|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||Kinetics of Low-temperature Spinodal Decomposition in a Fe-Ni-C Martensite: A Discrete Mean-field Model
||Philippe Maugis, Mohamed Gouné, Frédéric Danoix, Sophie Cazottes, Sergiu Curelea, Myriam Dumont
|On-Site Speaker (Planned)
The kinetics of low-temperature carbon redistribution in a Fe-Ni-C martensite was investigated by means of hardness measurements, Atom Probe Tomography and Transmission Electron Microscopy. The results suggest that the phase alpha’’-Fe16C2 (with 11.1 at%C) forms from the supersaturated martensite via a spinodal decomposition mechanism, in the time range of a few days at room temperature. To investigate the thermodynamic and kinetic parameters controlling this transformation, a discrete 1D mean-field model has been developed, based on the Cahn-Hilliard approach. The adjustment of the model parameters allowed retrieving the energy of the alpha / alpha’’ interface, as well as the diffusion coefficient of carbon, as function of carbon content, in the supersaturated martensite. At room temperature, the intrinsic diffusion coefficient of carbon is found to be non-monotonous, and negative inside the spinodal region. The effect of the martensite tetragonality is highlighted.
||Planned: Supplemental Proceedings volume