Martensite Spread: Analytical Modeling and Computer Simulation

In bulk polycrystals, the first nucleation event in a single grain may induce transformationin neighboring grains, resulting in a cluster of partially transformed grains. This cluster of partiallytransformed grains is normally designated as a ‘spread event’. The collection of these single spreadevents can be defined as the ‘spread’or ‘martensite spread’. In this paper we show how the martensitespreadmay be well described by formal kinetics. Spread taking place as a result of athermalmartensitetransformation, isothermal martensite transformation and even martensite burst are analyzed with thehelp of such a methodology. Formal kinetics is essentially based on a stochastic geometry approach ofthe transformations considered as nucleation and growth (or birth-and-growth ) processes. Therefore,the success of such an analysis strongly suggests the possibility of a computer simulation of the spreadentirely based on probabilistic considerations. Such a simulation has been carried out and the resultsare discussed in this paper with reference to the results obtained by the analytical methods.