Seminars and Events

New approaches for quantitative analysis of single crystal superalloys based on advanced transmission electron microscopy

Date/Time: 16.09.2014. 9:00 a.m.
Place: Ruhr-Universität Bochum, Bochum, Germany

Erdmann Spiecker, Department for Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen

In this contribution we present new approaches based on advanced TEM techniques and FIB technology for investigating key aspects of the γ-γ' microstructure which govern the creep behavior of Ni- and Co-based superalloys. (i) A fully reliable technique for determining the complete Burgers vector of superdislocations by means large-angle convergent beam electron diffraction (LACBED) is demonstrated. (ii) A site-specific FIB preparation is devised which enables atomic resolution studies of the core structure of preselected superdislocations. (iii) An automized STEM-CBED-EDX technique for combined mapping of local strain fields and chemical composition in the γ-γ' microstructure is demonstrated. (iv) In situ TEM heating experiments are shown to be capable of addressing temperature dependent structural properties, like γ-γ' lattice misfit and phase stability. The different techniques are discussed with respect to their potential to contribute quantitative data for computational studies.

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