Bilinear Behavior in Nano and Microindentation Tests of fcc Polycrystalline Materials

α-brass and aluminum microhardness and deep nanoindentation data when fitted to the Taylor dislocation-hardening (TDH) model produced a straight-line behavior consistent with the model. Literature data, including copper, silver, and tungsten when also fitted to TDH model, exhibited results similar to the ones produced by the α-brass and aluminum data. The nanohardness data obtained at shallower depths also exhibited straight-line behavior but with a shallower slope. Taken together, the nano-microindentation data constituted what we term a “bilinear behavior,” and we shall discuss possible mechanisms for this behavior.