Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MM: Fachverband Metall- und Materialphysik
MM 48: Invited talk Gunkelmann
MM 48.1: Hauptvortrag
Donnerstag, 19. März 2020, 09:30–10:00, BAR 205
Molecular dynamics simulations of pressure induced phase transformations in iron and iron-carbon: Interplay of defects and phase transition — •Nina Gunkelmann1, Hoang-Thien Luu1, Ramon J. Ravelo2, Timothy C. Germann3, Eduardo M. Bringa4, and Herbert M. Urbassek5 — 1TU Clausthal, Germany — 2University of Texas, El Paso, USA — 3Los Alamos National Laboratory, USA — 4University of Mendoza, Argentina — 5TU Kaiserslautern, Germany
The study of iron under high-pressure conditions is essential not only for industrial activities but also for geological and astronomical applications. We consider iron and iron-carbon alloys showing a pressure induced phase transformation from the bcc to the hexagonal close-packed phase at around 13 GPa depending on the carbon content. We study compression waves in polycrystalline Fe and Fe-C using interatomic potentials that faithfully incorporate this phase transition at the desired equilibrium pressure. Our simulations show that the phase transformation is preceded by plastic activity, leading to the so-called 3-wave structure: An elastic compression wave is followed by a plastic wave, which then leads to a phase-transformation front. We investigate the interplay of defects in bcc with the transformation process. The role of twins, dislocations, and Cottrell atmospheres has a strong influence on the crystalline iron structure during the phase transformation. Our results show that the presence of Cottrell atmospheres surrounding an edge dislocation in bcc iron retards the development of the hcp phase.