Ultralow-temperature superplasticity of high strength Fe–10Mn-3.5Si steel

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2022-07, Vol.848, p.143408, Article 143408
• Main Authors: Jeong, Hyun-Bin, Choi, Seok-Won, Kang, Seok-Hyeon, Lee, Young-Kook
• Format: Article
• Language: English
• Subjects: Dislocation creep; Dynamic reverse transformation; Elongation; Energy consumption; Grain boundary sliding; High strength; High strength steel; High strength steels; Oxidation; Strain rate sensitivity; Superplasticity; Ultralow-temperature superplasticity
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2022.143408

Superplastic steels with high elongations above 300% are expected to be used for manufacturing complex-shaped mechanical parts without joining. However, their practical application is difficult due to high energy consumption and surface oxidation caused by a high deformation temperature (≥873 K). Here, we propose a new high strength Fe–10Mn-3.5Si steel, which is superplastically deformed at 763 K. This steel exhibits different microstructural and deformation features from previous superplastic steels, such as single phase before deformation, coarse elongated grains, low strain rate sensitivity, and strong texture. The superplasticity of the steel results from both dislocation creep and grain boundary sliding due to dynamic reverse transformation. Because the steel has a low material cost and is produced by conventional rolling, it is suitable for practical application. •10MnSi steel had superplasticity at the lowest temperature (763 K) reported to date.•10MnSi steel also revealed ultrahigh tensile strength (1336 MPa) at room temperature.•Outstanding superplasticity was caused by the GBS of dynamically reverted γ grains.