Influence of an exclusion radius around each nucleus on the microstructure and transformation kinetics

It is reasonable and it has also been found in experimental work that the probability of a new nucleus forming very close to another one is likely to be low. Therefore, one might suppose that in some cases there is effectively an “exclusion radius” around each nucleus so that within that radius nucleation cannot occur. Here, four point processes in which there is an exclusion radius around each nucleus are used to model nucleation: Matérn I, Matérn II, Strauss hard core and Sequential. Computer simulations of the nucleation and growth for each point process are carried out. It is found that there is a significant effect of the exclusion zone on the transformation compared to the usual Poisson point process in which there is no exclusion zone. The main effect of the exclusion zone on the transformation kinetics for the point processes used here is to delay impigement. As a result the exclusion zone causes a faster transformation kinetics. The microstructure is also strongly affected by the underlying point process. Stereological parameters as well as the two-point correlation function and the correction function are determined in order to characterize the effect of each point process on the microstructural evolution.