The orientation imaging of ultrafine-grained nickel processed by high pressure torsion (HPT) and equal channel angular pressing (ECAP) was discussed. The grain boundary misorientation distributions were measured by both procedures. High fractions of high-angle boundaries and higher fractions of low-angle boundaries were obtained by the techniques. Higher fraction of high-angle boundaries obtained after HPT indicates that the rotation mode and dynamic recovery are more pronounced in HPT than in ECAP due to higher imposed strain.
- Equal channel angular pressing
- Grain boundaries
- High-pressure torsion
- Orientation imaging microscopy