Dresden 2017 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 34: Poster session II
MM 34.7: Poster
Dienstag, 21. März 2017, 18:30–20:30, P4
Spatially resolved in-situ defect spectroscopy with a positron beam during tensile tests — •Matthias Thalmayr, Thomas Gigl, Marcel Dickmann, Benjamin Rienäcker, and Christoph Hugenschmidt — Heinz Maier-Leibnitz Zentrum (MLZ) and Physik Department E21, Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany
The positron beam facility NEPOMUC at the Research Neutron Source FRM II provides the worlds most intense mono-energetic positron beam with an intensity of 109 moderated positrons per second. The CDB spectrometer at NEPOMUC enables depth dependent and spatially resolved defect studies by using Doppler broadening spectroscopy (DBS), and measurements with coincident DBS. Among the numerous techniques applied for characterizing solids, (C)DBS is non-destructive and has an outstanding sensitivity on open volume defects like vacancies, dislocations and nano-voids. A novel device is presented that enables both, in-situ tensile tests and simultaneously spatially resolved high resolution defect spectroscopy of the specimen in the sample chamber of the upgraded CDB spectrometer. While recording the stress-strain curve of the specimen being deformed during conventional tensile tests, the changes of the lattice and in particular the formation of lattice defects and the increase of the defect concentration can be studied by analyzing the observables of the electron-positron annihilation process. With the new setup it will be possible to image the distribution of lattice defects at the annihilation site with an anticipated resolution in the micrometer range.