Structural refinement of low alloyed steels during severe plastic deformation

The rail steel S900A and Armco-iron have been deformed by severe plastic deformation, the microstructural evolution and the changes in microhardness have been investigated. In both materials the deformation leads to a decrease in structure size. In the case of the steel an alignment of the lamellae parallel to the shear plane and a decrease of the lamellae spacing is observed. Lamellae which have been originally not favourably aligned are heavily bent and broken into small fragments. This refinement is also reflected in the evolution of the microhardness.