Effects of ThermoMechanical Coupling in Tribological Surface Transformations: A One-Dimensional Modelling Including Irreversible Solid-Solid Phase Transformations and Classical Plasticity

Grégory Antoni

doi:10.1155/2013/892050

Abstract

Under compressive loads combined with friction, some materials undergo Tribological Surface Transformations (TSTs) on the surface of the loaded parts and in the immediately vicinity, which in the case of metals, are known as irreversible solid-solid phase transformations. During the solid-solid phase transformations occurring under mechanical loads, TRansformation Induced Plasticity (TRIP) processes are generated at much lower stress levels than those associated with the yield strength of the material in classical plasticity. In order to assess the effects of thermomechanical coupling in these TSTs, a one-dimensional modelling based on irreversible solid-solid phase transformations and classical plasticity is presented and discussed.

Highlights

The TSTs which have been affecting some rails of the French railroad for the last twenty years consist of irreversible solidsolid phase transformations resulting in the development of a “White Etching Layer” (WELs) on the rail tread and which grows in depths from several nanometers to more than 100 μm [1]
During the solid-solid phase transformations occurring under mechanical loads, TRansformation Induced Plasticity (TRIP) processes are generated at much lower stress levels than those associated with the yield strength of the material in classical plasticity
In order to assess the effects of thermomechanical coupling in these TSTs, a one-dimensional modelling based on irreversible solid-solid phase transformations and classical plasticity is presented and discussed

Summary

Introduction

The TSTs which have been affecting some rails of the French railroad for the last twenty years consist of irreversible solidsolid phase transformations resulting in the development of a “White Etching Layer” (WELs) on the rail tread and which grows in depths from several nanometers to more than 100 μm [1]. In this model, the irreversible phase transformations are taken to result from “strong” thermomechanical coupling, that is, from the combined effects of the change in temperature and the mechanical dissipation. The quantities on the right-hand side of (15) are the “source terms” corresponding to the thermoelasticity, the classical plasticity, and the irreversible solid-solid phase transformation, respectively It is worth noting the thermodynamic consistency of this model [9] is checked since the laws of evolution of the internal state variables verify systematically (8)

Numerical Example

Conclusion