Note: Descriptions are shown in the official language in which they were submitted.
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
HIGH-STRENGTH CORROSION-RESISTANT ALUMINUM ALLOY AND METHOD OF MAKING THE SAME
FIELD
The present disclosure relates to aluminum alloys and methods of making and
processing
the same. The present disclosure further relates to aluminum alloys exhibiting
high mechanical
strength, formability, and corrosion resistance.
BACKGROUND
Recyclable aluminum alloys with high strength are desirable for improved
product
performance in many applications, including transportation (encompassing
without limitation,
e.g., trucks, trailers, trains, and marine) applications, electronics
applications, and automobile
applications. For example, a high-strength aluminum alloy in trucks or
trailers would be lighter
than conventional steel alloys, providing significant emission reductions that
are needed to meet
new, stricter government regulations on emissions. Such alloys should exhibit
high strength,
high formability, and corrosion resistance. Further, it is desirable for such
alloys to be formed
from recycled content.
However, identifying processing conditions and alloy compositions that will
provide such
an alloy, particularly with recycled content, has proven to be a challenge.
Forming alloys from
recycled content may lead to higher zinc (Zn) and copper (Cu) content Higher
Zn alloys
traditionally lack strength, and Cu-containing alloys are susceptible to
corrosion.
SUMMARY
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.
1
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Described herein are aluminum alloys comprising about 0.25 - 1.3 wt. % Si, 1.0
- 2.5 wt.
% Mg, 0.5 - 1.5 wt. % Cu, up to 0.2 wt. % Fe, up to 3.0 wt. % Zn, up to 0.15
wt. % impurities,
with the remainder as Al. In some cases, the aluminum alloys can comprise
about 0.55 - 1.1 wt.
% Si, 1.25 -2.25 wt. % Mg, 0.6 - 1.0 wt. % Cu, 0.05 -0.17 wt. % Fe, 1.5 -3.0
wt. % Zn, up to
0.15 wt % impurities, with the remainder as Al. In some cases, the aluminum
alloys can
comprise about 0.65 -1.0 wt. % Si, 1.5 -2.25 wt. % Mg, 0.6 - 1.0 wt. % Cu,
0.12 -0.17 wt. %
Fe, 2.0 - 3.0 wt. % Zn, up to 0.15 wt. % impurities, with the remainder as Al.
Optionally, the
aluminum alloys described herein can further comprise Zr and/or Mn. The Zr can
be present in
an amount of up to about 0.15 wt. % (e.g., from about 0.09 - 0.12 wt. %). The
Mn can be
present in an amount of up to about 0.5 wt, % (e.g., from about 0.05 -0.3 wt.
%).
Optionally, the ratio of Mg to Si (i.e., the Mg/Si ratio) is from about 1.5 to
1 to about 3.5
to 1. For example, the Mg/Si ratio can be from about 2.0 to Ito about 3.0 to
1. Optionally, the
ratio of Zn to the Mg/Si ratio (i.e., the Zn/(Mg/Si) ratio) is from about 0.75
to 1 to about 1.4 to 1.
For example, the Zn/(Mg/Si) ratio can be from about 0.8 to 1 to about 1.1 to
1. Optionally, the
ratio of Cu to the Zn/(Mg/Si) ratio (i.e., the Cu/[Zn/(Mg/Si)] ratio) is from
about 0.7 to 1 to about
1.4 to 1. For example, the Cul[Zn/(Mg'Si)] ratio is from about 0.8 to 1 to
about 1.1 to 1.
Also described herein are aluminum alloy products comprising the aluminum
alloy as
described herein. The aluminum alloy product can have a yield strength of at
least about 340
MPa (e.g., from about 360 MPa to about 380 MPa) in the T6 temper. The aluminum
alloy
products described herein are corrosion resistant and can have an average
intergranular corrosion
pit depth of less than about 100 pm in the T6 temper. The aluminum alloy
products also display
excellent bendability and can have an rlt (bendability) ratio of about 0.5 or
less in the T4 temper.
Optionally, the aluminum alloy product comprises one or more precipitates
selected from
the group consisting of MgZn2 Mg(Zn,Cu)2, Mg2Si, and Al4MgsSi7Cu2. The
aluminum alloy
product can comprise MgZn2 / Mg(Zn,Cu)2 in an average amount of at least about
300,000,000
particles per mm2, Mg2Si in an average amount of at least about 600,000,000
particles per mm2,
and/or A14.1VIgsSi7Cu2 in an average amount of at least about 600,000,000
particles per mm2. In
some examples, the aluminum alloy product comprises MgZn2 / Mg(Zn,Cu)2, Mg2Si,
and
Al4Mg8Si7Cu2. A ratio of Mg2Si to Al4MggSi7Cu2 can be from about 1:1 to about
1.5:1, a ratio
of Mg2Si to MgZn2 / Mg(Zn,Cu)2 can be from about 1.5:1 to about 3:1, and a
ratio of
Al4Mg8Si7Cu2 to MgZn2 / Mg(Zn,Cu)2 can be from about 1.5:1 to about 3:1.
2
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Further described herein is a method of producing an aluminum alloy. The
method
comprises casting an aluminum alloy as described herein to form an aluminum
alloy cast
product, homogenizing the aluminum alloy cast product, hot rolling the
homogenized aluminum
alloy cast product to provide a final gauge aluminum alloy, and solution heat
treating the final
gauge aluminum alloy. The method can further comprise pre-aging the final
gauge aluminum
alloy. Optionally, the aluminum alloy is cast from a molten aluminum alloy
comprising scrap
metal, such as from scrap metal containing a 6xxx series aluminum alloy, a
7xxx series
aluminum alloy, or a combination of these.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1 is a graph showing an increase in magnesium zinc precipitates with
increased
magnesium content in aluminum alloys prepared according to certain aspects of
the present
disclosure.
Figure 2 is a differential scanning calorimetry graph of an aluminum alloy
according to
certain aspects of the present disclosure.
Figure 3 is a differential scanning calorimetry graph of an aluminum alloy
according to
certain aspects of the present disclosure.
Figure 4A is a transmission electron microscope micrograph showing precipitate
types in
an aluminum alloy according to certain aspects of the present disclosure.
Figure 4B is a transmission electron microscope micrograph showing precipitate
types in
an aluminum alloy according to certain aspects of the present disclosure
Figure 5 is a graph showing precipitate composition of an aluminum alloy
according to
certain aspects of the present disclosure.
Figure 6 is a series of optical micrographs showing precipitate formation
after various
processing steps of an aluminum alloy according to certain aspects of the
present disclosure.
Figure 7 is a series of optical micrographs showing precipitate formation
after various
processing steps of an aluminum alloy according to certain aspects of the
present disclosure.
Figure 8 is a series of optical micrographs showing precipitate formation
after various
processing steps of an aluminum alloy according to certain aspects of the
present disclosure.
Figure 9 is a series of optical micrographs showing particle population and
grain structure
of an aluminum alloy according to certain aspects of the present disclosure.
3
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Figure 10 is a series of optical micrographs showing particle population and
grain
structure of an aluminum alloy according to certain aspects of the present
disclosure.
Figure ills a graph showing electrical conductivities of an aluminum alloy
according to
certain aspects of the present disclosure.
Figure 12 is a graph showing electrical conductivities of an aluminum alloy
according to
certain aspects of the present disclosure.
Figure 13 is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 14A is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 14B is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 15 is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 16A is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 16B is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 17A is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 17B is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
4
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Figure 18A is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 18B is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle) and
total elongation (open
diamond) of aluminum alloys according to certain aspects of the present
disclosure.
Figure 19 is a graph showing load displacement data from a 900 bend test of
aluminum
alloys according to certain aspects of the present disclosure.
Figure 20 is a graph showing load displacement data from a 90 bend test of
aluminum
alloys according to certain aspects of the present disclosure.
Figure 21 is a graph showing load displacement data from a 90 bend test of an
aluminum alloy according to certain aspects of the present disclosure.
Figure 22 is a series of optical micrographs showing corrosion attack in
aluminum alloys
according to certain aspects of the present disclosure.
Figure 23 is a series of optical micrographs showing corrosion attack in
aluminum alloys
according to certain aspects of the present disclosure.
Figure 24A is an optical micrograph of an aluminum alloy according to certain
aspects of
the present disclosure.
Figure 24B is an optical micrograph of an aluminum alloy according to certain
aspects of
the present disclosure.
Figure 24C is an optical micrograph of an aluminum alloy according to certain
aspects of
the present disclosure.
DETAILED DESCRIPTION
Described herein are high-strength aluminum alloys and methods of making and
processing such alloys. The aluminum alloys described herein exhibit improved
mechanical
strength, deformability, and corrosion resistance properties. In addition, the
aluminum alloys can
be prepared from recycled materials. Aluminum alloy products prepared from the
alloys
described herein include precipitates to enhance strength, such as MgZn2 /
Mg(Zn,Cu)2, Mg2Si,
and Al4Mg8Si7Cu2.
5
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Definitions and Descriptions:
The terms "invention," "the invention," "this invention" and "the present
invention" used
herein 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.
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.
As used herein, the meaning of "a," "an," or "the" includes singular and
plural references
unless the context clearly dictates otherwise.
As used herein, a plate generally has a thickness of greater than about 6 mm.
For
example, a plate may refer to an aluminum product having a thickness of
greater than 6 mm,
greater than 10 mm, greater than 15 mm, greater than 20 mm, greater than 25
mm, greater than
30 mm, greater than 35 mm, greater than 40 mm, greater than 45 mm, greater
than 50 mm, or
greater than 100 mm.
As used herein, the term "slab" indicates an alloy thickness in a range of
approximately 5
mm to approximately 50 mm. For example, a slab may have a thickness of 5 mm,
10 mm, 15
mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, or 50 mm.
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 4 mm,
5 mm, 6 mm,
7 nun, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, or 15 mm.
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 4 mm,
less than 3 mm,
less than 2 mm, less than 1 mm, less than 0.5 mm, less than 0.3 mm, or less
than 0.1 mm.
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
6
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
aluminum alloy as fabricated. An 0 condition or temper refers to an aluminum
alloy after
annealing. A T4 condition or temper refers to an aluminum alloy after solution
heat treatment
(SHT) (i.e., solutionization) followed by natural aging. A T6 condition or
temper refers to an
aluminum alloy after solution heat treatment followed by artificial aging
(AA). A T8x condition
or temper refers to an aluminum alloy after solution heat treatment, followed
by cold working
and then by artificial aging.
As used herein, terms such as "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.
As used herein, the meaning of "room temperature" can include a temperature of
from
about 15 C to about 30 C, for example about 15 C, about 16 C, about 17 CC,
about 18 C,
about 19 C, about 20 C, about 21 C, about 22 C, about 23 C, about 24 C,
about 25 C,
about 26 C, about 27 C, about 28 C, about 29 C, or about 30 C.
All ranges disclosed herein are to be understood to encompass 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.
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 Composidions
Described below are novel aluminum alloys. In certain aspects, the alloys
exhibit high
strength, high formability, and corrosion resistance. The properties of the
alloys are achieved
due to the elemental compositions of the alloys as well as the methods of
processing the alloys to
produce aluminum alloy products, including sheets, plates, and shates.
7
CA 03069499 2020-01-09
WO 2019/013744 PCT1US2017/041313
In certain aspects, for a combined effect of strengthening, formability, and
corrosion
resistance, the alloy has a Cu content of from about 0.5 wt. % to about 1.5
wt. %, a Zr content of
from 0.07 wt. % to about 0.12 wt. %, and a controlled Si to Mg ratio, as
further described below.
The alloys can have the following elemental composition as provided in Table
1:
Table 1
Element Weight Percentage (Wt. %)
Si 0.25 - 1.3
Fe 0 --- 0.2
Mn 0 - 0.5
Ma 1.0-2.5
Cu 0.5 - 1.5
Zn 0---3.0
Zr 0 - 0.15
0 - 0.05 (each)
Others
0 - 0.15 (total)
Al Remainder
In some examples, the alloys can have the following elemental composition as
provided
in Table 2.
Table 2
Element Weight Percentage (wt. %)
Si 0.55 - 1.1
Fe 0.05 - 0.17
Mn 0.05 - 0.3
Mg l.25-- 2.25
Cu 0.6 - 1.0
Zn 1.5-3.0
Zr 0.09 - 0.12
0 - 0.05 (each)
Others
0-0.15 (total)
8
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Al Remainder
In some examples, the alloys can have the following elemental composition as
provided
in Table 3.
Table 3
Element Weight Percentage (wt. %)
Si 0.65 - 1.0
Fe 0.12 - 0.17
Mn 0.05 - 0.2
Mg 1.5 2.25
Cu 0.6 - 1.0
Zn 2.0 - 3.0
Zr 0.08 - 0.11
0- 0.05 (each)
Others
0 - 0.15 (total)
Al Remainder
In some examples, the disclosed alloy includes silicon (Si) in an amount from
about 0.25
% to about 1.3 % (e.g., from about 0.55 % to about 1.1 % or from about 0.65 %
to about 1.0 %)
based on the total weight of the alloy. For example, the alloy can include
about 0.25 %, about
0.26 %, about 0.27 %, about 0.28 %, about 0.29 %, about 0.3 %, about 0.31 %,
about 0.32 %,
about 0.33 %, about 0.34 %, about 0.35 %, about 0.36 %, about 0.37 %, about
0.38 %, about
0.39 %, about 0.4 % ,0.41 %, about 0.42 %, about 0.43 %, about 0.44 %, about
0.45 %, about
0.46 %, about 0.47 %, about 0.48 %, about 0.49 %, about 0.5 %, about 0.51 %,
about 0.52 %,
about 0.53 %, about 0.54 %, about 0.55 %, about 0.56 %, about 0.57 %, about
0.58 %, about
0.59 %, about 0.6 %, about 0.61 %, about 0.62 %, about 0.63 %, about 0.64 %,
about 0.65 %,
about 0.66%, about 0.67%, about 0.68 %, about 0.69%, about 0.7%, about 0.71 %,
about 0.72
%, about 0.73 %, about 0.74 %, about 0.75 %, about 0.76 %, about 0.77 %, about
0.78 %, about
0.79 %, about 0.8 %, about 0.81 %, about 0.82 %, about 0.83 %, about 0.84 %,
about 0.85 %,
about 0.86 %, about 0.87 %, about 0.88 %, about 0.89 %, about 0.9 %, about
0.91 %, about 0.92
%, about 0.93 %, about 0.94 %, about 0.95 %, about 0.96 %, about 0.97 %, about
0.98 %, about
9
CA 03069499 2020-01-09
WO 2019/013744 PCTIUS2017/041313
0.99 %, about 1.0 %, about 1.01 %, about 1.02 %, about 1.03 %, about 1.04 %,
about 1.05 %,
about 1.06%, about 1.07%, about 1.08 %, about 1.09%, about 1.1 %, about 1.11
%, about 1.12
%, about 1.13 %, about 1.14 %, about 1.15 %, about 1.16 %, about 1.17 %, about
1.18 %, about
1.19 %, about 1.2 %, about 1.21 %, about 1.22 %, about 1.23 %, about 1.24 %,
about 1.25 %,
about 1.26 %, about 1.27 %, about 1.28 %, about 1.29 %, or about 1.3 % Si. All
percentages are
expressed in wt. %.
In some examples, the alloy described herein includes iron (Fe) in an amount
up to about
0.2 % (e.g., from about 0.05 % to about 0.17 % or from about 0.12 % to about
0.17 %) based on
the total weight of the alloy. For example, the alloy can include about 0.01
%, about 0.02 %,
about 0.03 %, about 0.04 %, about 0.05 %, about 0.06 %, about 0.07 %, about
0.08 %, about
0.09 %, about 0.1 %, about 0.11 %, about 0.12 %, about 0.13 %, about 0.14 %,
about 0.15 %,
about 0.16 %, about 0.17 %, about 0.18 %, about 0.19 %, or about 0.2 % Fe. In
some cases, Fe
is not present in the alloy (i.e., 0 %). All percentages are expressed in wt.
%.
In some examples, the alloy described herein includes manganese (Mn) in an
amount up
to about 0.5 % (e.g., from about 0.05 % to about 0.3 % or from about 0.05 % to
about 0.2 %)
based on the total weight of the alloy. For example, the alloy can include
about 0.01 %, about
0.02 %, about 0.03 %, about 0.04 %, about 0.05 %, about 0.06 %, about 0.07 %,
about 0.08 %,
about 0.09%, about 0.1 %, about 0.11 %, about 0.12%, about 0.13 %, about
0.14%, about 0.15
%, about 0.16 %, about 0.17 %, about 0.18 %, about 0.19 %, about 0.2 %, about
0.21 %, about
0.22 %, about 0.23 %, about 0.24 %, about 0.25 %, about 0.26 %, about 0.27 %,
about 0.28 %,
about 0.29%, about 0.3 %, about 0.31 %, about 0.32%, about 0.33 %, about
0.34%, about 0.35
%, about 0.36 %, about 0.37 %, about 0.38 %, about 0.39 %, about 0.4 %, about
0.41 %, about
0.42 %, about 0.43 %, about 0.44 %, about 0.45 A), about 0.46 %, about 0.47
%, about 0.48 %,
about 0.49 %, or about 0.5 % Mn. In some cases, Mn is not present in the alloy
(i.e., 0 %). All
percentages are expressed in wt. %.
In some examples, the disclosed alloy includes magnesium (Mg) in an amount
from
about 1.0 % to about 2.5 % (e.g., from about 1.25 % to about 2.25 % or from
about 1.5 % to
about 2.25 %) based on the total weight of the alloy. For example, the alloy
can include about
1.0 %, about 1.01 %, about 1.02 %, about 1.03 %, about 1.04 %, about 1.05 %,
about 1.06 %,
.. about 1.07 %, about 1.08 %, about 1.09 %, about 1.1 %, about 1.11 %, about
1.12 %, about 1.13
%, about 1.14 %, about 1.15 %, about 1.16 %, about 1.17 %, about 1.18 %, about
1.19 %, about
CA 03069499 2020-01-09
WO 2019/013744 PCT1US2017/041313
1.2 %, about 1.21 %, about 1.22 %, about 1.23 %, about 1.24 %, about 1.25 %,
about 1.26 %,
about 1.27%, about 1.28%, about 1.29%, about 1.3 %, about 1.31 %, about 1.32%,
about 1.33
%, about 1.34 %, about 1.35 %, about 1.36%, about 1.37 %, about 1.38 %, about
1.39 %, about
1.4 %, about 1.41 %, about 1.42 %, about 1.43 %, about 1.44 %, about 1.45 %,
about 1.46 %,
about 1.47%, about 1.48%, about 1.49%, about 1.5 %, about 1.51 %, about 1.52%,
about 1.53
%, about 1.54%, about 1.55 %, about 1.56%, about 1.57%, about 1.58 %, about
1.59%, about
1.6 %, about 1.61 %, about 1.62 %, about 1.63 %, about 1.64 %, about 1.65 %,
about 1.66 %,
about 1.67%, about 1.68%, about 1.69%, about 1.7%, about 1.71 %, about 1.72%,
about 1.73
%, about 1.74 %, about 1.75 OA, about 1.76%, about 1.77 %, about 1.78 %, about
1.79 %, about
1.8 %, about 1.81 %, about 1.82 %, about 1.83 %, about 1.84 94), about 1.85 %,
about 1.86 %,
about 1.87%, about 1.88%, about 1.89%, about 1.9%, about 1.91 %, about 1.92%,
about 1.93
%, about 1.94%, about 1.95 %, about 1.96%, about 1.97%, about 1.98 %, about
1.99%, about
2.0 %, about 2.01 %, about 2.02 %, about 2.03 %, about 2.04 %, about 2.05 %,
about 2.06 %,
about 2.07 %, about 2.08 %, about 2.09 %, about 2.1 %, about 2.11 %, about
2.12 %, about 2.13
%, about 2.14%, about 2.15 %, about 2.16%, about 2.17%, about 2.18 %, about
2.19%, about
2.2 %, about 2.21 %, about 2.22 %, about 2.23 %, about 2.24 %, about 2.25 %,
about 2.26 %,
about 2.27 %, about 2.28 %, about 2.29 %, about 2.3 %, about 2.31 %, about
2.32 %, about 2.33
%, about 2.34 %, about 2.35 %, about 2.36 %, about 2.37 %, about 2.38 %, about
2.39 %, about
2.4 %, about 2.41 %, about 2.42 A), about 2.43 %, about 2.44 %, about 2.45 %,
about 2.46 %,
about 2.47 %, about 2.48 %, about 2.49 %, or about 2.5 % Mg. All percentages
are expressed in
wt. %.
In some examples, the disclosed alloy includes copper (Cu) in an amount from
about 0.5
% to about 1.5 % (e.g., from about 0.6 % to about 1.0 % or from about 0.6 % to
about 0.9 %)
based on the total weight of the alloy. For example, the alloy can include
about 0.5 %, about
0.51 %, about 0.52 %, about 0.53 %, about 0.54 %, about 0.55 %, about 0.56 %,
about 0.57 %,
about 0.58 %, about 0.59 %, about 0.6 %, about 0.61 %, about 0.62 %, about
0.63 %, about 0.64
%, about 0.65 %, about 0.66 %, about 0.67 %, about 0.68 %, about 0.69 %, about
0.7 %, about
0.71 %, about 0.72 %, about 0.73 %, about 0.74 %, about 0.75 %, about 0.76 %,
about 0.77 %,
about 0.78 %, about 0.79 %, about 0.8 %, about 0.81 %, about 0.82 %, about
0.83 %, about 0.84
cY0, about 0.85 %, about 0.86 %, about 0.87 %, about 0.88 %, about 0.89 %,
about 0.9 %, about
0.91 %, about 0.92 %, about 0.93 %, about 0.94 %, about 0.95 %, about 0.96 %,
about 0.97 %,
11
CA 03069499 2020-01-09
WO 2019/013744 PCT1US2017/041313
about 0.98 %, about 0.99%, about 1.0 %, about 1.01 %, about 1.02 %, about 1.03
%, about 1.04
%, about 1.05 %, about 1.06 %, about 1.07 %, about 1.08 %, about 1.09 %, about
1.1 %, about
1.11 %, about 1.12 %, about 1.13 %, about 1.14 %, about 1.15 %, about 1.16 %,
about 1.17 %,
about 1.18%, about 1.19%, about 1.2%, about 1.21 %, about 1.22%, about 1.23 %,
about 1.24
%, about 1.25 %, about 1.26 %, about 1.27 %, about 1.28 %, about 1.29 %, about
1.3 %, about
1.31 %, about 1.32 %, about 1.33 %, about 1.34 %, about 1.35 %, about 1.36 %,
about 1.37 %,
about 1.38 %, about 1.39 %, about 1.4 %, about 1.41 %, about 1.42 %, about
1.43 %, about 1.44
%, about 1.45 %, about 1.46 %, about 1.47 %, about 1.48 %, about 1.49 %, or
about 1.5 % Cu.
All percentages are expressed in wt. %.
In some examples, the alloy described herein includes zinc (Zn) in an amount
up to about
3.0 % (e.g., from about 1.0 % to about 3.0 %, from about 1.5 % to about 3.0 %,
or from about
2.0 % to about 3.0 %) based on the total weight of the alloy. For example, the
alloy can include
about 0.01 %, about 0.02 %, about 0.03 %, about 0.04 %, about 0.05 %, about
0.06 %, about
0.07 %, about 0.08 %, about 0.09 %, about 0.1 %, about 0.11 %, about 0.12 %,
about 0.13 /0,
about 0.14%, about 0.15 %, about 0.16%, about 0.17%, about 0.18 %, about
0.19%, about 0.2
%, about 0.21 %, about 0.22 %, about 0.23 %, about 0.24 %, about 0.25 %, about
0.26 %, about
0.27 %, about 0.28 %, about 0.29 %, about 0.3 %, about 0.31 %, about 0.32 %,
about 0.33 %,
about 0.34 %, about 0.35 %, about 0.36 %, about 0.37 %, about 0.38 %, about
0.39 /0, about 0.4
%, about 0.41 %, about 0.42 %, about 0.43 %, about 0.44 %, about 0.45 %, about
0.46 %, about
0.47 %, about 0.48 %, about 0.49 %, about 0.5 %, about 0.51 %, about 0 52 A),
about 0.53 %,
about 0.54 %, about 0.55 %, about 0.56 %, about 0.57 %, about 0.58 %, about
0.59 %, about 0.6
%, about 0.61 %, about 0.62 %, about 0.63 %, about 0.64 %, about 0.65 %, about
0.66 %, about
0.67 %, about 0.68 %, about 0.69 %, about 0.7 %, about 0.71 %, about 0.72 %,
about 0.73 %,
about 0.74 %, about 0.75 %, about 0.76 %, about 0.77 %, about 0.78 %, about
0.79 %, about 0.8
%, about 0.81 %, about 0.82 %, about 0.83 %, about 0.84 %, about 0.85 %, about
0.86 %, about
0.87 %, about 0.88 %, about 0.89 %, about 0.9 %, about 0.91 A), about 0.92 %,
about 0.93 %,
about 0.94 %, about 0.95 %, about 0.96 %, about 0.97%, about 0.98 %, about
0.99 %, about 1.0
%, about 1.01 %, about 1.02 %, about 1.03 %, about 1.04 %, about 1.05 %, about
1.06 %, about
1.07 %, about 1.08 %, about 1.09 %, about 1.1 %, about 1.11 %, about 1.12 %,
about 1.13 %,
about 1.14 %, about 1.15 %, about 1.16 %, about 1.17 %, about 1.18 %, about
1.19 %, about 1.2
%, about 1.21 %, about 1.22%, about 1.23 %, about 1.24%, about 1.25 %, about
1.26%, about
12
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
1.27 %, about 1.28 %, about 1.29 %, about 1.3 %, about 1.31 A), about 1.32 %,
about 1.33 %,
about 1.34%, about 1.35 %, about 1.36%, about 1.37%, about 1.38 %, about
1.39%, about 1.4
%, about 1.41 %, about 1.42 %, about 1.43 %, about 1.44 %, about 1.45 %, about
1.46 %, about
1.47 %, about 1.48 %, about 1.49 %, about 1.5 %, about 1.51 %, about 1.52 %,
about 1.53 %,
about 1.54%, about 1.55 %, about 1.56%, about 1.57 %, about 1.58 %, about
1.59%, about 1.6
%, about 1.61 %, about 1.62%, about 1.63 %, about 1.64%, about 1.65 %, about
1.66%, about
1.67 %, about 1.68 %, about 1.69 %, about 1.7 %, about 1.71 %, about 1.72 %,
about 1.73 %,
about 1.74%, about 1.75 %, about 1.76%, about 1.77%, about 1.78 %, about
1.79%, about 1.8
%, about 1.81 %, about 1.82 %, about 1.83 %, about 1.84 %, about 1.85 %, about
1.86 %, about
1.87 %, about 1.88 %, about 1.89 %, about 1.9 %, about 1.91 110, about 1.92
(!lo, about 1.93 %,
about 1.94 %, about 1.95 %, about 1.96 %, about 1.97 %, about 1.98 %, about
1.99 %, about 2.0
%, about 2.01 %, about 2.02 %, about 2.03 %, about 2.04 %, about 2.05 %, about
2.06 %, about
2.07 %, about 2.08 %, about 2.09 %, about 2.1 %, about 2.11 %, about 2.12 %,
about 2.13 %,
about 2.14%, about 2.15 %, about 2.16%, about 2.17%, about 2.18%, about 2.19%,
about 2.2
%, about 2.21 %, about 2.22 %, about 2.23 %, about 2.24 %, about 2.25 %, about
2.26 /0, about
2.27 %, about 2.28 %, about 2.29 %, about 2.3 %, about 2.31 %, about 2.32 %,
about 2.33 %,
about 2.34 %, about 2.35 %, about 2.36 %, about 2.37 %, about 2.38 %, about
2.39 %, about 2.4
%, about 2.41 %, about 2.42 %, about 2.43 %, about 2.44 %, about 2.45 %, about
2.46 %, about
2.47 %, about 2.48 %, about 2.49 %, about 2.5 %, about 2.51 %, about 2.52 %,
about 2.53 %,
about 2.54 %, about 2.55 %, about 2.56 %, about 2.57 %, about 2.58 %, about
2.5943/0, about 2.6
%, about 2.61 %, about 2.62 %, about 2.63 '34), about 2.64 %, about 2.65 %,
about 2.66 %, about
2.67 %, about 2.68 %, about 2.69 %, about 2.7 %, about 2.71 %, about 2.72 %,
about 2.73 %,
about 2.74 %, about 2.75 %, about 2.76 %, about 2.77 %, about 2.78 %, about
2.79 %, about 2.8
%, about 2.81 %, about 2.82 %, about 2.83 %, about 2.84 %, about 2.85 %, about
2.86 %, about
2.87 %, about 2.88 %, about 2.89 %, about 2.9 %, about 2.91 %, about 2.92 %,
about 2.93 %,
about 2.94 %, about 2.95 %, about 2.96 %, about 2.97 %, about 2.98 %, about
2.99 %, or about
3.0 % Zn. In some cases, Zn is not present in the alloy (i.e., 0 %). All
percentages are expressed
in wt. %.
Optionally, zirconium (Zr) can be included in the alloys described herein. In
some
examples, the alloy includes Zr in an amount up to about 0.15 % (e.g., from
about 0.07 % to
about 0.15 %, from about 0.09 % to about 0.12 %, or from about 0.08 % to about
0.11 %) based
13
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
on the total weight of the alloy. For example, the alloy can include about
0.01 %, about 0.02 %,
about 0.03 %, about 0.04 %, about 0.05 %, about 0.06 %, about 0.07 %, about
0.08 %, about
0.09%, about 0.1 %, about 0.11 %, about 0.12 %, about 0.13 %, about 0.14 %, or
about 0.15 %
Zr. In some examples, Zr is not present in the alloys (i.e., 0 %). All
percentages are expressed in
wt. %. In certain aspects, Zr is added to the above-described compositions to
form (A1,Si)Zr
dispersoids (D022/13023 dispersoids) and/or AbZr dispersoids (L12
dispersoids).
Optionally, the alloy compositions can further include other minor elements,
sometimes
referred to as impurities, in amounts of about 0.05 % or below, 0.04 % or
below, 0.03 % or
below, 0.02 % or below, or 0.01 % or below each. These impurities may include,
but are not
limited to, Ga, V, Ni, Sc, Ag, B, Bi, Li, Pb, Sn, Ca, Cr, Ti, Hf, Sr, or
combinations thereof.
Accordingly, Ga, V, Ni, Sc, Ag, B, Bi, Li, Pb, Sn, Ca, Cr, Ti, Hf, or Sr may
be present in an
alloy in amounts of 0.05 % or below, 0.04 % or below, 0.03 % or below, 0.02 %
or below, or
0.01 % or below. In certain aspects, the sum of all impurities does not exceed
0.15 % (e.g., 0.1
%). All percentages are expressed in wt. %. In certain aspects, the remaining
percentage of the
alloy is aluminum.
Suitable exemplary alloys can include, for example, 1.0 % Si, 2.0 % - 2.25 %
Mg, 0.6 %
- 0.7 % Cu, 2.5 % - 3.0 '34) Zn, 0.07 - 0.10 % Mn, 0.14 - 0.17 % Fe, 0.09 -
0.10 % Zr, and up to
0.15 % total impurities, with the remainder Al. In some cases, suitable
exemplary alloys can
include 0.55 % -0.65 % Si, 1.5 % Mg, 0.7% - 0.804) Cu, 1.55 % Zn, 0.14 - 0.15
% Mn, 0.16 -
0.18 % Fe, and up to 0.15 % total impurities, with the remainder Al. In some
cases, suitable
exemplary alloys can include 0.65 % Si, 1.5 % Mg, 1.0 A) Cu, 2.0 % -3.0 % Zn,
0.14 - 0.15 %
Mn, 0.17 % Fe, and up to 0.15 % total impurities, with the remainder Al.
Alloy Microstructure and Properties
In certain aspects, the Cu, Mg, and Si ratios and Zn content are controlled to
enhance
corrosion resistance, strength, and formability. The Zn content can control
corrosion
morphology as described below, by, for example, inducing pitting corrosion and
suppressing
intergranular corrosion (IGC).
In some examples, a ratio of Mg to Si (also referred to herein as Mg/Si ratio)
can be from
about 1.5:1 to about 3.5:1 (e.g., from about 1.75:1 to about 3.0:1 or from
about 2.0:1 to about
3.0:1). For example, the Mg/Si ratio can be about 1.5:1, about 1.6:1, about
1.7:1, about 1.8:1,
14
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
about 1.9:1, about 2.0:1, about 2.1: 1 , about 2.2:1, about 2.3:1, about 2.4:
1 , about 2.5:1, about
2.6: 1 , about 2.7:1, about 2.8:1, about 2.9:1, about 3.0:1, about 3.1:1,
about 3.2:1, about 3.3:1,
about 3.4:1, about 3.5:1, about 3.6:1, about 3.7:1, about 3.8:1, about 3.9:1,
or about 4.0:1. In
some non-limiting examples, an aluminum alloy having an Mg/Si ratio of about
1.5:1 to about
3.5:1 (e.g., from about 2.0:1 to about 3.0:1) can exhibit high strength and
increased formability.
In some non-limiting examples, an aluminum alloy having an Mg/Si ratio of
about 2.0:1
¨ 3.0:1 and a Zn content of about 2.5 wt. % ¨ about 3.0 wt. % can exhibit
suppression of IGC
typically observed in aluminum alloys having Mg and Si as predominant alloying
elements, and
instead can induce pitting corrosion. In some cases, pitting corrosion can be
favorable over IGC
due to a limited attack depth, as IGC can occur along grain boundaries and
propagate deeper into
the aluminum alloy than pitting corrosion. In some non-limiting examples, a
ratio of Zn to the
ratio of Mg/Si (i.e., the Zn/(Mg/Si) ratio) can be from about 0.75:1 to about
1.4:1 (e.g., from
about 0.8:1 to about 1.1:1). For example, the Zn/(Mg/Si) ratio can be about
0.75:1, about 0.8:1,
about 0.85:1, about 0.9:1, about 0.95:1, about 1.0:1, about 1.05:1, about
1.1:1, about 1.15:1,
about 1.2:1, about 1.25:1, about 1.3:1, about 1.35:1, or about 1.4:1.
In some still further non-limiting examples, a ratio of Cu to the Zn/(Mg/Si)
ratio (i.e., the
Cu/[Zn/(Mg/Si)] ratio) can be from about 0.7:1 to about 1.4:1 (e.g., the
CuI[ZnI(Mg/Si)] ratio
can be about 0.8:1 to about 1.1:1). For example, the ratio of Cui[Zni(Mg/Si)]
can be about 0.7:1,
about 0.75:1, about 0.8:1, about 0.85:1, about 0.9:1, about 0.95:1, about
1.0:1, about 1.05.1,
about 1.1:1, about 1.15:1, about 1.2:1, about 1 25:1, about 1.3:1, about
1.35:1, or about 1.4.1. In
some non-limiting examples, the ratio of Cul[Zn/(Mg/Si)] can provide high
strength, high
deformability, and high corrosion resistance.
In certain aspects, Cu, Si, and Mg can form precipitates in the alloy to
result in an alloy
with higher strength and enhanced corrosion resistance. These precipitates can
form during the
aging processes, after solution heat treatment. The Mg and Cu content can
provide precipitation
of an 114/g phase or M phase (e.g., MgZn2 / Mg(Zn,Cu)2), resulting in
precipitates that can
increase strength in the aluminum alloy. During the precipitation process,
metastable Guinier
Preston (GP) zones can form, which in turn transfer to fl" needle shape
precipitates (e.g.,
magnesium suicide, Mg2Si) that contribute to precipitation strengthening of
the disclosed alloys.
In certain aspects, addition of Cu leads to the formation of lathe-shaped L
phase precipitation
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
(e.g., Al4Mg8Si7Cu2), which is a precursor of Q' precipitate phase formation
and which further
contributes to strength.
In some examples, the M phase precipitates, including MgZn2 and/or Mg(Zn,Cu)2,
can be
present in the aluminum alloy in an average amount of at least about
300,000,000 particles per
square millimeter (mm2). For example, the M phase precipitates can be present
in an amount of
at least about 310,000,000 particles per mm2, at least about 320,000,000
particles per mm2, at
least about 330,000,000 particles per mm2, at least about 340,000,000
particles per mm2, at least
about 350,000,000 particles per mm2, at least about 360,000,000 particles per
mm2, at least about
370,000,000 particles per mm2, at least about 380,000,000 particles per mm2,
at least about
390,000,000 particles per mm2, or at least about 400,000,000 particles per
mm2.
In some examples, the L phase precipitates, including Al4Mg8Si7Cu2, can be
present in
the aluminum alloy in an average amount of at least about 600,000,000
particles per square
millimeter (mm2). For example, the L phase precipitates can be present in an
amount of at least
about 610,000,000 particles per mm2, at least about 620,000,000 particles per
mm2, at least about
630,000,000 particles per mm2, at least about 640,000,000 particles per mm2,
at least about
650,000,000 particles per mm2, at least about 660,000,000 particles per mm2,
at least about
670,000,000 particles per mm2, at least about 680,000,000 particles per mm2,
at least about
690,000,000 particles per mm2, or at least about 700,000,000 particles per
mm2.
In some examples, the /3" phase precipitates, including Mg2Si, can be present
in the
aluminum alloy in an average amount of at least about 600,000,000 particles
per square
millimeter (mm2). For example, theft" phase precipitates can be present in an
amount of at least
about 610,000,000 particles per mm2, at least about 620,000,000 particles per
mm2, at least about
630,000,000 particles per mm2, at least about 640,000,000 particles per mm2,
at least about
650,000,000 particles per mm2, at least about 660,000,000 particles per mm2,
at least about
670,000,000 particles per mm2, at least about 680,000,000 particles per mm2,
at least about
690,000,000 particles per mm2, at least about 700,000,000 particles per mm2,
at least about
710,000,000 particles per mm2, at least about 720,000,000 particles per mm2,
at least about
730,000,000 particles per mm2, at least about 740,000,000 particles per mm2,
or at least about
750,000,000 particles per mm2.
In some examples, a ratio of the /3" phase precipitates (e.g., Mg2Si) to the L
phase
precipitates (e.g., Al4Mg8Si7Cu2) can be from about 1:1 to about 1.5:1 (e.g.,
from about 1.1:1 to
16
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
about 1.4:1). For example, the ratio of the /3" phase precipitates to the L
phase precipitates can
be about 1:1, about 1.1:1, about 1.2:1, about 1.3:1, about 1.4:1, or about
1.5:1.
In some examples, a ratio of the fl" phase precipitates (e.g., Mg2Si) to the M
phase
precipitates (e.g., MgZn2 and/or Mg(Zri,Cu)2) can be from about 1.5:1 to about
3:1 (e.g., from
about 1.6:1 to about 2.8:1 or from about 2.0:1 to about 2.5:1). For example,
the ratio of the /3"
phase precipitates to the M phase precipitates can be about 1.5:1, about
1.6:1, about 1.7:1, about
1.8:1, about 1.9:1, about 2.0:1, about 2.1:1, about 2.2:1, about 2.3:1, about
2.4:1, about 2.5:1,
about 2.6:1, about 2.7:1, about 2.8:1, about 2.9:1, or about 3.0:1.
In some examples, a ratio of the L phase precipitates (e.g., Al4Mg8Si7Cu2) to
the M phase
precipitates (e.g., MgZn2 and/or Mg(Zn,Cu)2) can be from about 1.5:1 to about
3:1 (e.g., from
about 1.6:1 to about 2.8:1 or from about 2.0:1 to about 2.5:1). For example,
the ratio of the L
phase precipitates to the M phase precipitates can be about 1.5:1, about
1.6:1, about 1.7:1, about
1.8:1, about 1.9:1, about 2.0:1, about 2.1:1, about 2.2:1, about 2.3:1, about
2.4:1, about 2.5:1,
about 2.6:1, about 2.7:1, about 2.8:1, about 2.9:1, or about 3.0:1.
The alloys described herein display exceptional mechanical properties, as
further
provided below. The mechanical properties of the aluminum alloys can be
further controlled by
various aging conditions depending on the desired use. As one example, the
alloy can be
produced (or provided) in the T4 temper or the T6 temper. T4 aluminum alloy
articles that are
solution heat-treated and naturally aged can be provided. These 14 aluminum
alloy articles can
optionally be subjected to additional aging treatment(s) to meet strength
requirements upon
receipt. For example, aluminum alloy articles can be delivered in other
tempers, such as the T6
temper, by subjecting the T4 alloy material to the appropriate aging treatment
as described herein
or otherwise known to those of skill in the art. Exemplary properties in
exemplary tempers are
provided below.
In certain aspects, the aluminum alloy can have a yield strength of at least
about 340
MPa in the 16 temper. In non-limiting examples, the yield strength can be at
least about 350
MPa, at least about 360 MPa, or at least about 370 MPa. In some cases, the
yield strength is
from about 340 MPa to about 400 MPa. For example, the yield strength can be
from about 350
MPa to about 390 MPa or from about 360 MPa to about 380 MPa.
In certain aspects, the aluminum alloy can have an ultimate tensile strength
of at least
about 400 MPa in the 16 temper. In non-limiting examples, the ultimate tensile
strength can be
17
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
at least about 410 MPa, at least about 420 MPa, or at least about 430 MPa. In
some cases, the
ultimate tensile strength is from about 400 MPa to about 450 MPa. For example,
the ultimate
tensile strength can be from about 410 MPa to about 440 MPa or from about 415
MPa to about
435 MPa.
In certain aspects, the aluminum alloy has sufficient ductility or toughness
to meet a
90 bendability of 1.0 or less in the T4 temper (e.g., 0.5 or less). In
certain examples, the et
bendability ratio is about 1.0 or less, about 0.9 or less, about 0.8 or less,
about 0.7 or less, about
0.6 or less, about 0.5 or less, about 0.4 or less, about 0.3 or less, about
0.2 or less, or about 0.1 or
less, where r is the radius of the tool (die) used and t is the thickness of
the material.
In certain aspects, the aluminum alloy exhibits a uniform elongation of
greater than or
equal to 20 % in the T4 temper and a total elongation of greater than or equal
to 30 % in the T4
temper. In certain aspects, the alloys exhibit a uniform elongation of greater
than or equal to 22
% and a total elongation of greater than or equal to 35 %. For example, the
alloys can exhibit a
uniform elongation of 20 % or more, 21 % or more, 22 % or more, 23 % or more,
24 % or more,
25 % or more, 26 % or more, 27 % or more, or 28 % or more. The alloys can
exhibit a total
elongation of 30 % or more, 31 % or more, 32 % or more, 33 % or more, 34 % or
more, 35 % or
more, 36 % or more, 37 % or more, 38 % or more, 39 % or more, or 40 % or more.
In certain aspects, the aluminum alloy exhibits a suitable resistance to IGC,
as measured
by ISO 11846B. For example, the pitting in the aluminum alloys can be
completely suppressed
or improved, such that the average intergranular corrosion pit depth of an
alloy in the 16 temper
is less than 100 gm. For example, the average intergranular corrosion pit
depth can be less than
90 gm, less than 80 gm, less than 70 gm, less than 60 gm, less than 50 gm, or
less than 40 gm.
Methods of Preparing the Aluminum Alloys
In certain aspects, the disclosed alloy composition is a product of a
disclosed method.
Without intending to limit the disclosure, 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.
18
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Casting
The alloy described herein can be cast using a casting method. In some non-
limiting
examples, the aluminum alloy as described herein can be cast from molten
aluminum alloy that
includes scrap alloys (e.g., from an AA6xxx series aluminum alloy scrap, an
AA7)ooc series
aluminum alloy scrap, or a combination of these). The casting process can
include a Direct Chill
(DC) casting process. Optionally, the ingot can be scalped before downstream
processing.
Optionally, the casting process can include a continuous casting (CC) process.
The cast
aluminum alloy can then be subjected to further processing steps. For example,
the processing
methods as described herein can include the steps of homogenizing, hot
rolling, solution heat
treating, and quenching. In some cases, the processing methods can also
include a pre-aging step
and/or an artificial aging step.
Homogenization
The homogenization step can include heating the ingot prepared from an alloy
composition described herein to attain a peak metal temperature (PMT) of
about, or at least
.. about, 500 C (e.g., at least 520 QC, at least 530 C, at least 540 C, at
least 550 C, at least 560
C, at least 570 C, or at least 580 C). For example, the ingot can be heated
to a temperature of
from about 500 C to about 600 C, from about 520 C to about 580 C, from
about 530 C to
about 575 C, from about 535 C to about 570 C, from about 540 C to about
565 C, from
about 545 C to about 560 C, from about 530 C to about 560 C, or from about
550 C to about
580 C. in some cases, the heating rate to the PMT can be about 70 C/hour or
less, 60 C/hour
or less, 50 C/hour or less, 40 C/hour or less, 30 C/hour or less, 25
C/hour or less, 20 C/hour
or less, or 15 C/hour or less. In other cases, the heating rate to the PMT
can be from about 10
C/min to about 100 C/min (e.g., about 10 C/min to about 90 C/min, about 10
C/min to about
70 C/min, about 10 C/min to about 60 C/min, from about 20 C/min to about
90 C/min, from
about 30 C/min to about 80 C/min, from about 40 Clinin to about 70 C/min,
or from about 50
C/min to about 60 C/min).
The ingot is then allowed to soak (i.e., held at the indicated temperature)
for a period of
time. According to one non-limiting example, the ingot is allowed to soak for
up to about 6
hours (e.g., from about 30 minutes to about 6 hours, inclusively). For
example, the ingot can be
soaked at a temperature of at least 500 C for 30 minutes, 1 hour, 2 hours, 3
hours, 4 hours, 5
hours, or 6 hours, or anywhere in between.
19
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Hot Rolling
Following the homogenization step, a hot rolling step can be performed to form
a hot
band. In certain cases, the ingots are laid down and hot-rolled with an exit
temperature ranging
from about 230 C to about 300 C (e.g., from about 250 C to about 300 C).
For example, the
hot roll exit temperature can be about 230 C, about 235 C, about 240 C,
about 245 C, about
250 C, about 255 C, about 260 C, about 265 C, about 270 C, about 275 C,
about 280 C,
about 285 C, about 290 C, about 295 C, or about 300 C.
In certain cases, the ingot can be hot rolled to an about 4 mm to about 15 mm
thick gauge
(e.g., from about 5 mm to about 12 mm thick gauge). For example, the ingot can
be hot rolled to
an about 4 mm thick gauge, about 5 mm thick gauge, about 6 mm thick gauge,
about 7 mm thick
gauge, about 8 mm thick gauge, about 9 mm thick gauge, about 10 mm thick
gauge, about 11
mm thick gauge, about 12 mm thick gauge, about 13 mm thick gauge, about 14 mm
thick gauge,
or about 15 mm thick gauge. In certain cases, the ingot can be hot rolled to a
gauge greater than
mm thick (e.g., a plate gauge). In other cases, the ingot can be hot rolled to
a gauge less than
15 4 mm (e.g., a sheet gauge).
Solution Heat Treating
Following the hot rolling step, the hot band can be cooled by air and then
solutionized in
a solution heat treatment step. The solution heat treating can include heating
the final gauge
aluminum alloy from room temperature to a temperature of from about 520 C to
about 590 C
(e.g., from about 520 C to about 580 C, from about 530 C to about 570 C,
from about 545 C
to about 575 C, from about 550 C to about 570 C, from about 555 C to about
565 C, from
about 540 C to about 560 C, from about 560 C to about 580 C, or from about
550 C to about
575 C). The final gauge aluminum alloy can soak at the temperature for a
period of time. In
certain aspects, the final gauge aluminum alloy is allowed to soak for up to
approximately 2
hours (e.g., from about 10 seconds to about 120 minutes, inclusively). For
example, the final
gauge aluminum alloy can be soaked at the temperature of from about 525 C to
about 590 C
for 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,
125 seconds, 130
seconds, 135 seconds, 140 seconds, 145 seconds, 150 seconds, 5 minutes, 10
minutes, 15
minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45
minutes, 50 minutes,
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85
minutes, 90
minutes, 95 minutes, 100 minutes, 105 minutes, 110 minutes, 115 minutes, or
120 minutes, or
anywhere in between.
Quenching
In certain aspects, the final gauge aluminum alloy can then be cooled to a
temperature of
about 35 C at a quench speed that can vary between about 50 C/s to 400 C/s
in a quenching
step that is based on the selected gauge. For example, the quench rate can be
from about 50 C/s
to about 375 C/s, from about 60 C/s to about 375 C/s, from about 70 C/s to
about 350 C/s,
from about 80 C/s to about 325 C/s, from about 90 C/s to about 300 C/s,
from about 100 C/s
to about 275 C/s, from about 125 C/s to about 250 C/s, from about 150 C/s
to about 225 C/s,
or from about 175 C/s to about 200 C/s.
In the quenching step, the final gauge aluminum alloy is rapidly quenched with
a liquid
(e.g., water) and/or gas or another selected quench medium. In certain
aspects, the final gauge
aluminum alloy can be rapidly quenched with water.
Pre-Aging
Optionally, a pre-aging step can be performed. The pre-aging step can include
heating
the final gauge aluminum alloy after the quenching step to a temperature of
from about 100 C to
about 160 C (e.g., from about 105 C to about 155 C, about 110 C to about
150 C, about 115
C to about 145 C, about 120 C to about 140 C, or about 125 C to about 135
C). In certain
aspects, the aluminum alloy sheet, plate, or shate is allowed to soak for up
to approximately three
hours (e.g., for up to about 10 minutes, for up to about 20 minutes, for up to
about 30 minutes,
for up to about 40 minutes, for up to about 45 minutes, for up to about 60
minutes, for up to
about 90 minutes, for up to about two hours, or for up to about three hours).
Aging
The final gauge aluminum alloy can be naturally aged or artificially aged. In
some
examples, the final gauge aluminum alloy can be naturally aged for a period of
time to result in
the T4 temper. In certain aspects, the final gauge aluminum alloy in the T4
temper can be
artificially aged (AA) at about 180 C to 225 C (e.g., 185 C, 190 C, 195 C,
200 C, 205 C,
210 C, 215 C, 220 C, or 225 C) for a period of time. Optionally, the final
gauge aluminum
alloy can be artificially aged for a period from about 15 minutes to about 8
hours (e.g., 15
21
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7
hours, or 8 hours or
anywhere in between) to result in the 16 temper.
Methods of Using
The alloys and methods described herein can be used in automotive,
electronics, and
transportation applications, such as commercial vehicle, aircraft, or railway
applications, or other
applications. For example, the alloys could be used for chassis, cross-member,
and intra-chassis
components (encompassing, but not limited to, all components between the two C
channels in a
commercial vehicle chassis) to gain strength, serving as a full or partial
replacement of high-
strength steels. In certain examples, the alloys can be used in T4 and T6
tempers.
In certain aspects, the alloys and methods can be used to prepare motor
vehicle body part
products. For example, the disclosed alloys and methods can be used to prepare
automobile
body parts, such as bumpers, side beams, roof beams, cross beams, pillar
reinforcements (e.g., A-
pillars, B-pillars, and C-pillars), inner panels, side panels, floor panels,
tunnels, structure panels,
reinforcement panels, inner hoods, or trunk lid panels. The disclosed aluminum
alloys and
methods can also be used in aircraft or railway vehicle applications, to
prepare, for example,
external and internal panels. In certain aspects, the disclosed alloys can be
used for other
specialties applications, such as automotive battery platesishates.
The described alloys and methods can also be used to prepare housings for
electronic
devices, including mobile phones and tablet computers. For example, the alloys
can be used to
prepare housings for the outer casing of mobile phones (e.g., smart phones)
and tablet bottom
chassis, with or without anodizing. The alloys can also be used to prepare
other consumer
electronic products and product parts. Exemplary consumer electronic products
include mobile
phones, audio devices, video devices, cameras, laptop computers, desktop
computers, tablet
computers, televisions, displays, household appliances, video playback and
recording devices,
and the like. Exemplary consumer electronic product parts include outer
housings (e.g., facades)
and inner pieces for the consumer electronic products.
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. During the studies described in
the following
22
CA 03069499 2020-01-09
WO 2019/013744 PCT1US2017/041313
examples, conventional procedures were followed, unless otherwise stated. Some
of the
procedures are described below for illustrative purposes.
EXAMPLES
Example 1.: Aluminum Alloy Compositions
Tables 4A and 4B below summarize exemplary aluminum alloys and Table 5
provides
the properties of the alloys, including yield strength (YS), intergranular
corrosion pit depths
(IGC), and 900 bendability (Bend).
Table 4A
Alloy Cu Mg Mn Si Zn Fe Zr
1 0.60 0.9- 1.2 0.19 0.9 - 1.1 <0.01 0.16-
0
0.19
2 0.80 . 1.0 0.17 - 0.19 1.1 1.5 - 3.0
0.18- 0.006
0.20
3 0.6 - 0.7 2.0 - 2.25 0.07 - 0.10 1 0 2.5 - 3.0
0.14- 0.09 --
0.17 0.10
4 0.7 - 0.8 1.5 0.14 - 0.15 0.55 - 0.65 1.55 0.16-
0
0.18
3 1.0 1.5 0.14 - 0.15 0.63 - 0.67 2.0 - 3.0 0.17
0
All expressed in wt. A); total impurities up to 0.15 wt. %; remainder Al.
Table 4B
Alloy . Mg/Si Zn/(MWSi) - Cu/Rn/(Mg/Si)1
-
II 0.87- 1.19 0 0 .
2 0.97- 1.1 1.3 - 3.1 0.25 -
0.62
3 2.0 - 2.25 1.1 - 1.5 0.4 -
0.64
4 2.3 - 2.8 055... 0.67 1.04 -
1.4
51 2.2 - 2.4 0.8 - 1.4 0.71 -
1.25
Table 5
Alloy YS IGC Bend
(MPa) (Pm) (90 )
1 380 300 Fail
2 370 250 Fail
3 340 0 Pass
4 360 200 Fail
5 370 120 Pass
23
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
The properties of the alloys were achieved by controlling the ratios of
alloying elements.
Alloy 1 represents comparative AA6xxx series aluminum alloys exhibiting high
strength due to
Mg2Si strengthening precipitates in the aluminum alloy. Alloy 2 represents
comparative
aluminum alloys exhibiting improved corrosion resistance and a slight decrease
in strength upon
adding Zn. Alloys 1 and 2, wherein the ratio of Cu/Vril(Mg/Si)] does not fall
in the range of
from about 0.7 to about 1.4, exhibit significant IGC and failure in a 900 bend
test. Alloy 3
represents exemplary aluminum alloys wherein the ratios of Cu/[Zn/(MWSi)] are
closer to the
range of from about 0.7 to about 1.4 than Alloy 2, exhibiting a decrease in
strength with
excellent formability and resistance to IGC. Alloy 4 represents exemplary
aluminum alloys
wherein the ratios of Cui[Zn/(MgiSi)] fall within the range of from about 0.7
to about 1.4, but the
ratios of Zn/(Mg/Si) do not fall within a range of from about 0.75 to about
1.4, exhibiting
significant IGC and poor formability, and increased strength when compared to
Alloy 3. Alloy 5
represents exemplary aluminum alloys wherein the ratios of Mg/Si, Zn/(Mg/Si),
and
Cui[Zn/(Mg/Si)] all fall within the respective ranges, exhibiting high
strength, good formability,
and good resistance to corrosion.
In addition, exemplary alloys were produced according to the direct chill
casting methods
described herein. The alloy compositions are summarized in Table 6 below:
Table 6
Alloy Si Fe Cu Mn Mg Cr Zn Ti
A 0.65 0.20 1.10 0.15 1.50 0.05 2.0 0.02
0.65 0.20 1.10 0.15 1.50 0.05 2.5 0.02
0.65 0.20 1.10 0.15 1.50 0.05 3.0 0.02
All expressed in wt. %; remainder Al.
Example 2: Aluminum Alloy Microstructure
Exemplary alloys were produced by direct chill casting and processed according
to the
methods described herein. As described above, the Mg and Cu content can
provide precipitation
of an M phase (e.g., MgZn2 Mg(Zn, C1)2), providing precipitates that can
increase strength in
the aluminum alloy. Evaluation of the M phase (e.g., MgZn2) precipitates was
performed as a
function of Mg content in the exemplary alloys. Figure 1 is a graph showing an
increase in Mg
content from 1.0 wt. % to 3.0 wt. %. Evident in the graph, a mass fraction of
the M phase
24
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
precipitates (i) increases proportionally with increasing Mg content from 1.0
wt. % to 1.5 wt. %,
(ii) remains constant when Mg content is increased from 1.5 wt. % to 2.0 wt.
%, (iii) increases
proportionally with increasing Mg content from 2.0 wt. % to 2.5 wt. %, and
(iv) plateaus with
Mg content greater than 2.5 wt. %. The increase in Al phase precipitates
provides increased
strength in the exemplary alloys.
Figure 2 is a graph showing differential scanning calorimetry (DSC) analysis
of samples
of exemplary Alloy 3 described above (referred to as "Hl ," "H2," and "H3").
Exothermic peak
A indicates precipitate formation in the exemplary alloys and endothermic peak
B indicates
melting points for the exemplary Alloy 3 samples.
Figure 3 is a graph showing DSC analysis of samples of the exemplary Alloy 5
described
above (referred to as "H5," "H6," and "H7"). Exothermic peak A indicates M
phase precipitates.
Exothermic peak B indicates fl" (Mg2Si) precipitates, showing formation of the
strengthening
precipitates during an artificial aging step and corresponding to the increase
in strength of the
exemplary aluminum alloys. Endothermic peak C indicates melting points for the
exemplary
Alloy 5 samples.
Figure 4A is a transmission electron microscope (TEM) micrograph showing three
distinct strengthening precipitate phases, Al (MgZn2) 410, fl" (Mg2Si) 420,
and L
(A14Mg8Si7Cu2) 430. A combination of the three precipitate phases produces a
yield strength of
about 370 MPa in a 16 temper for a 10 mm gauge aluminum alloy (e.g., Alloy 5).
Figure 4B is a
TEM micrograph showing Zr-containing precipitate particles 440. Excess Zr in
the exemplary
alloys can cause coarse needle-like particles to form. The coarse, needle-like
Zr-containing
precipitate particles 440 can reduce formability of the exemplary alloys.
Likewise, too little Zr
in the exemplary alloys can fail to provide desired Al3Zr and/or (A1,Si)3Zr
dispersoids.
Figure 5 is a graph showing the density of each distinct strengthening
precipitate phase,
.. Al (Mgn2), L (A14Mg8Si7Cu2), and 13" (Mg2Si), in number of precipitate
particles per square
millimeter (#/mm2) and as a fraction of analyzed area each distinct
precipitate phase occupies
(%) for Alloy C (see Table 6). The fl" precipitates are predominant in both
density and occupied
area due to their shape. The smaller Al and L precipitates occupy less area
accordingly, and are
present in densities comparable to the fl" precipitates.
Figure 6 shows optical micrographs of samples of Alloy 3 as described above.
Precipitates were analyzed in as-cast samples (top row), homogenized samples
(center row), and
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
hot rolled samples reduced to a 10 mm gauge (bottom row). Eutectic phase
precipitates are
evident in the as-cast samples. Precipitates did not fully dissolve after
homogenization, as shown
in the center row of micrographs. Coarse (e.g., greater than about 5 microns)
precipitates are
evident in the hot rolled samples.
Figure 7 shows optical micrographs of samples of Alloy 3 described above after
casting,
homogenization, hot rolling to a 10 mm gauge and various solution heat
treatment procedures to
achieve maximum dissolution of strengthening precipitates during solution heat
treatment.
Figure 7, panel A shows an Alloy 3 sample solutionized at a temperature of 555
C for 45
minutes. Figure 7, panel B shows an Alloy 3 sample solutionized at a
temperature of 350 C for
45 minutes, then at a temperature of 500 C for 30 minutes, and finally at a
temperature of 565
C for 30 minutes. Figure 7, panel C shows an Alloy 3 sample solutionized at a
temperature of
350 C for 45 minutes, then at a temperature of 500 C for 30 minutes and
finally a temperature
of 565 C for 60 minutes. Figure 7, panel D shows an Alloy 3 sample
solutionized at a
temperature of 560 C for 120 minutes. Figure 7, panel E shows an Alloy 3
sample solutionized
at a temperature of 500 C for 30 minutes, then at a temperature of 570 C for
30 minutes.
Figure 7, panel F shows an Alloy 3 sample solutionized at a temperature of 500
C for 30
minutes, then at a temperature of 570 C for 60 minutes.
Figure 8 shows optical micrographs of samples of Alloy 5 as described above.
Precipitates were analyzed in as-cast samples (top row) and homogenized
samples (bottom row).
Eutectic phase precipitates are evident in the as-cast samples. The
precipitates did not fully
dissolve after homogenization, as seen in the bottom row of micrographs. Alloy
5, however,
exhibited fewer undissolved precipitates as compared to Alloy 3 after
homogenization, due to
changes in solute levels (e.g., the Mg levels, Si levels, and the Mg/Si
ratio).
Figure 9 shows optical micrographs of samples of Alloy 5 described above after
hot
rolling to a 10 mm gauge. Figure 9, panels A, B, and C show precipitate
particles (seen as dark
spots) in the exemplary alloy samples after hot rolling to a 10 mm gauge.
Figure 9, panels D, E,
and F show grain structure after hot rolling the exemplary Alloy 5 samples to
a gauge of 10 mm.
Grains were not fully recrystallized due to a low hot rolling exit temperature
of about 280 C to
about 300 C.
Figure 10 shows optical micrographs of samples of Alloy 5 described above
after hot
rolling to a 10 mm gauge, solution heat treating, and natural aging to a T4
temper. Figure 10,
26
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
panels A, B, and C show very few precipitate particles in the exemplary alloy
samples in T4
temper. Figure 10, panels D, E, and F show a fully recrystallized grain
structure of the
exemplary Alloy 5 samples in 14 temper.
Figure 11 is a graph showing the electrical conductivities of samples of Alloy
3 after
casting, homogenization, hot rolling, various solution heat treatment
procedures, and artificial
aging (AA). The electrical conductivity data (i.e., conductivity as a percent
of the International
Annealed Copper Standard (%IACS)) show large amounts of precipitation after
hot rolling.
Various solution heat treatment procedures were evaluated in an attempt to
dissolve the
precipitates. Solution heat treating was not effective in dissolving
precipitates. Furthermore,
there was insufficient strengthening precipitate formation during artificial
aging to provide
optimal strength.
Figure 12 is a graph showing the electrical conductivities of samples of Alloy
5 (referred
to as "HR5," "HR.6," and "HR7") after casting, homogenization, hot rolling,
solution heat
treating, and artificial aging. The electrochemical testing data shows large
amounts of
precipitation after hot rolling. Various solution heat treatment procedures
were evaluated in an
attempt to dissolve the precipitates. Solution heat treating was effective in
dissolving
precipitates.
Furthermore, artificial aging provided strengthening precipitate formation
providing optimal strength.
Example 3: Aluminum Alloy Mechanical Properties
Figure 13 is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle), and
total elongation
(open diamond) for the exemplary Alloys A, B, and C described above. The
alloys were
solutionized at a temperature of 565 C for 45 minutes, pre-aged at a
temperature of 125 C for 2
hours, and artificially aged at a temperature of 200 C for 4 hours to result
in a 16 temper. Each
alloy exhibited a yield strength greater than 370 MPa, an ultimate tensile
strength greater than
425 MPa, a uniform elongation greater than 10 %, and a total elongation
greater than 17 %.
Increased Zn content did not significantly affect the strength of the
exemplary aluminum alloys,
but did improve resistance to intergranular corrosion and formability.
Figure 14A is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle), and
total elongation
(open diamond) for samples of the exemplary Alloy 3 in T4 temper (referred to
as "H1 T4," "112
27
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
T4," and "H3 T4"). Figure 14B is a graph showing yield strength (left
histogram in each set),
ultimate tensile strength (right histogram in each set), uniform elongation
(open circle), and total
elongation (open diamond) for samples of the exemplary Alloy 3 in 16 temper
(referred to as
"Hl T6," "H2 16," and "H3 T6").
Figure 15 is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle), and
total elongation
(open diamond) for samples of the exemplary Alloy 3 in T6 temper (referred to
as "Hl ," "H2,"
and "H3") after various aging procedures, as indicated in the x-axis of the
graph. Evident in the
graph, a three-step aging procedure was able to produce a high-strength (e.g.,
348 ME)a)
aluminum alloy. Also evident in the graph, aging at low temperatures (e.g.,
less than 250 C)
was not sufficient to produce strengthening precipitates in the alloy samples.
Figure 16A is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle), and
total elongation
(open diamond) for samples of the exemplary Alloy 4 in T4 temper (referred to
as "HR1,"
"HR2," "HR3," and "HR4"). Figure 16B is a graph showing yield strength (left
histogram in
each set), ultimate tensile strength (right histogram in each set), uniform
elongation (open circle),
and total elongation (open diamond) for samples of the exemplary Alloy 4 in T6
temper after
various aging procedures (referred to as "HR1," "HR2," "HR3," and "HR4").
Evident in the
graph, a maximum strength of 360 MPa was achieved. Also evident in the graph,
aging at low
temperatures (e.g., less than 250 C) was not sufficient to produce
strengthening precipitates in
the alloy samples.
Figure 17A is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle), and
total elongation
(open diamond) for samples of the exemplary Alloy 5 in T4 temper after
casting,
homogenization, hot rolling to a gauge of 10 mm, solution heat treating, and
various quenching
techniques (referred to as "HR5," "HR6," and "HR7"). Air cooled samples are
referred to as
"AC" and water quenched samples are referred to as "WQ" after hot rolling.
Figure 17B is a
graph showing yield strength (left histogram in each set), ultimate tensile
strength (right
histogram in each set), uniform elongation (open circle), and total elongation
(open diamond) for
samples of the exemplary Alloy 5 in 16 temper after casting, homogenization,
hot rolling to a
gauge of 10 mm, solution heat treating, various quenching techniques, and
various aging
28
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
procedures (referred to as "HR5," "HR6," and "HRT'). Air cooled samples are
referred to as
"AC" and water quenched samples are referred to as "WQ" after hot rolling.
Artificial aging to a
T6 temper provided high-strength aluminum alloys having yield strengths of
about 360 MPa to
about 370 MPa.
Figure 18A is a graph showing yield strength (left histogram in each set),
ultimate tensile
strength (right histogram in each set), uniform elongation (open circle), and
total elongation
(open diamond) for samples of the exemplary Alloy 5 in T4 temper (referred to
as
"HR6," and "HRT') after casting, homogenization, hot rolling to a gauge of 10
mm, and solution
heat treating. Figure 18B is a graph showing yield strength (left histogram in
each set), ultimate
tensile strength (right histogram in each set), uniform elongation (open
circle), and total
elongation (open diamond) for samples of the exemplary Alloy 5 in T6 temper
(referred to as
"HR5," "HR6," and "HRT') after casting, homogenization, hot rolling to a gauge
of 10 mm,
solution heat treating, and various aging procedures, as indicated in the
graph. Artificial aging to
a 16 temper provided high-strength aluminum alloys having yield strengths of
about 360 MPa to
about 370 MPa.
Figure 19 is a graph showing load displacement data for a 90 bend test
formability of
samples of the exemplary Alloy 5 as described above (referred to as "HR5,"
"HR6," and
"HRT'). Samples tested in a direction longitudinal to a rolling direction are
indicated by "-L,"
and sample tested in a transverse direction to the rolling direction are
indicated by "-T." Alloy 5
was subjected to casting, homogenization, hot rolling to a gauge of 10 mm,
solution heat
treating, and natural aging for one week to provide Alloy 5 samples in T4
temper. Samples were
subjected to a 90 bend test and load displacement (left axis) and maximum
load (right axis)
were recorded.
Figure 20 is a graph showing load displacement data for a 90 bend test
formability of
samples of the exemplary Alloy 5 as described above (referred to as "HR5,"
"HR6," and
"HRT'). Samples tested in a direction longitudinal to a rolling direction are
indicated by "-L,"
and sample tested in a transverse direction to the rolling direction are
indicated by "-T." Alloy 5
was subjected to casting, homogenization, hot rolling to a gauge of 10 mm,
solution heat
treating, pre-aging at a temperature of 125 C for 2 hours (referred to as
"PX") and natural aging
for one week to provide Alloy 5 samples in 14 temper. Samples were subjected
to a 90 bend
test and load displacement (left axis) and maximum load (right axis) were
recorded.
29
CA 03069499 2020-01-09
WO 2019/013744 PCT/US2017/041313
Figure 21 is a graph showing load displacement data for a 90 bend test
formability of
samples of the exemplary Alloy 5 as described above. The sample tested in a
direction
longitudinal to a rolling direction is indicated by "-L" and the sample tested
in a transverse
direction to the rolling direction is indicated by "-T." The samples were
subjected to casting,
homogenization, hot rolling to a gauge of 10 mm, solution heat treating, pre-
aging at a
temperature of 125 C for 2 hours and natural aging for one month to provide
Alloy 5 samples in
T4 temper. The samples were subjected to a 90 bend test and load displacement
(left axis) and
maximum load (right axis) were recorded. There was no noticeable change in
formability from
one week of natural aging to one month of natural aging with pre-aging
employed during
production.
Figure 22 shows optical micrographs showing the effects of corrosion testing
on alloys
described above. The alloys were subjected to corrosion testing according to
ISO standard
11846B (e.g., 24 hour immersion in a solution containing 3.0 wt. % sodium
chloride (NaCl) and
1.0 volume % hydrochloric acid (HCl) in water). Figure 22, panel A, and Figure
22, panel B
show effects of corrosion testing in comparative Alloy 2 described above.
Corrosion
morphology is an intergranular corrosion (IGC) attack. Figure 22, panels C, D,
and E show the
effects of corrosion testing in exemplary Alloy 3 as described above.
Corrosion morphology is a
pitting attack. A pitting attack is a more desirable corrosion morphology
causing less damage to
the alloy and indicating corrosion resistance in the exemplary alloys.
Figure 23 shows optical micrographs showing the effects of corrosion testing
on samples
of exemplary Alloy 4 as described above. Evident in the micrographs is
significant MC attack
due to the composition of Alloy 4, wherein the ratio of CuiZn/(Mg/Si)] is
within the range of
from about 0.7 to about 1.4, but the ratio of Zn/(Mg/Si) is not within the
range of from about
0.75 to about 1.4, resulting in significant IGC attack.
Figures 24A, 24B, and 24C are optical micrographs showing the results of
corrosion
testing on the exemplary alloys described above. Figure 24A shows
intergranular corrosion
(IGC) attack in Alloy A. Figure 24B shows intergranular corrosion attack in
Alloy B. Figure
24C shows intergranular corrosion attack in Alloy C. Evident in Figures 24A,
24B, and 24C,
increasing Zn content changes corrosion morphology from IGC to pitting, and
corrosion attack
depth is decreased from about 150 gm (Alloy A, Figure 24A) to less than 100 gm
(Alloy C,
Figure 24C).
WO 2019/013744 PCT/US2017/041313
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.
31
Date Recue/Date Received 2021-07-12
