Mesomechanics of the Frictional Contact in Low-Cycle Fatigue Conditions

The behavior of contacting bodies under the thermomechanical loading in the conditions of low-cycle fatigue was analyzed within the developed mesomechanical framework, and the nature of formation of the tribodestruction centers in the near-surface metal layer is examined. It is shown that the further development of cracks is obtained between the braking cycles as a result of heating and cooling of the surface layer and formation of the temperature gradient, when thermal stresses under the surface layer reach the highest values. These stresses become proportional to the flash point temperature and cause strong heating in the thin layers of the friction surface, leading to the formation of burns, thermal spots ("bird's eye") and foci of microcracks, while the microscopically observed relief determines the region of quantum fatigue. At first, these centers of microcracks develop along normal to the side of the friction surface, and, then, according to the bifurcation diagram of metal fatigue, the bifurcation region expands in the direction of surface tangent of friction during transitions from macro- to meso- and nanoscale fracture level. Based on the development of fundamental concepts of physical mesomechanics, a discussion was held of the mechanism of self-organized formation at various scale levels of microstructures, which can be used in the developed complex tribological processes.