An investigation into the dynamic indentation response of metallic materials

The dynamic indentation response of several ductile metallic materials Al(111), polycrystalline copper, Fe, and Ti6Al4V] has been investigated using a pendulum-based nano-impact test. The impact process involves repetitive contact cycles until finally coming to rest in the material. Each cycle includes four phases: acceleration, indentation, rebound, and deceleration. The dynamic indentation resistance of the metallic materials scales with their hardness determined under quasi-static conditions. However, through a one-dimensional analytical model, it has been shown that the relationship between the dynamic resistance and the depth during indentation cannot be adequately described using the quadratic relationship commonly found under quasi-static conditions. A power law relationship with a reduced index was proposed and it is found the index is around 1 when the quasi-static and dynamic compliance are similar. A linear relationship between impact resistance and depth has been found during rebound, where the released elastic energy is much higher than that produced by quasi-static nanoindentation.