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MM: Fachverband Metall- und Materialphysik

MM 4: Microstructure and Phase Transformations - Characterization

MM 4.5: Vortrag

Montag, 16. März 2020, 11:15–11:30, IFW B

Atomistic investigation of the elastocaloric effect in nanoporous NiTi structures — •Arne J. Klomp and Karsten Albe — Fachgebiet Materialmodellierung, Institut für Materialwissenschaft, Technische Universität Darmstadt, Germany

Shape memory or superelastic alloys exhibit strong elastocaloric response and can potentially be used in solid state cooling devices. The most promising material is NiTi due to the large latent heat released during the martensitic phase transition.

By constructing nanosized open porosity foams of NiTi one can in principle strongly increase the surface to volume ratio in order to improve the heat transfer between elastocaloric medium and heat transport medium. Using classical molecular dynamics simulations the thermomechanical properties and stability of NiTi nanofoams under cyclic mechanical loading is investigated.

Our work reveals that even in complex and random nanosized structures a martensic phase transition can be triggered by uniaxial compression and thus the elastocaloric effect can be exploited for cooling applications. We further show the impact of temperature on the amount of transformed phase, accumulated damage during cyclic loading, latent heat of the phase transformation and a possible coefficient of performance. Finally, the results give implications for limits of the maximum deformation as well as speed of deformation.