Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 55: Topical Session Growth Kinetics V

MM 55.4: Vortrag

Donnerstag, 25. März 2010, 14:45–15:00, H4

Role of Nucleation in Multi-Scale Phenomena of Solidification — •Abhik Choudhury and Britta Nestler — Institute of Materials and Processes, Moltkestrasse 30, Karlsruhe 76131

Solidification has been an interesting topic of study considering the vast scale of structures possible during the evolution of solids from an undercooled liquid. Considering their significance, it is worthwhile to get a basic understanding of the principles underlying the pattern formations, such that control mechanisms are possible to design their production. Epicentric are structures such as interdendritic lamellar eutectics and island banded and coupled growth morphologies in peritectic systems, which are principally formed as a result of interplaying multi-scale phenomena. Nucleation is understood to be an important phenomenon in maintaining scale of the eutectic lamellae in the case of interdendritic structures and the switching from island banded structures to coupled growth in some peritectic systems.

In the present study, we investigate the process of nucleation using the phase-field method. The presentation involves the calculation of the barrier to nucleation in eutectic and peritectic systems through the solution of the Euler-Lagrange(EL) equations which are formulated in the framework of the phase-field method. Special emphasis is placed on the description of a novel technique to solve the EL equations, based on an extension of the volume preservation method. The generality of the method allows for applications to a range of possible EL equations in material systems. The calculations are compared with phase-field simulations of nucleation with random noise.