Fig. 2: Effect of impactor shape and mass on accessing lower strain rates in LIPIT.

A Mass versus incident velocity (vi) of impactors impacting a material of hardness 3.5 GPa. Contours representing final indentation depth (hind) of 1 µm and 2 µm are illustrated for alumina impactors of conical, spherical and cylindrical shape. The faded gray region indicates the empirical power law that establishes an upper velocity limit based on impactor mass. B Indentation area (Aind) as a function of strain rate for impacts considered in (A). Source data are provided as a Source Data file.