Enhancement of pearlite nucleation by deformation of austenite matrix in an Fe-12Mn-0.8C Alloy

The effect of plastic deformation of austenite on the nucleation of pearlite was investigated using an Fe-12Mn-0.8C (mass%) alloy. Slight warm deformation of austenite prior to pearlite transformation effectively accelerates the intragranular nucleation of pearlite although intragranular pearlite is hardly formed without deformation. Formation of pearlite at annealing twin boundaries is promoted in the warm-rolled specimens. Additionally MnS particles are activated as intragranular nucleation sites of pearlite. Cold rolling of austenite introduces many deformation twins in the alloy used. Subsequent isothermal transformation heat treatments result in nucleation of pearlite at intersections of the deformation twins. It is concluded that incoherent portions introduced by deformation onto the annealing or deformation twin boundaries are effective nucleation sites in the pearlite transformation. The effect of plastic deformation of austenite on the nucleation of pearlite was investigated in an high-manganese, high-carbon steel. Slight warm deformation of austenite promotes the intragranular nucleation of pearlite at annealing twins and inclusions. Slight cold rolling of austenite results in formation of deformation twins of which intersections are preferential nucleation sites in subsequent pearlite transformation.