EFFECT OF MAGNETISM ON THE PARTITION OF ALLOYING ELEMENTS BETWEEN CEMENTITE AND FERRITE.

Abstract

It has been pointed out by Hillert et al. in 1967 that the partition of manganese between cementite and ferrite is markedly influenced by the magnetism of ferrite, and that the temperature dependence of the partition coefficient shows an abnormal deviation from the ordinary Arrehnius equation in the vicinity of the Curie temperature. This work is aimed at extending their idea to the other elements, and thus the partition coefficient of chromium, manganese, cobalt and nickel between cementite and ferrite at 700-500 degree C was measured. It was found that the partition coefficient of chromium and manganese increases considerably, and that of cobalt decreases abnormally as the equilibration temperature falls. In the case of nickel, the coefficient hardly shows any signs of decrease, contrary to the prediction from the Arrehnius equation. These findings are in good agreement with the theory proposed by Hillert et al.