The Mapping of Metallic Sliding Wear

Abstract

Mechanisms of machining (abrasive), fatigue and transfer wear are reviewed in the context of the interfacial shear stress (adhesive) and surface roughness (deformation) conditions in which they occur. In the first part it is shown how model predictions of surface flow, friction and wear may be mapped on to a field with surface shear strength and roughness slope as its coordinates and in the second part the response of real metals to these variables is considered. The main attention is given to abrasive wear, with a review of lubricant, geometry, bulk mechanical and microstructural effects on abrasive wear resistance; but briefer reviews of fatigue and transfer wear are also given. Any overview of metallic wear requires consideration to be given to wear not of the metal but by removal of surface reaction films (usually oxides): regimes of oxidational wear do not plot on to a map of surface shear strength and slope but on to a map of nominal contact pressure and sliding speed. The need is argued for two sorts of map on which to classify wear phenomena.