초록 ▼

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

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.

대표청구항 ▼

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 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. 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.