ICAMS / Interdisciplinary Centre for Advanced Materials Simulation

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Phase-field simulations of austenite decomposition

Date: 07.03.2013
Time: 5:30 p.m.
Place: TMS 2013, San Antonio, USA

Adam Gießmann
Oleg Shchyglo
Ingo Steinbach

We present the results of the phase-field simulation for plain carbon steel using a model with
finite interface dissipation. Within this model the total concentration is separated in concentration fields for each phase which are linked by a kinetic equation describing the
exchange of components instead of using an equilibrium partitioning condition. Therefore this
model is capable of addressing systems which are far from equilibrium. A key feature of the
model is the interface permeability for redistribution fluxes which allows describing both,
diffusion controlled and interface controlled transformations.
As an example of a diffusion controlled phase transformation we simulate the formation and
cooperative growth of pearlite. Firstly, the correlation between cooling rate, carbon enrichment of austenite and the resulting pearlite fraction for hypoeutectoid carbon steel is analyzed and compared with experimental observations. Secondly, the relation of undercooling ΔT, lamellar spacing λ and growth velocity V during the eutectoid reaction is presented. The simulations investigate the role of diffusion of carbon in ferrite and take the influence of lattice strain on the growth kinetics of pearlite into account. Finally, an example for a transformation involving solute trapping is presented which may be related to bainite formation.

Supporting information:

Phase field simulation of austenite decomposition.pdf
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