Regensburg 2025 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 23: Phase Transformations
MM 23.5: Vortrag
Mittwoch, 19. März 2025, 18:15–18:30, H23
Formation mechanism of bicontinuous structure during peritectic melting of TiAg — •Zhongyang Li1, Lukas Lührs1, Tobias Krekeler2, and Jörg Weissmüller1,3 — 1Institute of Materials Physics and Technology, Hamburg University of Technology, Hamburg, Germany — 2Electron Microscopy Unit, Hamburg University of Technology, Hamburg, Germany — 3Institute of Hydrogen Technology, Helmholtz-Zentrum Hereon, Geesthacht, Germany
Reverse peritectic reactions, and specifically the peritectic melting of TiAg, have been proposed as dealloying-like processes that produce quite similar microstructures but avoid the restrictions on sample size inherent in liquid-metal dealloying (LMD). Here, studies of the microstructure evolution during peritectic melting of TiAg suggest a formation mechanism that is not LMD-like but rather relies on liquid film migration. The process starts with wetting of the TiAg grain boundaries by the alloy melt. Successively, both Ti and Ag continue to dissolve from one side of, while β-Ti deposits on the other side and the liquid film sweeps the pristine TiAg crystal. TiAg-Ti interfaces with well-defined orientation relationship and with concentration gradients support this picture, as does the phase morphology in partly decomposed samples. The process generates a bicontinuous structure with a solid Ti skeleton, interpenetrated by the Ag-rich melt, which is conserved even after coarsening. This study clarifies the mechanism of peritectic melting in TiAg, and it may provide a basis for identifying other alloy systems suitable for producing bicontinuous microstructures by that process.
Keywords: Liquid film migration; TiAg alloy; Bicontinuous structure; Dealloying; Peritectic melting