Scaling-up of high pressure torsion using ring shape

A l00 mm-diameter ring sample of high purity Al (99.99%) was processed by high-pressure torsion (HPT). It was confirmed that the results of hardness measurements were consistent with those obtained using disk samples and demonstrated that scaling-up the HPT process was feasible using the ring-shaped sample. Evaluating the advantage of using ring sample, the potential for the scaling-up arises from the fact that the ring diameter can be increased by the amount corresponding to the inner central area of disk sample. Furthermore, the applied load is entirely used for the introduction of intense strain and thus for the development of a homogeneous microstrcuture throughout the ring sample.