US4626409A
Expired / Lapsed
US
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Aluminium alloys
Assignee: Rio Tinto Alcan International Ltd
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Filing: 1984-03-30
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Granted: 1986-12-02
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Expires: 2004-03-30
Abstract
Abstract An aluminium base alloy having a composition within the following ranges in weight percent: ______________________________________ Lithium 2.3 to 2.9 Magnesium 0.5 to 1.0 Copper 1.6 to 2.4 Zirconium 0.05 to 0.25 Titanium 0 to 0.5 Manganese 0 to 0.5 Nickel 0 to 0.5 Chromium 0 to 0.5 Zinc 0 to 2.0 Aluminium Remainder (apart from incidental impurities). ______________________________________
Inventors
- 👤 William S. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:27
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/04; C22C; C22C21/00
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
73 words
An aluminium base alloy consisting of a composition within the following ranges in weight percent: ______________________________________
Lithium 2.3 to 2.9
Magnesium 0.5 to 1.0
Copper 1.6 to 2.4
Zirconium 0.05 to 0.25
Titanium 0 to 0.5
Manganese 0 to 0.5
Nickel 0 to 0.5
Chromium 0 to 0.5
Zinc 0 to 0.5
Aluminium Remainder (apart from
incidental impurities),
______________________________________ and in which the ratio of copper to magnesium is between 1.6:1 and 4.8:1.
Claim 2
Dependent Claim
73 words
An aluminium base alloy consisting of a composition within the following ranges in weight percent: ______________________________________
Lithium 2.3 to 2.9
Magnesium 0.5 to 1.0
Copper 1.6 to 2.4
Zirconium 0.05 to 0.25
Titanium 0 to 0.5
Manganese 0 to 0.5
Nickel 0 to 0.5
Chromium 0 to 0.5
Zinc 0 to 0.5
Aluminium Remainder (apart from
incidental impurities),
______________________________________ and in which the ratio of copper to magnesium is between 1.6:1 and 4.8:1.
Claim 3
Dependent Claim
17 words
An alloy according to claim 1, in which the ratio of copper to magnesium is about 3:1.
Claim 4
Dependent Claim
136 words
A method of producing a sheet or strip comprising hot rolling a rolling ingot of an alloy according to claim 1 in one or more stages to produce a hot blank; holding the hot blank at a temperature and for a time which causes substantially all of the lithium, magnesium, copper and any zinc present to be in solid solution; positively cooling the hot blank; subjecting the cooled blank to a further heat treatment at a temperature sufficient to reprecipitate those age hardening phases in solid solution, continuing the heat treatment to produce a coarse overaged morphology and thereafter cold rolling the blank to form a sheet or strip which at any position therein and in any direction therefrom has properties of elongation that vary from those in the rolling direction by no more than 2.0%.
Claim 5
Dependent Claim
45 words
A method according to claim 3 in which the sheet or strip at any position therein and in any direction therefrom has properties of elongation that vary from those in the rolling direction by no more than 25 MPa (0.2% proof stress and tensile stress).
Claim 6
Dependent Claim
41 words
A method according to claim 3 in which the initial hot blank holding temperature is between 480° C. and 540° C. and the time varies between 20 and 120 minutes depending upon the thickness and previous thermal history of the blank.
Claim 7
Dependent Claim
18 words
A method according to claim 5, in which the hot blank is positively cooled by air blast cooling.
Claim 8
Dependent Claim
32 words
A method according to claim 3 in which if the hot blank falls to a temperature below 480° C. the blank is re-heated to solutionise the Li, Mg, Cu and any Zn.
Claim 9
Dependent Claim
20 words
A method according to claim 3 in which the hot blank has a thickness of 12.5 mm to 3 mm.
Claim 10
Dependent Claim
19 words
A method according to claim 3 in which the sheet or strip has a thickness up to 10 mm.
Claim 11
Dependent Claim
33 words
A method according to claim 5 in which the positive cooling terminates at the temperature of the further heat treatment so that the positive cooling and further heat treatment steps are merged together.
Claim 12
Dependent Claim
30 words
A method according to claim 10 in which the further heat treatment is at a temperature between 300° C. and 400° C. for a period of 8 to 16 hours.
Claim 13
Dependent Claim
41 words
A method according to claim 4 in which the initial hot blank holding temperature is between 480° C. and 540° C. and the time varies between 20 and 120 minutes depending upon the thickness and previous thermal history of the blank.
Claim 14
Dependent Claim
18 words
A method according to claim 12, in which the hot blank is positively cooled by air blast cooling.
Claim 15
Dependent Claim
32 words
A method according to claim 5 in which if the hot blank falls to a temperature below 480° C. the blank is re-heated to solutionize the Li, Mg, Cu and any Zn.
Claim 16
Dependent Claim
20 words
A method according to claim 7 in which the hot blank has a thickness of 12.5 mm to 3 mm.
Claim 17
Dependent Claim
20 words
A method according to claim 5 in which the hot blank has a thickness of 12.5 mm to 3 mm.
Claim 18
Dependent Claim
20 words
A method according to claim 3 in which the sheet or strip has a thickness no more than 5 mm.
Claim 19
Dependent Claim
19 words
A method according to claim 5 in which the sheet or strip has a thickness up to 10 mm.
Claim 20
Dependent Claim
20 words
A method according to claim 8 in which the sheet or strip has a thickness no more than 5 mm.
Claim 21
Dependent Claim
33 words
A method according to claim 12 in which the positive cooling terminates at the temperature of the further heat treatment so that the positive cooling and further heat treatment steps are merged together.
References Cited (Backward Citations)
US3984260A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-01 | 1990-06-02 | 1990-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-01 | 1994-06-02 | 1994-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-01 | 1998-06-02 | 1998-12-02 | $7700.00 | Window Closed / Lapsed |