Scale-Bridging Thermodynamic and Kinetic Simulation (STKS)
Simulation of vanadium carbides in microalloyed steel
Master Thesis, Ruhr-University Bochum, Interdisciplinary Centre for Advanced Materials Simulation (2013)
In this work, the nucleation and growth of vanadium carbides in microalloyed steels were simulated under the inuence of stress above austenitic temperatures in the context of hot rolling at the nanometre scale. The defnition of the project was the creation of a working simulation of vanadium carbides, to lay the groundwork for further projects for researching the positive effect of vanadium carbides on the grain size and strength of precipitation hardening steels.
- An iron-vanadium-carbon model was realised as a multi-component multi-phase field model in the software OpenPhase.
- Phase transformations were controlled by calculation of Gibbs energy density with CALPHAD models and the diffusion data calculated internally using the chemical potentials.
- Elastic stress contributes to the chemical potentials. The possible effect on the diffusion and the morphology of the VC precipitate was studied.
- The inuence of varying concentrations, external stresses and other material constants were measured and compared with experiments.
While some questions remain unanswered about the shape of the carbide, good results were achieved with the convergence of chemical potentials, final component concentrations in the carbide and growth in agreement to experimental data.