Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 10: Intermetallic Phases II

MM 10.3: Vortrag

Montag, 23. März 2009, 16:30–16:45, IFW B

Characterization of MAX phases via hyperfine interactions — •Daniel Jürgens¹, Michael Uhrmacher¹, Hans Hofsäss¹, Agnieszka Kulinska^{1, 2}, Jose Mestnik Filho³, and Michel Barsoum⁴ — ¹II. Physikalisches Institut, Universität Göttingen, 37073 Göttingen, Germany — ²IFJ PAN, 31-342 Krakow, Poland — ³Instituto de Pesquisas Energeticas e Nucleares, 05422-970 Sao Paulo, Brazil — ⁴Dep. Mat. Science and Eng. Drexel University, Philadelphia, PA 19104, USA

M_n+1AX_n phases, where n is 1, 2 or 3, are nanolaminated layered ternary carbides and nitrides, which feature a unique combination of the best attributes of both metals and high-performance ceramics. This class of solids possesses good electrical and thermal conductivities as well as high thermal shock resistance and damage tolerance.

The method of perturbed angular correlation (PAC), which is sensitive to hyperfine interactions, is used for material characterization on microscopic scale. ¹¹¹In was implanted as probe nuclei to measure the electric field gradients (EFG) in the key-compounds Ti₂InC and Zr₂InC to determine strength and symmetry of the EFG on the In-site or more general on the A-site. Regarding to the question of lattice location of In-probes in In-free MAX phases, PAC studies of Ti₂AlN and Cr₂GeC were performed to confirm the assumption occupying the A-site. The experimental results are compared with those from ab initio calculations using the FP-LAPW+LO method implemented in the WIEN2k code. Additionally investigations of annealing behavior, thermal stability and behavior under isostatic stresses are presented.