- Magnetic shape memory alloys (MSMAs) have recently drawn considerable research interest due to their ability to produce magnetic field-induced strains (MFIS), at least one order of magnitude higher than those of ordinary magnetostrictive materials. In the present work microstructure dependence of martensitic phase transformation and reorientation is taken into account by introducing internal variables into the model. The magneto-thermo-mechanical constitutive equations are derived in a thermodynamic consistent way. A 3-D stress-field-temperature phase diagram is predicted using the model for the case of field induced phase transformation (FIPT). 2011 SPIE.