Aspects of the Nature of Wear

Abstract

Purpose of reseach was a comprehensive study of the nature of wear of rubbing surfaces.Methods. The wear of parts is accompanied by complex physico-chemical phenomena. The wear rate depends on the material and quality of the rubbing surfaces, the nature of the contact and the speed of their mutual movement, the type and value of the load, the type of friction and lubrication, the quality of the lubricant, the presence of a third body between the contacting surfaces and many other factors. If we proceed from the definition of wear according to GOST, the key cause of wear is the destruction of the crystal lattice of a solid, due to the loss of its strength, into fragments (blocks or particles) of a certain dimension with their subsequent removal from the contact zone of tribosurfaces. However, the detailed mechanism of material separation from the friction surface is far from clear and has not been worked out from the standpoint of classical materials science. An approach to the representation of the nature of friction and wear is proposed. The crystal lattice of any metal, and even more so of an alloy, is an anisotropic medium and this anisotropy is significantly enhanced on the scale of the crystal structure of the alloy, since the orientation of the crystal structure inside each grain is multidirectional. Consequently, the stress-strain state of the structure in the surface layer of tribo-tension must be evaluated from the standpoint of the anisotropy of the medium.Results. To assess the impact on the wear processes, the following factors were investigated: load-speed; physical and mechanical; structural; thermophysical. An original technique for determining the intensity of wear has been developed, which makes it possible to evaluate and predict the durability of a particular friction unit. Comparison with the experiment showed satisfactory convergence in this range of changes in factors affecting the wear process.Conclusion. The nature of wear consists in the presence of stresses in the materials of the contacting surfaces, which tend to get rid of them by dispersing individual particles of different dimensions, approaching the minimum of entropy production.