Berlin 2008 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 17: SYM Phase Transformations in Metallic Melts VI

MM 17.4: Vortrag

Dienstag, 26. Februar 2008, 12:15–12:30, H 1058

Modelling of dendrite growth and fragmentation in multicomponent melts — Peter Galenko and •Dieter Herlach — Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt, 51170 Köln, Germany

A progress reached in direct experimental measurements of non-equilibrium solidification allows for developing and verifying theoretical models in a wide range of undercooling. Both sharp-interface model and diffuse interface model are applied to solidification of pure (one component) melts, binary alloys (both dilute and concentrated), and ternary diluted alloys. The current theories of dendritic growth based on these models correlate the undercooling to the dendrite growth velocity. It is shown that the sharp-interface model reasonably predicts kinetics of dendritic solidification in agreement with the experimental data obtained by the methods of in situ diagnostic (e.g., using high-speed camera). In addition to the predominant effect of diffusion transport of atoms and conductive transport of heat on growth kinetics, convection of the liquid may quantitatively influence on the growth and fragmentation of dendrites. Combined with in situ diagnostic of solidification, advanced computer modelling of microstructure formation on the basis of experimentally proven physical models allows for developing the perspective of virtual materials design of high functional materials. Financial support by DFG under SPP-1120 through the project DFG-HE1601/13 is acknowledged.