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R. Radis:
"Numerical Simulation of the Precipitation Kinetics of Nitrides and Carbides in Microalloyed Steel";
Verlag der Technischen Universität Graz, Graz, 2010, ISBN: 978-3-85125-123-4; 157 pages.

The present work deals with the numerical simulation of the precipitation kinetics of nitrides and carbides during isothermal annealing of microalloyed steel. A newly developed model is employed, which takes into account the predominant precipitation of particles at grain boundaries, together with the classical treatment for randomly distributed precipitates in the grain interior. It is demonstrated, that the precipitation of nitrides and carbides can be modelled in a consistent way if simultaneous precipitation at grain boundaries and at dislocations is taken into account, dependent on chemical composition, grain size and annealing temperature. It is also demonstrated that, for consistent simulations, it is necessary to account for several physical mechanisms that are often neglected in this type of simulations, among them the precipitate/matrix volumetric misfit, the temperature dependent Young`s modulus, composition-, temperature- and size-dependent interfacial energies, as well as the ratio between bulk and grain boundary diffusion. Finally, a new simulation approach is presented for the calculation of the precipitation kinetics of microalloying phases during casting. It is shown that segregation effects during solidification play an important role and must be considered when doing precipitation kinetics calculations. All precipitation kinetics simulations are compared to independent experimental results from literature.

precipitation kinetics, nitrides, carbides, microalloyed steel