US2009159159A1PendingUtilityA1
Al-Li ROLLED PRODUCT FOR AEROSPACE APPLICATIONS
Est. expiryDec 21, 2027(~1.4 yrs left)· nominal 20-yr term from priority
C22F 1/057C22C 21/12C22C 21/16
59
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Claims
Abstract
The present invention is directed to a substantially unrecrystallized rolled aluminum alloy product, obtained from a plate with a thickness of at least 30 mm, comprising 2.2 to 3.9 wt. % Cu, 0.7 to 2.1 wt. % Li, 0.2 to 0.8 wt. % Mg, 0.2 to 0.5 wt. % Mn, 0.04 to 0.18 wt. % Zr, less than 0.05 wt. % Zn, and optionally 0.1 to 0.5 wt. % Ag, remainder aluminum and unavoidable impurities having a low propensity to crack branching during L-S a fatigue test. A product of the invention has a crack deviation angle Θ of at least 20° under a maximum equivalent stress intensity factor Keff max of 10 MPa √m for a S-L cracked test sample under a mixed mode I and mode II loading wherein the angle Ψ between a plane perpendicular to the initial crack direction and the load direction is 75°
Claims
exact text as granted — not AI-modified1 . A method for producing a substantially unrecrystallized aluminum alloy plate with a thickness of at least 30 mm said method comprising:
a) casting an ingot comprising 2.2 to 3.9 wt. % Cu, 0.7 to 2.1 wt. % Li, 0.2 to 0.8 wt. % Mg, 0.2 to 0.5 wt. % Mn, 0.04 to 0.18 wt. % Zr, less than 0.05 wt. % Zn, and optionally 0.1 to 0.5 wt. % Ag, remainder aluminum and unavoidable impurities, b) homogenizing said ingot at 470-510° C. for a duration from 2 to 30 hours, c) hot rolling said ingot with an exit temperature of at least 410° C. to a plate with a final thickness of at least 30 mm, d) solution heat treating by soaking at 490 to 540° C. for 15 min to 4 h, wherein the total equivalent time of homogenization and solution heat treatment t(eq)
t
(
eq
)
=
∫
exp
(
-
26100
/
T
)
t
exp
(
-
26100
/
T
ref
)
does not exceed 30 h, where T (in Kelvin) is the instantaneous temperature of treatment, which evolves with the time t (in hours), and T ref is a reference temperature set at 773 K,
e) cold water quenching,
f) stretching said plate with a permanent set from 2 to 5%,
g) aging said plate by heating at 130-160° C. for 5 to 60 hours.
2 . A method according to claim 1 wherein Li+Cu>4 wt. % and preferably Li+Cu>4.3 wt. %.
3 . A method according to claim 1 wherein Li+0.7 Cu<4.3
4 . A method according to claim 1 wherein the lithium content is from 0.8 to 1.8 wt. %.
5 . A method according to claim 1 wherein the lithium content is from 0.9 to 1.4 wt. %
6 . A method according to claim 1 wherein the copper content is from 2.7 to 3.9 wt. %.
7 . A method according to claim 6 wherein the copper content is from 3.2 to 3.9 wt. %.
8 . A method according to claim 1 wherein the manganese content is from 0.3 to 0.5 wt. %.
9 . A method according to claim 1 wherein said hot rolling exit temperature is at least 430° C.
10 . A method according to claim 1 wherein said aging is done by heating at 140-160° C. from 12 to 50 hours.
11 . A substantially unrecrystallized rolled aluminum alloy product with a thickness of at least 30 mm having a low propensity to crack branching obtained from a process according to claim 1 .
12 . A substantially unrecrystallized rolled aluminum alloy product, obtained from a plate with a thickness of at least 30 mm, which has a crack deviation angle Θ of at least 20° under a maximum equivalent stress intensity factor K eff max of 10 MPa √m for a S-L cracked test sample under a mixed mode I and mode II loading wherein the angle Ψ between a plane perpendicular to the initial crack direction and the load direction is 75°.
13 . A substantially unrecrystallized rolled aluminum alloy product, obtained from a plate with a thickness of at least 30 mm, which exhibit crack branching on not more than 20% L-S test samples after testing at least four different samples in a fatigue test according to ASTM E 647 with R=0.1 and σ max =220 MPa.
14 . A product according to claim 11 with a thickness of at most 100 mm having in a T8 temper at least one of a1 and a2 and/or at least one of b1, b2 and b3 where a1, a2, b1, b2 and b3 are the following:
a1: a tensile yield strength at T/4 and T/2 of at least 455 MPa in the L-direction. a2: an ultimate tensile strength at T/4 and T/2 of at least 490 MPa, in the L-direction. b1: a fracture toughness K 1C : in L-T direction at T/4 and T/2 of at least 31 MPa√m; b2: a fracture toughness K 1C : in T-L direction at T/4 and T/2 of at least 28 MPa√m; b3: a fracture toughness K 1C : in S-L direction at T/4 and T/of at least 25 MPa√m.
15 . A product according to claim 11 with a thickness higher than 100 mm having in a T8 temper at least one of a4 and a5 and/or at least one of b4, b5 and b6 where a4, a5, b4, b5 and b6 are the following:
a4: a tensile yield strength at T/4 and T/2 of at least 440 MPa in the L-direction. a5: an ultimate tensile strength at T/4 and T/2 of at least 475 MPa, in the L-direction. b4: a fracture toughness K 1C : in L-T direction at T/4 and T/2 of at least 26 MPa√m; b5: a fracture toughness K 1C : in T-L direction at T/4 and T/2 of at least 25 MPa√m; b6: a fracture toughness K 1C : in S-L direction at T/4 and T/of at least 24 MPa√m.
16 . A product according to claim 12 with a thickness of at most 100 mm having in a T8 temper at least one of a1 and a2 and/or at least one of b1, b2 and b3 where a1, a2, b1, b2 and b3 are the following:
a1: a tensile yield strength at T/4 and T/2 of at least 455 MPa in the L-direction. a2: an ultimate tensile strength at T/4 and T/2 of at least 490 MPa, in the L-direction. b1: a fracture toughness K 1C : in L-T direction at T/4 and T/2 of at least 31 MPa√m; b2: a fracture toughness K 1C : in T-L direction at T/4 and T/2 of at least 28 MPa√m; b3: a fracture toughness K 1C : in S-L direction at T/4 and T/of at least 25 MPa√m.
17 . A product according to claim 12 with a thickness higher than 100 mm having in a T8 temper at least one of a4 and a5 and/or at least one of b4, b5 and b6 where a4, a5, b4, b5 and b6 are the following:
a4: a tensile yield strength at T/4 and T/2 of at least 440 MPa in the L-direction. a5: an ultimate tensile strength at T/4 and T/2 of at least 475 MPa, in the L-direction. b4: a fracture toughness K 1C : in L-T direction at T/4 and T/2 of at least 26 MPa√m; b5: a fracture toughness K 1C : in T-L direction at T/4 and T/2 of at least 25 MPa√m; b6: a fracture toughness K 1C : in S-L direction at T/4 and T/of at least 24 MPa√m.
18 . A product according to claim 13 with a thickness of at most 100 mm having in a T8 temper at least one of a1 and a2 and/or at least one of b1, b2 and b3 where a1, a2, b1, b2 and b3 are the following:
a1: a tensile yield strength at T/4 and T/2 of at least 455 MPa in the L-direction. a2: an ultimate tensile strength at T/4 and T/2 of at least 490 MPa, in the L-direction. b1: a fracture toughness K 1C : in L-T direction at T/4 and T/2 of at least 31 MPa√m; b2: a fracture toughness K 1C : in T-L direction at T/4 and T/2 of at least 28 MPa√m; b3: a fracture toughness K 1C : in S-L direction at T/4 and T/of at least 25 MPa√m.
19 . A product according to claim 13 with a thickness higher than 100 mm having in a T8 temper at least one of a4 and a5 and/or at least one of b4, b5 and b6 where a4, a5, b4, b5 and b6 are the following:
a4: a tensile yield strength at T/4 and T/2 of at least 440 MPa in the L-direction. a5: an ultimate tensile strength at T/4 and T/2 of at least 475 MPa, in the L-direction. b4: a fracture toughness K 1C : in L-T direction at T/4 and T/2 of at least 26 MPa√m; b5: a fracture toughness K 1C : in T-L direction at T/4 and T/2 of at least 25 MPa√m; b6: a fracture toughness K 1C : in S-L direction at T/4 and T/of at least 24 MPa√m.
20 . A structural member obtained from a product according to claim 11 .
21 . A structural member obtained from a product according to claim 12 .
22 . A structural member obtained from a product according to claim 13 .
23 . A structural member according to claim 20 comprising a spar, a rib or a frame suitable for aircraft construction.
24 . A structural member according to claim 20 comprising a complex shaped part made by integral machining which is suitable for aircraft wing construction.
25 . A structural member according to claim 21 comprising a spar, a rib or a frame suitable for aircraft construction.
26 . A structural member according to claim 21 comprising a complex shaped part made by integral machining which is suitable for aircraft wing construction.
27 . A structural member according to claim 22 comprising a spar, a rib or a frame suitable for aircraft construction.
28 . A structural member according to claim 22 comprising a complex shaped part made by integral machining which is suitable for aircraft wing construction.Join the waitlist — get patent alerts
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