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Mesoscale simulation of elastocaloric cooling in SMA films

Wendler, Frank; Ossmer, Hinnerk; Chluba, Christoph; Quandt, Eckhard; Kohl, Manfred

Abstract (englisch):
A model for the evolution of the mechanical and thermal properties of shape memory alloy (SMA) films during elastocaloric cycling is developed and compared with experiments. The focus is on Ti-Ni-Cu-Co films of 20 mm thickness showing ultra-low fatigue properties. The films undergo a highly localized pseudoelastic transformation under tensile load cycling featuring strain and temperature band patterns that depend on the loading conditions. The corresponding temperature change is of special interest for film-based elastocaloric cooling applications. Starting from a thermodynamics-based Gibbs free energy model comprising mechanical and chemical contributions, we include a martensite-austenite interface
free energy term, for which formulations from a phase-field model are adapted. A 3D continuum mechanics description is modified to treat plane stress conditions appropriate for polycrystalline thin films. The nucleation mechanism of strain bands under dynamic loading is described by introducing a spatial random distribution of the transformation stress barriers reflecting the degree of material inhomogeneity. Heat transfer due to condu ... mehr

Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2017
Sprache Englisch
Identifikator DOI: 10.1016/j.actamat.2017.06.044
ISSN: 1359-6454, 1873-2453
KITopen ID: 1000071601
HGF-Programm 43.22.01; LK 01
Erschienen in Acta materialia
Band 136
Seiten 105–117
Bemerkung zur Veröffentlichung
Schlagworte Martensitic transition; Shape memory alloys; Phase-field model; Elastocaloric cooling
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