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Planar Extrinsic Biasing Of Thin Film Shape-Memory MEMS Actuators.

  • D. S. Grummon (a1), R. Gotthardt (a2) and T. LaGrange (a2)


Although slow and dissipative, sputtered thin-film shape-memory alloys like equiatomic titanium-nickel can exert a large ohmically-excited force displacement product when deployed in photolithographically micromachined actuators. They give energy densities far exceeding those typically produced by competing microactuator materials [1], and their size can probably be scaled down to the nanometer range (where the benefits of high surface to volume ratio are best exploited for speed and efficiency). But a large, energetic, and resettable actuation stroke is possible only if some agency has imparted a non-trivial initial plastic strain, of between one and five percent, to the martensite phase. Is not always obvious how this strain is to be achieved when discrete mechanical manipulation of the active element is difficult. Furthermore, for cyclic actuation, a resetting-force that periodically re-deforms the martensite during the cooling interval must arise naturally from mechanical elements in the design. Here, several methods responding these requirements are discussed in relation to various kinematic themes.



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Planar Extrinsic Biasing Of Thin Film Shape-Memory MEMS Actuators.

  • D. S. Grummon (a1), R. Gotthardt (a2) and T. LaGrange (a2)


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