ROLE OF MICRONESTRESSES OF THE 2ND KIND IN MECHANO-PHYSICAL-CHEMICAL PROCESSES OF SEIZURE OF DISSIMILAR CRYSTALLINE MATERIALS UNDER THERMODEFORMATION IMPACT

Previously, a methodology was developed for studying the contact interaction between dissimilar materials under thermal deformation impact over time. Kinetic curves of contact formation, plastic deformation of microprotrusions, height of microprotrusions, change in contact stresses on microprotrusions, change in mechanical properties on the surface and depth of the near-contact volume of microprotrusions from room to premelting temperatures and in the pressure range before and after threshold values were constructed. The nature of crushing and kinetics of contact interaction between dissimilar materials with sharply different resistance to plastic deformation and the nature of chemical bonds under thermal deformation impact. It is shown that plastic deformation of microprotrusions is responsible for contact formation and activation processes on contact surfaces. It is shown that the level of stresses of the 2nd kind on contact pads of microprotrusions significantly exceeds the nominal stress values included in the calculation formulas. A constant of the ratio between normal and tangential microstresses of the 2nd kind (compensated in the volume of the microprotrusion grain) in the entire studied range of temperatures and pressures in time was established, equal to K = 3.03. It was established that temperature and pressure have different effects on the intensity of plastic deformation and contact formation, changes in mechanical properties on the surface of contact pads and the depth of the near-contact volume. The proposed process scheme allows obtaining high-purity flat metal surfaces with adjustable mechanical properties and precision joints (detachable and non-detachable).