Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 2: Topical Session: Nanomechanics of nanostructured materials and systems I - Grain size effects

MM 2.1: Topical Talk

Montag, 31. März 2014, 10:15–10:45, BAR 205

Effects of grain size, alloying and temperature on the mechanical behavior of nanocrystalline metals — •Ruth Schwaiger — Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM-WBM)

Characterization, control and optimization of mechanical properties are key issues in materials engineering. While nanocrystalline metals are very attractive candidates for applications requiring high strength, size-dependent deformation, deformation mechanisms and microstructural stability are still under debate. Experimentally, the transition from bulk to interface-dominated deformation mechanisms in nanocrystalline metals is reflected by increased strain rate sensitivity at low temperatures and smaller activation volumes compared to coarse-grained materials. Introducing miscible solutes can be expected to lead to modified mechanical properties compared to the pure metals. Furthermore, alloying of nanocrystalline metals may stabilize the microstructure if the solute segregates to the boundaries facilitating mechanical testing at elevated temperatures. Our investigations of PdAu and PdAg alloys showed a hardness increase with increasing alloying content. The grain size was observed to increase with increasing plastic strain at room temperature while the grain size was stable at annealing temperatures up to 95°C. In this presentation, mechanical behavior and size effects will be discussed for different metallic alloying systems and grain sizes.