Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 23: Mechanical Properties II

MM 23.1: Vortrag

Dienstag, 8. März 2016, 11:45–12:00, H52

Dislocation structure and ordering effects in high entropy alloys — •Leonie Koch, Alexander Stukowski, and Karsten Albe — FG Materialmodellierung, FB Materialwissenschaft, Technische Universität Darmstadt, Germany

High entropy alloys, mixtures of least five elements, have recently attracted considerable attention in the field of high-performance materials. It is assumed that a high configurational entropy stabilizes solid solution states at low temperatures and simultaneously avoids the formation of brittle intermetallic phases. These structural simple solid solutions exhibit a considerable strength, while preserving sufficient ductility. Nevertheless, there has been some disagreement about the high entropy effect on phase formation and stability and chemical ordering instabilities in N-component alloys have not yet been clarified for a variety of alloy systems. Therefore, we investigate the competing effects of entropy and enthalpy with decreasing temperatures by using variance-constraint semi-grand canonical Monte Carlo simulations and subsequently quantify short-range order. We further show how inherent lattice strains in atomic-scale composites affect dislocation motion under external stress at different temperatures.