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MM: Fachverband Metall- und Materialphysik

MM 30: Liquid and Amorphous Metals

MM 30.3: Vortrag

Donnerstag, 8. September 2022, 10:45–11:00, H46

Glass Formation and Shear Banding in High-Entropy Metallic Glasses: A Molecular Dynamics Study — •Marie J. Charrier, Daniel T. Utt, Arne J. Klomp, and Karsten Albe — Fachgebiet Materialmodellierung, Institut fuer Materialwissenschaft, Technische Universitaet Darmstadt

Bulk metallic glasses (BMGs) and High-Entropy Alloys (HEAs) both comprise a large number of elements but deviate strongly in their mechanical properties. BMGs are strong but brittle and usually derived from crystalline binary subsystems with deep eutectics and intermetallic phases. HEAs, on the other hand, show remarkable ductility, a small heat of mixing, and are thus typically not glass formers. The open question is whether a classically crystalline random solid solution HEA can be transformed into a BMG using appropriate processing. In this work, we use atomistic computer simulations to study the combination of the two materials classes, HE-MGs. Here, we are able to kinetically suppress crystallization in the CrMnFeCoNi alloy, which in the real world remains a crystalline single-phase solid solution using conventional quench rates. First, we investigate the thermodynamics of the glass transition and its dependence on quench rate. Second, the phase stability of the HE-MG is compared to the crystalline HEA. Third, the atomic-level structure is characterized in terms of chemical and structural short- and medium-range order. Last, we perform compressive and tensile testing on HE-MG samples to assess failure by homogeneous deformation or shear localization and compare the mechanical properties against a CoCrFeMnNi nanocrystal.