Microstructure changes in ultrafine-grained nickel processed by high pressure torsion under ultrasonic treatment

A A Samigullina; A A Mukhametgalina; S N Sergeyev; A P Zhilyaev; A A Nazarov; Yu R Zagidullina; N Yu Parkhimovich; V V Rubanik; Yu V Tsarenko

doi:10.1016/j.ultras.2017.09.005

Microstructure changes in ultrafine-grained nickel processed by high pressure torsion under ultrasonic treatment

Ultrasonics. 2018 Jan:82:313-321. doi: 10.1016/j.ultras.2017.09.005. Epub 2017 Sep 15.

Authors

A A Samigullina¹, A A Mukhametgalina², S N Sergeyev¹, A P Zhilyaev¹, A A Nazarov³, Yu R Zagidullina⁴, N Yu Parkhimovich¹, V V Rubanik⁵, Yu V Tsarenko⁵

Affiliations

¹ Institute for Metals Superplasticity Problems, Russian Academy of Sciences, 39 Khalturin Str., 450001 Ufa, Russia.
² Institute for Metals Superplasticity Problems, Russian Academy of Sciences, 39 Khalturin Str., 450001 Ufa, Russia; Bashkir State University, 32 Zaki Validi Str., 450076 Ufa, Russia.
³ Institute for Metals Superplasticity Problems, Russian Academy of Sciences, 39 Khalturin Str., 450001 Ufa, Russia. Electronic address: aanazarov@imsp.ru.
⁴ Institute for Metals Superplasticity Problems, Russian Academy of Sciences, 39 Khalturin Str., 450001 Ufa, Russia; Ufa State Petroleum Technological University, 14 Pervomayskaya Str., 450000 Ufa, Russia.
⁵ Institute of Technical Acoustics NAS of Belarus, 13 Lyudnikova pr., 210023 Vitebsk, Belarus.

PMID: 28942271
DOI: 10.1016/j.ultras.2017.09.005

Abstract

Commercially pure nickel was processed by high pressure torsion (HPT) and subjected to ultrasonic treatment (UST) with different amplitudes of compression-tension stresses in the zone of stress antinode of a standing wave. It was found that microstructure parameters such as the dislocation density, low- and high-angle grain boundary fractions, microhardness, and the stored excess energy as well, non-monotonically depend on the ultrasound amplitude. A structure relaxation leading to a reduction of internal stresses and stored energy and increase of the fraction of high-angle boundaries was observed at some intermediate amplitudes of the oscillating stress. The maximum relaxation effect was observed in the samples after UST with the amplitude of 60MPa. Possible mechanisms of the influence of ultrasound on the microstructure of deformed materials are discussed.

Keywords: High pressure torsion; Microstructure; Structure relaxation; Ultrafine-grained nickel; Ultrasonic treatment.

Publication types

Research Support, Non-U.S. Gov't