Regensburg 2019 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 12: Poster session I
MM 12.4: Poster
Monday, April 1, 2019, 19:15–20:45, Poster C
Combining small-angle neutron scattering and analytical microscopy: An advanced method to characterize nanoprecipitates in Ni-based superalloys — •Robert Lawitzki1, Ralph Gilles2, Michael Hofmann2, Julia Wagner1, and Guido Schmitz1 — 1Universität Stuttgart, IMW, Lehrstuhl für Materialphysik — 2TU München, FRMII
We present an experimental method for the differentiation and quantification of the two strengthening phases, γ' and γ'', in the Ni-based superalloy Inconel 718. For this alloy, an individual quantification of those phases is experimentally very difficult and was, by now, only achieved by nano-scaled characterization techniques. In this contribution, we were applying the technique small-angle neutron scattering (SANS) on differently heat-treated specimens to individually quantify the nanoprecipitates in bulk average. The interpretation of the SANS signal required a structural model that could only be set up by complementary information that were obtained mainly by transmission electron microscopy (TEM) and atom probe tomography (APT). The advantage of using bulk neutron diffraction for quantification is that several tens of cubic millimeters are analyzed and thus, significantly better statistics are obtained. The measured volume fractions of the γ''- precipitates are remarkably lower than stated in previous works, but now well fulfill the chemical mass balance. It will be further shown how this method can be adapted to other superalloys.