A micromechanical constitutive model for porous ferromagnetic shape memory alloys considering magneto-thermo-mechanical coupling

In this work, a three-phase constitutive model describing the magneto-thermo-mechanical behaviors of porous Ferromagnetic Shape Memory Alloys (FSMAs) is established through a combination of micromechanical and thermodynamic theories. The kinetic equation is obtained in accordance with the thermodynamic driving force caused by the reduction of Gibb’s free energy of porous FSMAs. The thermodynamic driving force in combination with the corresponding resistance is used to establish the balance equation for calculating the volume fractions of martensitic variants under the action of different given magnetic fields, stresses and temperatures. Good agreement between the theoretical prediction of dense FSMA models and published experimental data is observed. The mechanical behaviors of porous FSMAs under magneto-thermo-mechanical coupling with different porosities and initial conditions are then discussed, which will provide a reliable theoretical basis for the future research of these functional materials as sensors or actuators.