lnitial stages of milling, mechanical alloying and mechanical activation processes involve fast local plastic deformation in "hot spots" on contacting surfaces. However, very little is known about dynamic mechanical properties of materials in localized microcontacts. A new pulse nanoindentation technique is developed to investigate dynamics and micromechanisms of plastic deformations in the above-described conditions. The nanohardness tester allowed in-situ recording of local plastic deformation with high spatial and time resolution (similar to1 nm and similar to50 mus accordingly). It was also capable of recording electrical polarization of the indentation zone with a time resolution of similar to100 ns. It is established that the process of the indenter penetration under pulse loading conditions can be described by several distinct stages (as many as four in some cases) differing in kinetics and activation parameters. Relative contributions of non-equilibrium point defects and dislocations in each stage are discussed.