Experimentally validated constitutive model for NiTi-based shape memory alloys featuring intermediate R-phase transformation: A case study of Ni48Ti49Fe3

• Published in: Materials & design Vol. 203; p. 109593
• Main Authors: Frost, M., Jury, A., Heller, L., Sedlák, P.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-05-2021; Elsevier
• Subjects: Constitutive model; Finite element analysis; NiTiFe shape memory alloys; R-phase; NiTiFe shape memory alloys; Constitutive model; Finite element analysis; R-phase
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2021.109593

An important group of NiTi-based alloys employed in applications exhibits an intermediate R-phase transformation, which substantially modifies the material's thermomechanical response. Finite element analysis of products from such alloys requires a constitutive model covering the two-stage transformation sequence in its full thermodynamic nature. We propose an enhanced constitutive model for NiTi-based alloys, which incorporates R-phase as a distinctive phase with loading-dependent transformation strain. We validate the model on a newly acquired extensive experimental dataset on the thermomechanical response of Ni48Ti49Fe3 shape memory alloy and illustrate the capabilities of its implementation into finite element software on a computational structural analysis of a tightening ring.
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•An enhanced constitutive model for NiTi-based alloys incorporating R-phase is proposed.•The model is validated using an experimental dataset on the thermomechanical response of Ni48Ti49Fe3 shape memory alloy.•The algorithmic implementation into finite element software is tested on a computational analysis of a tightening ring.