Thermal stability of ultrafine-grained commercial purity Ti and Ti-6Al-7Nb alloy investigated by electrical resistance, microhardness and scanning electron microscopy

Ultrafine-grained (UFG) commercial purity Ti and Ti-6Al-7Nb alloy produced by equal channel angular pressing (ECAP) were investigated in this study. In-situ electrical resistance measurements conducted on ultra-fine grained and coarse grained material during linear heating revealed different behaviors of UFG material. Electrical resistance measurements were capable to detect recovery and recrystallization processes in UFG material. Thermal stability of UFG structure was further investigated by microhardness measurements and scanning electron microscopy.