Superior mechanical properties of heterostructure 1045 steel obtained by cold rolling and subsequent electropulsing treatment

• Electropulsing treatment enhances strength and ductility in cold-rolled 1045 steel. • Electropulsing treatment promotes precipitation of cementite and recrystallization. • Heterostructure 1045 steel with superior mechanical properties was prepared. A novel high-density electropulsing treatment (ET) method was proposed to ameliorate the microstructure and mechanical properties of severe plastic deformed 1045 steel. Simultaneously, a heterostructure (HS) was obtained, which consists of a ferrite matrix with multi-scale distribution of grain size and high-density nanocarbide particles. Due to multiple strengthening mechanisms about dislocation strengthening, Orowan strengthening and grain boundary strengthening, the strength of HS 1045 steel was improved significantly; and the favorable ductility is ascribed to the additional hetero-deformation induced (HDI) work hardening effect of the HS microstructure. This technique can be utilized as an energy-efficient post-treatment method for the preparation of HS carbon steel with excellent strength–ductility synergy.