Dispersion and clustering of particles in metal matrix materials are evaluated by the “Law of the First Contact Point”, which is a function that uses morphological recursive dilations and erosions on an image analyzer. The technique is based on a fully automatic procedure that leads to an estimate of the mean boundary-to-boundary planar spacing between particles and to the mean diameter of inscribed circle to particle. Analysis has been performed on fourteen Duralcan composite alloys, and has permitted them to be classified according to their particle dispersion and clustering.