Just another WordPress site - Ruhr-Universität Bochum

Abstract

The phase-field method, being based on a diffuse representation of the phase boundaries, has emerged as a powerful tool to simulate the microstructural evolution in various materials processes during their life time. In order for a quantitative simulation, the coupling of the phase-field method and the CALPHAD (CALculation of PHAse Diagrams) technique is commonly performed.

Based on the unique features in our recently developed phase-field model with finite interface dissipation [1, 2], a new approach to directly incorporate the CALPHAD sublattice model into a phase-field model was developed. In binary alloys, the sublattice models can be classified into two types (i.e., “Type I” and “Type II”), depending on whether a direct one-to-one relation between the element site fraction in the CALPHAD database and the phase concentration in the phase-field model exists. For “Type I” sublattice model, such a direct one-to-one relation was found to exist. As for “Type II” sublattice model, the one-to-one relation can be established via an internal relaxation between different sublattices. With the present coupling techniques, the free energy and potential information from the CALPHAD database can be directly utilized in the phase-field simulation. The present coupling technique was successfully applied to study the peritectic reaction in the Fe-C alloys as well as the ripening process in the Ni-Al alloys. Moreover, the hints on the extension of the present coupling techniques into multicomponent alloys were also pointed out.

References
[1] I. Steinbach, L. Zhang, and M. Plapp, Acta Mater. 60, 2689-2701 (2012).
[2] L. Zhang and I. Steinbach, Acta Mater. 60, 2702-2710 (2012).