Small Angle Neutron Scattering Study of Nanoscale Structure of Low-Carbon Steel After Rolling with Shear Followed by Cold Drawing

Abstract

Small angle neutron scattering was applied to steel produced by rolling with shear (RS) technology and compared to samples produced by standard technology (ST). Based on small angle neutron scattering measurements the morphology of the grains and pores of RS steels were compared to those of the ST steels. The scattering in small scattering vector region showed anisotropy, attributed to the elongation of the pores; the pearlite lamellae distances along and perpendicular to the rolling directions difered by a factor of 1.5. The results of the Small angle neutron scattering measurements were in accordance with the electrical characteristics of the specimens. They showed smaller and less anisotropic average sizes of the cracks and nanopores for the RS samples than for the ST rods. This confrms the dynamic healing of the nanosized defects during the cold drawing of the RS rods. This fundamental result shows that during severe plastic deformation a cyclic process of nucleation and healing of the nanovoids took place. However, during the standard deformation process only nucleation of the nanovoids is present.