Figure 3

Dependence of (a) viscosity and (b) hardness on increasing strain rate for different materials tested by quasi-static and impact nanoindentation across seven orders of magnitude. The viscosity exhibits a linear change with strain rate in double logarithmic presentation (see Fig. 4 for a double logarithmic plot of the normalised hardness). The filled symbols correspond to the impact indentation tests, the empty ones to quasi-static indentation.