Regensburg 2016 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 52: Topical session: In-situ Microscopy with Electrons, X-Rays and Scanning Probes in Materials Science VI - Structural transitions
MM 52.1: Vortrag
Donnerstag, 10. März 2016, 12:00–12:15, H38
Grain growth of nc-Pd during heating using ACOM-STEM — •KK Neelisetty1,4, A Kobler1,4, VSK Chakravadhanula1,3,4, T Scherer1,2, H Hahn1,3,4, and C Kübel1,2,3 — 1INT, Karlsruhe Institute of Technology (KIT), Germany — 2KNMF, KIT, Germany — 3HIU, KIT, Germany — 4TU Darmstadt, Germany
Understanding grain growth in nanocrystalline (nc) metals and how it can be controlled and tuned is a major objective for applications and provides new fundamental insights. In-situ heating experiments in TEM using Automated Crystal Orientation Mapping (ACOM) is a powerful approach to reveal the microstructure and orientation of grains in nanoscale and follow it's structural evolution. In this study, sputtered ncPd thin-films about 50 nm thick were used to evaluate the grain growth in 2D. Mapping grain orientation in an area initially containing more than thousand grains with a resolution of 1.5 nm allowed for a statistically meaningful analysis of grain orientation, presence of twins, grain rotation and grain boundary migration over time at elevated temperature. Evaluation of maps was performed using MATLAB using Mtex tool-box, providing information about the local misorientations between grains, CSL boundary, twin density and grain size distribution, texture, and number of neighbors of selected growing grains. Global analysis of grains growing is in good agreement with the structural changes observed in bulk samples. Local analysis shows that grain boundary curvature and grain boundary angle are not sufficient criteria to explain grain growth in nc-metals, but triple- and quadruple line networks appear to stabilize nanograins locally.