Regensburg 2004 – scientific programme

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M: Metallphysik

M 29: Quasikristalle I

M 29.4: Talk

Thursday, March 11, 2004, 15:30–15:45, H16

Crack propagation in icosahedral quasicrystals — •Frohmut Rösch¹, Christoph Rudhart¹, Peter Gumbsch^2,3, and Hans-Rainer Trebin¹ — ¹Universität Stuttgart, Institut für Theoretische und Angewandte Physik, 70550 Stuttgart — ²Universität Karlsruhe, Institut für die Zuverlässigkeit von Bauteilen und Systemen, 76131 Karlsruhe — ³Fraunhofer Institut für Werkstoffmechanik, 79194 Freiburg

We present numerical experiments on the propagation of mode I cracks in a three dimensional icosahedral model quasicrystal. In particular, the dependence on the plane structure and the influence of clusters have been investigated. For this purpose samples in different orientations are endowed with atomically sharp seed cracks and subsequently loaded by linear scaling of the displacement field. The response of the system is then monitored by molecular dynamics simulations.

Brittle fracture without any crack tip plasticity is observed. The fracture surfaces turn out to be rough on the scale of the clusters. These are not strictly avoided, but to some extent intersected by the dynamic crack. However, compared to the flat seed cracks the clusters are cut less often. Hence the roughness of the crack surfaces can be attributed to the clusters, whereas the constant average heights of the fracture surfaces reflect the plane structure of the quasicrystal. Moreover a distinct anisotropy with respect to the in-plane propagation direction is found.