IMPACT OF BOUNDARY NUCLEATION ON PRODUCT GRAIN-SIZE DISTRIBUTION

We examine quantitatively the impact of boundary nucleation on the siz e distribution of product grains in a computer simulation of a two-dim ensional phase transformation. This is accomplished by determining the probability distribution of product grain areas under different nucle ation conditions. Specifically, a comparison of the moments of normali zed area distributions of product grains arising from site-biased nucl ei with the corresponding moments of the area distribution of Voronoi grains reveals those spatial features of the collection of catalytic s ites which most affect product microstructure. The impact of other rel evant length scales, including the square root of the inverse nucleati on site density, the lattice parameter, and the system size, on micros tructure is also discussed.