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MM: Fachverband Metall- und Materialphysik

MM 17: SYM Phase Transformations in Metallic Melts VI

MM 17.5: Vortrag

Dienstag, 26. Februar 2008, 12:30–12:45, H 1058

Dendritic solidification in the diffusive regime and under the influence of buoyancy driven melt convection — •Ingo Steinbach and Markus Apel — RWTH-Aachen, Access e.V.

Simulations of dendritic solidification in binary and ternary alloys in the diffusive regime and under the influence of buoyancy driven melt convection are performed using a quantitative phase-field model. At first, in the diffusive regime rapid solidification into a highly undercooled melt of ternary Ni-Al-Zr is investigated and compared to levitation experiments and sharp interface calculations. Secondly, the stability of dendritic arrays dependent on the primary spacing is investigated for a binary Al-Cu alloy under directional solidification conditions. Thirdly, melt convection driven by solutal buoyancy is introduced to the latter case and the influence of buoyancy on the spacing selection is discussed. A scaling relation for the dependence of primary spacing on the gravity level is derived and compared to experimental results from centrifugal casting under increased gravity.