Dresden 2006 – wissenschaftliches Programm
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MM: Metall- und Materialphysik
MM 3: Symposium Modern Metallic Materials Design I
MM 3.4: Vortrag
Montag, 27. März 2006, 11:00–11:15, IFW B
Atomic Structure Determination of structurally complex alloy Ψ Al-Pd-Mn Phase — •H. Tian1, W. Sun2, and Z. Zhang2 — 1Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100080, China — 2Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, 100 Pingle Yuan, Chao Yang District, Beijing 100022, China
Base on the study of two-dimensional planar defects [1,2] (phason planes) in the complex metallic alloy phase ξ’-Al-Pd-Mn, the atomic structure of the-Al-Pd-Mn phase [3] was determined by means of high-resolution electron microscopy (HREM) observations and theoretical HREM simulations. The Ψ-Al-Pd-Mn phase has an orthorhombic unit cell with lattice parameters of a =23.54 Å, b =16.56 Å, and c =56.98 Å. The structure of the Ψ-Al-Pd-Mn phase can be characterized as stacking of phason planes in the ξ’-Al-Pd-Mn phase [4] along the c axis. The dimension along the c axis for the Ψ-phase is τ+3 times larger than that of the ξ’-phase. A close comparison between the experimental and simulated diffraction pattern, based on phason-plane stacking model, shows that both of the position and intensity distribution of the simulated diffraction pattern agree well with the experimental result. Furthermore, the simulated HREM image of the Ψ-Al-Pd-Mn phase based on above structure model matches also very well with the experimental results. All of the agreements indicate that the structural model of the Ψ-Al-Pd-Mn phase we proposed here is reasonable.
[1] H. Klein, M. Feuerbacher, P. Schall, K. Urban, Phys. Rev. Lett. 82 (1999) 3468. [2] H. Klein, M. Feuerbacher, K. Urban, Mat. Sci. Eng. 294 (2000) 769. [3] H. Klein, M. Feuerbacher, P. Schall, K. Urban, Phil. Mag. Lett. 80 (2000) 11. [4] H. Klein, M. Feuerbacher, Phil. Mag. 83(2003) 4103.