Influence of the Dynamic Indentation Parameters on the Behavior of Metals during the Penetration of an Indenter with a Spherical Tip

The relation between the parameters of the impact indentation of a rigid spherical indenter (its velocity before impact, mass, diameter), the strain rate, and the hardness of a metal is studied. Expressions for the normal and radial strain rates at the initial stage of indentation are obtained. The most rational characteristic of impact processes is shown to be the average strain rate per impact, which is determined by the Tabor equation and the impact contact time. At an indenter velocity of 0.4–4.0 m/s before an impact, the dynamic Meyer hardness is found to be mainly determined by the strain-rate sensitivity of a metal, which depends on the type of crystal lattice.