Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 11: Topical Session: TEM-Symposium - STEM

MM 11.8: Vortrag

Montag, 11. März 2013, 17:45–18:00, H4

High-resolution HAADF-STEM analysis of hetero-interfaces — •Anna Moros, Harald Rösner, and Gerhard Wilde — WWU Münster

Nanoparticles embedded in an inert immiscible matrix offer ideal conditions to study the impact of hetero-interfaces on reversible phase transitions as for instance melting. Al-Pb composites consisting of nanometer-sized Pb inclusions embedded in a polycrystalline Al matrix serve as model systems for such structural studies. The large lattice constant mismatch of 22.2% between Al and Pb leads to strain at the hetero- matrix-particle interfaces, which is accommodated by misfit dislocations. In order to correlate the thermodynamic properties and the atomic structure of the hetero-interface between the Pb particles and the matrix, an addition of Ga (1 and 3 at. %) selectively into the Al matrix was implemented. Since the lattice constant of the Al(Ga) matrix is extended in comparison with the pure Al matrix, the lattice mismatch between the matrix and the embedded Pb nanoparticles should be reduced. To investigate the interface structure and the particle morphology, aberration-corrected high-resolution HAADF-STEM was performed using the ultra stable stage of the TEAM I microscope. These results will be discussed with the focus on the arrangement of misfit dislocations at the particle-matrix interfaces. The authors acknowledge support of the National Center for Electron Microscopy, Lawrence Berkeley Lab, which is supported by the U.S. Department of Energy under Contract # DE-AC02-05CH11231. Funding by DFG is gratefully acknowledged.