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Mechanical properties

Metallic alloys

We carry out macroscopic deformation experiments in compression using a ZWICK Z050 testing system, equipped with a high-temperature furnace (up to 1200 °C), a high-precision strain gauge (± 10 nm) and a video system for in-situ sample monitoring during deformation.

The group has long standing expertise in the analysis of mechanical testing experiments including incremental testing (e.g. stress-relaxation, temperature cycling, etc.) to determine thermodynamic activation parameters of the deformation process. We characterize the microstructure of deformed materials in depth, employing the transmission electron microscopes of the Ernst-Ruska Centre, and applying techniques such as Bragg-contrast imaging, Convergent Beam Electron Diffraction, and high-resolution imaging.

Particular achievements of the group are the consistent characterization of quasicrystal plasticity in terms of a cluster friction model, and the discovery of metadislocations, a novel class of defects enabling plastic deformation of complex, large unit-cell materials. Currently we are focusing on the mechanical characterization of high-entropy alloys.

M. Feuerbacher. Dislocations in Icosahedral Quasicrystals Invited Review. Chem. Soc. Rev. 41, 2012, 6745.
H. Klein, M. Feuerbacher, P.Schall and K.Urban. A novel type of dislocation in an Al-Pd-Mn quasicrystal approximant, Phys. Rev. Lett, 82 1999, 3468. 
M. Heggen, L. Houben, M. Feuerbacher. Plastic deformation mechanism in complex solids Nature Materials 9, 2010, 332.