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Title: Superelasticity and cryogenic linear shape memory effects of CaFe 2As 2

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. But, their performance is often limited by the energetics and geometry of the martensitic-austenitic phase transformation. We report a unique shape memory behavior in CaFe 2As 2, 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 50 K. These properties are acheived through a reversible uni-axial phase transformation mechanism, the tetragonal/orthorhombic-to-collapsed-tetragonal phase transformation. These results offer the possibility of 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, ThCr 2Si 2-structured intermetallic compounds.
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  1. Univ. of Connet. Dept. of Materials Science and Engineering, Inst. of Materials Science
  2. Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics
  3. Iowa State Univ., Ames, IA (United States). Ames Lab., Dept. of Physics and Astronomy
  4. Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics; Colorado State Univ., Fort Collins, CO (United States). Dept. of Mechanical Engineering
Publication Date:
Report Number(s):
IS-J 9415
Journal ID: ISSN 2041-1723; PII: 1275
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2041-1723
Nature Publishing Group
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE; 42 ENGINEERING; aerospace engineering; mechanical engineering; mechanical properties; metals and alloys
OSTI Identifier: