Deformation Zone Geometry and Texture Gradients in Cold-Rolled Niobium

Several niobium plates were cold-rolledat room temperature to a total reduction of 60%maintaining the geometry of the zone of deformationconstant for each plate. Pole figures were obtainedby means of the Schulz x-ray reflection techniquefrom various depths in the thickness direction forplates rolled with different ∆, the ratio of the meanheight of the deformation zone to its contact length.Severe texture gradients were noted and characterizedfor Δ > 1 ; a modified texture different from thenormal texture was observed at intermediate through-the-thickness locations. Both lateral widening andmicrohardness gradients were also in evidence forthis case. No previously proposed theoretical explanationcould account for these results.