An energy description of wear mechanisms and its applications to oscillating sliding contacts

To quantify wear rates, the Archard approach is classically applied. It relates the wear volume to the product of the sliding distance and the normal load. A wear coefficient is then extrapolated and is supposed to establish the wear resistance of the studied material. This synthesis shows that this approach does not work when the friction coefficient is not constant. It appears to be much more relevant to consider the interfacial shear work as a significant wear parameter. This approach is applied to study the wear response of different steels and then extended to different hard TiN, TiC coatings under reciprocating sliding conditions. By identifying wear energy coefficients the wear quantification can be rationalized and the wear resistance of the studied tribosystems can be classified. This also appears to be a convenient approach to interpret the different wear mechanisms. Metallic materials involving plastic strain are analyzed from FEM computations. The energy balance confirms that a minor part of the dissipated energy is consumed by plasticity, whereas the major part participates in the heat and debris flow through the interface. When a load energy approach is introduced an accumulated density of the dissipated energy variable is considered to quantify the TTS (Tribologically Transformed Structure) formation. A wear ”scenario” of metallic structures is then discussed. This energy wear approach is applied to analyze hard coating wear mechanisms focusing on abrasion and oxidation phenomena. The local wear energy analysis is transposed, thus allowing the lifetime of hard coatings to be quantified.