Sclerometric characterization of nearly brittle materials

Abstract

The abrasion of nearly brittle materials can be considered as a multipoint scratching and indenting process. Knowledge of flow morphologies around the abrasive protuberances, the determination of the energy dissipated during single-contact scratching experiments and the estimation of the forces acting on the abrasive particles are therefore essential for a better understanding of the wear and finishing processes based on abrasion phenomena. Experiments using linear and pendular sclerometers were conducted on various materials such as glass, ceramics, metals and polymers. The results described in the present paper show the effects of the geometry, the speed and the rheology on the abrasive process. The forces induced and the morphologies of the scratches are studied. The behaviour of the abrasive contact is in particular very nicely described by a critical transition from ductile to brittle abrasion which is analysed in detail for soda-lime glass. This transition is itself correlated with the dynamic hardness and the dynamic toughness of the tested materials. The results have a bearing on the prediction of the behaviour of nearly brittle materials when used as bulk materials or surface coatings in tribological applications dealing with abrasive wear.