Mechanical Behaviour and Phase Transition Mechanisms of a Shape Memory Alloy by Means of a Novel Analytical Model

• Main Authors: Carpinteri Andrea, Di Cocco Vittorio, Fortese Giovanni, Iacoviello Francesco, Natali Stefano, Ronchei Camilla, Scorza Daniela, Vantadori Sabrina, Zanichelli Andrea
• Format: Article
• Language: English
• Published: Sciendo 2018-06-01
• Series: Acta Mechanica et Automatica
• Subjects: fatigue behaviour; phase transition mechanisms; shape memory alloy; tensile cyclic test; x-ray diffraction analyses
• Online Access: https://doi.org/10.2478/ama-2018-0017

The aim of the present paper is to examine both the fatigue behaviour and the phase transition mechanisms of an equiatomic pseudo-elastic NiTi Shape Memory Alloy through cyclic tests (up to 100 loading cycles). More precisely, miniaturised dog-bone specimens are tested by using a customised testing machine and the contents of both austenite and martensite phase are experimentally measured by means of X-Ray diffraction (XRD) analyses. On the basis of such experimental results in terms of martensite content, an analytical model is here formulated to correlate the stress-strain relationship to the phase transition mechanisms. Finally, a validation of the present model by means of experimental data pertaining the stress-strain relationship is performed.