Abstract: An actuator system for use in an electrical relay or the like. An actuator member is carried by a frame and is movable between a first and a second position, being biased toward its first position by a spring and having an actuating wire coupled between it and the frame. This wire is stretched from its original length to a second length by the spring when the actuator member is in its first position. The wire is of a selected metal alloy which, upon being heated, shortens its length and thus causes the tension in the wire to increase an amount sufficient to overcome the bias of the spring and to move the actuator member towards its second position.

Abstract: A process for increasing the tensile strength of a martensitic alloy of titanium and nickel and for improving the alloy's ability to retain its original properties during use by stabilizing it against progressive elongation when cycled through successive martensitic transformations. The process comprises maintaining the alloy under a tensile stress of between about 30,000 and 100,000 psi while annealing the alloy at a temperature above a first diffusional phase transformation temperature. The first diffusional phase temperature is the first temperature above the martensitic transformation range at which there is a negative slope in the electrical resistivity versus temperature curve for the alloy. The product of this process has a tensile strength of at least about 175,000 psi and a martensitic elongation activity under stress of at least about 2% and will survive over one million martensitic transformation cycles when placed under sufficient stress that the elongation activity is about 2%.

Abstract: A two-stage process for conditioning an annealed martensitic alloy of titanium and nickel to improve its service life and provide enhanced elongation activity under high operating stress. In the first stage of the process, the alloy is maintained under a tensile stress sufficient to strain it beyond its plastic yield point while it is repeatedly thermally cycled in a primary temperature range between a lower temperature limit below the temperature at which conversion of martensite to austenite commences on heating and an upper temperature limit at least about equal to the temperature at which essentially all the martensite is converted to austenite on heating.