EP0143580A1
Expired / Lapsed
EP
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Shape memory alloys
Assignee: Raychem Corp
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Filing: 1984-11-14
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Granted: —
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Expires: 2004-11-14
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 Melton
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 21:07
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/006
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
120 words
A method of processing nickel-titanium-base shape-memory alloys substantially to 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 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 wa'lls of higher dislocation density and to provide said alloy in a desired shape; deforming the alloy in the martensitic state; and heating said alloy to the austenitic state to recover and substantially to retain said desired shape.
Claim 2
Independent Claim
120 words
A method of processing nickel-titanium-base shape-memory alloys substantially to 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 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 wa'lls of higher dislocation density and to provide said alloy in a desired shape; deforming the alloy in the martensitic state; and heating said alloy to the austenitic state to recover and substantially to retain said desired shape.
Claim 3
Dependent Claim
17 words
A method according to claim 1 wherein said alloy is annealed for from 20 to 90 minutes.
Claim 4
Dependent Claim
24 words
A method according to claim 1 or 2 wherein the alloy is subsequently cooled to the martensitic state and substantially retains said desired shape.
Claim 5
Independent Claim
26 words
A method according to any preceding claim, wherein the alloy is annealed at a temperature higher than the temperature at which the alloy is fully pseudoelastic.
Claim 6
Dependent Claim
15 words
A method according to claim 4, wherein said annealing temperature is in excess of 125°C.
Claim 7
Independent Claim
25 words
A method according to any preceding claim, wherein the alloy is hot worked in the austenitic state to provide said alloy in a specified shape.
Claim 8
Independent Claim
20 words
A method according to any preceding claim, wherein said desired shape is machined or stamped after annealing and before deforming.
Claim 9
Dependent Claim
68 words
A composite structure which comprises a first member and a second member in contacting relationship therewith, wherein said second member is a nickel-titanium shape-memory alloy exhibiting the two-way effect, with said second member firmly contacting said first member when said second member is in the austenitic state, wherein said second member maintains said firm contact when said second member is at least partly transformed to the martensitic state.
Claim 10
Dependent Claim
68 words
A composite structure which comprises a first member and a second member in contacting relationship therewith, wherein said second member is a nickel-titanium shape-memory alloy exhibiting the two-way effect, with said second member firmly contacting said first member when said second member is in the austenitic state, wherein said second member maintains said firm contact when said second member is at least partly transformed to the martensitic state.
Claim 11
Dependent Claim
56 words
A composite structure according to claim 8 wherein said second member has been cold worked in the martensitic state to provide a microstructure containing a high concentration of substantially random dislocations and annealed without restraint to rearrange the dislocations into an ordered network of dislocations comprising essentially dislocation-free cells surrounded by walls of higher dislocation density.
Claim 12
Dependent Claim
15 words
A composite structure according to claim 8 or 9, wherein said structure is a coupling.
References Cited (Backward Citations)
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