Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 16: Microstructure and Phase Transformations III - Precipitaion hardening/ Alloying elements
MM 16.5: Vortrag
Montag, 31. März 2014, 16:45–17:00, IFW B
Phase transformations in Ti-Fe and Ti-Fe-Nb alloys by in situ X-ray diffraction — •Olga Shuleshova1, Ivan Kaban1,2, Dirk Holland-Moritz3, Jan Gegner3, Fan Yang3, Jozef Bednarcik4, Junhee Han1, Norbert Mattern1, and Jürgen Eckert1,2 — 1IFW Dresden, Institute for Complex Materials, 01171 Dresden, Germany — 2TU Dresden, Institute of Materials Science, 01062 Dresden, Germany — 3DLR, Institut für Materialphysik im Weltraum, 51170 Köln, Germany — 4DESY Photon Science, 22607 Hamburg, Germany
In this work the solid-liquid phase transformations, as well as phase equilibria in the binary Ti-Fe and ternary Ti-Fe-Nb systems are studied by means of in situ X-ray diffraction of the synchrotron radiation. To avoid contamination the reactive titanium alloys have been processed containerlessly, using electrostatic levitator. Levitated samples were repeatedly heated from the room temperature above their liquidus temperatures and subsequently cooled down to undergo solidification. Analysis of the lattice constants shows that below approx. 800°C solid-state diffusion is negligible and samples are only subjected to thermal expansion. On heating above this temperature near-equilibrium conditions are reached before the onset of melting. These data have been used to verify the binary Ti-Fe phase diagram and to map solidus and liquidus surfaces in Ti-rich corner of the ternary Ti-Fe-Nb system. On cooling the liquid melts were subjected to considerable undercooling. Detailed evolution of the lattice parameters of the samples solidified under non-equilibrium conditions is presented. Financial support by DFG under project No. SH 578/1-1 is gratefully acknowledged.