About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Steels in Extreme Conditions
|
| Presentation Title |
Intercritical Annealing-Tailored Microstructural Evolution and Tensile Properties in Extremely Low-Carbon Dual-Phase Steels |
| Author(s) |
Won Hui Jo, Seonghyeon Yang, Taehyeong Kim, Jun seok Lee, Seong-Tak Oh, Yong-Min Hyun, Jeong Min Park, Seok Su Sohn, Jae Wung Bae, Jae Bok Seol |
| On-Site Speaker (Planned) |
Jae Bok Seol |
| Abstract Scope |
A hierarchical microstructure of soft ferrite and hard martensite governs the strength-ductility synergy in typical dual-phase (DP) steels containing 0.08–0.15 wt% C. Here, we explore an ultralow-carbon (0.05 wt%) DP steel processed by intercritical annealing (IA), aiming to preserve strength while enhancing ductility. The low C content led to BCC martensite with minimal tetragonality, while IA promoted Mn/Ni-enriched fresh martensite within the DP matrix. Two morphologies of fresh martensite emerged: lath-type within existing ferrite/martensite grains and blocky-type along grain boundaries. Tensile tests, combined with μ-DIC and site-specific EBSD/EDS, revealed a sequential load transfer mechanism at strain levels: ferrite → Mn/Ni-enriched fresh martensite. Load-unload-reload experiments further quantified back stress strengthening, highlighting the role of interphase deformation incompatibility. The reduced yield strength was attributed to the low tetragonality of martensite and to transformation-induced compressive stress, while the activation of slip in fresh martensite contributed to tensile strength retention. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Other, Other |