Mechanical properties of polycrystalline graphene based on a realistic atomistic model

Autor(en)

Jani Kotakoski, Jannik C. Meyer

Abstrakt

Graphene can at present be grown at large quantities only by the chemical vapor deposition method, which produces polycrystalline samples. Here, we describe a method for constructing realistic polycrystalline graphene samples for atomistic simulations, and apply it for studying their mechanical properties. We show that cracks initiate at points where grain boundaries meet and then propagate through grains predominantly in zigzag or armchair directions, in agreement with recent experimental work. Contrary to earlier theoretical predictions, we observe normally distributed intrinsic strength (similar to 50% of that of the monocrystalline graphene) and failure strain which do not depend on the misorientation angles between the grains. Extrapolating for grain sizes above 15 nm results in a failure strain of similar to 0.09 and a Young's modulus of similar to 600 GPa. The decreased strength can be adequately explained with a conventional continuum model when the grain boundary meeting points are identified as Griffith cracks.

Organisation(en)

Physik Nanostrukturierter Materialien

Journal

Physical Review B

Band

85

Anzahl der Seiten

6

ISSN

1098-0121

Publikationsdatum

2012

Peer-reviewed

Ja

ÖFOS 2012

210006 Nanotechnologie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/9be251be-4f3c-4823-ba4b-73465d08edcf