Dislocation structures in 16MND5 pressure vessel steel strained in uniaxial tension at −196°C

Abstract Cylindrical specimens of bainitic pressure vessel steel 16MND5 were strained in uniaxial tension at a temperature of −196°C. Dislocation structure and surface relief were studied at 2.5 and 8% of plastic deformation and their evolution with increasing plastic strain is documented. Great heterogeneities were observed in the dislocation arrangements of individual laths. The dislocation substructure is dominated by short straight dislocation segments of the screw type and by dislocation debris. Dislocation clusters and walls can be seen with increasing deformation. Slip markings are wavy, and some of them become pronounced with increasing plastic strain.