US4582544A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of metallic articles
Assignee: Rio Tinto Alcan International Ltd
•
Filing: 1984-03-30
•
Granted: 1986-04-15
•
Expires: 2004-03-30
Abstract
Abstract A method of superplastically deforming a blank of a metallic alloy which: 1. has a composition suitable for superplastic deformation and 2. has a grain structure suitable for superplastic deformation and 3. contains less than that percentage of a constituent known to inhibit grain coarsening after recrystallization which is necessary for such inhibition, comprising raising the blank to a forming temperature, deforming the blank at a first strain rate to induce dynamic recrystallization and continuing to deform the blank at a second strain rate lower than the first rate.
Inventors
- 👤 Roger Grimes
- 👤 William S. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:41
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/04; C22F1/053; Y; Y10; Y10S; Y10S420/00; Y10S420/902; Y10S72/00; Y10S72/709
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
89 words
A method of superplastically deforming a blank of a metallic alloy which: A. has a composition suitable for superplastic deformation and B. has a grain structure suitable for superplastic deformation and C. contains less than that percentage of a constituent known to inhibit grain coarsening after recrystallisation which is necessary for such inhibition, comprising raising the blank to a forming temperature, deforming the blank at a first strain rate to induce dynamic recrystallisation and continuing to deform the blank at a second strain rate lower than the first rate.
Claim 2
Independent Claim
89 words
A method of superplastically deforming a blank of a metallic alloy which: A. has a composition suitable for superplastic deformation and B. has a grain structure suitable for superplastic deformation and C. contains less than that percentage of a constituent known to inhibit grain coarsening after recrystallisation which is necessary for such inhibition, comprising raising the blank to a forming temperature, deforming the blank at a first strain rate to induce dynamic recrystallisation and continuing to deform the blank at a second strain rate lower than the first rate.
Claim 3
Dependent Claim
35 words
A method according to claim 1 in which the first strain rate is between 1×10 -2 /sec and 5×10 -2 /sec and the second strain rate is between 1×10 -3 /sec and 5×10 -3 /sec.
Claim 4
Dependent Claim
35 words
A method according to claim 1 in which the first strain rate is at a velocity of 8 to 40 mm/min and the second strain rate is at a velocity of 0.75 to 3.75 mm/min.
Claim 5
Dependent Claim
33 words
A method according to claim 3 in which the first strain rate is at a velocity of approximately 12.5 mm/min and the second strain rate is at a velocity of approximately 3.38 mm/min.
Claim 6
Dependent Claim
37 words
A method according to claim 1 in which the first strain rate is applied for a time between 60 and 180 seconds and the second strain rate is applied for a time between 20 and 30 minutes.
Claim 7
Dependent Claim
78 words
A blank of an aluminium base alloy, deformed according to the method of claim 1, and selected from the following: A. 7075 or B. 7475 or C. 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).
Claim 8
Dependent Claim
35 words
A method according to claim 2 in which the first strain rate is at a velocity of 8 to 40 mm/min and the second strain rate is at a velocity of 0.75 to 3.75 mm/min.
Claim 9
Dependent Claim
33 words
A method according to claim 7 in which the first strain rate is at a velocity of approximately 12.5 mm/min and the second strain rate is at a velocity of approximately 3.38 mm/min.
Claim 10
Dependent Claim
37 words
A method according to claim 2 in which the first strain rate is applied for a time between 60 and 180 seconds and the second strain rate is applied for a time between 20 and 30 minutes.
Claim 11
Dependent Claim
37 words
A method according to claim 3 in which the first strain rate is applied for a time between 60 and 180 seconds and the second strain rate is applied for a time between 20 and 30 minutes.
Claim 12
Dependent Claim
37 words
A method according to claim 4 in which the first strain rate is applied for a time between 60 and 180 seconds and the second strain rate is applied for a time between 20 and 30 minutes.
Claim 13
Dependent Claim
37 words
A method according to claim 7 in which the first strain rate is applied for a time between 60 and 180 seconds and the second strain rate is applied for a time between 20 and 30 minutes.
Claim 14
Dependent Claim
37 words
A method according to claim 8 in which the first strain rate is applied for a time between 60 and 180 seconds and the second strain rate is applied for a time between 20 and 30 minutes.
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) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |