Dresden 2003 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 8: Harte Schichten II

DS 8.6: Vortrag

Montag, 24. März 2003, 16:30–16:45, GER/38

Mechanical properties and structure of TiC/VC and TiN/VN multilayers — •A. Belger¹, T. Boettger², B. Wolf¹, P. Paufler¹, H. Mai² und E. Beyer² — ¹Institut f. Kristallographie u. Festkoerperphysik der TU, D-01062 Dresden — ²Fraunhofer-Institut f. Werkstoff- u. Strahlforschung, D-01277 Dresden

The superlattice hardening effect for TiC/VC and TiN/VN multilayers on the level of nanoindentations in relation to their structural parameters was investigated. Various multilayers of different period thicknesses were grown on sapphire (012) using PLD. X-ray diffraction revealed the nanocrystalline structure of the thin layers. Moreover, a preferred orientation was found by texture analysis. Polarized fluorescence EXAFS experiments were carried out at HASYLAB to determine the distance of the nearest neighbors in-plane and out-of-plane of the thin films. These parameters exhibit a legible dependency on the period thickness of the multilayers and allow the determination of internal stresses in the multilayers. Nanoindentation experiments were carried out using a depth sensing electrostatic transducer (HYSITRON TriboScope). Nanohardness and elastic modulus of the TiC/VC-substrate combination showed only a slight dependence on the contact indentation depth. The hardness of the TiC/VC multilayers increased after high-temperature heat treatment (5 h at 773 K) and decreased for the single-layer films. For the annealed films a maximum of the nanohardness of 39 GPa could be observed for a period thickness of about 5 nm. Thus superlattice hardening on a nanoscale has been found in this system.