Modelling of pressure-induced magnetic and magnetocaloric effects in dissipative magnetic shape memory alloy systems

Abstract

This article presents a coupled magneto-thermo-mechanical model of pressure-dependent magneto-caloric effect (MCE) and magnetization responses for polycrystalline magnetic shape memory alloys (MSMA). Coupled constitutive equations are derived from a Helmholtz free energy function in a consistent thermodynamic way. The hysteretic and dissipative characteristics of phase transformations in MSMAs are captured by the internal state variables approach with their evolution equations. A relation of adiabatic temperature change is established for such a dissipative material system. The model is calibrated and validated with the existing experimental data. The validated constitutive model is then exploited to predict MCEs at different pressure and magnetic field level. Some predicted results are compared with the available experimental data.