Regensburg 2019 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

MM: Fachverband Metall- und Materialphysik

MM 14: Topical session (Symposium MM): High entropy and compositionally complex alloys

MM 14.1: Topical Talk

Tuesday, April 2, 2019, 10:15–10:45, H43

Nanocrystalline high-entropy alloys studied by atomistic computer simulations — Daniel Utt, Leonie Koch, Alexander Stukowski, and •Karsten Albe — TU Darmstadt, FB 11, FG Materialmodellierung, Otto-Berndt-Str. 3, D-64287 Darmstadt

The superior mechanical properties of high-entropy alloys (HEA) can be mainly attributed to the fact that multiple principle elements tend to strengthen materials markedly by the solid-solution hardening mechanism. Randomly distributed elements in grain interiors can, however, also affect relative grain-boundary energies and minimize thermodynamic driving forces for grain- boundary migration. Moroever, segregation may occur at grain boundaries and work as barriers to prevent grain-boundary motion. These effects become particular imporant in the small grain-size regime. In this contribution results from combined molecular dynamics and Monte-Carlo simulations for a four-component model alloy are presented, which were carried out using an embedded-atom approach and an average potential method. After discussing the impact of local disorder on phonons and stacking fault energies, we present results on the structure and mobility of grain boundaries in bicrystal geometry and compare to result obtained from polycrytalline model structures. The simulations provide no evidence for a change in migration mechanisms, but show the influence of GB segregation and secondary phase formation. Furthermore, samples are studied under mechanical load and deformation mechanisms -in particular twin formation- are investigated.