Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 38: Topical Session: Fundamentals of Fracture - Atomistic Modelling

MM 38.1: Topical Talk

Wednesday, March 13, 2013, 15:00–15:30, H4

Modelling fracture scattering by defects in brittle crystals — •Alessandro De Vita, James Kermode, Giovanni Peralta, Marco Caccin, and Zhenwei Li — King's College London, Physics Department, Strand, London WC2R 2LS, United Kingdom

We present the results of an atomistic modelling investigation of crack-defect interaction, using the ``Learn On The Fly" (LOTF) hybrid multi-scale simulation scheme [1]. The scheme is particularly well-suited to incorporate machine-learning (ML) approaches based on the predictive inference of atomic forces, and has been previously used to model both ``intrinsic" crack propagation instabilities [2] and the interaction of propagating cracks with defects such as dislocations and implanted ions [3].

Here, taking as a target system B-doped ultra-pure Si samples, we provide theoretical and experimental evidence suggesting that contrary to common wisdom, propagating cracks can be deflected by hitting a single, isolated impurity atom, yielding predictable patterns of macroscopic roughness on the cleavage surface.

[1] G.Csanyi, T.Albaret, M.C.Payne and A.De Vita, PRL 93, 175503 (2004); [2] J.R.Kermode, T.Albaret, D. Sherman, N. Bernstein, P.Gumbsch, M.C.Payne, G.Csanyi and A.De Vita, Nature 455, 1224-U41 (2008); [3]G.Moras, L.C.Ciacchi, C.Elsaesser, P.Gumbsch and A.De Vita, PRL 105, 075502 (2010);