High-pressure rotational deformation apparatus to 15 GPa

A new apparatus has been developed that allows large-strain plastic deformation experiments under high pressure with a controlled strain rate in simple shear deformation geometry. A modification is made to a Drickamer-type opposed anvil apparatus to allow torsion tests by attaching a rotation actuator composed of a dc servomotor and a gear box. A thin disk of a sample (less than ∼0.8 mm thick and to ∼4 mm diameter) can be sheared between two anvils under pressure by a rotation actuator. Specimens of Fe were sheared to strains exceeding γ∼6 at pressures up to ∼15 GPa. Nearly simple shear deformation was achieved when the initial sample thickness is less than ∼0.4 mm. This apparatus allows studies of plastic flow and deformation microstructures under high pressures.