This work reviews issues and advances a formalism for quantitative interpretation of martensite microstructure, heeding the influence of transformation uniformity and the interaction of martensite with its surroundings. The relationship of volume fraction and number density of martensite units required for kinetics analysis is derived. Additionally we apply the new model to obtain the microstructural path function (MPF) of martensite, and to analyze the autocatalytic spread of the transformation during the martensite burst in Fe-31 wt. (%) Ni-0.02 wt. (%) C. The growth of an autocatalytic spread event relates to the chemical driving force, whereas the number of such events relates to the probability of finding a nucleation site to initiate the reaction.
martensitic phase transformation; kinetics; nucleation; microstructure; analytical methods
