S158 Segregation and local partitioning of Mn at migrating ferrite / austenite interface

摘要

Mn is one of the most important elements in steels and added to obtain high strength structure formed at lower temperature since Mn delays ferrite (α) transformation during cooling. Delaying effects of Mn has been discussed in terms of development of spike in austenite (γ ) in front of α / γ interface, which is predicted in negligible partitioning local equilibrium (NPLE) model, or segregation of Mn at α / γ interface (solute drag model). Recently, Mo segregation at α / γ interface was quantitatively investigated by means of three dimensional atom probe (3DAP) and was found to depend on interfacial orientation relationship (OR) [1]. In this study, we aim to clarify Mn segregation and local partitioning at migrating α / γ interface using 3DAP measurement.