Patent US4571272A successfully refreshed from Google Patents.
US4571272A
Expired / Lapsed
US
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Light metal alloys, product and method of fabrication
Assignee: Rio Tinto Alcan International Ltd
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Filing: 1983-08-26
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Granted: 1986-02-18
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Expires: 2003-08-26
Abstract
Abstract A method of superplastically forming an article from a light metal base alloy, of the kind capable of having its crystal structure modified by cold working in such a way that subsequent dynamic recrystallization by hot working is facilitated, comprises cold working a first blank of the alloy to form a second blank having the modified crystal structure, and then forming the second blank into the article by hot working so that dynamic recrystallization is induced and super plastic deformation occurs. The degree of modification of the crystal structure during cold working is such that as the dynamic recrystallization continues, the grain size is progressively refined.
Inventors
- 👤 Roger Grimes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:50
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/06; C22F1/04; C22F1/047; Y; Y10; Y10S; Y10S420/00; Y10S420/902
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
133 words
A method of superplastically forming an article from a light metal base alloy selected from: (1) Li 1.5% to 4.0% by weight Mg 0% to 5.0% by weight Zr 0% to 0.4% by weight Cu 0% to 6.0% by weight Zn 0% to 5.0% by weight Al remainder with normal impurities (2) lithium containing magnesium alloys including 10.0% to 15.0% by weight of lithium and (3) magnesium containing aluminium alloys including 6.0% to 12.0% by weight of magnesium comprising cold working a first blank of the alloy to form a second blank having a modified crystal structure and forming the second blank into the article by hot working so that dynamic recrystallisation is induced therein and superplastic deformation occurs and so that as the dynamic recrystallisation continues the grain size is progressively refined.
Claim 2
Independent Claim
133 words
A method of superplastically forming an article from a light metal base alloy selected from: (1) Li 1.5% to 4.0% by weight Mg 0% to 5.0% by weight Zr 0% to 0.4% by weight Cu 0% to 6.0% by weight Zn 0% to 5.0% by weight Al remainder with normal impurities (2) lithium containing magnesium alloys including 10.0% to 15.0% by weight of lithium and (3) magnesium containing aluminium alloys including 6.0% to 12.0% by weight of magnesium comprising cold working a first blank of the alloy to form a second blank having a modified crystal structure and forming the second blank into the article by hot working so that dynamic recrystallisation is induced therein and superplastic deformation occurs and so that as the dynamic recrystallisation continues the grain size is progressively refined.
Claim 3
Dependent Claim
47 words
A method according to claim 1 in which the alloy selected from: Li 1.5% to 4.0% by weight Mg 0% to 4.0% by weight Zr 0% to 0.2% by weight Cu 0% to 3.0% by weight Zn 0% to 3.0% by weight Al remainder with normal impurities.
Claim 4
Dependent Claim
62 words
A method according to claim 2 in which the alloy is selected from: Li 2.0% Li 3.0%; Zr 0.19% Li 2.9%; Mg 2.20%; Zr 0.18% Li 2.7%; Mg 2.8%; Zr 0.15% Li 2.7%; Mg 0.7%; Cu 1.2%; Zr 0.09% Li 2.8%; Mg 0.8%; Cu 2.5%; Zr 0.11% Li 2.6%; Mg 1.0%; Cu 1.5%; Zr 0.16%; Zn 1.60% Al remainder with normal impurities.
Claim 5
Dependent Claim
24 words
A method according to claim 1 in which the alloy does not include any grain refining constituent added primarily to enhance subsequent superplastic deformation.
Claim 6
Dependent Claim
34 words
A method according to claim 1, including alloys selected from groups (1) and (2) in which the second blank is treated to remove lithium containing compounds from its surface prior to the hot working.
Claim 7
Dependent Claim
28 words
A method according to claim 1 in which the cold working of the first blank to form the second blank is carried out without an intermediate annealing step.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-17 | 1989-08-19 | 1990-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-17 | 1993-08-19 | 1994-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-17 | 1997-08-19 | 1998-02-18 | $7700.00 | Window Closed / Lapsed |