Abstract
A research program has been conducted to measure the surface tension and interfacial energy of three irons in contact with basal and prism graphite planes. The objective of the program was to define the forces controlling the graphite growth direction. A consistent relationship was found between the interfacial energy of the iron on the graphite planes and the graphite growth direction. In each case, graphite precipitated from the melt and grew along the pole of the plane with the lowest interfacial energy. In cerium and magnesium treated irons, the basal graphite plane had the lowest interfacial energy and growth occurred along the basal pole to produce nodular graphite shapes. In the presence of sulfur, the prism plane exhibited the lowest interfacial energy, and growth occurred along the prism pole to produce flake graphite.