US4889569A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lithium bearing alloys free of Luder lines
Assignee: Boeing Co
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Filing: 1988-03-24
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Granted: 1989-12-26
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Expires: 2008-03-24
Abstract
Abstract Aluminum-lithium alloy sheets are stretched under predetermined temperature and stretch rate conditions to provide contoured metal sheets. The temperature and stretch rate conditions provide a stretched sheet which is substantially free of Luder lines that are conventionally associated with stretch-formed aluminum-lithium alloy sheets.
Inventors
- 👤 Wesley H. Graham
- 👤 Sven E. Axter
- 👤 Fu-Shiong Lin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:55
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/04; C22F1/057
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
89 words
A metal sheet comprising: a sheet of an aluminum-lithium alloy consisting essentially of: (a) about 1.7 to about 2.8% by weight lithium; (b) about 1.0 to about 3.0% by weight copper; (c) about 0.0 to about 2.0% by weight magnesium; (d) about 0.04 to about 0.16% by weight zirconium; and (e) aluminum; the sheet intentionally stretched at least 3% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that provides the stretched sheet substantially free of Luder lines.
Claim 2
Dependent Claim
89 words
A metal sheet comprising: a sheet of an aluminum-lithium alloy consisting essentially of: (a) about 1.7 to about 2.8% by weight lithium; (b) about 1.0 to about 3.0% by weight copper; (c) about 0.0 to about 2.0% by weight magnesium; (d) about 0.04 to about 0.16% by weight zirconium; and (e) aluminum; the sheet intentionally stretched at least 3% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that provides the stretched sheet substantially free of Luder lines.
Claim 3
Dependent Claim
45 words
The metal sheet of claim 1, wherein the sheet is intentionally stretched at least 6% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that provides the stretched sheet substantially free of Luder lines.
Claim 4
Dependent Claim
105 words
The metal sheet of claim 1, wherein the aluminum-lithium alloy consists of: (a) about 1.7 to about 2.3% by weight lithium; (b) about 1.8 to about 2.5% by weight copper; (c) about 1.1 to about 1.9% by weight magnesium; (d) about 0.06 to about 0.16% by weight zirconium; (e) about 0 to about 0.12% by weight iron; (f) about 0 to about 0.10% by weight silicon; (g) about 0 to about 0.10% by weight chromium; (h) about 0 to about 0.10% by weight manganese; (i) about 0 to about 0.25% by weight zinc; (j) about 0 to about 0.10% by weight titanium; and (k) aluminum.
Claim 5
Dependent Claim
30 words
The metal sheet of claim 3, including about 0 to about 0.15% by weight trace impurities, with the maximum amount of any one trace impurity being about 0.05% by weight.
Claim 6
Dependent Claim
24 words
The metal sheet of claim 3 wherein the metal sheet has a temper selected from the group consisting of T4, T6 and T8 tempers.
Claim 7
Independent Claim
107 words
A method for stretching an aluminum-lithium alloy sheet comprising the step of intentionally stretching the aluminum-lithium alloy sheet at least about 3% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that is outside the region defined by the polygon ABCDA in FIG. 1, such that the stretched sheet is substantially free of Luder lines, the aluminum-lithium alloy sheet consisting essentially of about 1.7 to about 2.8% by weight lithium, about 1.0 to about 3.0% by weight copper, about 0.0 to about 2.0% by weight magnesium, about 0.04 to about 0.16% by weight zirconium, and aluminum.
Claim 8
Independent Claim
107 words
A method for stretching an aluminum-lithium alloy sheet comprising the step of intentionally stretching the aluminum-lithium alloy sheet at least about 3% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that is outside the region defined by the polygon ABCDA in FIG. 1, such that the stretched sheet is substantially free of Luder lines, the aluminum-lithium alloy sheet consisting essentially of about 1.7 to about 2.8% by weight lithium, about 1.0 to about 3.0% by weight copper, about 0.0 to about 2.0% by weight magnesium, about 0.04 to about 0.16% by weight zirconium, and aluminum.
Claim 9
Dependent Claim
48 words
The method of claim 6, wherein the aluminum-lithium alloy sheet is stretched at least about 6% of its original dimensions in the direction of the stretch under a combination of temperature and stretch rate conditions that is outside the region defined by the polygon EFGHE in FIG. 1.
Claim 10
Dependent Claim
48 words
The method of claim 7, wherein the aluminum-lithium alloy sheet is stretched at least about 9% of its original dimensions in the direction of the stretch under a combination of temperature and stretch rate conditions that is outside the region defined by the polygon IJKLI in FIG. 1.
Claim 11
Dependent Claim
24 words
The method of claim 6, wherein the aluminum-lithium alloy sheet has a temper selected from the group consisting of T4, T6 and T8 tempers.
Claim 12
Dependent Claim
13 words
The aluminum-lithium alloy sheet prepared in accordance with the method of claim 6.
Claim 13
Dependent Claim
13 words
The aluminum-lithium alloy sheet prepared in accordance with the method of claim 7.
Claim 14
Dependent Claim
76 words
A metal sheet comprising: a stretched sheet of an aluminum-lithium alloy consisting essentially of: (a) about 1.7 to about 2.3% by weight lithium; (b) about 1.8 to about 2.5% by weight copper; (c) about 1.1 to about 1.9% by weight magnesium; (d) about 0.06 to about 0.16% by weight zirconium; and (e) aluminum, the stretched sheet having a total yield strength of at least about 51,000 psi, the stretched sheet being substantially free of Luder lines.
Claim 15
Dependent Claim
76 words
A metal sheet comprising: a stretched sheet of an aluminum-lithium alloy consisting essentially of: (a) about 1.7 to about 2.3% by weight lithium; (b) about 1.8 to about 2.5% by weight copper; (c) about 1.1 to about 1.9% by weight magnesium; (d) about 0.06 to about 0.16% by weight zirconium; and (e) aluminum, the stretched sheet having a total yield strength of at least about 51,000 psi, the stretched sheet being substantially free of Luder lines.
Claim 16
Dependent Claim
16 words
The metal sheet of claim 12, having an ultimate tensile strength of at least 65,000 psi.
Claim 17
Dependent Claim
14 words
A metal aircraft body skin prepared in accordance with the method of claim 6.
Claim 18
Dependent Claim
14 words
A metal aircraft body skin prepared in accordance with the method of claim 7.
Claim 19
Dependent Claim
20 words
The metal sheet of claim 1, wherein the sheet is in the form of a body skin for an aircraft.
Claim 20
Dependent Claim
20 words
The metal sheet of claim 12, wherein the sheet is in the form of a body skin for an aircraft.
Claim 21
Dependent Claim
53 words
The metal sheet of claim 1, wherein the sheet is intentionally stretched at least 3% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that is outside the polygon ABCDA in FIG. 1, the stretched sheet being substantially free of Luder lines.
Claim 22
Dependent Claim
53 words
The metal sheet of claim 2, wherein the sheet is intentionally stretched at least 6% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that is outside the polygon EFGHE in FIG. 1, the stretched sheet being substantially free of Luder lines.
Claim 23
Independent Claim
93 words
A method for stretching an aluminum-lithium alloy sheet comprising the step of intentionally stretching the aluminum-lithium alloy sheet at least about 3% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that provides the stretched sheet substantially free of Luder lines, the aluminum-lithium alloy sheet consisting essentially of about 1.7 to about 2.8% by weight lithium, about 1.0 to about 3.0% by weight copper, about 0.0 to about 2.0% by weight magnesium, about 0.04 to about 0.16% by weight zirconium, and aluminum.
Claim 24
Independent Claim
93 words
A method for stretching an aluminum-lithium alloy sheet comprising the step of intentionally stretching the aluminum-lithium alloy sheet at least about 3% of its original dimensions in the direction of the stretch under a predetermined combination of temperature and stretch rate conditions that provides the stretched sheet substantially free of Luder lines, the aluminum-lithium alloy sheet consisting essentially of about 1.7 to about 2.8% by weight lithium, about 1.0 to about 3.0% by weight copper, about 0.0 to about 2.0% by weight magnesium, about 0.04 to about 0.16% by weight zirconium, and aluminum.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-25 | 1993-06-26 | 1993-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-25 | 1997-06-26 | 1997-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-25 | 2001-06-26 | 2001-12-26 | $7700.00 | Window Closed / Lapsed |