Relevant aspects of allotriomorphic and idiomorphic ferrite transformation kinetics

Recently, the grain boundary -intragranular nucleation of ferrite has received much attention in the search for an improvement in toughness of steel, especially when conventional austenite grain refinement techniques are not enough. The present paper deals with some relevant aspects of the competitive process of allotriomorphic and idiomorphic ferrite transformation in a medium carbon V-Ti microalloyed steel, for two different isothermal temperatures and values of prior austenite grain size. It is concluded that consideration of proeutectoid ferrite (allotriomorphic plus idiomorphic) as a single transformation might lead to wrong conclusions in an analysis of the isothermal decomposition of austenite.