Regensburg 2022 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 35: Nanomaterials: Structure & Properties

MM 35.5: Vortrag

Donnerstag, 8. September 2022, 16:45–17:00, H46

plastic deformation of nanoporous gold modified with organic layers: a TEM study — •Xin Zhang and Nadiia Mameka — Institute of Materials Mechanics, Helmholtz-Zentrum hereon, 21502 Geesthacht, Germany

As a result of their large specific surface area, strength of high-specific area materials must be sensitive to environment and surface chemistry. This notion is confirmed, e.g., by the enhanced flow stress found in single metal nanowires [1] and metallic networks like nanoporous metals when their surface is modified by adsorbed layers or surface coatings [2]. Yet, experimental studies of microstructural origins of the surface constraints impact on small-scale plasticity is still in its infancy. Here, were examine a defect structure of plastically deformed nanoporous gold (NPG) via ex-situ transmission electron microscopy. We exploit self-assembled monolayers (SAM) to modify a surface of NPG as inspired by a substantial flow stress increase due to SAM adsorption reported in [3]. In bare NPG deformed by rolling, we reveal higher density of twins consistent with [4]. In the deformed NPG with SAM, the formation of twins is strongly suppressed near the surface. Meanwhile, the existence of the organic layer apparently increases the density of twins in NPG. In the contribution, we discuss the TEM observations and link them to the findings from mechanical tests of the SAM-modified NPG. [1] Shin et al, Acta Mat. 166 (2019) 572e586. [2] Wu et al, Mater. Res. Lett. 6 (2018) 508. [3] Mameka et al, ACS Appl. Nano Mater. 1 (2018) 6613. [4] Liu, Weissmüller, Mater. Res. Lett. 9 (2021) 359.