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US4533411A
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US
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Method of processing nickel-titanium-base shape-memory alloys and structure
Assignee: Memry Corp
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Filing: 1983-11-15
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Granted: 1985-08-06
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Expires: 2003-11-15
Abstract
Abstract Method of processing nickel-titanium-base shape-memory alloys to substantially suppress the two-way effect including the steps of cold working and low-temperature annealing without restraint. A composite structure is also provided including a nickel-titanium-base shape-memory alloy with the two-way effect substantially suppressed.
Inventors
- 👤 Keith N. Melton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:46
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/006
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
142 words
A method of processing nickel-titanium-base shape-memory alloys to substantially suppress the two-way effect which comprises: providing a nickel-titanium-based shape-memory alloy in the austenitic state in a specified shape; cold working said alloy in the martensitic state from 15% to 40% to provide a microstructure containing a high concentration of substantially random dislocations; annealing said alloy without restraint at 300° C. to 500° C. for at least 20 minutes to rearrange the dislocations into an ordered network of dislocations comprising essentially dislocation-free cells surrounded by walls of higher dislocation density; providing said alloy in a desired shape while maintaining the dislocation-free cells obtained in the annealing step; and deforming the alloy in the martensitic state; whereby when the alloy is recovered by heating the alloy to the austenitic state and subsequently cooled to the martensitic state, the alloy substantially retains said desired shape.
Claim 2
Independent Claim
142 words
A method of processing nickel-titanium-base shape-memory alloys to substantially suppress the two-way effect which comprises: providing a nickel-titanium-based shape-memory alloy in the austenitic state in a specified shape; cold working said alloy in the martensitic state from 15% to 40% to provide a microstructure containing a high concentration of substantially random dislocations; annealing said alloy without restraint at 300° C. to 500° C. for at least 20 minutes to rearrange the dislocations into an ordered network of dislocations comprising essentially dislocation-free cells surrounded by walls of higher dislocation density; providing said alloy in a desired shape while maintaining the dislocation-free cells obtained in the annealing step; and deforming the alloy in the martensitic state; whereby when the alloy is recovered by heating the alloy to the austenitic state and subsequently cooled to the martensitic state, the alloy substantially retains said desired shape.
Claim 3
Dependent Claim
33 words
A method according to claim 1 wherein after the step of deforming the alloy, the method further comprises heating said alloy to the austenitic state to recover and substantially retain said desired shape.
Claim 4
Dependent Claim
17 words
A method according to claim 1 wherein said alloy is annealed for from 20 to 90 minutes.
Claim 5
Dependent Claim
22 words
A method according to claim 2 wherein the alloy is subsequently cooled to the martensitic state and substantially retains said desired shape.
Claim 6
Dependent Claim
28 words
A method according to claim 2 wherein the step of heating said alloy is at a temperature higher than the temperature at which the alloy is fully pseudoelastic.
Claim 7
Dependent Claim
16 words
A method according to claim 5 wherein said heating temperature is in excess of 125° C.
Claim 8
Dependent Claim
24 words
A method according to claim 1 wherein the alloy is hot worked in the austenitic state to provide said alloy in a specified shape.
Claim 9
Dependent Claim
19 words
A method according to claim 1 wherein said desired shape is machined or stamped after annealing and before deforming.
Claim 10
Dependent Claim
145 words
A coupling member produced by the process of processing nickel-titanium-base shape-memory alloys to substantially suppress the two-way effect which comprises: providing a nickel-titanium-base shape-memory alloy in the austenitic state in a specified shape; cold working said alloy in the martensitic state from 15% to 40% to provide a microstructure containing a high concentration of substantially random dislocations; annealing said alloy without restrain at 300° C. to 500° C. for at least 20 minutes to rearrange the dislocations into an ordered network of dislocations comprising essentially dislocation-free cells surrounded by walls of higher dislocation density and to provide said alloy in a desired shape; and deforming the alloy in the martensitic state; whereby when the alloy is recovered by heating the alloy to the austenitic state and subsequently cooled to the martensitic state, the alloy will revert to the martensitic state without exhibiting the two-way effect.
Claim 11
Dependent Claim
145 words
A coupling member produced by the process of processing nickel-titanium-base shape-memory alloys to substantially suppress the two-way effect which comprises: providing a nickel-titanium-base shape-memory alloy in the austenitic state in a specified shape; cold working said alloy in the martensitic state from 15% to 40% to provide a microstructure containing a high concentration of substantially random dislocations; annealing said alloy without restrain at 300° C. to 500° C. for at least 20 minutes to rearrange the dislocations into an ordered network of dislocations comprising essentially dislocation-free cells surrounded by walls of higher dislocation density and to provide said alloy in a desired shape; and deforming the alloy in the martensitic state; whereby when the alloy is recovered by heating the alloy to the austenitic state and subsequently cooled to the martensitic state, the alloy will revert to the martensitic state without exhibiting the two-way effect.
Claim 12
Dependent Claim
38 words
The coupling member produced by the process according to claim 9 wherein after the step of deforming the alloy, the process further comprises heating said alloy to the austenitic state to recover and substantially retain said desired shape.
Claim 13
Dependent Claim
27 words
The coupling member produced by the process according to claim 10 wherein the alloy is subsequently cooled to the martensitic state and substantially retains said desired shape.
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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) | 1988-08-05 | 1989-02-04 | 1989-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-05 | 1993-02-04 | 1993-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-05 | 1997-02-04 | 1997-08-06 | $7700.00 | Window Closed / Lapsed |