Unified Model for Plate and Lath Martensite with Athermal Kinetics

A unified formalism was developed to describe the transformation curve of athermal martensite with plate and lath/packet morphologies, which exhibit unique spatial aspects. Plates tend to partition grains and spread the reaction into a next grain, whereas laths generally do not exhibit grain partitioning and are contained within the packets. Using extended space concepts, it was possible to factor out the spatial aspects of martensite and to derive a unified model for the transformation curves. This model showed very good agreement with experimental data regarding carbon steels (lath) and nickel-carbon alloys (plate) martensite transformations that exhibit practical and scientific interest.