Low-carbon bainitic steels derive much of their mechanical performance from the complex interplay between microstructure formation and transformation-induced residual stresses. During the bainitic transformation, deformation associated with the formation of bainitic ferrite generate internal stress fields that significantly influence the final strength, toughness, and dimensional stability of the material. In this work, we investigate the evolution of these transformation-induced residual stresses and their effect on the mechanical response of low-carbon bainitic steels using a three-dimensional phase-field modeling framework. The model captures the coupled phenomena of phase transformation, microstructural morphology development, and the resulting stress distribution. The results highlight how the spatial arrangement of bainitic plates and retained austenite contributes to heterogeneous residual stress patterns and how these stresses ultimately affect macroscopic mechanical properties. The insights gained provide a foundation for optimizing processing routes to control residual stresses and enhance the performance of bainitic steels.

Dhanunjaya Kumar Nerella (M.Sc.)