Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 8: Topical Session: Nanomechanics of nanostructured materials and systems II - Thin films

MM 8.2: Vortrag

Montag, 31. März 2014, 12:15–12:30, BAR 205

Fracture Behavior of Freestanding Thin Metal Films Characterized by Bulge Testing — •Eva Preiß, Benoit Merle, and Mathias Göken — Department of Materials Science and Engineering, Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany

A bulge test setup was used to perform mechanical tests on rectangular membranes with thicknesses ranging from below 100 nm to 400 nm. From conventional bulge tests, stress-strain curves can be calculated and parameters such as residual stress and plane-strain modulus can be determined. Alternatively, the used setup can be inserted into an atomic force microscope (AFM). During in-situ bulge testing in the AFM the surface of the deforming membrane can be imaged.

In order to determine the fracture toughness of thin films, narrow slits of 10 um length were milled into the center of the membranes by focused ion beam (FIB). Subsequently, the membranes were loaded until rupture. The fracture toughness obtained for freestanding and supported gold films is far below the fracture toughness reported for bulk gold. By in-situ testing in the AFM out-of-plane motion of individual columnar grains could be revealed as active deformation mechanism in freestanding films.