Phase stresses induced by the γ → α transformation in an iron polycrystal

The evolution of the phase stresses induced in the course of the γ ? α transformation in polycrystalline iron is analyzed in the framework of the elastoplastic model of a spherical inclusion. The isolated regions of the α phase (ferrite) and the γ phase (austenite) are treated as inclusions at the initial and final stages of the transformation, respectively. The stresses are calculated with due regard for the plastic flow in a spherical layer (matrix) around these inclusions. The calculated dependence of the hydrostatic phase stresses on the volume fraction of ferrite suggests that these stresses retard the initial stage and promote the final stage of the transformation.