Molecular dynamics study on the fracture mechanism in bimodal nanotwinned Cu with a composite structure

F Zhang and YR Zhi and G Li and C Xun and DS Zhu, APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 127, 370 (2021).

DOI: 10.1007/s00339-021-04534-5

Utilizing molecular dynamics simulations, the authors investigate the notion of bimodal nanotwinned (NT) microstructure in strength-ductility trade-off. Using a coarse circular grain with twins embedded in a sea of nano-grains (without twins) as a surrogate, the paper explores three scenarios pertaining to the strength and failure strain mapping: (i) the effect of twin boundary (TB) inclination; (ii) the effect of coarse- grain size; (ii) the effect of twin boundaries spacings (TBSs). The central result is that there exists an optimum grain size at which the strength and failure strain are simultaneously improved. Meanwhile, the fracture mechanisms of bimodal NT microstructure are demonstrated by analyzing dislocation-TB interactions, which involve TB migration, deformation twinning, void generation, etc.

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