Formation of nanolaminated structure in an interstitial-free steel

Nanolaminated (NL) structure has been produced in an interstitial-free steel by means of surface mechanical grinding treatment. The NL structure is characterized by an average lamella thickness of ∼20 nm and also exhibits a strong deformation texture. Various dislocation substructures and individual dislocations exist inside these lamellae from submicron size to a few nanometers. Due to this extraordinary grain refinement, the NL structure exhibits a record hardness of 5.3 ± 0.6 GPa.