Seok Woo Lee
University of Connecticut
Space missions often involve ultra-cold environments, and cryogenic actuators must be mechanically robust for long-term cyclic work, generate high power per volume, as well as perform high precision motion in such extreme environments. These demanding requirements have asked a material scientist to seek for a new type of actuator materials. Recently, we discovered a bulk-scale novel intermetallic compound CaFe2As2 that can exhibit superelastic deformation and ultra-high strength, which leads to unusually high actuation power per volume, 10~1000 times larger than most actuator materials, as well as cryogenic linear shape memory effects even near 0 K. The cryogenic linear actuation of this crystal is exceptionally repeatable, precise, and reliable with almost no fatigue damage, which would guarantee the long lifetime and high accuracy in actuation motion. Therefore, the research objective of this proposal is to develop a small-volume, high-precision and mechanically-robust cryogenic linear actuator by performing the combined set of works that include (1) large single crystal growth of novel intermetallic compound CaFe2As2 and related structures, (2) evaluation of their cryogenic linear actuation performance, (3) understanding of fundamental physics behind cryogenic actuation properties, and (4) development of proto-type linear actuators that operates at a temperature between 4 and 150 K.