  A model for the study of hysteresis and avalanches in a first-order phase
transition from a single variant phase to a multivariant phase is presented.
The model is based on a modification of the Random Field Potts model with
metastable dynamics by adding a dipolar interaction term truncated at nearest
neighbors. We focus our study on hysteresis loop properties, on the
three-dimensional (3D) microstructure formation and on avalanche statistics.
