Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Poster Session
MM 17.81: Poster
Montag, 26. März 2012, 17:00–19:00, Poster B
The effect of the stacking sequence on the EFG in the MAX phase systems Ti-Al-X (X = C, N) — •Daniel Jürgens1, Michael Uhrmacher1, Ulrich Vetter1, Hans Hofsäss1, Jose Mestnik-Filho2, and Michel W. Barsoum3 — 1Georg-August-Universität Göttingen, II. Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 2Instituto de Pesquisas Energeticas e Nucleares, 05422-970 São Paulo, Brazil — 3Dep. Mat. Science and Eng. Drexel University, Philadelphia, PA 19104, USA
Mn+1AXn phases are nanolaminated layered ternary compounds and show both metallic and ceramic characteristics. These materials show an unusual set of properties and are therefore potential candidates e.g. for high-temperature applications. Most MAX phases belong to the 211 subclass (i.e. n=1) and are made up of M6X octahedra layers, which are separated from each other by one inserted A-layer. Only a few compounds exist with 312 (and 413) stoichiometry, where two (three) M6X layers are embedded between two A-layers. The Ti-Al-C system is one among the few which can be synthesized in the 211 and 312 structure. For the Ti-Al-N system, the only stable compounds belong to the 211 and 413 classes.
By means of perturbed angular correlation (PAC), we measured the electric field gradients (EFGs) at the Al-site in these compounds. We could observe that the strength of the EFGs differ significantly between the different stacking sequences of the same system. In this contribution we show the experimental results and discuss the potential reasons for this effect.