Abstract :
The changes in friction and wear, especially during the run-in period, are strongly correlated to the blockage of energy dissipation paths within the sliding materials. As such, the preservation of the tribological integrity of a rubbing material depends, mainly, on the efficiency of dissipation of the friction induced thermal energy (FITE). This paper therefore, studies the mechanistic evolution of FITE and the process of its dissipation during sliding. The study focuses on the intrinsic aspects of the dissipation process. In particular, the role of the mechano-physical properties (conductivity, diffusivity, hardness, etc.) and their respective variation with temperature is studied comprehensively. This is achieved by studying the behavior of two contrasting rubbing pairs: mild steel (AISI 1020) sliding on itself and, a stainless steel (AISI 304HN) sliding on a mild steel counterpart. The results indicate that the external sliding parameters (nominal load and speed) are of limited influence on the dissipation process. The major influence, however, is assumed by the change in the thermal properties and more dominantly, by the rate of degradation of the conductivity in the contacting layers of the rubbing pair. These results support the view that wear generation is, in essence, an intrinsic energy dissipation mechanism the aim of which is to consume part of the FITE released at the surface.
