The investigation of localized deformation bands in polycrystalline Ni by a strain

The features of the kinetics of macroscopic localization of plastic deformation in samples of pure nickel NP2 with a nickel content of at least 99.5% are considered. Uniaxial stretching of flat samples was performed in the “load-unloading“ mode with an increase in total deformation of 5% at room temperature with a speed of 0.2 mm/min of the movable gripping of the testing machine. Stretching diagrams demonstrate intermittent fluidity from the yield point to the formation of the neck. The correlation method of digital speckle images revealed the features of the movement of bands of localized plastic deformation under the conditions of the Portevin-Le Chatelier effect. It is shown that stress jumps with intermittent Ni flow are accompanied by the formation of morphologically simple single bands of localized deformation. It was found that with the increase in the total deformation, the number of localized deformation bands and their speed of movement along the sample decrease, while the time period increases.

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