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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



Originalveröffentlichung
DOI: 10.1016/j.actamat.2017.06.044
Scopus
Zitationen: 8
Web of Science
Zitationen: 7
Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2017
Sprache Englisch
Identifikator ISSN: 1359-6454, 1873-2453
KITopen-ID: 1000071601
HGF-Programm 43.22.01 (POF III, LK 01)
Erschienen in Acta materialia
Band 136
Seiten 105–117
Bemerkung zur Veröffentlichung http://www.sciencedirect.com/science/article/pii/S1359645417305190
Schlagworte Martensitic transition; Shape memory alloys; Phase-field model; Elastocaloric cooling
Nachgewiesen in Web of Science
Scopus
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