A phenomenological modelling with thermo-mechanical coupling for Tribological Surface Transformations (TSTs)

Irreversible solid–solid phase transformations can be observed on samples of some metallic materials subjected to repeated compression loads. These phenomena, which are also known as “Tribological Surface Transformations” (TSTs), have been affecting some of French railroad network’s rails for about twenty years. Although the exact mechanisms responsible for apparition of the TSTs are not well understood so far, they seem to develop when the mechanical loads are combined with thermal effects occurring in the wheel/rail contact areas. The two thermo-mechanical models developed in the present study are based on the assumption that the thermo-mechanical loads may generate solid–solid phase transformations during the rolling contact. 2-D finite element analysis is conducted in order to illustrate the ability of these models to describe TSTs initiation and development in the immediate vicinity where the mechanical loads are applied.