Magnetic indication of the stress-induced martensitic transformation in ferromagnetic Ni–Mn–Ga alloy

• Published in: Journal of magnetism and magnetic materials 2006-07, Vol.302 (2), p.387-390
• Main Authors: Heczko, O., L’vov, V.A., Straka, L., Hannula, S.-P.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Ferromagnetism; Magnetic properties and materials; Martensite; Martensitic transformation; Martensitic transformations; Materials science; Ni–Mn–Ga; Other ferromagnetic metals and alloys; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Stress-induced transformation; Studies of specific magnetic materials
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2005.09.038

A quantitative study of the stress-induced martensitic transformation in Ni 49.7Mn 29.1Ga 21.2 magnetic shape memory alloy has been carried out in two different ways: the first way is based on the measurements of saturation magnetization under variable mechanical stress and the second one is founded on the quantitative theoretical treatment of experimental stress–strain loops. A functional dependence between the volume fraction of transformed martensite and applied stress has been determined from both magnetization and strain values. A quantitative agreement between the functions determined in two different ways has been observed, and hence, the effectiveness of the magnetic indication of the stress-induced martensitic transformations has been proved. This method can be used to monitor stress-induced transformations in martensitic films, needles and small specimens.