THERMODYNAMIC CALCULATION AND KINETIC SIMULATION RELATED TO SOLIDIFICATION PROCESS

摘要

This paper presents a brief review and some new results of the thermodynamic calculation and kinetic simulation related to the micro-modelling of solidification processes by using Thermo-Calc and DICTRA. Emphasis is given on a partial-equilibrium approach developed as a modification of the Scheil-Gulliver non-equilibrium approximation to treat effectively the back diffusion of fast diffusing elements in solid phases. We start with a DICTRA simulation and successfully explain why the P peak drifts away from those of Mn and Si in the experimentally observed composition profiles of a carbon steel. Then, for this steel and other 16 carbon and low alloy steels, we perform both non-equilibrium and partial-equilibrium solidification calculations and demonstrate the significant improvement of the partial-equilibrium approach by comparing the freezing range results with those from either DICTRA simulations or experimental observations.