4 wt. % Cu, up to 0.5
wt. % Mg, 0.02 to 0.1 wt. % Mn, 0.01 to 0.1 wt. % Cr, up to 0.15
wt. % Sr, up to 0.15 wt. % impurities, and Al.
[0100] Illustration 2 is the aluminum alloy of any preceding or
subsequent illustration, comprising about 0.7 to 1.4 wt. % Si, 0.2
to 0.3 wt. % Fe, up to 0.2 wt. % Cu, up to 0.4 wt. % Mg, 0.02 to
0.08 wt. % Mn, 0.02 to 0.05 wt. % Cr, 0.01 to 0.12 wt. % Sr, up to
0.15 wt. % impurities, and Al.
[0101] Illustration 3 is the aluminum alloy of any preceding or
subsequent illustration, comprising about 1.0 to 1.4 wt. % Si, 0.22
to 0.28 wt. % Fe, up to 0.15 wt. % Cu, up to 0.35 wt. % Mg, 0.02 to
0.06 wt. % Mn, 0.02 to 0.04 wt. % Cr, 0.02 to 0.10 wt. % Sr, up to
0.15 wt. % impurities, and Al.
[0102] Illustration 4 is the aluminum alloy of any preceding or
subsequent illustration, wherein a combined content of Fe and Cr is
from about 0.22 wt. % to 0.50 wt. %.
[0103] Illustration 5 is an aluminum alloy product, comprising the
aluminum alloy according to any preceding or subsequent
illustration.
[0104] Illustration 6 is the aluminum alloy product of any
preceding or subsequent illustration, wherein the aluminum alloy
product comprises a grain size of up to about 35 .mu.m.
[0105] Illustration 7 is the aluminum alloy product of any
preceding or subsequent illustration, wherein the grain size is
from about 25 .mu.m to about 35 .mu.m.
[0106] Illustration 8 is the aluminum alloy product of any
preceding or subsequent illustration, comprising iron-containing
intermetallic particles.
[0107] Illustration 9 is the aluminum alloy product of any
preceding or subsequent illustration, wherein at least about 36% of
the iron-containing intermetallic particles are spherical.
[0108] Illustration 10 is the aluminum alloy product of any
preceding or subsequent illustration, wherein at least about 36% of
the iron-containing intermetallic particles present in the aluminum
alloy product have an equivalent circular diameter of about 3 .mu.m
or less.
[0109] Illustration 11 is the aluminum alloy product of any
preceding or subsequent illustration, wherein at least about 50% of
the iron-containing intermetallic particles present in the aluminum
alloy product have an equivalent circular diameter of about 3 .mu.m
or less.
[0110] Illustration 12 is the aluminum alloy product of any
preceding or subsequent illustration, wherein at least about 75% of
the iron-containing intermetallic particles present in the aluminum
alloy product have an equivalent circular diameter of about 3 .mu.m
or less.
[0111] Illustration 13 is the aluminum alloy product of any
preceding or subsequent illustration, wherein at least about 36% of
the iron-containing intermetallic particles comprise
.alpha.-AlFe(Mn,Cr)Si intermetallic particles.
[0112] Illustration 14 is the aluminum alloy product of any
preceding or subsequent illustration, wherein at least about 50% of
the iron-containing intermetallic particles comprise
.alpha.-AlFe(Mn,Cr)Si intermetallic particles.
[0113] Illustration 15 is the aluminum alloy product of any
preceding or subsequent illustration, wherein at least about 80% of
the iron-containing intermetallic particles comprise
.alpha.-AlFe(Mn,Cr)Si intermetallic particles.
[0114] Illustration 16 is the aluminum alloy product of any
preceding or subsequent illustration, wherein a volume fraction of
a cube textural component in the aluminum alloy product comprises
at least about 12%.
[0115] Illustration 17 is the aluminum alloy product of any
preceding or subsequent illustration, wherein the aluminum alloy
product comprises a total elongation of at least about 32%.
[0116] Illustration 18 is the aluminum alloy product of any
preceding or subsequent illustration, wherein the aluminum alloy
product comprises an automobile body part.
[0117] Illustration 19 is a method of producing an aluminum alloy
product, comprising: casting an aluminum alloy according to any
preceding or subsequent illustration to produce a cast aluminum
alloy article; homogenizing the cast aluminum alloy article to
produce a homogenized cast aluminum alloy article; hot rolling and
cold rolling the homogenized cast aluminum alloy article to produce
a final gauge aluminum alloy product; and solution heat treating
the final gauge aluminum alloy product.
[0118] Illustration 20 is the method of any preceding or subsequent
illustration, wherein the homogenizing is performed at a
homogenization temperature of from about 530.degree. C. to about
570.degree. C.
[0119] Illustration 21 is the method of any preceding illustration,
wherein the aluminum alloy in the casting comprises a recycled
content in an amount of at least about 40 wt. %.
[0120] The following examples will serve to further illustrate the
present invention without, however, constituting any limitation
thereof. On the contrary, it is to be clearly understood that
resort may be had to various embodiments, modifications, and
equivalents thereof which, after reading the description herein,
may suggest themselves to those skilled in the art without
departing from the spirit of the invention.
Examples
Example 1: Properties of the Aluminum Alloy Product
[0121] Aluminum alloy products were prepared having the
compositions as shown in Table 4:
TABLE-US-00004 TABLE 4 Alloy Si Fe Cu Mn Mg Ti Zn Cr Alloy 1 1.33
0.26 0.12 0.057 0.31 0.017 0.006 0.025 Alloy 2 1.34 0.14 0.11 0.056
0.30 0.018 0.015 0.015 Alloy 3 0.79 0.23 0.10 0.074 0.63 0.019
0.008 0.036 Alloy 4 0.62 0.23 0.12 0.076 0.65 0.023 0.008 0.034
[0122] In Table 4, all values are weight percent (wt. %) of the
whole. The alloys can contain up to 0.15 wt. % total impurities and
the remainder is aluminum. Alloy 1 is a highly recyclable aluminum
alloy as described herein, containing 0.26 wt. % Fe and 0.025 wt. %
Cr. Alloy 2, Alloy 3, and Alloy 4 are comparative 6xxx series
aluminum alloys.
[0123] Alloy 1 and Alloy 2 were each processed by a method without
a batch inter-annealing step (referred to herein as "no BA"), with
a batch inter-annealing step (referred to herein as "BA"), and by a
process with a coil cooling step (referred to herein as "CC"). FIG.
1A is a schematic depicting a processing method 100 employed
herein. Alloy 1 and Alloy 2 were direct chill cast to provide an
ingot 110. The ingot 110 was subjected to a homogenization step as
described above. The ingot 110 was then subjected to hot rolling in
a reversing mill to break down the ingot 110. After break down, the
ingot 110 was further subjected to hot rolling in a tandem mill to
provide an intermediate gauge aluminum alloy product. The
intermediate gauge aluminum alloy product was further subjected to
cold rolling in a cold mill to provide a final gauge aluminum alloy
product.
[0124] FIG. 1B is a schematic depicting a second processing method
150 including a batch inter-annealing step employed herein. Alloy 1
and Alloy 2 were each direct chill cast to provide an ingot 110.
The ingot 110 was subjected to a homogenization step as described
above. The ingot 110 was then subjected to hot rolling in a
reversing mill to break down the ingot 110. After break down, the
ingot 110 was further subjected to hot rolling in a tandem mill to
provide an intermediate gauge aluminum alloy product. The
intermediate gauge aluminum alloy product was further subjected to
cold rolling in a cold mill. Alloy 1 and Alloy 2 were coiled and
annealed in a furnace in a batch inter-annealing step as described
above. After batch inter-annealing, Alloy 1 and Alloy 2 were
further cold rolled to the final gauge.
[0125] FIG. 1C is a schematic depicting a third processing method
175 employed herein. Alloy 3 and Alloy 4 were each direct chill
cast to provide an ingot 110. The ingot 110 was subjected to a
homogenization step as described above. The ingot 110 was then
subjected to hot rolling in a reversing mill to break down the
ingot 110. After break down, the ingot 110 was further subjected to
hot rolling in a tandem mill to provide an intermediate gauge
aluminum alloy product. After hot rolling, the intermediate gauge
aluminum alloy product was coiled and the aluminum alloy
intermediate gauge product coil was allowed to cool to room
temperature. The intermediate gauge aluminum alloy product was
further subjected to cold rolling in a cold mill to provide a final
gauge aluminum alloy product.
[0126] FIG. 2 is a graph showing the yield strengths of test
samples taken from Alloy 1, Alloy 2, Alloy 3, and Alloy 4. Tensile
properties were evaluated in three directions including
longitudinal (referred to as "L"), transverse (referred to as "T"),
and diagonal (referred to as "D"), all with respect to the rolling
direction during processing. Alloy 1 and Alloy 2 were processed
according to the processing method of FIG. 1A without a batch
inter-annealing step during cold rolling ("no BA") and also
according to the processing method of FIG. 1B including the batch
inter-annealing step during cold rolling ("BA") to provide Alloy 1
and Alloy 2 in a T4 temper. Alloy 3 and Alloy 4 were processed via
the processing method of FIG. 1C with a coil cooling step before
cold rolling ("CC"). In FIG. 2, the tensile properties are shown in
sets based on the direction (i.e., L, T, or D). The first histogram
bar for each set represents Alloy 1 processed without batch
annealing ("Alloy 1 No BA"), the second histogram bar for each set
represents Alloy 2 processed without batch annealing ("Alloy 2 No
BA"), the third histogram bar for each set represents Alloy 1
processed with batch annealing ("Alloy 1 BA"), the fourth histogram
bar for each set represents Alloy 2 processed with batch annealing
("Alloy 2 BA"), the fifth histogram bar for each set represents
Alloy 3 processed according to the coil cooling method ("Alloy 3
CC"), and the sixth histogram bar for each set represents Alloy 4
processed according to the coil cooling method ("Alloy 4 CC"). As
shown in FIG. 2, the yield strengths of both Alloy 1 and Alloy 2 in
T4 temper ranged from 105 MPa to 125 MPa irrespective of tensile
test direction or processing method, demonstrating isotropic
tensile properties. Additionally, Alloy 1 exhibited excellent yield
strength, thus demonstrating a recyclable, highly formable aluminum
alloy having ample strength for various automotive applications
(e.g., structural parts, aesthetic parts, and/or any combination
thereof).
[0127] FIG. 3 is a graph showing the ultimate tensile strength of
test samples taken from Alloy 1, Alloy 2, Alloy 3, and Alloy 4.
Preparation, processing and testing were performed as in the
example of FIG. 2. In FIG. 3, the tensile properties are shown in
sets based on the direction (i.e., L, T, or D). The first histogram
bar for each set represents Alloy 1 processed without batch
annealing ("Alloy 1 No BA"), the second histogram bar for each set
represents Alloy 2 processed without batch annealing ("Alloy 2 No
BA"), the third histogram bar for each set represents Alloy 1
processed with batch annealing ("Alloy 1 BA"), the fourth histogram
bar for each set represents Alloy 2 processed with batch annealing
("Alloy 2 BA"), the fifth histogram bar for each set represents
Alloy 3 processed according to the coil cooling method ("Alloy 3
CC"), and the sixth histogram bar for each set represents Alloy 4
processed according to the coil cooling method ("Alloy 4 CC"). As
shown in FIG. 3, Alloy 1 exhibited excellent ultimate tensile
strength, thus demonstrating a recyclable, highly formable aluminum
alloy having ample strength for various automotive
applications.
[0128] FIG. 4 is a graph showing the uniform elongation of test
samples taken from Alloy 1, Alloy 2, Alloy 3, and Alloy 4.
Formability properties were evaluated in three directions including
longitudinal (referred to as "L"), transverse (referred to as "T"),
and diagonal (referred to as "D"), all with respect to the rolling
direction during processing. Alloy 1 and Alloy 2 were processed
according to the methods depicted in FIGS. 1A and 1B, as described
above, and Alloy 3 and Alloy 4 were processed according to the
method depicted in FIG. 1C, as described above with a coil cooling
step before cold rolling ("CC"). In FIG. 4, the tensile properties
are shown in sets based on the direction (i.e., L, T, or D). The
first histogram bar for each set represents Alloy 1 processed
without batch annealing ("Alloy 1 No BA"), the second histogram bar
for each set represents Alloy 2 processed without batch annealing
("Alloy 2 No BA"), the third histogram bar for each set represents
Alloy 1 processed with batch annealing ("Alloy 1 BA"), the fourth
histogram bar for each set represents Alloy 2 processed with batch
annealing ("Alloy 2 BA"), the fifth histogram bar for each set
represents Alloy 3 processed according to the coil cooling method
("Alloy 3 CC"), and the sixth histogram bar for each set represents
Alloy 4 processed according to the coil cooling method ("Alloy 4
CC"). As shown in FIG. 4, Alloy 1 exhibited greater elongation in
each direction (L, T, and D) than Alloy 2 and Alloy 4.
[0129] FIG. 5 is a graph showing the total elongation of test
samples taken from Alloy 1, Alloy 2, Alloy 3, and Alloy 4. Alloy 1
and Alloy 2 were processed according to the methods described above
and depicted in FIGS. 1A and 1B, respectively, and Alloy 3 and
Alloy 4 were processed according to the method depicted in FIG. 1C,
as described above, with a coil cooling step before cold rolling
("CC"). In FIG. 5, the tensile properties are shown in sets based
on the direction (i.e., L, T, or D). The first histogram bar for
each set represents Alloy 1 processed without batch annealing
("Alloy 1 No BA"), the second histogram bar for each set represents
Alloy 2 processed without batch annealing ("Alloy 2 No BA"), the
third histogram bar for each set represents Alloy 1 processed with
batch annealing ("Alloy 1 BA"), the fourth histogram bar for each
set represents Alloy 2 processed with batch annealing ("Alloy 2
BA"), the fifth histogram bar for each set represents Alloy 3
processed according to the coil cooling method ("Alloy 3 CC"), and
the sixth histogram bar for each set represents Alloy 4 processed
according to the coil cooling method ("Alloy 4 CC"). As shown in
FIG. 5, the total elongations of both Alloy 1 and Alloy 2 in T4
temper were between 26-32% irrespective of the tensile test
direction or processing method, showing the isotropic properties of
Alloy 1 and Alloy 2. Additionally, Alloy 1 exhibited higher
formability than Alloy 2 and Alloy 4, and comparable formability to
Alloy 3. Thus, Alloy 1 as prepared and processed herein is a highly
formable recyclable aluminum alloy.
[0130] FIG. 6 is a graph showing n-values (i.e., increase in
strength after deformation) for Alloy 1, Alloy 2, Alloy 3, and
Alloy 4, each prepared and processed as described above. In FIG. 6,
the n-values are shown in sets based on the direction (i.e., L, T,
or D). The first histogram bar for each set represents Alloy 1
processed without batch annealing ("Alloy 1 No BA"), the second
histogram bar for each set represents Alloy 2 processed without
batch annealing ("Alloy 2 No BA"), the third histogram bar for each
set represents Alloy 1 processed with batch annealing ("Alloy 1
BA"), the fourth histogram bar for each set represents Alloy 2
processed with batch annealing ("Alloy 2 BA"), the fifth histogram
bar for each set represents Alloy 3 processed according to the coil
cooling method ("Alloy 3 CC"), and the sixth histogram bar for each
set represents Alloy 4 processed according to the coil cooling
method ("Alloy 4 CC"). As shown in FIG. 6, Alloy 1 and Alloy 2
samples subjected to the method of FIG. 1A without the batch
inter-annealing step exhibited higher n-values, and thus improved
forming ability. Additionally, Alloy 1 exhibited isotropic
properties having equivalent n-values regardless of testing
direction (e.g., L, T, and D).
[0131] FIG. 7 is a graph showing r-values (i.e., anisotropy) for
Alloy 1, Alloy 2, Alloy 3, and Alloy 4, each prepared and processed
as described above. In FIG. 7, the r-values are shown in sets based
on the direction (i.e., L, T, or D). The first histogram bar for
each set represents Alloy 1 processed without batch annealing
("Alloy 1 No BA"), the second histogram bar for each set represents
Alloy 2 processed without batch annealing ("Alloy 2 No BA"), the
third histogram bar for each set represents Alloy 1 processed with
batch annealing ("Alloy 1 BA"), the fourth histogram bar for each
set represents Alloy 2 processed with batch annealing ("Alloy 2
BA"), the fifth histogram bar for each set represents Alloy 3
processed according to the coil cooling method ("Alloy 3 CC"), and
the sixth histogram bar for each set represents Alloy 4 processed
according to the coil cooling method ("Alloy 4 CC"). As shown in
the graph, Alloy 1 processed via the method of FIG. 1B (including
the batch inter-annealing step) exhibited r-values greater than 0.5
in all three directions (e.g., longitudinal, transverse, and
diagonal.
[0132] FIG. 8 is a graph showing average r-values for Alloys 1, 2,
3, and 4. The first histogram bar represents Alloy 1 processed
without batch annealing ("Alloy 1 No BA"), the second histogram bar
represents Alloy 2 processed without batch annealing ("Alloy 2 No
BA"), the third histogram bar represents Alloy 1 processed with
batch annealing ("Alloy 1 BA"), the fourth histogram bar represents
Alloy 2 processed with batch annealing ("Alloy 2 BA"), the fifth
histogram bar represents Alloy 3 processed according to the coil
cooling method ("Alloy 3 CC"), and the sixth histogram bar
represents Alloy 4 processed according to the coil cooling method
("Alloy 4 CC"). As shown in FIG. 8, Alloy 1 and Alloy 2 prepared
according to the process of FIG. 1B (including batch
inter-annealing) provided lower r-values than alloys processed
according to the process of FIG. 1A (without the batch
inter-annealing step). Alloys 1 and 2 exhibited similar r-values
regardless of processing route.
[0133] FIG. 9 is a graph showing the change in yield strength after
paint baking for Alloy 1 and Alloy 2 prepared and processed
according to the methods described above in the examples of FIG. 1A
and FIG. 1B, and Alloy 3 and Alloy 4 prepared and processed
according to the methods described above in the example of FIG. 1C.
After processing, paint baking was performed by applying a 2%
strain and a subsequent thermal treatment by heating to 185.degree.
C. and maintaining the sample at this temperature for 20 minutes.
In FIG. 9, the change in yield strength values are shown in sets
based on the direction (i.e., L, T, or D). The first histogram bar
for each set represents Alloy 1 processed without batch annealing
("Alloy 1 No BA"), the second histogram bar for each set (if
present) represents Alloy 2 processed without batch annealing
("Alloy 2 No BA"), the third histogram bar for each set represents
Alloy 1 processed with batch annealing ("Alloy 1 BA"), the fourth
histogram bar for each set represents Alloy 2 processed with batch
annealing ("Alloy 2 BA"), the fifth histogram bar for each set
represents Alloy 3 processed according to the coil cooling method
("Alloy 3 CC"), and the sixth histogram bar for each set represents
Alloy 4 processed according to the coil cooling method ("Alloy 4
CC"). As shown in FIG. 9, the yield strength of Alloy 1 and Alloy 2
increased to 190-220 MPa by employing the additional straining and
thermal treatment. Additionally, no significant difference in paint
bake response was observed between Alloy 1 and Alloy 2 regardless
of Fe content (Alloy 1 having 0.26 wt. % Fe and Alloy 2 having 0.16
wt. % Fe). Further, Si in aluminum alloys is known to bind with Fe
to form more Fe--constituent particles and reduce the paint bake
response, which is not shown in Alloy 1.
[0134] FIG. 10 is a graph showing the bendability of Alloy 1 and
Alloy 2 prepared and processed according to the process of FIG. 1A
and subjected to the VDA 238-100 three-point bend test. Prior to
bend testing, Alloy 1 and Alloy 2 were subjected to a 10% strain in
the transverse direction. As shown in the graph, Alloy 1 and Alloy
2, having significantly different Fe content, exhibited similar
bendability. An increase in Fe content can adversely affect
formability (e.g., bending); however, due to added Cr,
Fe-containing intermetallic particles exhibited a lower aspect
ratio and reduced average equivalent circular diameter, providing
excellent formability.
[0135] FIG. 11 is a graph showing the bendability of Alloy 1 and
Alloy 2 prepared and processed according to the process of FIG. 1B,
and Alloy 4 prepared and processed according to the process of FIG.
1C, all three of which were subjected to the VDA 238-100
three-point bend test. Prior to bend testing, Alloy 1, Alloy 2, and
Alloy 4 were subjected to a 15% strain in the transverse direction.
The first histogram bar represents Alloy 1 processed with batch
annealing ("Alloy 1 BA"), the second histogram bar represents Alloy
2 processed with batch annealing ("Alloy 2 BA"), and the third
histogram bar represents Alloy 4 processed according to the coil
cooling method ("Alloy 4 CC"). As shown in the graph, Alloy 1 and
Alloy 2, having significantly different Fe content, exhibited
similar bendability. Also, Alloy 1 and Alloy 2 exhibited greater
bendability than Alloy 4.
[0136] FIG. 12 is a graph showing the deep drawability of Alloy 1
and Alloy 2 subjected to an Erichsen cupping test (DIN EN ISO
20482). As shown in the graph, Alloy 1 and Alloy 2, having a
significantly different Fe content, exhibited similar drawability.
An increase in Fe content can adversely affect formability (e.g.,
bending); however, due to added Cr, Fe-containing intermetallic
particles exhibited a lower aspect ratio and reduced average
equivalent circular diameter, providing excellent drawability.
[0137] FIG. 13A is a SEM micrograph showing that Alloy 1 processed
according to the process of FIG. 1A, as described herein, results
in iron-containing (Fe-containing) intermetallic particles having
the desired shape and distribution. As shown in the micrograph, the
aluminum alloy product as described herein had few .beta.-AlFeSi
intermetallic particles and displayed spherical Fe-containing
intermetallic particles, including .alpha.-AlFe(Mn,Cr)Si
intermetallic particles. FIG. 13B is a SEM micrograph showing that
Alloy 2 processed according to the process of FIG. 1A results in
iron-containing (Fe-containing) intermetallic particles having an
increased amount of the needle-like shaped .beta.-AlFeSi
intermetallic particles. Alloy 2 provided an aluminum alloy product
having an amount of .beta.-AlFeSi intermetallic particles that is
detrimental to the forming properties of the aluminum alloy.
[0138] FIG. 13C is a SEM micrograph showing that Alloy 1 processed
according to the process of FIG. 1B, as described herein, resulted
in smaller iron-containing (Fe-containing) intermetallic particles
compared to Alloy 1 processed according to the process of FIG. 1A
(see FIG. 13A). FIG. 13D is a SEM micrograph showing that Alloy 2
processed according to the process of FIG. 1B also resulted in
smaller iron-containing (Fe-containing) intermetallic particles
compared to Alloy 2 processed according to the process of FIG. 1B
(see FIG. 13B). FIG. 13E is a SEM micrograph showing that Alloy 3
processed according to the process of FIG. 1C exhibited more and
larger Fe-containing intermetallic particles.
[0139] FIGS. 14 and 15 are graphs showing Fe-containing
intermetallic particle size distribution and aspect ratio,
respectively. As shown in FIG. 14, Alloy 1 and Alloy 2 exhibited
similar Fe-containing intermetallic particle average size and size
distribution. In FIG. 15, Alloy 1 and Alloy 2 exhibited similar
Fe-containing intermetallic particle aspect ratio. By adding Cr,
Fe-containing intermetallic particles exhibited a lower aspect
ratio and reduced average equivalent circular diameter by forming
.alpha.-AlFe(Mn,Cr)Si intermetallic particles during processing.
Alloy 3 exhibited smaller particle sizes and aspect ratios than
Alloy 1 and Alloy 2, attributed to the lower Si content (e.g., 0.79
wt. % Si).
[0140] FIGS. 16 and 17 are graphs showing the Fe-containing
intermetallic particle concentration distribution of .beta.-AlFeSi
intermetallic particles (labelled as ".beta.") and
.alpha.-AlFe(Mn,Cr)Si intermetallic particles (labelled as "a"). In
FIGS. 16 and 17, the first histogram bar for each set represents
Alloy 1 processed without batch annealing ("Alloy 1 No BA"), the
second histogram bar for each set represents Alloy 2 processed
without batch annealing ("Alloy 2 No BA"), the third histogram bar
for each set represents Alloy 1 processed with batch annealing
("Alloy 1 BA"), the fourth histogram bar for each set represents
Alloy 2 processed with batch annealing ("Alloy 2 BA"), and the
fifth histogram bar for each set represents Alloy 3 processed
according to the coil cooling method ("Alloy 3 CC"). As shown in
FIG. 16, Alloy 1 exhibited a greater volume fraction of
.alpha.-AlFe(Mn,Cr)Si intermetallic particles compared to Alloy 2.
Similarly, as shown in FIG. 17, Alloy 1 exhibited a greater number
density of .alpha.-AlFe(Mn,Cr)Si intermetallic particles compared
to Alloy 2. By adding Cr, Fe-containing intermetallic particles
exhibited a greater formation of .alpha.-AlFe(Mn,Cr)Si
intermetallic particles than .beta.-AlFeSi intermetallic particles
during processing. Additionally, Alloy 3 exhibited a smaller area
fraction and number density of Fe-containing intermetallic
particles than Alloy 1.
[0141] FIG. 18A is an OM micrograph showing that Alloy 1 processed
according to the process of FIG. 1A, as described herein, results
in an elongated grain structure. FIG. 18B is an OM micrograph
showing that Alloy 2 processed according to the process of FIG. 1A
results in an elongated grain structure. FIG. 18C is an OM
micrograph showing that Alloy 1 processed according to the process
of FIG. 1B, as described herein, results in an equiaxed grain
structure. FIG. 18D is an OM micrograph showing that Alloy 2
processed according to the process of FIG. 1B also results in an
equiaxed grain structure. FIG. 18E is an OM micrograph showing that
Alloy 3 processed according to the process of FIG. 1C exhibited a
finer, equiaxed grain structure.
[0142] FIG. 19 is a graph showing grain size distribution in Alloy
1 and Alloy 2, both processed with (FIG. 1B) and without (FIG. 1A)
a batch inter-annealing step, as well as Alloy 3 processed with a
coil cooling step (FIG. 1C). In FIG. 19, the first histogram bar
represents Alloy 1 processed without batch annealing ("Alloy 1 No
BA"), the second histogram bar represents Alloy 2 processed without
batch annealing ("Alloy 2 No BA"), the third histogram bar
represents Alloy 1 processed with batch annealing ("Alloy 1 BA"),
the fourth histogram bar represents Alloy 2 processed with batch
annealing ("Alloy 2 BA"), and the fifth histogram bar represents
Alloy 3 processed according to the coil cooling method ("Alloy 3
CC"). As shown in FIG. 19, the average grain size in Alloy 1 was
from about 28-32 .mu.m, regardless of the processing route. Alloy 2
exhibited a larger grain size when subjected to the batch
inter-annealing step. Alloy 3 exhibited a smaller as compared to
Alloy 1 and Alloy 2.
[0143] FIG. 20 is a graph showing the distribution of texture
components in Alloy 1 and Alloy 2 processed with and without a
batch inter-annealing step. The texture components included Brass
("bs"), S ("s"), Copper ("cu"), G.sub.OSS, and Cube. In FIG. 20,
the first histogram bar for each set represents Alloy 1 processed
without batch annealing ("Alloy 1 No BA"), the second histogram bar
for each set represents Alloy 2 processed without batch annealing
("Alloy 2 No BA"), the third histogram bar for each set represents
Alloy 1 processed with batch annealing ("Alloy 1 BA"), and the
fourth histogram bar for each set represents Alloy 2 processed with
batch annealing ("Alloy 2 BA"). Alloy 1 exhibited a greater amount
of the cube textural component (e.g., 16-18%) as compared to Alloy
2 (e.g., 13-15%). Samples processed without the batch
inter-annealing step exhibited a greater amount of the G.sub.OSS
textural component as compared to samples processed including the
batch inter-annealing step.
[0144] All patents, publications, and abstracts cited above are
incorporated herein by reference in their entireties. Various
embodiments of the invention have been described in fulfillment of
the various objectives of the invention. It should be recognized
that these embodiments are merely illustrative of the principles of
the present invention. Numerous modifications and adaptions thereof
will be readily apparent to those skilled in the art without
departing from the spirit and scope of the present invention as
defined in the following claims.
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