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MM: Fachverband Metall- und Materialphysik

MM 57: Phase Transformations III

MM 57.4: Talk

Thursday, March 21, 2024, 12:30–12:45, C 230

Investigation of rapid solid-state phase transformations with temperature and concentration gradients — •Stephanie Lippmann — Friedrich-Schiller-Universität Jena

The mechanism of a phase transformation depends on composition, undercooling, diffusion kinetics and the nature of the interface. Using the example of the Cu-Zn bcc phase, the high competition between different transformation mechanisms during quenching is discussed in detail based on experimental observations with temperature and concentration gradients. The investigation of the various mechanisms requires a significant level of fine-tuning. Employing one- and multidimensional, multicomponent concentration gradients and pulse heating, the conditions for diffusion controlled mechanism under kinetic effects, coupled growth, massive transformation and martensitic transformation are analysed. For pulse heating, a new device was developed and built. The high-current-low-voltage-approach allows controlled heating of low-resistance samples and a simultaneous measurement and asignment of local T-t curves and microstructures.

Keywords: pulse heating; rapid phase transformation; massive transformation; martensitic transformation; metastable extensions of phase equilibria