Dynamic Strength of Iron at High Pressures and Strain Rates
Vatsa Gandhi, Suraj Ravindran, Guruswami Ravichandran
Abstract
Accurate modeling of meteorite impacts, and deformation of planetary cores require characterization of the flow strength and in-elasticity of iron in its different phases. In this Letter, we investigate the flow strength of both the ambient $\ensuremath{\alpha}$ phase and high-pressure $\ensuremath{\epsilon}$ phase of iron at strain rates of $1\ifmmode\times\else\texttimes\fi{}{10}^{5}\text{ }\text{ }{\mathrm{s}}^{\ensuremath{-}1}$ and pressures up to 42 GPa using high-pressure--pressure shear plate impact experiments. We report the strength of the $\ensuremath{\epsilon}$ iron to be significantly higher than $\ensuremath{\alpha}$ phase but consequently one order smaller than the previously reported dynamic strength at high pressures. The complete stress-strain response of the $\ensuremath{\epsilon}$ phase is reported for the first time.