Wear particles, surfaces and plastic flow generation in unimplanted and Mo ion implanted carbon steel under friction

Abstract

The purpose of the present work is to study the influence of the structure modified by ion implantation on mechanisms for wear particles, surfaces and plastic flow generation. The ‘block-on-shaft’ testing procedure was used to investigate the wear behavior of the ferritic/pearlitic carbon steel (in 0.45 wt% C) in the unimplanted and Mo ion implanted states. New approach to description of plastic deformation and destruction under friction is introduced on the basis of concepts of structural levels of plastic deformation and physical mesomechanics. In order to investigate the plastic flow behavior under friction, a unique method was applied using the optical TV-complex ‘TOMSC’. Reconstruction step-by-step of the displacement vector fields helps to reveal different plastic deformation stages evolving from fragmented mesostructure to large vortex mesostructure. It has been found that the character of plastic flow in the subsurface layers during friction determines the mechanism for generation and separation of the wear particles and formation of the wear surfaces. It was concluded that the formation of the modified structural-phase state in the surface layer of the Mo ion implanted specimens prevents the fragmented structure formation at mesolevel and retards the mesofragment vortex movement in the subsurface layer, thereby decreasing the intensity of the wear particles generation and finally increasing wear resistance.