About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
Steels for Sustainable Development IV
|
| Presentation Title |
Enhanced austenite stability and ductility by isothermal heat treatment of the 3Mn TRIP steel with bimodal grain structure |
| Author(s) |
Yong Su Lim, Jin kyung Kim |
| On-Site Speaker (Planned) |
Yong Su Lim |
| Abstract Scope |
The transformation-induced plasticity (TRIP) assisted steel typically utilizes a two-stage heat treatment, consisting of intercritical annealing and isothermal heat treatment. During isothermal heat treatment, carbon partitioning and austenite decomposition have been observed. We investigated the microstructures and mechanical properties of the cold-rolled Fe-3Mn-0.2C-1Al (wt.%) medium Mn steel subjected to intercritical annealing (700°C and 720°C for 5 minutes) followed by isothermal heat treatment (300°C for 10 minutes). The microstructure after intercritical annealing exhibited a bimodal grain structure consisting of fine austenite/ferrite grains and coarse ferrite grains. Fresh martensite was observed in the sample annealed at 720°C. The isothermally heat-treated samples demonstrated increased strength and ductility compared to those treated only by intercritical annealing, which is attributed to enhanced austenite stability due to carbon partitioning into austenite during the isothermal process. We discuss the detailed formation mechanisms of microstructures and deformation mechanisms to clarify the relationship between microstructural evolution and mechanical properties. |