Dresden 2017 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 18: Topical session: Interface-Controlled Microstructures: Mechanical Properties and Mechano-Chemical Coupling - Experimental Characterization

MM 18.2: Talk

Monday, March 20, 2017, 18:00–18:15, BAR 205

Mechanical Testing of Copper Alloy Micropillars Containing a Twin Boundary — •Sebastian Krauß, Jan Philipp Liebig, Mathias Göken, and Benoit Merle — Department of Materials Science and Engineering, Institute I, Friedrich-Alexander-University Erlangen-Nürnberg, Germany

Nanotwinned metals are a promising class of modern materials combining a very high strength with a high ductility and excellent electrical properties. This remarkable strength is connected to the very good efficiency of twin boundaries as obstacles to dislocation motion. In order to further characterize these interactions, micropillars containing single twin boundaries with different orientations were compressed with a flat punch, and subsequently investigated in the scanning electron microscope. The investigations concentrated on copper and α-brass, which is a low stacking-fault energy alloy exhibiting a high density of recrystallization twins. Coherent twin boundaries were selected from an EBSD orientation mapping of the sample and oriented by means of a custom sample holder. FIB-milling at these interfaces provided micropillar samples containing a single twin boundary. Single crystalline reference samples were obtained from the bulk of the grain located on both sides of the twin boundary. The microcompression tests allowed quantifying the influence of the twin boundary barrier on the strength of the sample. The activated glide systems were subsequently identified from slip trace analysis and STEM mapping of lamellas obtained by lift-off from the bulk of the tested micropillars.