INFLUENCE OF ALLOYING ELEMENT ACCUMULATION AT α/γ BOUNDARIES ON THE GROWTH OF PROEUTECTOID FERRITE IN FE-C-MN ALLOYS

摘要

A computer program is developed to simulate the growth of one-dimensional precipitate in ternary alloys under the assumption that the growth is controlled by diffusion of solutes in the matrix of finite grain size. It can simulate the growth up to a late stage growth at which substitutional diffusion occurs substantially, as long as the ratio of the diffusivities of two solutes is less than 3～ 4 orders of magnitude. The model was applied with some approximations to carbon diffusion-controlled growth of ferrite in Fe-C-Mn alloys incorporating solute drag arising out of alloying element accumulation to the α/γ boundary. The growth behavior of ferrite is expected to change widely with the species of substitutional solute, i.e. with the binding energy to the α/γ boundary, boundary diffusivity, and interaction with carbon and other subslituional elements.