Dislocation densities and arrangements were studied, as a function of specimen thickness, in metal crystals grown from the melt. Aluminum crystals containing fewer than 104dislocations per cm2were produced by this method. The results of this study are consistent with the mechanism of collapsing vacancy disks for generating dislocations in crystals grown from the melt.It was found, in aluminum, that below a dislocation density of about 106lines per cm2, dislocations remain in a random network and do not form sub‐boundary arrays. The range of effective interaction between dislocations, to form arrays, thus appears to be limited to the average distance between dislocations when the density is about 106lines per cm2, or about 10 &mgr;.