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M: Metallphysik

M 31: Quasikristalle II

M 31.4: Vortrag

Donnerstag, 11. März 2004, 17:15–17:30, H16

Micro-and nanoindentation studies of single quasicrystalline phase in Al-Ni-Co system — •Nilay Krishna Mukhopadhyay, Andre Belger und Peter Paufler — Institut fuer Strukturphysik TU Dresden, D-01062 Dresden, Germany

Single crystals of Al-Ni-Co decagonal phase have been employed for the study of mechanical propertied using the micro- and nano- indentation techniques. Decagonal quasicrystal gives rise to decagonal prismatic morphology exhibiting 10-fold and 2-fold planes as external facets. The microindentation, using load from 25g to 150g was performed on 10 fold and 2-fold planes. Meyers Hardness calculated from these studies was found to vary from 13.3GPa to 10.6GPa. The variation of hardness with load, which is known as indentation size effect (ISE), was clearly noticed. Nanoindentation experiments were carried out using Hysitron Triboscope attached to scanning probe microscope. From load-penetration curve nanohardness and elastic modulus were found out and compared with the data available from other techniques. The discontinuity in the load-penetration curve, which can be understood as pop-in-effect, characteristic of yielding, was observed at low load regime. It is interesting to point out that the pop-in effect is more prominent in case of 10fold plane. Attempts will be made to discuss the results obtained from the present investigation in the light of our current understanding of the mechanical responses of these aperiodic crystals.