  A simple model for the solidification of globular grains in metallic alloys
is presented. Based on the Voronoi diagram of the nuclei centers, it accounts
for the curvature of the grains near triple junctions. The predictions of this
model are close to those of more refined approaches such as the phase field
method, but with a computation cost decreased by several orders of magnitude.
Therefore, this model is ideally suited for granular simulations linking the
behavior of individual grains to macroscopic properties of the material.
