Mechanical properties of polycrystalline copper and single-crystal LiF initial components for composite system Cu/LiF

The paper deals with an investigation of mechanical properties and deformation features of polycrystalline copper and single-crystal LiF under dynamic nano/microindentation. It is shown that the values of hardness and Young’s modulus depend on the magnitude of the applied load ( P max ): when the load is increased, H and E decrease. General regularities of the indenter penetration process in a wide range of loads are revealed: the appearance of a “pop-in” effect at the initial stage of the loading process, the formation of more pop-in steps with the growth in load, and the formation of pileups around the indentations. Such a nature of deformation is the result of sequential activation of different dislocation mechanisms with indenter deepening. Along with a great similarity in the specificity of deformation, some differences are noted at the unloading stage. The results serve to compare the mechanical properties of Cu and LiF individual components with similar parameters of the “coating/substrate” composite systems (CS Cu/LiF) produced on their basis.