High-pressure torsion using ring specimens

A facility is developed for high-pressure torsion (HPT) using ring samples and the results are compared with those of conventional disk HPT samples. With pure Al (99.99%), both types of HPT are consistent. When hardness values are plotted against equivalent strain, they fall on a single line having a maximum at a strain of ∼2 followed by a steady-state at a strain of ∼6 or more where hardness remains constant with straining.