Research Projects

Shape memory materials have the ability to recover their original shape after a significant amount of deformation when they are subjected to certain stimuli, for instance, heat or magnetic fields. However, their performance is often limited by the energetics and geometry of the martensiticaustenitic phase transformation. An unique shape memory behavior in CaFe2As2, which exhibits superelasticity with over 13% recoverable strain, over 3 GPa yield strength, repeatable stress–strain response even at the micrometer scale, and cryogenic linear shape memory effects near 50K. These properties are achieved through a reversible uni-axial phase transformation mechanism, the tetragonal / orthorhombic-to collapsed- tetragonal phase transformation. The proposed work is for developing cryogenic linear actuation technologies with a high precision and high actuation power per unit volume for deep space exploration, and more broadly, suggest a mechanistic path to a class of shape memory materials, ThCr2Si2-structured intermetallic compounds.