JMAK model applied on the κ-carbide precipitation in FeMnAlC steels

Different lightweight steels alloys have been treated by different isothermal treatments in order to understand the basics of precipitation kinetics of κ-carbide for such class of new steel grades featured by high concentration of Mn and Al. The κ-carbide precipitation plays a significant role to induce the strengthening of these steel grades that maintain a significant ductility up to the fracture as a consequence of their duplex ferrite-austenite structure that exploits the twinning mechanism of austenite during the plastic deformation. In this paper the results about isothermal transformations involving the κ-carbide precipitation have been discussed. In order to deepen the comprehension of the mechanisms involved in precipitation of κ-carbides, the study has been performed by isothermal (Temperature Transformation Treatment) experiments applying different temperatures and holding times. The observed transformations have been measured and it has been possible to apply the JMAK model to fit such results. In addition, it has been observed a relationship between the steel composition and the activation energy for the transformation.