A Study of the Localized Strain Bands in Polycrystalline Nickel Under Tension

• Published in: Russian physics journal 2022-12, Vol.65 (8), p.1299-1303
• Main Author: Nadezhkin, M. V.
• Format: Article
• Language: English
• Subjects: Condensed Matter Physics; Hadrons; Heavy Ions; Lasers; Mathematical and Computational Physics; Nickel; Nuclear Physics; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; Plastic deformation; Portevin-le Chatelier effect; Room temperature; Serrated yielding; Stress-strain curves; Tensile stress; Theoretical; Yield point
• ISSN: 1064-8887; 1573-9228
• DOI: 10.1007/s11182-023-02765-y

A peculiar behavior of the kinetics of macroscopic localization of plastic deformation in pure nickel (NP2) samples with a nickel content of at least 99.5% is considered. Uniaxial tension of flat samples is performed in the loading-unloading mode at a 5% total deformation increment at room temperature at a motion velocity of the mobile testing-machine grip of 0.2 mm/min. The tensile stress-strain curves demonstrate discontinuous yielding from the yield point to the neck formation. The method of digital speckle correlation reveals the features of the localized strain band motion under the conditions of the Portevin–Le Chatelier effect. It is shown that stress jumps during discontinuous yielding of Ni are accompanied by the formation of morphologically simple single localized strain bands. It is found out that with an increase in the total deformation, the number of localized strain bands and their motion velocity along the sample decrease as the time period increases.