Präparationsmethoden und Untersuchung der Phasenchemie einer β-erstarrenden TiAl Legierung mittels Atomsondentomographie

Translated title of the contribution: Preparation methods and investigation of the chemical composition of a β-solidifying TiAl alloy by atom probe tomography

Michael Schachermayer

Research output: ThesisDiploma Thesis

Abstract

In order to develop high performance materials with improved properties it is necessary to characterize the material down to the atomic level. Atom probe tomography is a strong method which meets this requirement. Within this thesis preparation methods, which allow the reproducible and artifact-free production of atom probe tips out of the intermetallic titanium aluminide alloy TNM were developed. Initially, the chemical composition of the constituent phases was determined by atom probe tomography on electrolytic polished tips which were subsequently sharpened by a focussed ion beam. Specific heat treatments were conducted in order to adjust the volume fraction and particle size of the ordered ωo phase. Complementary characterization methods such as scanning electron microscopy and transmission electron microscopy (TEM) were applied for a basic characterization of these. For atom probe tomography analyses of the βo- and the ωo phase, a site-specific sample preparation by focussed ion beam was applied. For the choice of the preparation method and the substrate of the atom probe tip the applicability of transmission kikuchi diffraction for phase identification prior the atom probe tomography had to be considered. Molybdenum TEM grids as a substrate material offer the possibility of transmission kikuchi diffraction and efficient measurements, the preparation of these grids was also a part of this thesis. By application of this preparation process the chemical composition of the βo and ωo phase was evaluated and, moreover, a characterization of the βo/ωo-interface was conducted.
Translated title of the contributionPreparation methods and investigation of the chemical composition of a β-solidifying TiAl alloy by atom probe tomography
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Clemens, Helmut, Supervisor (internal)
  • Klein, Thomas, Co-Supervisor (internal)
  • Mayer, Svea, Co-Supervisor (internal)
Award date30 Oct 2015
Publication statusPublished - 2015

Bibliographical note

embargoed until null

Keywords

  • titanium aluminides
  • TNM
  • TiAl
  • atom probe tomography
  • APT
  • chemical composition

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