Microstructural origins of energy storage during plastic deformation of 310S TWIP steel

Abstract

The microstructural mechanisms governing energy storage during plastic deformation of twinning-induced plasticity (TWIP) steels remain insufficiently understood, particularly under conditions of strain localization. This study provides a crystallographic-scale interpretation of energy storage in 310S TWIP steel exhibiting complex deformation mechanisms. Electron backscatter diffraction (EBSD) was used to characterize the evolution of local crystallographic orientation and microtexture during uniaxial tensile deformation using two complementary approaches: tracking the same surface region at successive strain levels and analysing regions corresponding to known local plastic strain. Deformation was initially dominated by dislocation slip, while twinning activity increased significantly beyond an equivalent plastic strain of approximately 0.3. Progressive deformation produced pronounced lattice rotations and the development of a dual-fibre texture consisting of a dominant 111 parallel to RD component and a secondary 100 parallel to RD component associated with deformation twinning. Correlation with previously quantified energy storage behaviour obtained from coupled digital image correlation and infrared thermography measurements reveals that intensified twinning and texture evolution in strain-localized regions are accompanied by a marked reduction in the energy storage rate. The results indicate that twin-matrix refinement and lattice rotation progressively reduce the material's capacity to store deformation energy and create favourable conditions for shear-band-mediated deformation.

Figures (13)

• Figure 1: (a) IPF map representing grain orientations with respect to RD and (b) corresponding (111) pole figure of 310S steel in the reference state.
• Figure 2: Tracking of crystallographic orientation in the same area during deformation: (left) analysed region in the reference state; (right) schematic of sequential loading with intermediate unloadings and EBSD measurements.
• Figure 3: EBSD analysis of regions with different strain levels: (left) schematic of tensile test interrupted before fracture; (right) distribution of equivalent plastic strain with selected regions for EBSD measurements.
• Figure 4: (a) Surface distributions of energy storage rate $Z$ at selected stages of deformation and (b) evolution of $Z$ at representative points located within and outside the localization zone musial2022field, with the point corresponding to the Considére criterion indicated on the stress–strain curve.
• Figure 5: Orientation maps of the same area: (a) initial state, (b) macroscopically uniform deformation, (c) strain localization. The analysed region is marked by a white dashed line in (b) and (c).