Papers by Author: Ingo Steinbach

Abstract: The kinetics and topology of ideal grain growth were simulated using the phase-field model. Large scale phase-field simulations were carried out where ten thousands grains evolved into a few hundreds without allowing coalescence of grains. The implementation was first validated in two-dimensions by checking the conformance with square-root evolution of the average grain size and the von Neumann-Mullins law. Afterwards three-dimensional simulations were performed which also showed fair agreement with the law describing the evolution of the mean grain size against time and with the results of S. Hilgenfeld et al. in 'An Accurate von Neumann's Law for Three-Dimensional Foams', Phys. Rev. Letters, 86(12)/2685, March 2001. Finally the steady state grain size distribution was investigated and compared to the Hillert theory.

Abstract: Cooperative growth of pearlite is simulated for eutectoid steel using the multi-phase field method. This allows to take into account diffusion of carbon not only in γ phase, but also in α phase. The lamellar spacing and growth velocity are estimated for different undercoolings and compared with experimental results from literature and theoretical results from analytical models. It is predicted, that diffusion in ferrite and growth of cementite from the ferrite increase the kinetics of pearlitic transformation by a factor of four as compared to growth from austenite only, which is assumed by the classical Zener-Hillert model. Further on the effect of stress due to inhomogeneous carbon distribution in austenite and due to transformation strain is discussed shortly.