Papers by Author: John Ågren

Abstract: The Thermo-Calc and DICTRA software/database/programming-interface packages, through many successful applications in the fields of Computational Thermodynamics and Kinetics, have tremendously contributed to quantitative conceptual design and processing of various advanced materials. Materials scientists and engineers can efficiently apply such unique and comprehensive tools in calculating material properties, predicting material structures and simulating material processes, which are of wide-ranging industrial and academic importance.

Abstract: Ferrite formation during austenite decomposition in carbon-manganese steel is studied during slow continuous cooling by three-dimensional x-ray diffraction microscopy at a synchrotron source. The ferrite fraction and nucleation rate are measured simultaneously and independently in real time in the bulk of the specimen. Thermodynamic calculations involving both ortho- and paraequilibrium have been performed to determine the driving force for nucleation. From the experiments and thermodynamic calculations the activation energies are estimated for nucleation and the transfer of iron atoms across the interface of the cluster during ferrite nucleation in steel.