Composition and temperature dependence of twinning stress in non-modulated martensite of Ni-Mn-Ga-Co-Cu magnetic shape memory alloys

Influence of Doping Tb on the Mechanical Properties and Martensitic Transformation of Ni-Mn-Sn Magnetic Shape Memory Alloys

“…Compared to traditional shape memory alloys (SMAs), ferromagnetic shape memory alloys (FSMAs) can produce force and deformations by applying a magnetic field. Owing to the strong coupling between structure and magnetism, the ferromagnetic shape memory alloys (FSMAs) have attracted considerable attention [1][2][3][4][5][6][7][8][9][10]. As a typical magneto-structurally coupled ferromagnetic shape memory alloy (FSMAs), Ni-Mn-Sn alloys undergo a magnetic-field-induced reverse martensitic transformation from antiferromagnetic martensite to ferromagnetic austenite.…”

Thermal effects on high-frequency magnetic-field-induced martensite reorientation in ferromagnetic shape memory alloys: An experimental and theoretical investigation

“…where are also different, e.g., the two shaded zones in Fig. 11 represent the ranges of the experimental measured temperature-dependent twinning stresses in the literature (Heczko and Straka, 2003;Soroka et al, 2018;Sozinov et al, 2017;Straka et al, 2012;Zreihan et al, 2016): the twinning stress of Type II twin boundary is independent of temperature while that of Type I decreases linearly with temperature:…”

“…Although the temperature rise due to the low energy dissipation of martensite reorientation in FSMA is negligible in the slow or quasi-static loading conditions, it cannot be ignored in high-frequency magnetic loadings (> 100 Hz) because the dissipation due to the frictional twin boundary motion of martensite reorientation (Blanter et al, 2007;Cui et al, 2017;He et al, 2012Heczko et al, 2016;Karaca et al, 2006;Lagoudas, 2005, 2004;Molnar et al, 2008;Murray et al, 2000;O'Handley et al, 2000;Pagounis et al, 2014;Yu et al, 2015) and the eddy current inside the material can accumulate quickly to induce significant temperature rise (Henry, 2002;Henry et al, 2002;Lai, 2009;Lai et al, 2008). Moreover, several physical properties related to martensite reorientation of FSMA are sensitive to the temperature (Aaltio et al, 2008;Adachi et al, 2017;Glavatska et al, 2002;Heczko et al, 2018;Heczko and Straka, 2003;Okamoto et al, 2008;Soroka et al, 2018;Sozinov et al, 2017;Straka et al, 2011aStraka et al, , 2006Straka et al, , 2016Straka et al, , 2012Vronka et al, 2017;Zreihan et al, 2016).…”

“…However, in our current studies we found that while the phase transformation can be avoided, the output strain amplitude of FSMA was reduced significantly when the steady-state temperature was much lower than A s or M f . This is attributed to the fact that the internal friction of martensite reorientation is sensitive to temperature: the frictional twinning stress for the Type I twin boundary increases with decreasing temperature (Heczko and Straka, 2003;Soroka et al, 2018;Sozinov et al, 2017;Straka et al, 2012Straka et al, , 2011aStraka et al, , 2006. Therefore, for the optimal condition of the largest stable cyclic strain in dynamic actuation, the temperature of FSMA should be kept close to (but lower than) the characteristic phase transformation temperature by applying a proper ambient airflow.…”

Effect of Annealing on the Structural and Magnetic Properties of CoNiAl FSMA

“…Magnetic controls of shape memory behavior in FSMAs have much shorter response time than that of thermal controls in SMAs. So far, many FSMAs have been reported, in particular, Ni 2 MnGa alloys have been studied extensively. In general, diffusionless structural transformation in FSMAs alters the high‐temperature cubic phase (austenite) to a lower symmetric phase (martensite), like orthorhombic and monoclinic, at lower temperatures .…”