Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 34: Topical Session: Fundamentals of Fracture - Fracture at the Atomistic Scale

MM 34.5: Talk

Wednesday, March 13, 2013, 12:45–13:00, H4

Brittle fracture of rutile TiO₂: a first principles study — •Beatrix Elsner, Wolfgang Heckel, and Stefan Müller — Technische Universität Hamburg-Harburg, Institut für Keramische Hochleistungswerkstoffe, Denickestr. 15, D-21073 Hamburg

The potentiality of catastrophic failure poses a major challenge for the engineering application of brittle materials such as ceramics. Hence a fundamental understanding of the atomistic processes involved in brittle fracture is essential. Using density functional theory we have studied the failure of rutile titanium dioxide (TiO₂) in loading mode I accounting for various cleavage plane orientations. For ideal brittle cleavage no surface relaxations are allowed and the universal binding energy relation (UBER) [1] can be applied to calculate the theoretical cleavage energy and corresponding strength. This yields the (110) and (100) planes as the equally most likely cleavage planes. Further, structural relaxations have been treated as they have a significant influence on the cleavage properties by lowering the cleavage energy. Unlike for metals [2] the onset of cleavage in TiO₂ cannot be easily derived from the energy separation curves and the relation between elasticity and cleavage will be discussed.
Supported by DFG, SFB 986, project B3.

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