Strain hardening behavior and microstructure evolution of high-manganese steel subjected to interrupted tensile tests

Strain hardening behavior and the corresponding microstructure evolution of the high-manganese steel with additions of Si and Al were investigated in this study. Thermomechanically processed and solution-heat-treated sheet steels were compared under conditions of interrupted tensile tests. Relationships between microstructure and strain hardening were assessed for different strain levels using light microscopy and scanning electron microscopy techniques. It was found that the deformation of both steels at low strain levels was dominated by dislocation glide before the occurrence of mechanical twinning. The amount of twins, slip lines, and bands was increasing gradually up to the point of necking. As the strain level increased, dislocation density within twinning areas becomes higher, which enhances the strength, the work hardening exponent, and the work hardening rate of the investigated high-manganese sheet steels.