Experimentally measuring weak fracture toughness anisotropy in graphene

Shizhe Feng; Ke Cao; Yue Gao; Ying Han; Zhanli Liu; Yang Lu; Zhiping Xu

doi:10.1038/s43246-022-00252-4

Experimentally measuring weak fracture toughness anisotropy in graphene

Research output: Journal Publications and Reviews (RGC: 21, 22, 62) › 21_Publication in refereed journal › peer-review

Overview

1 Scopus Citations

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Author(s)

Shizhe Feng
Ke Cao
Yue Gao
Zhanli Liu
Yang Lu
Zhiping Xu

Related Research Unit(s)

Department of Mechanical Engineering

Detail(s)

Original language	English
Article number	28
Journal / Publication	Communications Materials
Volume	3
Online published	4 May 2022
Publication status	Published - 2022

Link(s)

DOI	DOI https://doi.org/10.1038/s43246-022-00252-4 Final Published version
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Attachment(s)	Documents 101169307.pdf Final Published version, 1.94 MB, PDF Publisher's Copyright Statement This full text is made available under CC-BY 4.0. https://creativecommons.org/licenses/by/4.0/
Link to Scopus	https://www.scopus.com/record/display.uri?eid=2-s2.0-85129609387&origin=recordpage
Permanent Link	https://scholars.cityu.edu.hk/en/publications/publication(5dad953a-5e06-44fa-9ef9-5a1ad4c76af5).html

Abstract

The two-dimensional nature of graphene offers a number of interesting mechanical properties. Amongst these, fracture toughness has received substantial interest, yet computational works have not reached a consensus regarding anisotropy in its fracture energy when graphene is loaded in armchair or zigzag directions. Here, we resolve the steps involved during fracture of graphene by carrying out in situ tensile tests. Embryo cracks nucleated from the graphene edges are observed to deflect into major cracks with local kinking features, as explained by an evolving stress intensity factor during crack advance. Extended finite element analysis with the maximum energy release rate criterion is used to model the fracture process. We determine a weak degree of anisotropy in the fracture toughness, G_c(armchair)/G_c(zigzag), of 0.94, which aligns with previous predictions from first-principles calculations and observed growth kinetics of graphene crystals in experiments.