The growth of holes in plates of cementite

Abstract

Isotropic and anisotropic of circular and elliptic holes in plates of cementite of lamelar pearlite is discussed. The driving force for hole growth is obtained either from the difference in surface energy of the plates or from the inverses of the curvature of the holes. Two types of model are developed. In the first, constant thickness of the plate and, in the second, constant volume of the plate is assumed. For both models it is shown that the growth of holes is possible if the holes are of minimum size. The dependence of the size of this critical hole on the shape of the holes and on the ratio of half the distance of the holes on the plate to the thickness of the plate is discussed. Using the proposed models, experimental observations on the spheroidization of lamellar pearlite can be explained. A short discussion is given on the anisotropy of the ferrite-cementite phase boundary energy.