Dresden 2009 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 37: Topical Session High Temperature Materials IV

MM 37.1: Topical Talk

Thursday, March 26, 2009, 10:15–10:45, IFW A

Experimental and computational analysis of the solidification path in TiAl-based alloys — •Ulrike Hecht, Julien Zollinger, Anne Drevermann, and Victor Witusiewicz — Access e.V., Intzestr. 5, 52ß72 Aachen, Deutschland

Research into the solidification behavior of TiAl-based alloys focuses on (i) the sequence of phase formation and the associated microsegregation, (ii) the morphological features of the mushy zone and (iii) the effect of solidification on subsequent phase transformations in the solid state. Here we report on experimental and computational work that addresses the solidification kinetics of niobium containing TiAl-based alloys on the background of thermodynamic data. First, we briefly describe the thermodynamic database developed for the ternary system Ti-Al-Nb. This database was used to calculate the solidification path and the associated microsegregation for lever rule and Scheil-Gulliver conditions. Bridgman experiments and phase field simulations of dendritic growth bring further insight, mainly with regard to back-diffusion. Both methods were used to perform a statistic analysis of microsegregation and its evolution along the mushy zone of Ti-45Al-8Nb and Ti-47Al-7Nb. Experimental and computational results will be compared to one another and discussed with respect to the onset of peritectic *(Ti) formation in Ti-Al-Nb alloys.