On the possibility of evaluating the resistance of materials to wear by ploughing using a scratch method

Although the plastic strain that a material can withstand in sliding contact is an important mechanical characteristic determining its resistance to ploughing wear, this material property could not be measured so far. In this study, a scratch test to measure the critical plastic strain is explored. A hard spherical indenter scratches the tested surface under progressive loading to induce an increasing plastic strain on the surface. When the plastic strain exceeds the limit of plastic deformation on the surface, micro-fracture takes place at the ridges of the scratch groove. The critical load to initiate this micro-fracture is detected in the scratch test and then the critical plastic strain is calculated. A measure of the resistance of a material to wear by ploughing, this critical plastic strain to micro-fracture has been used both for evaluating the cohesion of coatings and for screening wear-resistant materials.