Microstructure and texture of zirconium and titanium grain refined by equal channel angular pressing

Zr702 and commercial purity Ti were grain refined through severe plastic deformation and their microstructure and texture characteristics were studied by optical microscopy, transmission electron microscopy, X-ray diffraction and electron back-scattered diffraction. The equal channel angular pressing was conducted at 350 degrees C using a 90 degrees/20 degrees die. Up to 8 passes of pressing were performed via three different routes, A, C and B-C, which resulted in reduction of the grain size down to 0.2-0.5 mu m. The two materials showed similar evolution characteristics of microstructure and texture. While the specimens pressed via route A showed lamellar grain shapes those via route C or B-C exhibited equiaxed grains. A split basal texture was developed in the microstructure obtained by the route A pressing, which was similar to the cold rolling texture, whereas an asymmetric texture was produced in the specimens pressed via route B-C. In the case of route C pressing, the texture characteristics were closer to those of the route B-C case.