Regensburg 2004 – wissenschaftliches Programm
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M: Metallphysik
M 9: Flüssige und amorphe Metalle III
M 9.1: Vortrag
Montag, 8. März 2004, 16:30–16:45, H16
Phase separation in bulk metallic glasses — •Shantanu Madge1, Gerhard Wilde1, and Lindsay Greer2 — 1Institute of Nanotechnology, Forschungszentrum Karlsruhe, P.O.B. 3640, D-76021, Germany — 2Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ, U.K
Phase separation has recently seen much attention in explaining nanocrystallisation in bulk metallic glasses. In the present paper, we explore two bulk glass-forming systems, namely, Mg-Ni-Nd and Zr-Ta-Cu-Ni-Al. Energy-filtered TEM shows that the alloy Mg65Ni20Nd15 phase-separates into Ni-rich and Ni-poor liquids during quenching. However, very surprisingly, annealing a phase-separated glass causes homogenisation, instead of crystallisation. The nature of the miscibility gap is considered. Secondly, a range of Zr-Ta-Cu-Ni-Al bulk glasses has been cast. Based on preliminary results and thermodynamic considerations, it appears that these alloys could be phase-separating prior to crystallisation. The prospects of using phase separation for optimising mechanical properties would be discussed.