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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 13: Microscopy, Tomography and Spectroscopy with X-ray Photons, Electrons, Ions and Positrons (joint session KFM/HL)
KFM 13.7: Talk
Wednesday, April 3, 2019, 11:50–12:10, H47
The influence of trace element additions to Al-1.7 at.% Cu alloys: preservation of quenched-in vacancies and atomistic mechanisms supporting θ ′-formation — •Torsten E.M. Staab1, Frank Lotter1, Uwe Mühle2, Mohamed Elsayed3, Danny Petschke1, Thomas Schubert4, Reinhard Krause-Rehberg3, and Bernd Kieback2,4 — 1University Wuerzburg, Dep. of Chemistry, LCTM, Roentgenring 11, D-97070 Wuerzburg — 2TU Dresden, Institute of Materials Science; Helmholtzstr. 7, D-01069 Dresden — 3Martin-Luther-University Halle-Wittenberg; Faculty of Natural Science II; von-Danckelmann-Platz 3; D-06120 Halle — 4Fraunhofer IFAM, Winterbergstrasse 28, D-01277 Dresden
Aluminium-copper alloys of the 2xxx type receive their strength during hardening at room or elevated temperature by the formation of copper-rich precipitates. They are responsible for the final mechanical properties of these alloys. Alloying small amounts of Cd, In or Sn influences the precipitation behavior as well as the final strength of Al-Cu alloys. Obviously, quenched-in vacancies are bound to trace element atoms in the aluminium matrix. Thus, the diffusion behavior of the copper atoms is influenced and the main type of the formed precipitates changes. For high-purity ternary alloys we investigate the interaction of copper atoms and trace elements (In, Sn, and Pb) with quenched-in vacancies. By employing Differential Scanning Calorimetry (DSC), Small Angle X-Ray Scattering (SAXS), Positron Annihilation Lifetime Spectroscopy (PALS) as well as Transmission Electron Microscopy (TEM) we obtain a comprehensive picture.