Raychem Limited

John A Simpson

Keith Nelson Melton

Tom Duerig

Disclosed are a group of nickel/titanium/niobium alloys wherein the niobium varies from about 2.5 to 30 atomic percent. Also disclosed is an aritcle made from these nickel/titanium/niobium alloys.

Nickel/titanium/niobium shape memory alloy & article

There is disclosed a method of preassembling a composite coupling. The coupling has at least one heat-recoverable driver member and at least one metallic insert. The driver member is made from a nickel/titanium-based shape memory alloy having a transformation hysteresis defined by M.sub.s, M.sub.f, A.sub.s and A.sub.f temperatures. The method includes the steps of overdeforming the driver member by applying a stress sufficient to cause nonrecoverable strain in the driver member so that the A.sub.s and A.sub.f temperatures are temporarily raised to A.sub.s' and A.sub.f', respectively; removing the stress; engaging the driver member and insert; and then warming the driver and insert to a temperature less than A.sub.s'. There is also disclosed a composite coupling processed by this method.

Method for preassembling a composite coupling

There is disclosed a method of processing a nickel/titanium-based shape memory alloy. The method comprises overdeforming the alloy so as to cause at least some amount of nonrecoverable strain, temporarily expanding the transformation hysteresis by raising the austenite transformation temperature, removing the applied stress and then storing the alloy at a temperature less than the new austenite transition temperature. There is also disclosed an article produced from this method.

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Mountain View, CA, United States of America

John A Simpson