Stages and Irregularities of Plastic Strain in Austenitic Stainless Steel within a Temperature Range of 143 < t < 420 k

Abstract

This work aims at investigating the stages and irregularity of plastic strain in austenitic stainless steel 12Kh18N9T within a temperature range of 143 < T < 420 K. The localized plastic strain fronts at different stages of strain hardening have been visualized and monitored via digital speckle photography (DSP). This method consists in the high-accuracy recording of the displacement field via tracking any material surface changes and the subsequent comparison of speckle images acquired under uniaxial tension. The stress-strain diagrams were found to strongly vary with a decrease in temperature due to strain-induced-phase transition. The analysis of localized strain distributions revealed the emergence of a mobile system of equidistant strain localization foci at the strain hardening stage. The temperature dependence of plastic strain localization parameters at the linear strain hardening stage was established as well.