ABSTRACT
Commercial pure Ni (99.9% wt%) rods with a diameter of 20 mm were annealed at 980°C for 5 h to form a solid solution with an initial grain size of approximately 40 μm. The equal channel angular pressing (ECAP) processing was carried out using a die with an intersecting channel angle of 90° and an outer arc angle of 45°. This die configuration imposes an effective strain of approximately one per one ECAP pass. The sample was processed for six passes by route Bc in which the work piece was rotated 90 along its longitudinal axis after the first pass. The ECAP-processed UFG Ni rod was then annealed at 580°C for 20 min to obtain the homogeneous grain structure. Finally, thin tensile samples were cut for tensile load/unload/reload tests in an orientation parallel to the pressing direction.
