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Registration Number

0213U006632, 0113U004298 , R & D reports

Title

Structural elements determining the mechanical properties of nanocrystalline cobalt.

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Head

Tabachnikova Olena,

Registration Date

18-12-2013

Organization

B.Verkin Institute for Low Temperature Physics and Engineering of National Academy of Science of Ukraine

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Several new nanocrystalline states of cobalt were obtained by high pressure torsion (HPT) at 300 and 77 K. It was shown that the low temperature HPT of Co at 77 K allows to obtain the nanocrystalline state with a smaller grain size (70 nm ) as compared to HPT at 300 K (grain size 110 nm). Significant (up to 2.5 fold) increase of strength of the nanocrystalline cobalt compared to coarse grained one was registered. The strength of HPT Co (77 K) is 20 % higher as compared to HPT Co (300 K) due to a significant increase in the nanocrystalline cobalt, especially after HPT at a cryogenic temperature of 77 K, the amount of barriers (grain boundaries, twins) for the motion of the carriers of plasticity - dislocations. Analysis and electron microscopy results and features of stress-strain curves in uniaxial compression revealed that dislocation slip and twinning are main microscopic mechanisms of plastic deformation of cobalt; mechanical properties of nanocrystalline Co essentially depend on structural characteristics, such as the state of the grain boundaries and the quantity of twin boundaries.

Product Description

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Подольський Олексій Володимирович
Псарук Ігор Андрійович
Табачнікова Олена Дмитрівна

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2020-04-02