Mechanical behavior and infrared imaging of ferromagnetic NiFeGaCo SMA single crystal subjected to subsequent compression cycles

• Published in: Meccanica (Milan) Vol. 50; no. 2; pp. 585 - 590
• Main Author: Pieczyska, Elzbieta A.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.02.2015
• Subjects: Automotive Engineering; Civil Engineering; Classical Mechanics; Compressing; Deformation; Experimental Solid Mechanics; Ferromagnetism; Martensitic transformations; Mechanical Engineering; Physics; Physics and Astronomy; Shape memory alloys; Single crystals; Stress-strain relationships; Transformations; Cyclic loading; Phase transformation; Transformation bands; Infrared camera; Mechanical properties; Ferromagnetic shape memory alloy; Temperature change; Thermomechanical coupling; Compression test; NiFeGaCo
• ISSN: 0025-6455; 1572-9648
• DOI: 10.1007/s11012-013-9868-7

In this paper, an experimental study of thermomechanical coupling related to pseudoelastic deformation of ferromagnetic shape memory alloy (FSMA) is presented. NiFeGaCo single crystal was subjected to subsequent loading–unloading compression cycles. The stress–strain parameters were recorded by mechanical and laser extensometers. Fast and sensitive infrared camera was used in order to record infrared radiation emitted by the sample surface during the deformation process and to calculate temperature changes related to both exothermic forward and endothermic reverse martensitic transformations. Thanks to the applied techniques, we could investigate a nucleation and development of the stress-induced martensitic transformation. The obtained thermograms exposure localized character of the transformation, initiating in form of inclined bands of higher temperature and developing throughout the sample. The elaborated average temperature change of the SMA sample surface reflects an instantaneous rate of the transformation development. High repeatability of both mechanical and temperature changes obtained in the subsequent loading cycles indicates good thermomechanical properties of the FSMA crystal and confirms high accuracy of the measurement.