Temperature increases and thermoplastic microstructural evolution in adiabatic shear bands in a high-strength and high-toughness 10 wt.% Ni steel

A 10 wt.% nickel-steel has been developed for high pressures and low-temperature applications, due to its strength, excellent toughness, low ductile-to-brittle transition temperature (DBTT). Under dynamic loading conditions this steel is, however, prone shear localization that manifests as adiabatic bands (ASBs). The increases thermoplastic microstructural evolution in the ASB are studied detail, from microscopic length scale atomic-scale employing correlative electron-backscatter diffraction (EBSD), transmission electron microscopy (TEM), atom-probe tomography (APT). From a calculation of increase under conditions, based on conversion plastic-work heat generation, transitions discussed specifically for: (i) b.c.c.-f.c.c. phase-transformation elemental partitioning alloying elements; (ii) thermodynamic model compositional change V(Nb)-rich carbonitride precipitates during increase; (iii) grain-refinement rotation by dynamic/mechanical recrystallization processes. Solute segregation at subgrain boundaries, measured using Gibbsian interfacial excess methodology, reveals how solute contributes instability localized shear-deformation promoting depinning elements migration grain boundary. Finally, kinetic refinement/rotation within an is described behavior with: sub-grain formation; rotation/refinement deformation; growth coalescence with further increase. deformation promotes boundary create large degree equiaxed grains density imperfections.