Atomistic Simulation of Scratch behavior of Ceramic/Metal (CerMet) nanolaminates

The promise of nanocomposites lies in their multi-functionality, the possibility of realizing unique combinations of properties that are not attainable in traditional materials. Ceramic/metal multilayers (CMMs) are one such unique combination that are becoming increasingly popular among researchers today. The idea is to combine the superior properties of ceramics like hardness and strength with favorable properties of metal such as ductility. Materials with these characteristics have potential for engineering applications such as highly efficient gas turbines, aerospace materials, automobiles, protective coatings, etc. Molecular dynamics atomistic simulations were performed to study the scratch behavior of different models of niobium carbide (NbC)-niobium (Nb) multilayers. The layer thicknesses were varied and the coefficient of friction was calculated at various depths of indentation. The deformation mechanisms were investigated to explain the observed mechanical behavior of the models under scratching. Model with the lowest metal/ceramic thickness ratio (2nm NbC/2nm Nb) showed the highest hardness, highest scratch resistance, and also highest friction coefficient. However, this model also showed the highest materials removal rate.