US2022106672A1PendingUtilityA1
Improved thick wrought 7xxx aluminum alloys, and methods for making the same
Est. expiryJun 24, 2039(~12.9 yrs left)· nominal 20-yr term from priority
C22F 1/002C22C 21/10C22F 1/053
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Claims
Abstract
Disclosed are improved thick wrought 7xxx aluminum alloy products, and methods for producing the same. The new 7xxx aluminum alloy products may realize an improved combination of properties, such as an improved combination of two or more of environmentally assisted crack resistance, strength, elongation, and fracture toughness, among other properties. The new 7xxx aluminum alloy products may include 5.5-6.5 wt. % Zn, 1.3-1.7 wt. % Mg, and 1.7-2.3 wt. % Cu.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A wrought 7xxx aluminum alloy product comprising:
5.5-6.5 wt. % Zn; 1.3-1.7 wt. % Mg; 1.7-2.3 wt. % Cu; less than 0.15 wt. % Mn; up to 1.0 wt. % of grain structure control materials, wherein the grain structure control materials comprise at least one of Zr, Cr, Sc, and Hf; and up to 0.15 wt. % Ti; the balance being aluminum and unavoidable impurities; wherein the wrought 7xxx aluminum alloy product has a thickness of from 2.5 to 12 inches.
2 . The wrought 7xxx aluminum alloy product of claim 1 , wherein the wrought 7xxx aluminum alloy product includes not greater than 0.12 wt. % Mn.
3 . The wrought 7xxx aluminum alloy product of claim 2 , comprising from 0.05 to 0.15 wt. % Zr and not greater than 0.04 wt. % Mn.
4 . The wrought 7xxx aluminum alloy product of claim 1 , wherein the wrought 7xxx aluminum alloy product includes not greater than 6.4 wt. % Zn.
5 . The wrought 7xxx aluminum alloy product of claim 4 , wherein the wrought 7xxx aluminum alloy product includes at least 5.6 wt. % Zn.
6 . The wrought 7xxx aluminum alloy product of claim 1 , wherein the wrought 7xxx aluminum alloy product includes not greater than 2.25 wt. % Cu.
7 . The wrought 7xxx aluminum alloy product of claim 6 , wherein the wrought 7xxx aluminum alloy product includes at least 1.75 wt. % Cu.
8 . The wrought 7xxx aluminum alloy product of claim 1 , wherein the wrought 7xxx aluminum alloy product includes at least 1.35 wt. % Mg.
9 . The wrought 7xxx aluminum alloy product of claim 8 , wherein the wrought 7xxx aluminum alloy product includes not greater than 1.65 wt. % Mg.
10 . The wrought 7xxx aluminum alloy product of claim 1 , wherein the 7xxx aluminum alloy product realizes a typical L-S crack deviation resistance (K max-dev ) of at least 25 ksi-sqrt-in.
11 . The wrought 7xxx aluminum alloy product of claim 1 , wherein the wrought aluminum alloy product passes HHSCC-G49 testing at 90° C. for 10 days.
12 . An aerospace structural component made from the wrought 7xxx aluminum alloy product of claim 1 .
13 . A method for producing a wrought 7xxx aluminum alloy, the method comprising:
(a) casting an alloy having the composition of claim 1 as an ingot or billet; (b) homogenizing the ingot or billet; (c) hot working the ingot or billet to an intermediate gauge product or final gauge product; (d) optionally cold working the intermediate gauge product into the final gauge product; (e) solution heat treating the final gauge product followed by quenching; (f) optionally stretching or compressing the solution heat treated and quenched product by 1-5%; (g) artificially aging the solution heat treated and quenched product.
14 . The method of claim 13 , wherein the homogenization temperature is at least T(homog.), wherein T(homog.) is calculated in degrees Fahrenheit from the formula 614.4+55.2*Cu+83.1*Mg−1.8*Zn, wherein the Cu, the Mg, and the Zn are the weight percent amounts of copper, magnesium and zinc, respectively, in the wrought 7xxx aluminum alloy.
15 . The method of claim 13 , wherein the artificial aging comprises first aging at a first aging temperature of from 200-300° F. followed by second aging at a second aging temperature of from 250-350° F., wherein the second aging temperature is at least 10° F. higher than the first aging temperature.
16 . The method of claim 13 , wherein the total equivalent artificial aging time is t(eq.), wherein t(eq.) is from 7 to 20 hours, wherein t(eq.) is calculated from the formula
t
(
eq
.
)
=
∫
exp
(
-
12800
/
T
)
dt
exp
(
-
12800
/
Tref
)
wherein T is the instantaneous temperature in ° K during the artificial aging, and wherein Tref is a reference temperature selected at 160° C. (433.15° K).
17 . The method of claim 16 , wherein t(eq) is not greater than 19 hours.
18 . A rolled 7xxx aluminum alloy plate product comprising:
5.9-6.2 wt. % Zn; 1.4-1.7 wt. % Mg; 2.0-2.3 wt. % Cu; 0.05-0.15 wt. % Zr; up to 0.20 wt. % Cr; up to 0.15 wt. % Ti; and not greater than 0.04 wt. % Mn; the balance being aluminum and unavoidable impurities; wherein the rolled 7xxx aluminum alloy plate product has a thickness of from 3 to 12 inches; and wherein the rolled 7xxx aluminum alloy plate product realizes at least three of:
(a) a typical tensile yield strength (ST) of at least 57 ksi;
(b) a typical K IC plane-strain fracture toughness (S-L) of at least 20 ksi-sqrt-inch;
(c) a typical elongation (ST) of at least 5%; and
(d) passing of the HHSCC-G49 test at 90° C. for 15 days.Cited by (0)
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