Martensitic Transformations in Fe-Mn Based Steels

In Fe-based alloys, atoms tend to arrange in three forms: face-centered cubic (FCC), hexagonal close-packed (HCP), and body-centered cubic (BCC). Regions of metal where atoms are arranged as FCC are called austenite, while the other two are referred to as martensite. Generally, by varying the temperature of the metal under study, it is possible to obtain martensitic or austenitic structures.

For over 3 decades, the group’s interest has focused on how the characteristics of martensitic transformation vary through the incorporation of various alloying elements into the material, especially with the addition of high amounts of Mn. Additional elements such as Si, Co, Cr, Al have been and are of strong interest. This has generated deep knowledge about the effect of composition on martensitic transformation temperatures and magnetic ordering.

The Division of Metal Physics produces the alloys and works experimentally, using techniques such as dilatometry, electrical resistivity, scanning and transmission electron microscopy, as well as mechanical tests. Both the alloys and the different techniques employed are mostly carried out in the laboratories of the Bariloche Atomic Center, the headquarters of our Division.

This topic is directly related to various functional properties and/or other topics of interest in Materials Science such as shape memory effect, superelasticity, high-entropy alloys, mechanical properties showing large deformation at high stresses, austenitic steels with potential use in the nuclear industry, etc. Therefore, the study of martensitic transformations seeks to investigate and evaluate the structural characteristics and mechanical and functional properties that these transformations impart to different alloys.