Note: Descriptions are shown in the official language in which they were submitted.
IMPROVED THICK WROUGHT 7XXX ALUMINUM ALLOYS, AND METHODS
FOR MAKING THE SAME
[001]
FIELD OF THE INVENTION
[002] The present patent application relates to improved thick wrought 7xxx
aluminum
alloy products and methods for producing the same.
BACKGROUND
[003] Aluminum alloys are useful in a variety of applications. However,
improving one
property of an aluminum alloy without degrading another property is elusive.
For example, it
is difficult to increase the strength of a wrought aluminum alloy without
affecting other
properties such as fracture toughness or corrosion resistance. 7xxx (Al-Zn-Mg
based) are
prone to corrosion. See, e.g., Bonn, W. Grubl, The stress corrosion behaviour
of high
strength AIZnMg alloys," Paper held at the International Meeting of
Associazione Italiana di
Metallurgie, "Aluminum Alloys in Aircraft Industries," Turin, October 1976.
SUMMARY OF THE DISCLOSURE
[004] Broadly, the present patent application relates to improved thick
wrought 7xxx
aluminum alloy products, and methods for producing the same. The new thick
wrought 7xxx
aluminum alloy products ("the new 7xxx aluminum alloy products") may realize
an improved
combination of environmentally assisted crack resistance and at least one of
strength,
elongation, and fracture toughness, among other properties.
[005] The new 7xxx aluminum alloy products generally include high amounts
of
manganese. Manganese in combination with appropriate amounts of zinc,
magnesium, and
copper has been found to facilitate production of thick 7xxx aluminum alloy
products having
a high resistance to environmentally assisted cracking. The new 7xxx aluminum
alloy
products thus generally include (and in some instances consist of, or consist
essentially of)
from 0.15 to 0.50 wt. % Mn in combination with 5.5-7.5 wt. % Zn, 0.95-2.20 wt.
% Mg, and
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1.50-2.40 wt. % Cu. The new wrought 7xxx aluminum alloy products are generally
at least
1.5 inches thick, and may be up to 12 inches thick, and realize resistance to
environmentally
assisted cracking in the short transverse (ST) direction, which resistance is
important for
aerospace and other applications, especially those with structural loading in
the short
transverse (ST) direction. Such thick, wrought 7xxx aluminum alloy product
generally also
realize good strength, elongation, fracture toughness and crack-deviation
resistance
properties. Thus, the new wrought 7xxx aluminum alloy products generally
realize an
improved combination of corrosion resistance and at least one of strength,
elongation,
fracture toughness and crack-deviation resistance. In
addition to manganese, zinc,
magnesium and copper, the new 7xxx aluminum alloy products may include normal
grain
structure control materials, grain refiners, and impurities. For instance, the
new 7xxx
aluminum alloy products may include one or more of Zr, Cr, Sc, and Hf as grain
structure
control materials (e.g., from 0.05-0.25 wt. % each of one or more of Zr, Cr,
Sc, and Hf),
limiting the total amounts of these elements such that large primary particles
do not folin in
the alloy. As another example, the new 7xxx aluminum alloy products may
include up to
0.15 wt. % Ti as a grain refiner, optionally with some of the titanium in the
form of TiB2
and/or TiC. The new 7xxx aluminum alloy products may include up to 0.20 wt. %
Fe and up
to 0.15 wt. % Si as impurities. Lower amounts of iron and silicon may be used.
The balance
of the new 7xxx aluminum alloy products is generally aluminum and other
unavoidable
impurities (other than iron and silicon).
[006] As noted above, the new 7xxx aluminum alloy products generally
include from
0.15 to 0.50 wt. % Mn. The new 7xxx aluminum alloy products generally include
a sufficient
amount of the manganese to facilitate realization of environmentally assisted
crack resistance
(EAC resistance) in the new 7xxx aluminum alloy products. In one embodiment, a
new 7xxx
aluminum alloy product includes at least 0.18 wt. % Mn to facilitate EAC
resistance. In
another embodiment, a new 7xxx aluminum alloy product includes at least 0.20
wt. % Mn.
In yet another embodiment, a new 7xxx aluminum alloy product includes at least
0.22 wt. %
Mn. In another embodiment, a new 7xxx aluminum alloy product includes at least
0.25 wt.
% Mn. In yet another embodiment, a new 7xxx aluminum alloy product includes at
least
0.275 wt. % Mn.
[007] The amount of manganese should be limited to restrict imparting undue
quench
sensitivity to the new 7xxx aluminum alloy products. In one embodiment, a new
7xxx
aluminum alloy product includes not greater than 0.45 wt. % Mn. In another
embodiment, a
new 7xxx aluminum alloy product includes not greater than 0.40 wt. % Mn. In
yet another
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embodiment, a new 7xxx aluminum alloy product includes not greater than 0.375
wt. % Mn.
In another embodiment, a new 7xxx aluminum alloy product includes not greater
than 0.35
wt. % Mn. In another embodiment, a new 7xxx aluminum alloy product includes
not greater
than 0.325 wt. % Mn. In yet another embodiment, a new 7xxx aluminum alloy
product
includes not greater than 0.30 wt. % Mn.
[008] As noted above, the new 7xxx aluminum alloy products generally
include tailored
amounts of zinc, magnesium and copper, in addition to the manganese, to
facilitate
realization of EAC resistance in combination with good strength and/or
fracture toughness
properties, among others. In this regard, the new 7xxx aluminum alloy products
generally
include from 0.15 to 0.50 wt. % Mn, such as any of the manganese limits /
ranges described
above, in combination with 5.5-7.5 wt. % Zn, 0.95-2.20 wt. % Mg, and 1.50-2.4
wt. % Cu.
In one embodiment, the new 7xxx aluminum alloy products generally include from
0.15 to
0.50 wt. % Mn, such as any of the manganese limits / ranges described above,
in combination
with 5.5-7.2 wt. % Zn, 1.05-2.05 wt. % Mg, and 1.5-2.2 wt. % Cu.
[009] As noted above, the new 7xxx aluminum alloy products generally
include from
5.5 to 7.5 wt. % Zn. In one embodiment, a new alloy includes not greater than
7.4 wt. % Zn.
In another embodiment, a new alloy includes not greater than 7.3 wt. % Zn. In
yet another
embodiment, a new alloy includes not greater than 7.2 wt. % Zn. In another
embodiment, a
new alloy includes not greater than 7.1 wt. % Zn. In another embodiment, a new
alloy
includes not greater than 7.0 wt. % Zn. In yet another embodiment, a new alloy
includes not
greater than 6.9 wt. % Zn. In another embodiment, a new alloy includes not
greater than 6.8
wt. % Zn. In yet another embodiment, a new alloy includes not greater than 6.7
wt. % Zn. In
one embodiment, a new alloy includes at least 5.5 wt. % Zn. In another
embodiment, a new
alloy includes at least 5.75 wt. % Zn. In yet another embodiment, a new alloy
includes at
least 6.0 wt. % Zn. In another embodiment, a new alloy includes at least 6.25
wt. % Zn. In
another embodiment, a new alloy includes at least 6.375 wt. % Zn. In another
embodiment, a
new alloy includes at least 6.5 wt. % Zn.
[0010] As noted above, the new 7xxx aluminum alloy products generally
include from
1.5 to 2.4 wt. % Cu. In one embodiment, a new alloy includes not greater than
2.3 wt. % Cu.
In another embodiment, a new alloy includes not greater than 2.2 wt. % Cu. In
one
embodiment, a new alloy includes not greater than 2.1 wt. % Cu. In another
embodiment, a
new alloy includes not greater than 2.0 wt. % Cu. In one embodiment, a new
alloy includes
at least 1.55 wt. % Cu. In another embodiment, a new alloy includes at least
1.60 wt. % Cu.
In yet another embodiment, a new alloy includes at least 1.65 wt. % Cu. In yet
another
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embodiment, a new alloy includes at least 1.70 wt. % Cu. In yet another
embodiment, a new
alloy includes at least 1.75 wt. % Cu. In another embodiment, a new alloy
includes at least
1.80 wt. A Cu.
[0011] As noted above, the new 7xxx aluminum alloy products generally
include from
0.95 to 2.2 wt. A Mg. In one embodiment, a new alloy includes at least 1.05
wt. A Mg. In
another embodiment, a new alloy includes at least 1.15 wt. A Mg. In yet
another
embodiment, a new alloy includes at least 1.25 wt. % Mg. In another
embodiment, a new
alloy includes at least 1.35 wt. % Mg. In yet another embodiment, a new alloy
includes at
least 1.40 wt. % Mg. In another embodiment, a new alloy includes at least 1.45
wt. A Mg.
In yet another embodiment, a new alloy includes at least 1.50 wt. A Mg. In
another
embodiment, a new alloy includes at least 1.55 wt. % Mg. In another
embodiment, a new
alloy includes at least 1.60 wt. % Mg. In yet another embodiment, a new alloy
includes at
least 1.65 wt. % Mg. In another embodiment, a new alloy includes at least 1.70
wt. % Mg.
In one embodiment, a new alloy includes not greater than 2.15 wt. % Mg. In
another
embodiment, a new alloy includes not greater than 2.10 wt. A Mg. In yet
another
embodiment, a new alloy includes not greater than 2.05 wt. % Mg. In another
embodiment, a
new alloy includes not greater than 2.00 wt. A Mg. In another embodiment, a
new alloy
includes not greater than 1.95 wt. A Mg. In yet another embodiment, a new
alloy includes
not greater than 1.90 wt. A Mg.
[0012] In one embodiment, a first 7xxx aluminum alloy product includes from
5.5 - 7.5
wt. % Zn, 1.7 - 2.2 wt. % Mg and 1.5 - 2.4 wt. % Cu. In one embodiment, the
first 7xxx
aluminum alloy product includes not greater than 7.2 wt. % Zn or not greater
than 7.0 wt. %
Zn (e.g., to facilitate improved EAC resistance). In one embodiment, the first
7xxx
aluminum alloy product comprises 6.0 - 7.0 wt. % Zn.
[0013] In another embodiment, a second 7xxx aluminum alloy product includes
from 5.5
-7.5 wt. % Zn, 1.35 - 1.7 wt. A Mg and 1.5 -2.1 wt. % Cu. The first 7xxx
aluminum alloy
product may realize, for instance, higher strength than the second aluminum
alloy product,
but possibly at the expense of reduced fracture toughness and/or reduced
elongation. In one
embodiment, the second 7xxx aluminum alloy product includes not greater than
7.2 wt. % Zn
or not greater than 7.0 wt. % Zn (e.g., to facilitate improved EAC
resistance). In one
embodiment, the second 7xxx aluminum alloy product comprises 6.0 - 7.0 wt. %
Zn.
[0014] In another embodiment, a third 7xxx aluminum alloy product includes
from 5.5 -
7.5 wt. % Zn, 1.7 - 2.2 wt. % Mg and 1.5 - 1.8 wt. % Cu. This third 7xxx
aluminum alloy
product may be a lower strength zone of the first 7xxx aluminum alloy product
region. In
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one embodiment, the third 7xxx aluminum alloy product includes not greater
than 7.2 wt. %
Zn or not greater than 7.0 wt. % Zn (e.g., to facilitate improved EAC
resistance). In one
embodiment, the third 7xxx aluminum alloy product comprises 6.0 - 7.0 wt. %
Zn.
[0015] In another embodiment, a fourth 7xxx aluminum alloy product includes
from 5.5 -
7.5 wt. % Zn, 1.7 - 2.2 wt. % Mg and 1.8 - 2.0 wt. ')//0 Cu. This forth 7xxx
aluminum alloy
product may be a middle strength zone of the first 7xxx aluminum alloy product
region. In
one embodiment, the fourth 7xxx aluminum alloy product includes not greater
than 7.2 wt. %
Zn or not greater than 7.0 wt. % Zn (e.g., to facilitate improved EAC
resistance). In one
embodiment, the fourth 7xxx aluminum alloy product comprises 6.0 - 7.0 wt. %
Zn.
[0016] In another embodiment, a fifth 7xxx aluminum alloy product includes
from 5.5 -
7.5 wt. % Zn, 1.7 - 2.2 wt. ')//0 Mg and 2.0 - 2.4 wt. ,/c. Cu. This fifth
7xxx aluminum alloy
product may be a higher strength zone of the first 7xxx aluminum alloy product
region. In
one embodiment, a fifth 7xxx aluminum alloy product includes 2.0 - 2.2 wt. %
Cu. In one
embodiment, the fifth 7xxx aluminum alloy product includes not greater than
7.2 wt. % Zn or
not greater than 7.0 wt. % Zn (e.g., to facilitate improved EAC resistance).
In one
embodiment, the fifth 7xxx aluminum alloy product comprises 6.0 - 7.0 wt. %
Zn.
[0017] The third 7xxx aluminum alloy product may realize higher toughness
and/or
elongation as compared to the fourth or fifth aluminum alloy products. The
fourth 7xxx
aluminum alloy product may realize higher toughness and/or elongation as
compared to the
fifth aluminum alloy products.
[0018] In one embodiment, a new alloy includes a total amount of copper and
magnesium
such that (wt. % Cu + wt. % Mg) > 2.9 wt. %. In another embodiment, a new
alloy includes
a total amount of copper and magnesium such that (wt. % Cu + wt. % Mg) > 3.0
wt. %. In
yet another embodiment, a new alloy includes a total amount of copper and
magnesium such
that (wt. % Cu + wt. % Mg) > 3.1 wt. %. In another embodiment, a new alloy
includes a
total amount of copper and magnesium such that (wt. % Cu + wt. % Mg) > 3.2 wt.
%. In
another embodiment, a new alloy includes a total amount of copper and
magnesium such that
(wt. % Cu + wt. % Mg) > 3.3 wt. %. In yet another embodiment, a new alloy
includes a total
amount of copper and magnesium such that (wt. % Cu + wt. % Mg) > 3.35 wt. %.
In another
embodiment, a new alloy includes a total amount of copper and magnesium such
that (wt. %
Cu + wt. % Mg) > 3.4 wt. //0. In yet another embodiment, a new alloy includes
a total
amount of copper and magnesium such that (wt. % Cu + wt. % Mg) > 3.45 wt. %.
In another
embodiment, a new alloy includes a total amount of copper and magnesium such
that (wt. %
Cu + wt. % Mg) > 3.5 wt. %. In yet another embodiment, a new alloy includes a
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amount of copper and magnesium such that (wt. % Cu + wt. % Mg) > 3.55 wt. %.
In another
embodiment, a new alloy includes a total amount of copper and magnesium such
that (wt. %
Cu + wt. % Mg) > 3.6 wt. %. In yet another embodiment, a new alloy includes a
total
amount of copper and magnesium such that (wt. % Cu + wt. % Mg) > 3.65 wt. %.
In another
embodiment, a new alloy includes a total amount of copper and magnesium such
that (wt. %
Cu + wt. % Mg) > 3.7 wt. %.
[0019] In one embodiment, a new alloy includes a total amount of copper and
magnesium
such that (wt. % Cu + wt. % Mg) < 4.5 wt. %. In another embodiment, a new
alloy includes
a total amount of copper and magnesium such that (wt. % Cu + wt. % Mg) < 4.4
wt. %. In
yet another embodiment, a new alloy includes a total amount of copper and
magnesium such
that (wt. % Cu + wt. % Mg) <4.3 wt. %. In another embodiment, a new alloy
includes a
total amount of copper and magnesium such that (wt. % Cu + wt. % Mg) < 4.2 wt.
%. In yet
another embodiment, a new alloy includes a total amount of copper and
magnesium such that
(wt. % Cu + wt. % Mg) <4.1 wt. %. In another embodiment, a new alloy includes
a total
amount of copper and magnesium such that (wt. % Cu + wt. % Mg) < 4.0 wt. %.
[0020] In one embodiment, the amounts of zinc, magnesium and copper within
the 7xxx
aluminum alloy product satisfy the relationship: 2.362 < Mg+0.429*Cu+0.067*Zn
< 3.062.
In another embodiment, the amounts of zinc, magnesium and copper within the
7xxx
aluminum alloy product satisfy the relationship: 2.502 < Mg+0.429*Cu+0.067*Zn
< 2.912.
In yet another embodiment, the amounts of zinc, magnesium and copper within
the 7xxx
aluminum alloy product satisfy the relationship: 2.662 < Mg+0.429*Cu+0.067*Zn
< 3.062.
In another embodiment, the amounts of zinc, magnesium and copper within the
7xxx
aluminum alloy product satisfy the relationship: 2.662 < Mg+0.429*Cu+0.067*Zn
< 2.912.
Any of the zinc, magnesium, and copper amounts described in the preceding
paragraphs may
be used in combination with the above-shown empirical relationships.
[0021] In one approach, the amounts of zinc and magnesium within the 7xxx
aluminum
alloy product are such that the weight ratio of zinc-to-magnesium is not
greater than 5.25:1
(i.e., (wt. % Zn / wt. % Mg) < 5.25:1). In one embodiment, a weight ratio of
zinc-to-
magnesium is not greater than 5.00:1 (i.e., (wt. % Zn / wt. % Mg) < 5.00:1).
In another
embodiment, a weight ratio of zinc-to-magnesium is not greater than 4.75:1
(i.e., (wt. % Zn /
wt. % Mg) < 4.75:1). In yet another embodiment, a weight ratio of zinc-to-
magnesium is not
greater than 4.60:1 (i.e., (wt. % Zn / wt. % Mg) < 4.60:1). In another
embodiment, a weight
ratio of zinc-to-magnesium is not greater than 4.50:1 (i.e., (wt. % Zn / wt. %
Mg) < 4.50:1).
In yet another embodiment, a weight ratio of zinc-to-magnesium is not greater
than 4.40:1
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(i.e., (wt. % Zn / wt. % Mg) < 4.40:1). In another embodiment, a weight ratio
of zinc-to-
magnesium is not greater than 4.35:1 (i.e., (wt. % Zn! wt. % Mg) < 4.35:1). In
yet another
embodiment, a weight ratio of zinc-to-magnesium is not greater than 4.30:1
(i.e., (wt. % Zn /
wt. % Mg) < 4.30:1). In another embodiment, a weight ratio of zinc-to-
magnesium is not
greater than 4.25:1 (i.e., (wt. % Zn / wt. % Mg) < 4.25:1). In yet another
embodiment, a
weight ratio of zinc-to-magnesium is not greater than 4.20:1 (i.e., (wt. % Zn
/ wt. % Mg) <
4.20:1). In another embodiment, a weight ratio of zinc-to-magnesium is not
greater than
4.15:1 (i.e., (wt. % Zn / wt. % Mg) < 4.15:1). In yet another embodiment, a
weight ratio of
zinc-to-magnesium is not greater than 4.10:1 (i.e., (wt. % Zn / wt. % Mg) <
4.10:1). In
another embodiment, a weight ratio of zinc-to-magnesium is not greater than
4.00:1 (i.e., (wt.
% Zn / wt. % Mg) < 4.00:1). In yet another embodiment, a weight ratio of zinc-
to-
magnesium is not greater than 3.95:1 (i.e., (wt. % Zn / wt. % Mg) < 3.95:1).
In another
embodiment, a weight ratio of zinc-to-magnesium is not greater than 3.90:1
(i.e., (wt. % Zn /
wt. % Mg) < 3.90:1).
[0022] In one approach, the amounts of zinc and magnesium within the 7xxx
aluminum
alloy product are such that the weight ratio of zinc-to-magnesium is at least
3.0:1 (i.e., (wt. %
Zn / wt. % Mg) > 3.0:1). In one embodiment, the amounts of zinc and magnesium
within the
7xxx aluminum alloy product are such that the weight ratio of zinc-to-
magnesium is at least
3.25:1 (i.e., (wt. % Zn / wt. % Mg) > 3.25:1). In another embodiment, the
amounts of zinc
and magnesium within the 7xxx aluminum alloy product are such that the weight
ratio of
zinc-to-magnesium is at least 3.33:1 (i.e., (wt. % Zn / wt. % Mg) > 3.33:1).
In yet another
embodiment, the amounts of zinc and magnesium within the 7xxx aluminum alloy
product
are such that the weight ratio of zinc-to-magnesium is at least 3.45:1 (i.e.,
(wt. % Zn! wt. %
Mg) > 3.45:1). In another embodiment, the amounts of zinc and magnesium within
the 7xxx
aluminum alloy product are such that the weight ratio of zinc-to-magnesium is
at least 3.55:1
(i.e., (wt. % Zn / wt. % Mg) > 3.55:1). In yet another embodiment, the amounts
of zinc and
magnesium within the 7xxx aluminum alloy product are such that the weight
ratio of zinc-to-
magnesium is at least 3.60:1 (i.e., (wt. % Zn! wt. % Mg) > 3.60:1).
[0023] As noted above, the new 7xxx aluminum alloy product may include one
or more
of Zr, Cr, Sc, and Hf as grain structure control materials (e.g., from 0.05-
0.25 wt. % each of
one or more of Zr, Cr, Sc, and Hf), limiting the total amounts of these
elements such that
large primary particles do not form in the alloy. Grain structure control
materials may, for
instance, facilitate an appropriate grain structure (e.g., an unrecrystallized
grain structure).
When employed, a new 7xxx aluminum alloy product generally includes at least
0.05 wt. %
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of the gain structure control materials. In one embodiment, a new 7xxx
aluminum alloy
product includes at least 0.07 wt. % of the grain structure control materials.
In another
embodiment, a new 7xxx aluminum alloy product includes at least 0.09 wt. % of
the grain
structure control materials. When employed, a new 7xxx aluminum alloy product
generally
includes not greater than 1.0 wt. % of the gain structure control materials.
In one
embodiment, a new 7xxx aluminum alloy product includes not greater than 0.75
wt. % of the
grain structure control materials. In yet another embodiment, a new 7xxx
aluminum alloy
product includes not greater than 0.50 wt. % of the grain structure control
materials. In one
embodiment, the grain structure control materials are selected from the group
consisting of
Zr, Cr, Sc, and Hf. In another embodiment, the grain structure control
materials are selected
from the group consisting of Zr and Cr. In another embodiment, the grain
structure control
material is Zr. In another embodiment, the grain structure control material is
Cr.
[0024] In one embodiment, the grain structure control materials comprise
both Zr and Cr,
and a new 7xxx aluminum alloy product includes at least 0.07 wt. % Zr and at
least 0.07 wt.
% Cr, wherein the wt. % Zr plus the wt. % Cr is not greater than 0.40 wt. %
(i.e., wt. % Zr +
wt. % Cr < 0.40 wt. %). In another embodiment, the grain structure control
materials
comprise both Zr and Cr, and a new 7xxx aluminum alloy product includes at
least 0.07 wt.
% Zr and at least 0.07 wt. % Cr, wherein the wt. % Zr plus the wt. % Cr is not
greater than
0.35 wt. % (i.e., wt. % Zr + wt. % Cr < 0.35 wt. %). In another embodiment,
the grain
structure control materials comprise both Zr and Cr, and a new 7xxx aluminum
alloy product
includes at least 0.07 wt. % Zr and at least 0.07 wt. % Cr, wherein the wt. %
Zr plus the wt.
% Cr is not greater than 0.30 wt. % (i.e., wt. % Zr + wt. % Cr < 0.30 wt. %).
In another
embodiment, the grain structure control materials comprise both Zr and Cr, and
a new 7xxx
aluminum alloy product includes at least 0.07 wt. % Zr and at least 0.07 wt. %
Cr, wherein
the wt. % Zr plus the wt. % Cr is not greater than 0.25 wt. % (i.e., wt. % Zr
+ wt. % Cr < 0.25
wt. %). In another embodiment, the grain structure control materials comprise
both Zr and
Cr, and a new 7xxx aluminum alloy product includes at least 0.07 wt. % Zr and
at least 0.07
wt. % Cr, wherein the wt. % Zr plus the wt. % Cr is not greater than 0.20 wt.
% (i.e., wt. %
Zr + wt. % Cr < 0.20 wt. %). In any of these embodiment, a new 7xxx aluminum
alloy
product may include at least 0.09 wt. % of at least one of Zr and Cr. In any
of these
embodiments, a new 7xxx aluminum alloy product may include at least 0.09 wt. %
of both Zr
and Cr.
[0025] In one embodiment, the grain structure control material is Zr, and a
new 7xxx
aluminum alloy product includes from 0.07 to 0.18 wt. % Zr. In another
embodiment, the
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grain structure control material is Zr, and a new 7xxx aluminum alloy product
includes from
0.07 to 0.16 wt. % Zr. In yet another embodiment, the grain structure control
material is Zr,
and a new 7xxx aluminum alloy product includes from 0.08 to 0.15 wt. % Zr. In
another
embodiment, the grain structure control material is Zr, and a new 7xxx
aluminum alloy
product includes from 0.09 to 0.14 wt. % Zr. In embodiments where the grain
structure
control material is Zr, a new 7xxx aluminum alloy product generally contains
low amounts of
the Cr, Sc, and Hf (e.g., < 0.04 wt. % each of Cr, Sc, and Hf). In one
embodiment, a new
7xxx aluminum alloy product contains not greater than 0.03 wt. % each of Cr,
Sc, and Hf. In
another embodiment, a new 7xxx aluminum alloy product contains not greater
than 0.02 wt.
% each of Cr, Sc, and Hf. In another embodiment, a new 7xxx aluminum alloy
product
contains not greater than 0.01 wt. % each of Cr, Sc, and Hf. In another
embodiment, a new
7xxx aluminum alloy product contains not greater than 0.005 wt. % each of Cr,
Sc, and Hf.
[0026] In one embodiment, the grain structure control material is Cr, and a
new 7xxx
aluminum alloy product includes from 0.07 to 0.25 wt. % Cr. In another
embodiment, the
grain structure control material is Cr, and a new 7xxx aluminum alloy product
includes from
0.07 to 0.20 wt. % Cr. In yet another embodiment, the grain structure control
material is Cr,
and a new 7xxx aluminum alloy product includes from 0.08 to 0.15 wt. % Cr. In
another
embodiment, the grain structure control material is Cr, and a new 7xxx
aluminum alloy
product includes from 0.10 to 0.15 wt. % Cr. In other embodiments, a new 7xxx
aluminum
alloy product contains low amounts of Cr (e.g., < 0.04 wt. % Cr.) In one
embodiment, a new
7xxx aluminum alloy product contains not greater than 0.03 wt. % Cr. In
another
embodiment, a new 7xxx aluminum alloy product contains not greater than 0.02
wt. % Cr. In
yet another embodiment, a new 7xxx aluminum alloy product contains not greater
than 0.01
wt. % Cr. In another embodiment, a new 7xxx aluminum alloy product contains
not greater
than 0.005 wt. % Cr.
[0027] In some embodiments, a new 7xxx aluminum alloy includes low amounts
of
zirconium (e.g., < 0.04 wt. % Zr). In one embodiment, a new 7xxx aluminum
alloy product
contains not greater than 0.03 wt. % Zr. In another embodiment, a new 7xxx
aluminum alloy
product contains not greater than 0.02 wt. % Zr. In yet another embodiment, a
new 7xxx
aluminum alloy product contains not greater than 0.01 wt. % Zr. In another
embodiment, a
new 7xxx aluminum alloy product contains not greater than 0.005 wt. % Zr.
[0028] As noted above, the new 7xxx aluminum alloy product may include up
to 0.15 wt.
% Ti. Titanium may be used to facilitate grain refining during casting, such
as by using TiB2
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or TiC. Elemental titanium may also or alternatively be used. In one
embodiment, the new
7xxx aluminum alloy product includes from 0.005 to 0.025 wt. % Ti.
[0029] As noted above, the new 7xxx aluminum alloy product may include up
to 0.15 wt.
% Si and up to 0.20 wt. % Fe as impurities. The amount of silicon and iron may
be limited so
as to avoid detrimentally impacting the combination of strength, fracture
toughness and crack
deviation resistance. In one embodiment, the new 7xxx aluminum alloy product
may include
up to 0.12 wt. % Si and up to 0.15 wt. % Fe as impurities. In another
embodiment, the new
7xxx aluminum alloy product may include up to 0.10 wt. % Si and up to 0.12 wt.
% Fe as
impurities. In another embodiment, the new 7xxx aluminum alloy product may
include up to
0.08 wt. % Si and up to 0.10 wt. % Fe as impurities. In yet another
embodiment, the new
7xxx aluminum alloy product may include up to 0.06 wt. % Si and up to 0.08 wt.
% Fe as
impurities. In yet another embodiment, the new 7xxx aluminum alloy product may
include up
to 0.04 wt. % Si and up to 0.06 wt. % Fe as impurities. In another embodiment,
the new 7xxx
aluminum alloy product may include up to 0.03 wt. % Si and up to 005 wt. % Fe
as
impurities.
[0030] As noted above, the new 7xxx aluminum alloy product has a thickness
of from 1.5
to 12.0 inches. In one embodiment, the new 7xxx aluminum alloy product has a
thickness of
from 2.0 to 10.0 inches. In another embodiment, the new 7xxx aluminum alloy
product has a
thickness of from 3.0 to 8.0 inches (7.62 - 20.3 cm). In another embodiment,
the new 7xxx
aluminum alloy product has a thickness of from 1.5 to 8.0 inches. In another
embodiment, the
new 7xxx aluminum alloy product has a thickness of from 1.5 to 6.0 inches In
another
embodiment, the new 7xxx aluminum alloy product has a thickness of from 1.5 to
4.0 inches.
In another embodiment, the new 7xxx aluminum alloy product has a thickness of
from 2.0 to
8.0 inches. In another embodiment, the new 7xxx aluminum alloy product has a
thickness of
from 2.0 to 6.0 inches. In another embodiment, the new 7xxx aluminum alloy
product has a
thickness of from 3.0 to 6.0 inches. In another embodiment, the new 7xxx
aluminum alloy
product has a thickness of from 4.0 to 10.0 inches. In another embodiment, the
new 7xxx
aluminum alloy product has a thickness of from 4.0 to 8.0 inches. In another
embodiment, the
new 7xxx aluminum alloy product has a thickness of from 4.0 to 6.0 inches.
[0031] In one embodiment, a new 7xxx aluminum alloy product is a rolled
product (e.g.,
a plate product). In another embodiment, a new 7xxx aluminum alloy product is
an extruded
product. In yet another embodiment, a new 7xxx aluminum alloy product is a
forged product
(e.g., a hand forged product, a die forged product).
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[0032] As mentioned above, the new 7xxx aluminum alloy products may realize
an
improved combination of properties. In one embodiment, a new 7xxx aluminum
alloy
product realizes a typical tensile yield strength (L) of at least 63 ksi as
per ASTM E8 and
B557. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical tensile
yield strength (L) of at least 64 ksi. In yet another embodiment, a new 7xxx
aluminum alloy
product realizes a typical tensile yield strength (L) of at least 65 ksi. In
another embodiment,
a 7xxx aluminum alloy product may realize a typical tensile yield strength (L)
of at least 66
ksi In yet another embodiment, a 7xxx aluminum alloy product may realize a
typical tensile
yield strength (L) of at least 67 ksi. In another embodiment, a 7xxx aluminum
alloy product
may realize a typical tensile yield strength (L) of at least 68 ksi. In yet
another embodiment,
a 7xxx aluminum alloy product may realize a typical tensile yield strength (L)
of at least 69
ksi. In another embodiment, a 7xxx aluminum alloy product may realize a
typical tensile
yield strength (L) of at least 70 ksi. In yet another embodiment, a 7xxx
aluminum alloy
product may realize a typical tensile yield strength (L) of at least 71 ksi.
In another
embodiment, a 7xxx aluminum alloy product may realize a typical tensile yield
strength (L)
of at least 72 ksi. In yet another embodiment, a 7xxx aluminum alloy product
may realize a
typical tensile yield strength (L) of at least 73 ksi.
[0033] In one embodiment, a new 7xxx aluminum alloy product realizes a
typical tensile
yield strength (ST) of at least 57 ksi as per ASTM E8 and B557. In another
embodiment, a
7xxx aluminum alloy product may realize a typical tensile yield strength (ST)
of at least 58
ksi. In yet another embodiment, a 7xxx aluminum alloy product may realize a
typical tensile
yield strength (ST) of at least 59 ksi. In another embodiment, a 7xxx aluminum
alloy product
may realize a typical tensile yield strength (ST) of at least 60 ksi. In yet
another embodiment,
a 7xxx aluminum alloy product may realize a typical tensile yield strength
(ST) of at least 61
ksi. In another embodiment, a 7xxx aluminum alloy product may realize a
typical tensile
yield strength (ST) of at least 62 ksi. In yet another embodiment, a 7xxx
aluminum alloy
product may realize a typical tensile yield strength (ST) of at least 63 ksi.
In another
embodiment, a 7xxx aluminum alloy product may realize a typical tensile yield
strength (ST)
of at least 64 ksi. In yet another embodiment, a 7xxx aluminum alloy product
may realize a
typical tensile yield strength (ST) of at least 65 ksi. In another embodiment,
a 7xxx
aluminum alloy product may realize a typical tensile yield strength (ST) of at
least 66 ksi.
[0034] In one embodiment, a new 7xxx aluminum alloy product realizes a
typical Kw
plane-strain fracture toughness (L-T) of at least 25 ksi-sqrt-inch as per ASTM
E8 and E399-
12. In yet another embodiment, a new 7xxx aluminum alloy product realizes a
typical Kir
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plane-stain fracture toughness (L-T) of at least 27 ksi-sqrt-inch. In another
embodiment, a
new 7xxx aluminum alloy product realizes a typical Kw, plane-stain fracture
toughness (L-T)
of at least 28 ksi-sqrt-inch. In yet another embodiment, a new 7xxx aluminum
alloy product
realizes a typical Kw plane-stain fracture toughness (L-T) of at least 29 ksi-
sqrt-inch. In
another embodiment, a new 7xxx aluminum alloy product realizes a typical Kic
plane-stain
fracture toughness (L-T) of at least 30 ksi-sqrt-inch. In yet another
embodiment, a new 7xxx
aluminum alloy product realizes a typical Kw plane-stain fracture toughness (L-
T) of at least
31 ksi-sqrt-inch. In another embodiment, a new 7xxx aluminum alloy product
realizes a
typical Kw plane-stain fracture toughness (L-T) of at least 32 ksi-sqrt-inch.
In yet another
embodiment, a new 7xxx aluminum alloy product realizes a typical Kw plane-
stain fracture
toughness (L-T) of at least 33 ksi-sqrt-inch In another embodiment, a new 7xxx
aluminum
alloy product realizes a typical Kw plane-stain fracture toughness (L-T) of at
least 34 ksi-sqrt-
inch. In yet another embodiment, a new 7xxx aluminum alloy product realizes a
typical Kic
plane-stain fracture toughness (L-T) of at least 35 ksi-sqrt-inch. In another
embodiment, a
new 7xxx aluminum alloy product realizes a typical Kic plane-stain fracture
toughness (L-T)
of at least 36 ksi-sqrt-inch. In yet another embodiment, a new 7xxx aluminum
alloy product
realizes a typical Kw plane-stain fracture toughness (L-T) of at least 37 ksi-
sqrt-inch. In
another embodiment, a new 7xxx aluminum alloy product realizes a typical Kw
plane-stain
fracture toughness (L-T) of at least 38 ksi-sqrt-inch. In yet another
embodiment, a new 7xxx
aluminum alloy product realizes a typical Kw plane-stain fracture toughness (L-
T) of at least
39 ksi-sqrt-inch. In another embodiment, a new 7xxx aluminum alloy product
realizes a
typical Kic plane-stain fracture toughness (L-T) of at least 40 ksi-sqrt-inch.
In yet another
embodiment, a new 7xxx aluminum alloy product realizes a typical Kr plane-
stain fracture
toughness (L-T) of at least 41 ksi-sqrt-inch. In another embodiment, a new
7xxx aluminum
alloy product realizes a typical Kw plane-stain fracture toughness (L-T) of at
least 42 ksi-sqrt-
inch. In yet another embodiment, a new 7xxx aluminum alloy product realizes a
typical Kw
plane-stain fracture toughness (L-T) of at least 43 ksi-sqrt-inch. In another
embodiment, a
new 7xxx aluminum alloy product realizes a typical Kic plane-stain fracture
toughness (L-T)
of at least 44 ksi-sqrt-inch. In yet another embodiment, a new 7xxx aluminum
alloy product
realizes a typical Kw plane-stain fracture toughness (L-T) of at least 45 ksi-
sqrt-inch.
[0035] In one embodiment, a new 7xxx aluminum alloy product realizes a
typical Kw
plane-strain fracture toughness (S-L) of at least 20 ksi-sqrt-inch as per ASTM
E8 and E399-
12. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical Kw plane-
strain fracture toughness (S-L) of at least 22 ksi-sqrt-inch. In another
embodiment, a new
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7xxx aluminum alloy product realizes a typical Kr plane-strain fracture
toughness (S-L) of at
least 24 ksi-sqrt-inch. In another embodiment, a new 7xxx aluminum alloy
product realizes a
typical Kw plane-strain fracture toughness (S-L) of at least 26 ksi-sqrt-inch.
In another
embodiment, a new 7xxx aluminum alloy product realizes a typical Kic plane-
strain fracture
toughness (S-L) of at least 28 ksi-sqrt-inch. In another embodiment, a new
7xxx aluminum
alloy product realizes a typical Kw plane-strain fracture toughness (S-L) of
at least 30 ksi-
sqrt-inch. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical Kw
plane-strain fracture toughness (S-L) of at least 32 ksi-sqrt-inch. In another
embodiment, a
new 7xxx aluminum alloy product realizes a typical Kw plane-strain fracture
toughness (S-L)
of at least 34 ksi-sqrt-inch. In another embodiment, a new 7xxx aluminum alloy
product
realizes a typical Kw plane-strain fracture toughness (S-L) of at least 36 ksi-
sqrt-inch. In
another embodiment, a new 7xxx aluminum alloy product realizes a typical Kic
plane-strain
fracture toughness (S-L) of at least 38 ksi-sqrt-inch. In another embodiment,
a new 7xxx
aluminum alloy product realizes a typical Kw plane-strain fracture toughness
(S-L) of at least
40 ksi-sqrt-inch.
[0036] In one embodiment, a new 7xxx aluminum alloy product realizes a
typical
elongation (L) of at least 8% as per ASTM E8 and B557. In another embodiment,
a new
7xxx aluminum alloy product realizes a typical elongation (L) of at least 9%.
In yet another
embodiment, a new 7xxx aluminum alloy product realizes a typical elongation
(L) of at least
10%. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical
elongation (L) of at least 11%. In yet another embodiment, a new 7xxx aluminum
alloy
product realizes a typical elongation (L) of at least 12%. In another
embodiment, a new 7xxx
aluminum alloy product realizes a typical elongation (L) of at least 13%. In
yet another
embodiment, a new 7xxx aluminum alloy product realizes a typical elongation
(L) of at least
14%. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical
elongation (L) of at least 15%. In yet another embodiment, a new 7xxx aluminum
alloy
product realizes a typical elongation (L) of at least 16%.
[0037] In one embodiment, a new 7xxx aluminum alloy product realizes a
typical
elongation (ST) of at least 3% as per ASTM E8 and B557. In another embodiment,
a new
7xxx aluminum alloy product realizes a typical elongation (ST) of at least 4%.
In yet another
embodiment, a new 7xxx aluminum alloy product realizes a typical elongation
(ST) of at
least 5%. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical
elongation (ST) of at least 6%. In yet another embodiment, a new 7xxx aluminum
alloy
product realizes a typical elongation (ST) of at least 7%. In another
embodiment, a new 7xxx
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aluminum alloy product realizes a typical elongation (ST) of at least 8%. In
yet another
embodiment, a new 7xxx aluminum alloy product realizes a typical elongation
(ST) of at
least 9%. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical
elongation (ST) of at least 10%.
[0038] In one embodiment, a new 7xxx aluminum alloy product realizes a
typical L-S
crack deviation resistance (Krnax-dev) of at least 25 ksi-sqrt-in. In another
embodiment, a new
7xxx aluminum alloy product realizes a typical L-S crack deviation resistance
(Kmax-dev) of at
least 27 ksi-sqrt-in. In yet another embodiment, a new 7xxx aluminum alloy
product realizes
a typical L-S crack deviation resistance (Kmax.d,) of at least 29 ksi-sqrt-in.
In another
embodiment, a new 7xxx aluminum alloy product realizes a typical L-S crack
deviation
resistance (Kmax-dev) of at least 31 ksi-sqrt-in. In yet another embodiment, a
new 7xxx
aluminum alloy product realizes a typical L-S crack deviation resistance (Kmax-
dev) of at least
33 ksi-sqrt-in. In another embodiment, a new 7xxx aluminum alloy product
realizes a typical
L-S crack deviation resistance (Kmax-dev) of at least 35 ksi-sqrt-in In yet
another embodiment,
a new 7xxx aluminum alloy product realizes a typical L-S crack deviation
resistance (Kmax_
del) of at least 37 ksi-sqrt-in. In another embodiment, a new 7xxx aluminum
alloy product
realizes a typical L-S crack deviation resistance (Kmax-dev) of at least 39
ksi-sqrt-in. In yet
another embodiment, a new 7xxx aluminum alloy product realizes a typical L-S
crack
deviation resistance (Kmax-dey) of at least 41 ksi-sqrt-in. In another
embodiment, a new 7xxx
aluminum alloy product realizes a typical L-S crack deviation resistance (Kmax-
dev) of at least
43 ksi-sqrt-in. In yet another embodiment, a new 7xxx aluminum alloy product
realizes a
typical L-S crack deviation resistance (Kma,d) of at least 45 ksi-sqrt-in. In
another
embodiment, a new 7xxx aluminum alloy product realizes a typical L-S crack
deviation
resistance (Kmax-dev) of at least 47 ksi-sqrt-in. In yet another embodiment, a
new 7xxx
aluminum alloy product realizes a typical L-S crack deviation resistance (Kmax-
dev) of at least
49 ksi-sqrt-in. In another embodiment, a new 7xxx aluminum alloy product
realizes a typical
L-S crack deviation resistance (Kmax-dev) of at least 50 ksi-sqrt-in.
[0039] In one embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 85% of TYS-ST of at least 80 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 85% of TYS-ST of
at least 100
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 85% of TYS-ST of at least 120 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 85% of TYS-ST of
at least 140
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
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resistance at 85% of TYS-ST of at least 160 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 85% of TYS-ST of
at least 180
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 85% of TYS-ST of at least 200 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 85% of TYS-ST of
at least 220
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 85% of TYS-ST of at least 240 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 85% of TYS-ST of
at least 260
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 85% of TYS-ST of at least 280 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 85% of TYS-ST of
at least 300
days.
[0040] In one embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 60% of TYS-ST of at least 90 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 60% of TYS-ST of
at least 120
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 60% of TYS-ST of at least 150 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 60% of TYS-ST of
at least 180
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 60% of TYS-ST of at least 210 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 60% of TYS-ST of
at least 240
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 60% of TYS-ST of at least 270 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 60% of TYS-ST of
at least 300
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 60% of TYS-ST of at least 330 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 60% of TYS-ST of
at least 360
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 60% of TYS-ST of at least 390 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 60% of TYS-ST of
at least 420
days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 60% of TYS-ST of at least 450 days. In another embodiment, a new
7xxx
aluminum alloy product realizes a typical EAC resistance at 60% of TYS-ST of
at least 480
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days. In another embodiment, a new 7xxx aluminum alloy product realizes a
typical EAC
resistance at 60% of TYS-ST of at least 500 days.
[0041] As noted above, the new thick 7xxx aluminum alloy products may be
suitable for
parts in various aerospace applications. In one embodiment, the alloy product
is an aerospace
structural component. The aircraft structural component may be any of an upper
wing panel
(skin), an upper wing stringer, an upper wing cover with integral stringers, a
spar, a spar cap,
a spar web, a rib, rib feet or a rib web, stiffening elements, frames, a
landing gear component
(e.g., a cylinders, beams), drag braces, bulkheads, flap track assemblies,
fuselage and
windshield frames, gear ribs, side stays, fittings, a fuselage component
(e.g., a fuselage skin),
and space components (e.g., for rockets and other vehicles that may exit the
earth). In one
embodiment, the alloy product is an armor component (e.g., of a motorized
vehicle). In one
embodiment, the alloy product is used in the oil and gas industry (e.g., as
pipes, structural
components). In one embodiment, the alloy product is a thick mold block / mold
plate
product (e.g., for injection molding). In one embodiment, the alloy product is
an automotive
product.
[0042] The new thick 7xxx aluminum alloy products may be made into wrought
products
by casting an aluminum alloy having any of the aforementioned compositions
into an ingot or
billet, followed by homogenizing of the ingot or billet. The homogenized ingot
or billet may
worked by rolling, extruding, or forging to final gauge, generally by hot
working, optionally
with some cold working. The final gauge product may be solution heat treated,
and then
quenched, and then stress relieved (e.g., by stretching or compression) and
then artificially
aged.
[0043] Aside from traditional wrought products, the new 7xxx aluminum
alloys may be
made into shape castings or by additive manufacturing into additively
manufactured products.
The additively manufactured products may be used as-is, or may be subsequently
processed,
e.g., processed via mechanical, thermal, or thermomechanical treatment.
Definitions
[0044] As used herein, "typical longitudinal (L) tensile yield strength" or
TYS(L) is
determined in accordance with ASTM B557-10 and by measuring the tensile yield
strength
(TYS) in the longitudinal direction (L) at the T/4 location from at least
three different lots of
material, and with at least duplicate specimens being tested for each lot, for
a total of at least
6 different measured specimen values, with the typical TYS(L) being the
average of the at
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least 6 different measured specimen values. Typical elongation (L) is measured
during
longitudinal tensile testing.
[0045] As used herein, "typical longitudinal (ST) tensile yield strength"
or TYS(ST) is
determined in accordance with ASTM B557-10 and by measuring the tensile yield
strength
(TYS) in the short transverse direction (ST) from at least three different
lots of material, and
with at least duplicate specimens being tested for each lot, for a total of at
least 6 different
measured specimen values, with the typical TYS(ST) being the average of the at
least 6
different measured specimen values. Short transverse tensile specimens are
taken so that the
midpoint of the gage section coincides with the plate mid-thickness plane.
Typical
elongation (ST) is measured during short transverse tensile testing.
[0046] As used herein, "typical plane strain fracture toughness (Kir) (L-
T)" is determined
in accordance with ASTM E399-12, by measuring the plane strain fracture
toughness in the
L-T direction at the T/4 location from at least three different lots of
material using a C(T)
specimen, where "W" is 4.0 inches, and where "B" is 2.0 inches for products
having a
thickness of at least 2.0 inches and where "B" is 1.5 inches for products
having a thickness
less than 2.0 inches, with at least duplicate specimens being tested for each
lot, for a total of
at least 6 different measured specimen values, and with the typical plane
strain fracture
toughness (Kw) (L-T) being the average of the at least 6 different valid Kw
measured
specimen values.
[0047] As used herein, "typical plane strain fracture toughness (Kw) (S-L)"
is determined
in accordance with ASTM E399-12, by measuring the plane strain fracture
toughness in the
S-L direction at the T/2 location from at least three different lots of
material using a C(T)
specimen, where "W" and "B" are per the below table, with at least duplicate
specimens
being tested for each lot, for a total of at least 6 different measured
specimen values, and with
the typical plane strain fracture toughness (Kw) (S-L) being the average of
the at least 6
different valid Kic measured specimen values
S-L specimen parameters
Product Thickness õW" _____ "B"
> 5.0 inches 4.0 inches 2.0 inches
<5.0 inches to > 3.8 inches 3.0 inches 1.5 inches
<3.8 inches to? 3.2 inches 2.5 inches 1.25 inches
<3.2 inches to > 2.6 inches 2.0 inches 1.0 inches
<2.6 inches to > 2.0 inches 1.5 inches 0.75 inches
17
Product Thickness õW" -B"
<2.0 inches to? 1.5 inches 1.0 inches 0.5 inches
[0048] The typical L-S crack deviation resistance properties (Kmax-dev) are
to be
determined per the procedure described in commonly-owned U.S. Patent
Application
Publication No. 2017/0088920, paragraph 0058, except: (a) the ``W" dimension
of the
specimen shall be 2.0 inches (5.08 cm), (b) the specimen shall be centered at
T/2 (as opposed
to the notch tip), and (c) the test specimens may be tested in lab air as
opposed to high
humidity air.
[0049] As used herein, -EAC resistance" is tested per ASTM G49 and per the
conditions
defined below. At least three short transverse (ST) samples are taken from mid-
thickness of
the final product and between W/4 and 3W/4 of the final product. The extracted
samples are
then machined into tensile specimens per ASTM E8 and matching the dimensions
of FIG. 3
(the dimensions of FIG. 3 are in inches). If the final product thickness is at
least 2.25 inches,
then the length of the tensile specimen is 2.00 inches, as shown in FIG. 3. If
the final product
thickness is from 1.50 inches to less than 2.25 inches, the length of the
specimen must be at
least 1.25 inches and should be as close to 2.00 inches as possible. Prior to
testing the tensile
specimens are to be cleaned / degreased by washing in acetone. The tensile
specimens are
then strained in the short-transverse direction at 85% or 60% of their ST
tensile yield strength
(strength being measured at room temperature). The stressing frame used is a
constant strain
type per ASTM G49, section 7.2.2 (see, e.g., FIG. 4a of ASTM G49). The
strained
specimens are then placed into a controlled cabinet having air at 85% relative
humidity
(without additions to the air, such as chlorides) and a temperature of 70 C.
At least three
specimens must be tested. The -typical EAC resistance" is the lowest failure
date of the at
least three specimens. For instance, if specimen A fails at 76 days, but
specimens B and C
fail at 140 and 180 days, respectively, the -typical EAC resistance" is 76
days. A failure is
when the specimen breaks into two halves, either along the gauge length or at
one of the
specimen shoulders adjoining the gauge length. Shoulder failures are
statistically equivalent
to gauge length failures. Thread failures are not included when determining
typical EAC
resistance. A thread failure is when a crack occurs in a threaded end of a
specimen as
opposed to in the gauge length. Thread failures are generally not detectable
until the
specimen is removed from the stressing frame.
[0050] The term -square root" may be abbreviated herein as -sqrt."
18
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[0051] Throughout the specification and claims, the following terms take
the meanings
explicitly associated herein, unless the context clearly dictates otherwise.
The phrases "in
one embodiment" and "in some embodiments" as used herein do not necessarily
refer to the
same embodiment(s), though they may. Furthermore, the phrases "in another
embodiment"
and "in some other embodiments" as used herein do not necessarily refer to a
different
embodiment, although they may. Thus, as described below, various embodiments
of the
invention may be readily combined, without departing from the scope or spirit
of the
invention.
[0052] In addition, as used herein, the term "or" is an inclusive "or"
operator, and is
equivalent to the term "and/or," unless the context clearly dictates
otherwise. The term
"based on" is not exclusive and allows for being based on additional factors
not described,
unless the context clearly dictates otherwise. In addition, throughout the
specification, the
meaning of "a," "an," and "the" include plural references, unless the context
clearly dictates
otherwise. The meaning of "in" includes "in" and "on", unless the context
clearly dictates
otherwise.
[0053] While a number of embodiments of the present invention have been
described, it
is understood that these embodiments are illustrative only, and not
restrictive, and that many
modifications may become apparent to those of ordinary skill in the art.
Further still, unless
the context clearly requires otherwise, the various steps may be carried out
in any desired
order, and any applicable steps may be added and/or eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] FIG. 1 is a graph showing EAC resistance properties of Example 1
alloys at 85%
of its TYS-ST.
[0055] FIG. 2 is a graph showing EAC resistance properties of Example 1
alloys at 60%
of its TYS-ST.
[0056] FIG. 3 is an illustration of a tensile specimen for testing EAC
resistance
properties.
[0057] FIG. 4 is a graph showing EAC resistance properties of Example 3
alloys at 85%
of its TYS-ST.
[0058] FIG. 5 is a graph showing EAC resistance properties of Example 3
alloys at 60%
of its TYS-ST.
[0059] FIG. 6 is a graph showing EAC resistance properties of Example 4
alloys at 85%
of its TYS-ST.
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[0060] FIG. 7 is a graph showing EAC resistance properties of Example 4
alloys at 60%
of its TYS-ST.
DETAILED DESCRIPTION
Example 1
[0061] Various 7xxx aluminum alloys were cast as six inch (15.24 cm) thick
ingots
(nominal). The actual compositions of the cast ingots are shown in Table 1,
below. 7085-LS
is a lab scale version of a conventional aluminum alloy, registered with the
Aluminum
Association as aluminum alloy 7085. The registered version of the 7085 alloy
requires,
among other things, 0.08 - 0.15 wt. % Zr, not greater than 0.04 wt. % Mn and
not greater than
0.04 wt. % Cr, as shown by the document "International Alloy Designations and
Chemical
Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys", The
Aluminum Association (2009), page 12. Commonly-owned U.S. Patent No. 6,972,110
(among others) also relates to the 7085 alloy. Alloys 1-7 are new alloys
having lower
amounts of zinc (Zn) and/or also having manganese (Mn).
Table 1 - Composition of Example 1 Alloys (wt. %) - Lab Scale Materials
Alloy Si Fe Cu Mn Mg Cr Zn Ti Zr
1 0.02 0.04 1.68 0.23 1.55 -- 7.42 0.03 0.11
2 0.02 0.05 1.59 0.35 1.47 -- 6.48 0.03 0.11
3 0.02 0.04 1.62 0.35 1.39 0.12 6.43 0.02 0.11
4 0.03 0.04 1.74 0.34 1.34 -- 7.44 0.03 0.10
0.02 0.04 1.67 0.36 1.33 0.15 7.52 0.02 0.11
6 0.02 0.04 1.92 0.36 1.53 -- 6.41 0.02 0.11
7 0.02 0.04 1.69 0.35 1.71 -- 6.43 0.02 0.11
7085-
LS 0.02 0.04 1.67 -- 1.51 -- 7.64 0.02 0.11
The balance of each alloy was aluminum and unavoidable impurities (< 0.03 wt.
% each, <
0.10 wt. % total). After casting, the ingots were stress-relieved, sawed into
multiple sections,
scalped, homogenized, and then hot rolled to plate having a final gauge of
about 1.75 inches
(4.445 cm). The alloy plates were then solution heat treated and then hot
water quenched in
190 F water (87.8 C) to simulate cooling conditions at T/2 (mid-thickness) for
5 inch plate
relative to cold water (ambient) quenching. The plates were then stretched
about 2.25% and
then artificially aged. Table 2, below, provides the aging conditions for the
various alloys.
Samples of alloys 4, 6 and 7 were aged using two different aging practices.
The 7085 plates
were aged to a T7451-type or a T7651-type temper (see, ANSI H35.1, AMS-4329A).
Table 2 ¨ Aging Practice for Various Alloys
Alloy Aging Practice
Alloy 1 6h/250F + 14-
15h/310F + Air Cool +
24h/250F
Alloy 2 6h/250F + 10-
11h/320F + Air Cool +
24h/250F
Alloy 3 6h/250F + 7h/320F +
Air Cool + 24h/250F
Alloy 4-1 6h/250F + 6-7h/320F +
Air Cool + 24h/250F
Alloy 4-2 6h/250F + 10h/320F +
Air Cool + 24h/250F
Alloy 5 6h/250F + 4-5h/320F +
Air Cool + 24h/250F
Alloy 6-1 6h/250F + 12-
13h/320F + Air Cool +
24h/250F
Alloy 6-2 6h/250F + 13-
14h/320F + Air Cool +
24h/250F
Alloy 7-1 6h/250F + 14-
15h/320F + Air Cool +
24h/250F
Alloy 7-2 6h/250F + 16-
17h/320F + Air Cool +
24h/250F
[0062] Various
properties of the aluminum alloy plates were then tested. Specifically, the
strength and elongation properties were tested in accordance with ASTM E8 and
B557 at the
T/2 location of the material. Plane strain fracture toughness properties were
tested in the L-T
direction and in accordance with ASTM E399 using a C(T) specimen taken from
the T/2
location of the material, where the "B" dimension of the specimen was 0.25
inch (6.35 mm)
and the "W" dimension of the specimen was 2.5 inches (63.5 mm). The typical L-
S crack
deviation resistance properties (K. 1 were
determined per the procedure described in
ax-dev,
commonly-owned U.S. Patent Application Publication No. 2017/0088920, paragraph
0058,
except, for this Example 1, the "W" dimension of the specimen was 1.3 inches
(33.02 mm).
The test is started using a Kmax of approximately 20 ksi-gin.
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[0063] The test results are shown in Table 3, below. The shown strength and
elongation
values are averages of duplicate specimens. The fracture toughness values are
taken from a
single specimen. The crack deviation values are averages of triplicate
specimens.
Table 3 - Measured Properties
KQ L-T
All Kmax-dcv =
TYS- UTS- elong- ST (ksi-
oy (ksi) TYS- ) (ksi)
ST UTS-) Elong- (ksi-
L (ksi) L (ksi) L (%) ST (%) sqrt-
sqrt-in.) in.)
1 71.2 77.9 13.5 64.5 75.9 9.4 29.4 32.0
2 67.3 75.3 15.0 60.5 72.8 10.2 40.9 39.7
,
3 66.4 74.5 14.5 61.9 73.4 10.2 45.3 42.5
4-1 70.9 77.2 14.0 63.7 75.0 10.2 31.6
34.9
4-2 65.8 73.2 13.3 59.8 71.2 10.2 N/A N/A
68.2 75.6 14.0 61.1 72.8 10.9 41.4 41.0
6-1 68.9 77.2 14.0 61.8 74.4 10.2 32.4
37.9
6-2 67.0 75.7 12.5 60.2 72.8 10.9 N/A N/A
7-1 69.0 77.5 14.0 62.2 74.8 9.4 34.6
38.3
7-2 65.7 75.0 14.1 60.0 73.1 10.9 N/A N/A
7085(LS)
(T7451) 69.6 76.6 15.5 64.3 74.7 9.4 33.5
36.2
7085(LS)
(T7651) 74.1 79.9 14.0 67.2 77.3 9.4 27.0
36.2
[0064] The EAC resistance of the materials were also tested, the results of
which are
shown in Tables 4a-4b, below. Days in test are included for materials that
have not yet failed
(T = still in test at the stated number of days).
Table 4a - EAC Properties - First Test
70 C / 85 % RH
Allo Stress Stress Stress Days Days to
failure
y
(% TYS-ST) (ksi) (Mpa) in
test rep 1 rep 2 rep 3
2 60 36.3 250 697
592 N/A T
85 51.4 354 -- 291 199 178
4 1 60 38.2 263 -- N/A N/A 38
- 85 54.1 373 -- N/A 35 N/A
60 37.1 256 697 604 T T
6-1
85 52.5 362 -- 221 312 337
60 37.4 258 697 T T 611
7-1
85 52.9 365 -- N/A 220 N/A
60 38.2 263 -- 119 46 53
7085(LS)-T7451
85 54.1 373 -- 46 53 44
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Table 4b - EAC Properties ¨ Second Test
70 C / 85 % RH
Stress Stress Stress
Alloy (% TYS-ST) (ksi) (Mpa) Days in Days to failure
test rep 1 rep
2 rep 3
1 60 38.7 267 -- 192 282 N/A
85 54.8 378 -- 84 106 147
60 37.2 256 533 T T 480
3
85 52.7 363 -- 198 N/A 333
60 35.8 247 66 105 156
4-2
85 50.7 350 51 53 63
60 36.9 254 -- 144 189 169
(Test 1)
85 52.2 360 -- 79 66 87
60 36.6 252 -- 130 206 291
5 (Test 2)
85 51.8 357 -- 120 137 127
6 2 60 36.1 249 533 T T T
- 85 51.2 353 -- 326 518 326
72 60 36 248 533 T T T
-
85 51 352 533 T T 441
7085(LS) 60 40.3 278 -- 73 123 109
-T7651 85 57 393 39 45 51
--
7085(LS) 60 38.5 265 120 106 129
-T7451 85 54.5 376 -- 60 53 60
"N/A" means specimen data not applicable due to thread failure.
[0065] As shown, the new alloys with manganese and having zinc, magnesium,
and
copper within the scope of the formula 2.362 < Mg+0.429*Cu+0.067*Zn < 3.062
realize an
improved combination of properties, including EAC resistance properties, over
the
conventional 7085 materials. This data also suggests that using a Zn/Mg (wt. %
ratio) of not
greater than 5.25:1 in combination with the use of manganese may lead to an
improved
combination of properties.
[0066] As a comparison, mechanical properties and EAC resistance of plant
produced
7050 and 7085 materials in the T7451 and T7651 tempers were also measured, the
results of
which are provided in Tables 5a-5b, below.
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Table 5a - Plant Mechanical Property Data
Kmax-
KQ L-
TYS- UTS- TYS- ITTS- elong- dev
Alloy- Gauge elong-
L L ST ST ST (ksi-
T (ksi-
Temper (in)
(ksi) (ksi.) L (/o) (ksi) sqrt-
) (ksi) CYO sqrt-
in.) in.)
7085-
T7651 4.331 73.8 76.6 12.1 67.4 77.0 5.95 N/A N/A
7085-
T7451 4.3 71.2
74.8 15.1 66.0 76.0 7.85 N/A N/A
7050-
T7651 5.42 68.2
76.0 12.5 60.9 72.4 8 27.5 33.4
7050-
T7451 3.92 68.9
77.2 12.45 62.9 74.4 5.8 N/A N/A
Table 5b - Plant EAC Data
Stress 70 C / 85 % RH
Alloy / Gauge (% Stress Stress Days Days to failure
Temper (in.) TYS- (ksi) (Mpa) in
ST) test rep
1 rep 2 rep 3 rep 4 rep 5
7085- 60 40.5
279 -- 68 N/A 42 N/A 39
T7651 *85** 57.4 396 -- 35 26 57 43 N/A
7085- 60 39.6 273 -- 92 71 46 53 92
4.3
T7451 85 56.1
387 -- 57 42 56 N/A 46
7050- 50 30.45 210 614 T T T
T7651 5.42
85 51.765 357 -- 203 401 260 246 147
7050- 60 37.7
260 -- 292 180 540 393 330
T7451 3=92
85 53.4 368 -- 292 292 386 162 469
** Three additional replicates of this material failed in 18, 14 and 26 days.
As shown in Tables 5a-5b, the EAC resistance of the conventional 7085
materials are
consistent with the results of the lab-scale materials.
[0067] FIGS. 1-2 illustrate the tensile strength versus EAC results. As
shown, alloys
falling within the scope of the composition ranges defined herein realize an
improved
combination of EAC resistance and strength. The plant produced materials
include the label
PP. The lab scale materials include the label LS. The plant produced materials
have a dark
border on the data markers.
Example 2
[0068] Additional testing was completed on Alloys 2, 3, 6 and 7 of Example
1.
Specifically, samples of Alloys 2, 3, 6, and 7 were artificially aged to
different conditions,
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after which mechanical and corrosion properties were tested. The aging
conditions and
results are shown in Tables 6-8, below.
Table 6 - Aging Practices for Example 2 Alloys
Alloy Aging Practice
6h/250F + 7-8h/320F +
Alloy 2
Air Cool + 24h/250F
6h/250F + 2h/320F + Air
Alloy 3
Cool + 24h/250F
6h/250F + 10-11h/320F +
Alloy 6
Air Cool + 24h/250F ,
6h/250F + 12h/320F + Air
Alloy 7
Cool + 24h/250F
Table 7 - Measured Properties - Example 2
TYS- UTS- Kmax-dev KQ L-T
TYS- UTS- elong- Elong-
Alloy ST ST (ksi- (ksi-
(ksi) (ksi) L (ksi) L ("A)
(ksi) (ksi) ST ("/0)
sqrt-in.) sqrt-in.)
2 68.5 76.3 11.7 61.6 73.7 9.4 32.3 37.3
3 69.8 77.4 12.5 62.4 74.5 11.7 31.7 43.7
6 68 76 12.5 60 73 9.4 31.8 36.4
7 69 78 12.5 62 75 9.4 31.8 37.3
Table 8 - EAC Properties ¨ Example 2
Stress 70 C / 85 % RH
Stress Stress
Alloy C/0 TYS-
.Days Days to failure
ST) in test rep 1 rep 2 rep 3
60 37 255 449 T 424 412
2
85 52.4 361 449 T 197 190
60 37.4 , 258 449 T , 288 , 291 .
3
85 53 365 449 T 137 N/A
6 60 36.2 250 449 T T T
85 51.3 354 449 T T T
60 37.4 258 449 T T 70
7
85 53 365 -- 242 344 340
[0069] As shown, Alloys 2, 3, 6 and 7 achieve an improved combination of
mechanical
and corrosion properties over the conventional 7085-T7451 alloy.
Example 3 - Additional Lab Scale Testing
[0070] Various 7xxx aluminum alloys were cast as six inch (15.24 cm) thick
ingots
(nominal). The actual compositions of the cast ingots are shown in Table 9,
below.
Conventional alloys 7085 and 7050 were also produced.
Table 9 - Composition of Example 3 Alloys (wt. %) - Lab Scale Materials
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Alloy Si Fe Cu Mn Mg Cr Zn Ti Zr
7085 0.02 0.03 1.64 -- 1.52 -- 7.59 0.02 0.11
7050 0.05 0.08 2.22 -- 2.09 -- 6.10 0.02 0.11
8 0.02 0.03 1.69 0.36 1.29 -- 6.55 0.02 0.11
9 0.03 0.03 1.89 0.35 1.30 -- 6.49 0.02 0.11
0.02 0.03 2.10 0.36 1.31 -- 6.57 0.02 0.11
11 0.02 0.03 2.06 0.34 1.55 -- 5.98 0.02 0.12
The balance of each alloy was aluminum and unavoidable impurities (< 0.03 wt.
% each, <
0.10 wt. % total). The ingots were then hot rolled to a final gauge of 1.75
inches, and then
solution heat treated, and then hot water quenched to simulate cooling
conditions at T/2 (mid-
thickness) for approximately 8-inch thick plate. The plates were then
stretched about 2.25%
and then artificially aged, after which mechanical and corrosion properties
were tested. The
aging conditions and results are shown in Tables 10-13, below.
[0071] For this Example 3, the same testing standards as Example 1 were
used for
strength, fracture toughness, EAC resistance and L-S crack deviation
resistance (K max-dev).
The shown strength and elongation values are averages of duplicate specimens.
The fracture
toughness values are taken from a single specimen. The crack deviation values
are averages
of triplicate specimens.
Table 10 - Aging Practices for Example 2 Alloys
Alloy Aging Practice 1 Aging Practice 2
7085 Both T7451
7050 Both T7651
8 6h/250F + 6.2h/320F + 6h/250F + 8.8h/320F +
Air Cool + 24h/250F Air Cool + 24h/250F
6h/250F + 6.8h/320F + 6h/250F + 9.8h/320F
+
9
Air Cool + 24h/250F Air Cool + 24h/250F
6h/250F + 6.8h/320F + 6h/250F + 9.8h/320F
+
Air Cool + 24h/250F Air Cool + 24h/250F
11 6h/250F + 7.3h/320F + 6h/250F + 11.1h/320F +
Air Cool + 24h/250F Air Cool + 24h/250F
Table 11 - Mechanical Properties of Example 3 Alloys - Aging Practice 1
UTS- TYS- UTS- Elong- Kmax- KQ L-T
TYS-L L Elong-
Alloy ST ST ST dev (ksi- (ksi-sqrt-
(ksi) L (%)
(ksi) (ksi) (ksi) (%) sqrt-in) in)
7085 68.7 76.0 14.1 62.3 73.3 9.4 28.1 35.3
7050 61.6 72.3 11.7 56.3 70.4 9.4 26.6 30.7
8 71.1 77.6 12.5 63.4 74.4 10.9 28.9 36.0
9 70.2 77.1 12.5 62.0 73.6 10.9 25.9 35.2
10 71.9 78.5 12.5 63.1 74.6 8.6 27.7 35.7
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UTS- TYS- UTS- Elong- Kmax- KQ L-T
TYS-L Elong-
Alloy ST ST ST dev (ksi-
(ksi-sqrt-
(ksi) L L (A)
(ksi) (ksi) (ksi) (%) sqrt-in) in)
11 71.0 78.6 11.7 62.5 74.2 7.8 25.4 32.7
Table 12 - Mechanical Properties of Example 3 Alloys - Aging Practice 2
UTS- TYS- UTS- Elong- Kmax- KQ L-T
TYS-L Elong-
Alloy ST ST ST dev (ksi-
(ksi-sqrt-
(ksi) L L (%)
(ksi) (ksi) (ksi) ("/0) sqrt-in) in)
7085 68.5 75.9 14.1 62.0 73.4 10.9 31.9 36.1
7050 61.2 72.2 12.5 56.2 70.3 10.2 29.0 28.2
8 66.9 74.4 13.3 59.0 71.2 10.9 30.4 40.7
9 66.7 74.4 14.9 59.2 71.4 10.2 30.8 38.2
66.2 74.3 13.3 59.0 71.4 10.2 32.6 40.0
11 67.6 76.2 14.1 60.4 71.8 7.1 29.6 36.0
Table 13 - EAC Properties - Example 3
Stress 70 C / 85 % RH
Alloy - Stress Stress
(% TYS i
(ksi) (Mpa) Days Days to failure
Aging
-ST) n test repl rep2 rep3
60 37.4 258 -- 175 187 301
7085-T7451
85 53 365 -- 79 98 N/A
60 37.2 256 -- N/A N/A 173
7085-T7451
85 52.7 363 -- N/A 79 N/A
60 33.8 233 301 T T T
7050-T7651
85 47.9 330 301 T T T
60 33.7 232 301 T T T
7050-T7651
85 47.8 330 301 T T T
Alloy 8 60 38 262 N/A 56 159
- Aging 1 85 53.9 372 -- N/A N/A 68
Alloy 8- 60 35.4 244 301 T 259 243
Aging 2 85 50.2 346 -- N/A 146 121
Alloy 9- 60 37.2 256 -- 64 N/A 153
Aging 1 85 52.7 363 -- N/A N/A 301
Alloy 9- 60 35.5 245 301 273 T 180
Aging 2 85 50.3 347 231 198 180
Alloy 10 - 60 37.9 261 -- 100 135 N/A
Aging 1 85 53.6 370 -- 65 100 79
Alloy 10- 60 35.4 244 -- 292 301 T
Aging 2 85 50.2 346 -- N/A 148 166
Alloy 11 - 60 37.5, 259 301 , T, T, T
Aging 1 85 53.1 366 301 T T T
Alloy 11 - 60 36.2 250 301 T T T
Aging 2 85 51.3 354 301 T T T
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[0072] As shown by the above data, alloy 7085 simulating around 8 inch
thick plate
realizes longer days to failure than alloy 7085 shown in Table 4a and 4b that
simulated
around 5 inch thick plate. As also shown, alloy 11 realizes no EAC failures
after 300 days,
but with significantly higher strength and fracture toughness than that of
alloy 7050. Alloy
11 realizes significantly better EAC resistance properties than alloy 7085 and
with similar
strength and fracture toughness properties. Alloys 8-10 have slightly lower
properties, but
may realize properties similar to alloy 11 if alloys 8-10 had at least 1.35
wt. % Mg and/or a
lower weight ratio of zinc-to-magnesium (e.g., a ratio of not greater than
4.75:1, (wt. %
Zn)/(wt. % Mg)).
Example 4 - Plant Scale Testing
[0073] Twenty industrial size ingots were cast, nine conventional 7085
ingots, two 7050
ingots, and nine experimental alloy ingots (three per alloy). The compositions
of the
experimental alloy ingots are provided in Table 14, below.
Table 14 - Composition of Plant Scale Ingot - Invention Alloys
Alloy Si Fe Cu Mn Mg Cr Zn Ti Zr
12 0.02 0.04 1.68 0.27 1.53 -- 6.62 0.02 0.11
13 0.02 0.04 1.87 0.25 1.52 6.43 0.02 0.11
14 0.02 0.04 1.64 0.25 1.65 -- 6.37 0.02 0.11
The balance of each alloy was aluminum and unavoidable impurities (< 0.03 wt.
% each, <
0.10 wt. % total). The ingots were then hot rolled to various final gauges,
and then solution
heat treated and quenched in cold water. The plates were then stretched about
2.25-2.50%
and then artificially aged. Table 15, below, provides the various conditions
for the various
alloys. Table 16 provides various artificial aging conditions listed in Table
15. The 7085
plates were aged to a T7451-type or a T7651-type temper (see, ANSI H35.1, AMS-
4329A).
The 7050 plates were also aged to a T7451-type or a T651-type temper.
Table 15 - Alloy Conditions
Final Gauge Artificial Aging
Alloy Plate
(in.) / Temper
7085 1 6.45 T7651
7085 2 6.50 T7651
7085 3 4.00 T7451
7085 4 6.00 T7451
7085 5 6.00 T7451
7085 6 7.00 T7451
7085 7 7.00 T7451
7085 8 8.50 T7451
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Alloy Plate Final Gauge Artificial Aging
(in.) / Temper
7085 9 8.50 T7451
7050 1 4.40 T7651
7050 2 3.94 T7651
12 1 3.94 A
12 2 3.94 B
12 3 6.70 A
12 4 6.70 B
12 5 7.87 A
12 6 7.87 B
13 1 3.94 C
13 2 3.94 D
13 3 6.70 C
13 4 6.70 D
13 5 7.87 C
13 6 7.87 D
14 1 3.94 C
14 2 3.94 D
14 3 , 6.70 , C
14 4 6.70 D
14 5 , 7.87 , C
14 6 7.87 D
Table 16 - Artificial Aging Practices for Table 15
Condition Aging Practice
A 6h/250 F + 8h/320F +
Air Cool + 24h/250F
B 6h/250F + 12.5h/320F +
Air Cool + 24h/250F
C 6h/250F + 9h/320F +
Air Cool + 24h/250F
6h/250F + 14h/320F +
D
Air Cool + 24h/250F
[0074] For this Example 4, the same ASTM testing standards as Example 1
were used for
strength, fracture toughness and EAC resistance. The typical L-S crack
deviation resistance
properties (Kmax-dev) were determined per the procedure described in commonly-
owned U.S.
Patent Application Publication No. 2017/0088920, paragraph 0058, as modified
above per the
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Definitions section, above. The shown strength, elongation and fracture
toughness values are
averages of duplicate specimens. The crack deviation values are averages of
triplicate
specimens. The test results are shown in Tables 17-19, below.
Table 17 - Mechanical Properties of Example 4 - Conventional Alloys
TYS- UTS- Elong- Kic Kic
TYS-L UTS-L Elong-
Alloy ST ST ST L-T (ksi- S-L
(ksi-
(ksi) (ksi) L (%)
(ksi) (ksi) (%) sqrt-in) sqrt-
in)
7085-1 74.1 77.3 9.5 68.0 75.8 5.1 31.0 23.4
7085-2 73.4 76.3 10.1 67.2 75.2 5.1 30.7 26.7
7085-3 69.7 74.3 16.2 63.4 73.9 9.0 46.4 32.7
7085-4 71.5 75.7 12.6 65.4 73.7 6.3 33.9 30.1
7085-5 70.2 74.0 14.0 63.7 72.4 6.0 32.6 28.9
7085-6 69.0 73.8 12.7 62.5 71.1 6.0 32.7 31.6
7085-7 69.4 73.3 12.5 62.4 71.1 6.3 32.4 29.1
7085-8 67.4 73.0 11.6 60.2 69.5 5.9 31.3 28.8
7050-1 67.9 75.9 12 61.9 73 5.7 N/A 26.6
7050-2 67.65 75.25 10.5 62.7 73.8 4.7 33.6 N/A
Table 18 - Mechanical Properties of Example 4 - Experimental Alloys
Kmax-
TYS- UTS- TYS- UTS- Elong- Kic S-L
Alloy- Elong- dev L-T
ST ST ST (ksi-
Specimen L (%) (ksi- (ksi-
(ksi) (ksi) (ksi) (ksi) (Y0) sqrt-in)
sqrt-in) sqrt-in)
12-1 71.3 75.3 15.0 64.5 75.4 6.8 33.3 41.4(*)
34.8
12-2 67.8 73.2 15.5 61.5 72.8 7.1 39.0 45.1
37.0
12-3 70.7 75.0 12.3 63.9 72.9 5.5 30.1 33.6
31.5
12-4 66.3 72.0 13.0 60.3 70.3 6.8 34.3 37.8
35.6
12-5 70.1 74.5 10.5 62.7 71.8 5.0 28.4 31.1
30.5
12-6 65.3 71.3 12.0 58.6 68.8 7.3 33.6 35.3
36.5
13-1 71.8 76.0 14.0 64.5 75.4 7.1 33.1 39.4(9)
34.9
13-2 68.9 75.3 13.0 61.0 72.8 7.1 42.3 44.8(*)
38.1
13-3 70.8 75.1 12.0 63.9 72.8 5.0 28.5 32.7
30.4
13-4 67.1 72.9 12.5 60.8 70.8 6.3 32.6 36.0
33.3
13-5 69.9 74.8 10.8 63.0 72.2 5.3 29.4 30.4 28.5
13-6 65.5 71.8 11.0 58.9 69.1 6.8 33.8 34.1
34.2
14-1 71.8 76.1 14.5 64.5 75.3 7.1 35.1 38.9(*)
34.7
14-2 67.5 73.4 15.0 60.8 72.5 7.1 37.2 44.2(*)
37.4
14-3 71.4 75.7 11.8 64.2 73.1 5.5 32.2 31.9
30.5
14-4 67.8 73.5 12.5 61.4 71.0 6.3 35.4 35.8
33.1
14-5 70.6 75.1 10.5 63.2 72.1 5.0 26.4 29.8
29.8
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TYS- UTS- TYS- UTS- Elong- Kmax- KicKic S-L
Alloy- L L - Elong-
ST ST ST dev L-T
(ksi-
Specimen L (%) (ksi-
(ksi) (ksi) (ksi) (ksi) (/0) sqrt-in)
sqrt-in) sqrt-in)
14-6 66.7 72.7 11.8 60.2 70.0 5.0 30.2 32.8 32.3
* = Test result was technically invalid per ASTM E399-17, and is thus a KQ
value, as
a result of Pniax/PQ being greater than 1.1. However, per ASTM B645-10, test
result is
usable for lot release given that B has been maximized at the specified test
location.
Table 19 - EAC Properties - Example 4
Stress 70 C / 85 ')/0 RH
Stress Stress
Alloy (% 'TYS- Days Days to failure
(ksi) (Mpa)
ST) in test rep 1 rep 2 rep
3 rep 4 rep 5
7085-1 60 40.8 281 -- 78 87 N/A 87 87
7085-1 85 57.8 399 -- 58 51 51 51 51
7085-2 60 40.3 278 -- N/A N/A 68 69 53
7085-2 85 57.1 394 -- N/A 38 56 N/A 46
7085-3 60 38.0 262 87 39 20 60 T 60
7085-3 85 53.9 372 87 39 15 T 25 25
7085-4 60 39.2 270 -- 171 164 129 94 157
7085-4 85 55.5 383 -- N/A 91 N/A 87 91
7085-5 60 39.2 270 -- 120 198 92 105 105
7085-5 85 55.5 383 -- 56 N/A 56 120 58
7085-6 60 37.9 261 327 81 T T T 91
7085-6 85 53.7 370 327 N/A T 55 67 67
7085-7 60 37.5 259 162 88 81 N/A 113
7085-7 85 53.1 366 327 70 T 57 57 70
7050-1 60 37.1 256 369 T T T T 225
7050-1 85 52.6 363 -- 176 225 186 368 176
7050-2 60 37.6 259 124 T T T T T
7050-2 85 53.3 368 124 T T T T T
12-1 60 38.7 267 124 T 69 T T 111
12-1 85 54.8 378 124 43 T 36 41 83
12-2 60 36.9 254 124 T T T 97 T
12-2 85 52.3 361 124 69 80 T 69 69
13-1 60 38.7 267 -- 62 90 62 83 115
13-1 85 54.8 378 -- 41 48 52 64 52
13-2 60 36.6 252 124 T T T T T
13-2 85 51.9 358 124 T T T 97 97
14-1 60 38.7 267 124 T T T T T
14-1 85 54.8 378 124 29 T 48 34 T
14-2 60 36.5 252 124 T T T T T
14-2 , 85 , 51.7 356 124 90 , T 83 , T 69 ,
12-3 60 38.3 264 115 T T T T T
12-3 85 54.3 374 115 T T T T T
31
CA 03066252 2019-12-04
WO 2018/237196
PCMJS2018/038838
Stress 70 C / 85 ')/0 RI!
Stress Stress
Alloy (% TYS- (Mpa)
Days Days to failure
ST) in test rep 1 rep 2 rep 3
rep 4 rep 5
12-4 60 36.2 250 115 T T T T T
12-4 85 51.2 353 115 T T T T T
13-3 60 38.3 264 115 T T T T T
13-3 85 54.3 374 115 T T T T T
13-4 60 36.5 252 115 T T T T T
13-4 85 51.7 356 115 T T T T T
14-3 60 38.5 265 115 T T T T T
14-3 85 54.6 376 115 T T T T T
14-4 60 36.8 254 115 T T T T T
14-4 85 52.2 360 115 T T T T T
12-5 60 37.6 259 117 T T T T T
12-5 85 53.3 368 117 T T T T T
12-6 60 35.2 243 117 T T T T T
12-6 85 49.8 343 117 T T T T T
13-5 60 37.8 261 117 T T T T T
13-5 85 53.5 369 117 T T T T T
13-6 60 35.3 243 117 T T T T T
13-6 85 50.1 345 117 T T T T T
14-5 60 37.9 261 117 T T T T T
14-5 85 53.7 370 117 T T T T T
14-6 60 36.1 249 117 T T T T T
14-6 85 51.1 352 117 T T T T T
[0075] As shown by the above data, alloys 12-14 show significantly improved
EAC
resistance over 7085 at equivalent gauge for at least one of the aging
conditions. In addition,
alloys 12-14 exhibit significantly better strength and fracture toughness
relative to 7050 in
similar gauges and a comparable strength and fracture toughness relative to
7085. As shown
in Example 3, EAC resistance increases with increasing gauge for given aging
practices.
[0076] While various embodiments of the present disclosure have been
described in
detail, it is apparent that modifications and adaptations of those embodiments
will occur to
those skilled in the art. However, it is to be expressly understood that such
modifications and
adaptations are within the spirit and scope of the present disclosure.
32
