| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Austenite Formation and Decomposition V: A Symposium in Memory of Prof. Mats Hillert
|
| Presentation Title |
CALPHAD-Based Modeling of Pearlite Transformation in Multicomponent Steels |
| Author(s) |
Jiayi Yan, John Agren, Johan Jeppsson, Paul Mason |
| On-Site Speaker (Planned) |
Paul Mason |
| Abstract Scope |
Based on the CALPHAD thermodynamic and kinetic databases for steels, a model for austenite-to-pearlite transformation in multicomponent steels has been implemented into the Thermo-Calc software.
The model for growth rate considers not only classic ingredients (formation of ferrite-cementite interface, volume diffusion, boundary diffusion and optimization of lamellar spacing) but also finite austinite-pearlite interfacial mobility which resolves some previous difficulties. A transition between orthopearlite and parapearlite is realized by optimizing the partitioning of substitutional alloying elements under constrained carbon equilibrium between ferrite and cementite. Solute drag is included to account for the bay in growth rate curves. The modeling approach for steady state growth can also be extended for non-steady-state growth of the so-called divergent pearlite.
Grain boundary nucleation rate is modeled as a function of chemical composition, driving force and temperature, with consideration of grain boundary equilibrium segregation. Overall transformation kinetics is calculated from growth rate and grain boundary nucleation. |