SKM 2021 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 1: Topical Session Interface-Dominated Phenomena - Moving Interfaces

MM 1.1: Hauptvortrag

Montag, 27. September 2021, 10:00–10:30, H8

Using mobile interfaces to rapidly move atoms and create sharp chemical boundaries in Fe-C-Mn alloys — •Sybrand van der Zwaag — TU Delft, Delft, the Netherlands

In this presentation we will show how cyclic partial phase transformations in Fe-X alloys and low alloyed steels can be used to rapidly displace substitutional solute atoms and to leave behind ridges of solute atoms upon reversal of the interface migration. These enriched regions locally retard the passing interfaces during a subsequent transformation and this causes a macroscopically detectable halting of the rate of transformation and/or a change in resulting microstructure.

The concept works not only for diffusional and bainitic phase transformations but can (under well-selected conditions) also be used to manipulate the austenite to martensite transformation and to create nano-structured medium Mn steels with exceptional mechanical properties such as a strength above 2 GPa and a uniform elongation in excess of 20%.

The experimental observations are linked to 1D and 3D transformation models and in-situ TEM observations of the moving interface.