Kinetic Transition during Ferrite Growth in Fe-C-Mn Medium Carbon Steel
The kinetics of austenite-to-ferrite diffusional transformation in a medium carbon Fe-C-Mn steel was calculated based on classical nucleation and growth theory coupled with CALPHAD multi-component thermodynamics. The description of the growth rate of proeutectoid ferrite includes a time-dependence d...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2011 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/62977 |
| Acceso en línea: | http://hdl.handle.net/10261/62977 |
| Access Level: | acceso abierto |
| Palabra clave: | phase transformations kinetic modeling medium-carbon manganese steel forging steel Multicomponent thermodynamics proeutectoid ferrite |
| Sumario: | The kinetics of austenite-to-ferrite diffusional transformation in a medium carbon Fe-C-Mn steel was calculated based on classical nucleation and growth theory coupled with CALPHAD multi-component thermodynamics. The description of the growth rate of proeutectoid ferrite includes a time-dependence due to the carbon enrichment in the remaining austenite. The experimental slower kinetics, especially a stagnating behavior at the later stage, has been successfully reproduced when a transition from initial paraequilibrium (PE) to local equilibrium negligible partition (LENP) conditions at austenite:ferrite (γ/α) interface was assumed. This transition is allowed when the velocity of moving γ/α interface is slow enough to be compared with Mn diffusivity, which leads to built up a Mn spike in the interface. This assumption is consistent with a series of scanning transmission electron microscopy (STEM) analyses for Mn and C which indicates that initial unpartitioned Mn ferrite growth is replaced by partitioned growth |
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