Orientation-dependent ductility and deformation mechanisms in body- centered cubic molybdenum nanocrystals

HY Peng and YX Hou and H Zheng and LG Zhao and Y Zhang and WW Meng and T Liu and PL Zhao and SF Jia and JB Wang, JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, 154, 107-113 (2023).

DOI: 10.1016/j.jmst.2022.12.062

The knowledge regarding anisotropic mechanical behaviors in nanoscale body-centered cubic (bcc) met-als remains obscure. Herein, we report the orientation-dependent ductility in bcc Mo nanocrystals (NCs), which exhibit poor ductility along 110 direction but possess relatively better ductility along the 001 and 112 orientations. The origin of different deformability can be traced down to the distinct defor-mation mechanisms: the unexpected crack nucleation and propagation induce premature fractures in 110-oriented NCs; in contrast, deformation twinning could contribute to the enhanced ductility in 001-oriented NCs; interestingly, we find the activation of multiple dislocation slips in 112-oriented NCs with the highest ductility. Further molecular dynamics simulations provide deeper insights into the defect dy-namics that are closely interlinked with experimental observations. Our findings advance the basic un-derstanding of orientation-dependent mechanical properties and help to guide endeavors to architecture the microstructures of bcc metals with enhanced ductility.(c) 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

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