Modeling the influence of bainite transformation on the flow behavior of steel using a macroscale finite element analysis

Abstract

This study comprehensively investigates the kinetics of bainitic ferrite transformation in steel alloys by integrating experimental results, finite element analysis, and thermodynamic modeling. Using a dilatometer and Gleeble tests, empirical data were acquired to calibrate the Bhadeshia and Hensel-Spittel models, forming the basis for subsequent finite element simulations. Owing to the high importance of temperature in bainite transformation, the accuracy of the predicted temperature fields was validated precisely against experimental measurements, confirming the reliability of the methodology. A modified Bhadeshia model was proposed incorporating the influence of the applied shear stress on the activation energy, thereby emphasizing the temperature-dependent ${\mathit{C}}_{\mathit{stress}}$${\mathit{C}}_{\mathit{stress}}$ coefficient. The electron backscatter diffraction results validate the finite element model, and further exploration reveals the implications for fracture patterns and density changes due to bainitic transformation. This study contributes to a nuanced understanding of bainitic ferrite kinetics, offering valuable insights for alloy design and optimization under various thermomechanical conditions, and paving the way for advanced research on phase transformation kinetics and material behavior.