Dresden 2017 – wissenschaftliches Programm

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MI: Fachverband Mikrosonden

MI 10: Positron Annihilation Spectroscopy (PALS)

MI 10.2: Vortrag

Donnerstag, 23. März 2017, 12:15–12:30, MER 02

Microstructural Changes in Welded AlCuLi-Alloys by Positron Annihilation Spectroscopy (PALS), SAXS and DSC — •Danny Petschke, Frank Lotter, and Torsten Staab — University Wuerzburg, Department of Chemistry, LCTM Röntgenring 11, 97070 Wuerzburg, Germany

We follow changes in the microstructure at several distances from the weld nugget of friction stir welded AlCuLi-alloy (AA2198) plates occurring due to the tool movement and the created heat by employing different methods: Small Angle X-ray Scattering (SAXS), giving information on type, size and density of precipitates, Differential Scanning Calorimetry (DSC), giving information on formed precipitates by their dissolution signal, and positron annihilation lifetime spectroscopy (PALS), being sensitive to vacancies and dislocations as well as to the formation and growth of precipitates. We start by characterizing the base material as a reference and proceed via the heat-affected zone to the weld nugget. By the use of complementary methods, we obtain information on structure, kind and distribution of precipitates and correlate this with hardness measurements.