Manufacturing of new dual phase steel with a combination of macro-laminated and micro-laminated morphology

In this study, a new dual phase steel with a combination of macro-laminated and micro-laminated morphology was fabricated for the first time. Friction stir welding, heat treatment, and cold rolling were employed to produce the new laminated DP steel. The microstructure of produced DP steels consisted of elongated ferrite and martensite phases in the St52 layers. The microhardness profiles and stress–strain curves of produced laminated DP steels showed that the best mechanical properties corresponded to the traverse speed of 70 mm/min due to less hardness gradient. The failure morphology indicated good interfacial bonding that prevented delamination during the tensile deformation.