Macroscopic Spatio-Temporal Patterns of Localized Plastic Flow Development under Tension of Fe-Cr-Ni Alloys

Abstract

This study examines the patterns of macroscopic inhomogeneity and localization of plastic flow in Fe-Cr-Ni polycrystals subjected to uniaxial tension. By varying the test temperature, the deformation curves can be altered, allowing us to explore the behavior of the material under different conditions. The stress-strain diagrams obtained from the samples reveal the areas of elastic deformation, plastic flow, and fracture. To experimentally study plastic flow, we used speckle photography to accurately reconstruct the displacement vector fields and calculate the components of the plastic distortion tensor. The results showed that plastic flow is localized at all stages of the process for test temperatures of+65, +24, and -60 °C. The forms oflocalization are entirely determined by the dependence of the strain hardening coefficient on the deformation during the relevant stage of the process. An analysis of the spatial distributions of local shifts and local rotations was conducted. We observed spatially periodic structures that can be interpreted as autowave processes and explained in terms of the concept of self-organization of the plastic flow process.