Tribological processes at materials interfaces are of major technological importance since they are the source of wear and degradation as well as frictional energy dissipation. Fundamental understanding of the physics and chemistry of tribological phenomena is of particular importance for the development of advanced materials required to function under extreme ambient conditions and for long periods of time. Although there is an immense body of empirical data, there is no detailed microscopic theory of tribological phenomena. This project is concerned with the microscopic mechanisms of friction, lubrication and wear at material interfaces. It focuses on two topics. They are studies of lubricants, lubrication, and plastic flow,and studies of tribological processes at interfaces between amorphous and crystalline materials. These studies will be performed through molecular dynamics (MD) simulations. The MD method allows one to follow the time evolution of the dynamical state of a system of interacting particles by integration of the classical equations of motion. In this method, the particle interactions are prescribed by pair potentials. The number of particles normally included in this type of analysis is between one and ten thousand. The method is applicable to systems in various stages of aggregation (solid, liquid, crystalline, or amorphous), under various conditions and in the presence of complex interactions and external fields. Furthermore, the method allows the study of structural changes that materials undergo at elevated pressure and temperature and there is evidence that careful simulations are in agreement with experimental structural data. The intent of the project is to provide a systematic method of predicting the complex phenomena of friction, lubrication and wear processes.
