Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 44: Topical Session (Symposium EPS and MM): Mechanical Properties at Small Scales
MM 44.2: Vortrag
Mittwoch, 14. März 2018, 17:30–17:45, H 0107
Deformation and failure mechanisms of metallic glass nanostructures — •Mehdi Jafary-Zadeh1, W. Gu2, R. Liontas2, S.W. Lee2, J Greer2, and Y.W. Zhang1 — 1Institute of High Performance Computing (IHPC), A*STAR, Singapore 138632 — 2Department of Materials Science and Engineering, California Institute of Technology (Caltech), USA
Metallic glasses (MGs) are at the cutting-edge of materials research in advanced applications such as nano-electro-mechanical systems (NEMS). The overall mechanical response of MGs is a combination of their intrinsic properties, e.g. chemical composition, atomistic structure, etc., and extrinsic factors, e.g. sample size, structural flaws, and structural hierarchy. Here, we report our recent works on fabrication and in situ fracture testing of nanosize MG structures with geometries ranging from simple nanopillars to complex nanolattices, i.e. metamaterials [1-3]. We also employ large-scale molecular dynamics (MD) simulations to reveal insights into the underlying atomistic mechanisms of the rich spectrum of deformation modes. We demonstrate the importance of processing and post-processing conditions in achieving MGs with certain intrinsic features such as atomic-level structure. We show that an extrinsic flaw (notch) can shift the failure mode from shear banding to cavitation and crack propagation [2]. We further present that in hollow-tube nanolattices, the shell thicknesses leads to a unique transition in deformation mode [3].
[1] Acta Materialia 118, 270-285 (2016) [2] Nano Letters 14, 5858 (2014) [3] Nano Letters 15, 5673 (2015).