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Deformation and ductile fracture of nanocrystalline gold ultrathin nanoribbon: Width effect
Author(s) -
Liu Jialin,
Fan Xiaofeng,
Shi Yunfeng,
Singh David J.,
Zheng Weitao
Publication year - 2021
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/ffe.13469
Subject(s) - materials science , necking , nanocrystalline material , composite material , fracture (geology) , flow stress , grain size , ductility (earth science) , deformation (meteorology) , modulus , stress (linguistics) , ultimate tensile strength , metallurgy , strain rate , nanotechnology , creep , philosophy , linguistics
Molecular dynamics simulations are used to investigate the mechanical properties of finite‐width nanocrystalline gold nanoribbons with a thickness of one grain size under tensile strain. We find strong variations in the Young's modulus and flow stress especially for the sample with narrow width. With statistical analysis, Young's modulus has a trend of increase with the decrease of width. Flow stress does not follow this trend. Ductile fracture is observed at large strain in these nanocrystalline nanoribbons, but the fracture strain and mechanism are different from those of thick films as observed in existing experiments. For small widths below 80 nm, fracture is a necking effect, while for larger widths, shear bands and formation of nanovoids due to stress concentration are the main mechanism. Voids are mainly distributed in special GBs that are parallel to the direction of the maximum principal stress of the plastic deformation tensor. We find there is a width regime (about 80–130 nm) for the ultrathin nanoribbon gold, which have good ductility and large fracture strain.