Loading Velocity and Kinetics of Localized Bands of Nickel Plastic Deformation

The paper considers macroscopic plastic deformation localized in pure nickel NP2 (99.5%). Uniaxial tension of plane specimens is conducted at room temperature and loading velocities of 0.05, 0.2 and 0.8 mm/min. Stress-strain curves demonstrate a discontinuous yielding from the yield strength to necking. Digital image correlation and tracking is used to measure the total displacement and plastic strains in the conditions of the Portevin–Le Chatelier effect. It is shown that the loading velocity affects the band propagation velocity induced by localized deformation during tension. The inverse relationship is identified between the propagation velocity of localized deformation bands and the total displacement.