Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 4: Topical session (Symposium EPS and MM): Mechanical Properties at Small Scales

MM 4.2: Talk

Monday, March 12, 2018, 10:45–11:00, TC 006

Insights into the deformation behavior of the superplastic alloy Zn22Al at the micro-scale — •Patrick Feldner, Benoit Merle, and Mathias Göken — Friedrich-Alexander-University Erlangen-Nuremberg, 91054 Erlangen, Germany

Due to their remarkable ductility, superplastic metallic alloys are promising candidates to create micro-scale components via micro-forming processes. However, it has not yet been established if the macroscopically observed superplastic behavior also persists at microscopic length scales.

For this reason, the superplastic alloy Zn22Al was characterized at small length scales using nanoindentation at elevated temperatures, pillar compression experiments as well as tensile testing in situ in a TEM.

Coupling the local strain-rate sensitivity with the apparent activation energy, strong evidences for superplastic like flow at the micrometer-scale were found. However, further successively decreasing the size of the plastic zone yields a significant change of the deformation kinetics, which suggests a critical length scale beneath which the superplastic material behavior disappears.

Supported by the deformation and fracture mechanisms observed during thin film tensile testing, a transition from boundary mediated ductility to boundary mediated brittleness is proposed.