Low-temperature superplasticity of Si-added medium-Mn steel

Abstract

Abstract. Grain boundary sliding, a deformation mechanism of superplasticity, occurs only at high temperatures, making it difficult for superplastic steels to be practically applied due to high energy consumption and surface oxidation. Therefore, in the present study, we introduce a newly developed Si-added medium-Mn steel, which can be superplastically deformed at such a low temperature of 763 K. The low-temperature superplasticity of this steel was caused by grain boundary sliding between recrystallized α grains and dynamically reverted γ grains. The steel also exhibited high room-temperature tensile strength (1336 MPa) after the superplastic forming simulation.