초록 ▼

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 whic

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.

대표청구항 ▼

[ What is claimed is:] [1.] A process for conditioning a shape memory alloy, comprising the steps of:deforming a shape memory alloy in a martensitic state; andheating said shape memory alloy to a temperature greater than a finish martensitic-austenitic transformation temperature A.sub.f of said shap

[ What is claimed is:] [1.] A process for conditioning a shape memory alloy, comprising the steps of:deforming a shape memory alloy in a martensitic state; andheating said shape memory alloy to a temperature greater than a finish martensitic-austenitic transformation temperature A.sub.f of said shape memory alloy; andapplying and releasing a conditioning force to said shape memory alloy while continuing said heating to maintain the shape memory alloy at a temperature greater than said temperature A.sub.f, wherein at least a portion of said shape memory alloy undergoes a phase transformation from an austenite phase to a martensite phase during said applying and releasing step.