Influence of Crystallographic Orientation on Regularities of Size Effect under a Tension of a Nanowire of Molybdenum
S. О. Kotrechko, O. V. Ovsyannikov, V. V. Lidych
G. V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03142 Kyiv, Ukraine
Received: 08.12.2016; final version - 08.01.2018. Download: PDF
The influence of diameter of the Mo single-crystal nanowires on their strength for the three crystallographic orientations ,  and  at temperatures of 77 and 300 K is revealed by means of the use of molecular-dynamic simulations. The existence of size effect in samples with diameter less than 4 nm is discovered. For cylindrical nanospecimen with the  orientation, size effect consists in the increase of strength by 17% with sample diameter decreasing from 4 to 1 nm. At the same time, when these nanospecimens are stretched along the  and  directions, an anomalous size effect is observed that manifests itself in a strength decreasing up to 14%. As shown, the reason for existence of these opposite tendencies in the manifestation of size effect is formation of different types of defects in nanosize specimens, namely, non-equilibrium twins under tension along the  direction and non-equilibrium dislocations under tension along the  and  directions.
Key words: b.c.c. nanowires, strength, size effect, local instability, surface tension.
PACS: 61.72.Bb, 62.20.F-, 62.20.mm, 62.23.Hj, 62.25.Mn, 81.07.Gf, 83.10.Rs
Citation: S. О. Kotrechko, O. V. Ovsyannikov, and V. V. Lidych, Influence of Crystallographic Orientation on Regularities of Size Effect under a Tension of a Nanowire of Molybdenum, Metallofiz. Noveishie Tekhnol., 40, No. 2: 183—199 (2018) (in Russian)