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US 6,149,742 AGranted
Process for conditioning shape memory alloys
AssigneeLockheed Martin Corporation
InventorsBernie F. Carpenter, Jerry L. Draper
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AssigneeLockheed Martin Corporation
InventorsBernie F. Carpenter, Jerry L. Draper
Estimating the term…
A process for conditioning shape memory alloys is disclosed. The process preferably includes force application/release cycling of a shape memory alloy at a temperature above the martensitic-austenitic transformation (A.sub.f) finish temperature of the alloy, but below the maximum temperature at which an austenitic-martensitic transformation will be effected by the force application. The alloy is preferably cold-worked and annealed prior to force application/release cycling. The invention yields greater control over martensitic-austenitic and austenitic-martensitic transformation temperatures and yields reduced hysteresis variability. In certain disclosed embodiments a TiNi or CuAl containing alloy may be cold-worked between about 20% and 45%, and annealed to maintain between about 3% and 8% of the cold working. The alloy may then be heated to between about A.sub.f and 5.degree. C. and A.sub.f 15.degree. C. and conditioned via the application/release of a force for at least about 50 cycles, wherein an austenitic-martensitic phase transformation is induced. The conditioned alloy may then be cooled and integrated into an application mechanism for subsequent selective activation upon heating.
A process for conditioning a shape memory alloy, comprising the steps of:
A process for conditioning a shape memory alloy selected from the group consisting of CuAl-containing alloys and NiTi-containing alloys, comprising the steps of:
A method for processing a shape memory alloy, the process comprising of steps:
Dependencies are inferred from the claim text.