Dresden 2009 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 2: Topical Session Nanoporous Functional Materials II

MM 2.3: Talk

Monday, March 23, 2009, 12:45–13:00, IFW A

Nanoporous Superalloys by Selective Phase Extraction: Processing, Properties, Applications — •Joachim Rösler, Oliver Näth, and Fabian Schmitz — Technische Universität Braunschweig, Langer Kamp 8, D-38106 Braunschweig

Nanoporous Ni-based superalloys are a new material class [1]. They are fabricated from sheets of the two phase g/g* base material by thermomechanical processing, followed by selective phase extraction of either the g- or g*-phase. As a result, a porous membrane is obtained, containing extremely regular and fine channel-like porosity on the nanoscale. First, manufacturing of these materials is described and considerable flexibility in controlling the pore morphology is demonstrated. Furthermore, (micro-)structuring of the membranes in solid and porous domains as well as coating processes for external and internal material deposition are illustrated. These options are of particular interest, e.g. for the design of micro-chemical reactors, heat exchangers or Pd-based oxygen membranes. Secondly, microstructure-property correlations are discussed and it is demonstrated that the thermomechanical processing parameters critically control mechanical strength and gas permeability. Tensile strength levels of up to 100 MPa are achieved when the processing parameters are adjusted accordingly. At the same time, molecular separation of gas mixtures is possible as the pore dimensions are comparable to the mean free path of the gas molecules. This may be of particular interest for the separation of hydrogen.

[1] J. Rösler, O. Näth, S. Jäger, F. Schmitz and D. Mukherji, Acta Mater., 53, 1397 (2005)