|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||High Performance Steels
||Manganese-diffusion Controlled Kinetics of Austenite Growth and Cementite Dissolution during Intercritical Annealing of Medium-Mn Steels
||Josh Mueller, John Speer, David Matlock, Emmanuel De Moor
|On-Site Speaker (Planned)
Simulations for microstructural evolution during intercritical annealing (IA) of medium-Manganese steels predict slow dissolution of cementite while austenite growth occurs via a Mn-diffusion controlled transformation. These simulations have been shown to be in good agreement with in situ austenite fractions during intercritical annealing measured with high energy X-ray diffraction. The present work aims to further elucidate austenite transformation and cementite dissolution mechanisms during IA. Consistent with simulation predictions, micrographs via scanning electron microscopy, and energy dispersive X-ray spectroscopy via scanning transmission electron microscopy, of a Fe 0.2C 4.5Mn steel indicate that cementite was enriched in Mn prior to IA, and was slow to dissolve during IA. Substantial growth of austenite with Mn enrichment also occurred during IA. Thermodynamic assessments were made which reveal Mn-diffusion controlled kinetics associated with the dissolution of cementite, and the inhibition of rapid initial austenite growth via so-called negligible-partitioning local-equilibrium.
||Iron and Steel, Phase Transformations,