Study of adhesion-active surface structures in P6M5 high-speed steel

Abstract

Adhesive processes are the main reason for wear of the metal-cutting tool. Adhesion-active surface structures (micro and meso-scale zones with increased density of defects having a crystal structure and high surface energy) can be identified by treating the surface with reactants by analogy with etching of a metalgraphic shlif. The level of free energy of the structural formation was estimated by the degree of darkening (dark gray color intensity) of the microstructure revealed by etching. The degree of darkening can be described and rankes quantitatively using color segmentation. Most specialized programs for metallographic image processing contain similar algorithm. The images were studied using the following indices of the structural arrangement of adhesion-active centers: the density of microstructural objects with a high value of the free energy, their relative surface area and dark gray color coefficient. A high value of the coefficient corresponds to the larger chemical potential. A comparative analysis of the character of distribution of adhesion-active zones in the surface structures of the crude and tempered P6M5 highspeed steel revealed that tempered structure contains more structural elements with high free energy (or chemical potential). Their distribution on the surface forms local zones of increased hardness, possessing high surface energy, as well as adhesion-active centers acting as potential foci for the formation of strong islet growths or zones of formation of stable adsorption films.