Growth of Cementite Particles in Austenite

Abstract

The coarsening of cementite particles in an austenite matrix has been studied in Fe-C, Fe-C-Cr, and Fe-C-Mo alloys. A quantitative metallographical technique was used to estimate the particle size distribution and the mean particle size. The observed growth rate was analysed using the Lifshitz Wagner theory. It was found that the coarsening process was fairly well explained by the diffusion controlled growth mechanism. A special interest was taken to examine the effect of alloying elements on the coarsening rate of cementite particles. The coarsening rate considerably decreased by a small addition of substitutional alloying elements. In ternary systems such as Fe-C-Cr and Fe-C-Mo alloys, the growth rate was found to be controlled by the diffusion of substitutional solute in the matrix as predicted by BJöRKLUND, DONAGHEY and HILLERT.