Enigma of dislocation patterning due to slip in fatigued austenite

Abstract

Strain controlled low cycle fatigue experiments on multiple specimens are performed by systematically varying strain amplitudes of austenitic stainless steel under laboratory atmosphere. Different dislocation substructures/patterns developed due to strain cycling are characterised, measured by analytical transmission electron microscope and austenite grains’ misorientation, extent of different types of grain boundaries, grain connectivity, slip-system activity are also measured by electron backscatter diffraction experiments. Present investigation clearly reveals the enigma of dislocation patterning through slip system activity during cyclic plastic deformation of austenite at different strain amplitudes. It has been experimentally examined that with the increase in strain amplitude, the activity of single slip system decreases and multiple slip system increases, which in turn help to decrease the dislocation cell size and to vary in their geometric configurations and patterns.