Christian Chimani

Diffusional phase transformation and deformation in steels

Abstract During diffusional phase transformations at high temperatures (e.g. γ–α transformation in low-alloy steels) the interface migrates due to a chemical and/or mechanical driving force. A low solubility in the product phase forces the solute atoms (C in α) to move by diffusion, and, therefore, the mole fraction of the solute depends on time and spatial position. In order to evaluate the transformation kinetics numerically, carbon diffusion and interface migration, coupled by appropriate boundary conditions, are simulated. The grain size, the mobility, and the diffusion coefficient determine the growth kinetics. A micromechanical study has been performed in order to investigate the influence of an external uniaxially applied load on the transformation kinetics.