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MM: Metall- und Materialphysik
MM 28: Amorphous and Liquid Materials III
MM 28.2: Vortrag
Donnerstag, 30. März 2006, 12:00–12:15, IFW B
Liquid phase separation in Cu-based alloys — •Matthias Kolbe1, Jianrong Gao2, Lorenz Ratke1, and Dieter M. Herlach1 — 1Institute for Space Simulation, DLR, Cologne, Germany — 2Key Lab of Electromagnetic Processing of Materials, Northeastern University, Shenyang 110004, China
Many Cu-based alloys as Cu-Cr, Cu-Co, Cu-Nb and Cu-Fe exhibit in the binary phase diagram a flat liquidus, which is often associated to metastable phase separation in the region of the undercooled melt: When the metastable miscibility gap is entered, the homogeneous alloy separates into a Cu-rich and a Cu-poor liquid. Due to undercooling, the melt solidifies rapidly and properties of the metastable liquids are frozen in the solidified microstructure. We studied metastable phase separation and phase growth by electromagnetic levitation (EML), drop tube experiments and splat cooling of metallic melts. In addition, samples have been processed and solidified in the TEMPUS facility during parabolic flights under low gravity conditions. Compared to processing in EML on ground, the fluid flow is reduced in TEMPUS by an order of magnitude. The solidified microstructures show the influence of the different convection levels in the liquid on phase growth. The results are discussed within current models of liquid phase growth.