Patent US4840682A successfully refreshed from Google Patents.
US4840682A
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Low temperature underaging process for lithium bearing alloys
Assignee: Boeing Co
•
Filing: 1985-11-21
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Granted: 1989-06-20
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Expires: 2005-11-21
Abstract
Abstract The combination of strength and fracture toughness properties of aluminum-lithium alloys are significantly enhanced by underaging the alloys at temperatures ranging from 200° F. to below 300° F. for relatively long periods of time.
Inventors
- 👤 R. Eugene Curtis
- 👤 G. Hari Narayanan
- 👤 William E. Quist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:25
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/04; C22C; C22C21/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
113 words
A process for improving the fracture toughness of an aluminum-lithium alloy without detracting from the strength of said alloy, said alloy consisting essentially of: ______________________________________
Element Amount (wt. %)
______________________________________
Li 1.0 to 3.2
Mg 0 to 5.5
Cu 0 to 4.5
Zr 0.08 to 0.15
Mn 0 to 1.2
Fe 0.3 max
Si 0.5 max
Zn 0.25 max
Ti 0.15 max
Other trace elements
each 0.05 max
total 0.25 max
Al Balance,
______________________________________ said alloy first being formed into an article, solution heat treated and quenched, said process comprising the step of aging said alloy article to a predetermined underaged strength level at from about 200° F. to less than 300° F.
Claim 2
Dependent Claim
113 words
A process for improving the fracture toughness of an aluminum-lithium alloy without detracting from the strength of said alloy, said alloy consisting essentially of: ______________________________________
Element Amount (wt. %)
______________________________________
Li 1.0 to 3.2
Mg 0 to 5.5
Cu 0 to 4.5
Zr 0.08 to 0.15
Mn 0 to 1.2
Fe 0.3 max
Si 0.5 max
Zn 0.25 max
Ti 0.15 max
Other trace elements
each 0.05 max
total 0.25 max
Al Balance,
______________________________________ said alloy first being formed into an article, solution heat treated and quenched, said process comprising the step of aging said alloy article to a predetermined underaged strength level at from about 200° F. to less than 300° F.
Claim 3
Dependent Claim
15 words
The process of claim 1 wherein said aging temperature is less than about 275° F.
Claim 4
Dependent Claim
18 words
The process of claim 1 wherein said aging temperature is between about 250° F. and about 275° F.
Claim 5
Dependent Claim
15 words
The process of claim 1 wherein said aging temperature is less than about 250° F.
Claim 6
Dependent Claim
61 words
The process of claim 1 wherein said alloy consists essentially of: ______________________________________
Element Amount (wt %)
______________________________________
Li 1.5 to 3.0
Mg 0 to 4.2
Cu 0 to 3.7
Zr 0.08 to 0.15
Mn 0 to 0.8
Fe 0.15 max
Si 0.12 max
Zn 0.10 max
Ti 0.10 max
Other trace
elements
each 0.05 max
total 0.25 max
Al Balance.
______________________________________
Claim 7
Dependent Claim
61 words
The process of claim 5 wherein said alloy consists essentially of: ______________________________________
Element Amount (wt %)
______________________________________
Li 1.8 to 2.7
Mg 0 to 3.2
Cu 0.5 to 3.0
Zr 0.08 to 0.15
Mn 0 to 0.6
Fe 0.10 max
Si 0.10 max
Zn 0.10 max
Ti 0.10 max
Other trace
elements
each 0.05 max
total 0.25 max
Al Balance.
______________________________________
Claim 8
Dependent Claim
9 words
The product produced by the process of claim 1.
References Cited (Backward Citations)
US2915391A
Cited
GB2115836A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |