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MM: Fachverband Metall- und Materialphysik
MM 17: Phase Transformations: Microstructural Transformations
MM 17.1: Talk
Tuesday, March 28, 2023, 10:15–10:30, SCH A 118
About the transformation speed of martensitic transformations — •Sebastian Fähler1, Stefan Schwabe2, Klara Lünser1, Daniel Schmidt3, Kornelius Nielsch3, and Peter Gaal3 — 1Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2Leibniz IFW Dresden, Dresden, Germany — 3Leibniz-Institut für Kristallzüchtung (IKZ), Berlin, Germany
Structural martensitic transformations enable various applications, which range from high stroke actuation and sensing to energy efficient magnetocaloric refrigeration and thermomagnetic energy harvesting. All these emerging applications benefit from a fast transformation, but up to now the speed limit of martensitic transformations has not been explored. Here, we demonstrate that a martensite to austenite transformation can be completed in under ten nanoseconds. We heat an epitaxial Ni-Mn-Ga film with a laser pulse and use synchrotron diffraction to probe the influence of initial sample temperature and overheating on transformation rate and ratio. We demonstrate that an increase of thermal energy drives this transformation faster. Though the observed speed limit of 2.5 x 1027 (Js)-1
per unit cell leaves plenty of room for a further acceleration of applications, our analysis reveals that the practical limit will be the energy required for switching. Our experiments unveil that martensitic transformations obey similar speed limits as in microelectronics, which are expressed by the Margolus-Levitin theorem.
[1] S. Schwabe, K. Lünser, D. Schmidt, K. Nielsch, P. Gaal and S. Fähler, Science and Technology of Advanced Materials, 23 (2022) 633