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M: Metallphysik
M 32: Poster TU B (Symposium Tomographic Methods in Materials Research M-32.32-55)
M 32.27: Poster
Montag, 7. März 2005, 14:30–16:30, Poster TU B
Fluid Flow Effects on Phase Formation and Microstructural Evolution in Nd-Fe-B Melts — •Sven Reutzel1,2, Takeshi Okutani3, Thomas Volkmann2, Jianrong Gao4, Jörn Strohmenger2, Heinrich Bach1, and Dieter M. Herlach2 — 1Ruhr-University, Bochum — 2German Aerospace Center, Cologne — 3National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan — 4Northeastern University, Shenyang, China
Experiments on peritectic and hyper-peritectic NdxFe100−1.5xB0.5x alloy melts (x = 11.8, 14, 16 and 18) were performed under microgravity during parabolic flight campaigns using the TEMPUS facility (Tiegelfreies elektromagnetische Positionieren unter Schwerelosigkeit) to elucidate the effect of melt convection on critical undercooling levels for the occurrence of metastable phases and the different solidification pathways which were observed in ground-based electromagnetic levitation experiments. Furthermore, the experiments were carried out to improve the knowledge on the relationship between undercooling, fluid flow, magnetic field, metastable phase formation and the structural properties, such as the homogeneity and crystallite orientation. Our main focus was (I) to analyse the influence of fluid flow in the undercooled melt on phase selection and on volume fraction of competing phases in the solidified samples and (II) to evaluate the influence of convection and static magnetic fields with respect to the crystallographic alignment of grains and homogeneity of microstructure.
This work is funded by the Space-flight Management of the German Aerospace Center, Bonn under contract No.50WM9930.