Cold rolling evolution in high purity niobium using a tapered wedge specimen

A multi-scale model for texture development in Zr/Nb nanolayered composites processed by accumulative roll bonding

“…Again, for all h, the Nb textures exhibit a typical BCC rolling texture recognized by two fibers, the (001) α-fiber and (111) γ-fiber with pronounced ሼ001ሽ〈110〉 and ሼ111ሽ〈110〉 texture components, respectively. These features are also consistent with previous pole figures [81,82] and orientation distribution function (ODF) sections in Euler space [83][84][85][86] reported for rolled single-phase Nb. In addition they are also similar to textures in ARB Cu/Nb composites with micron-thick Nb layers [17,39].…”

Processing strategies for niobium sheet used in advanced superconducting particle accelerator cavities

“…When the Wah-Chang sheet was annealed to obtain a greater degree of recrystallization and hence, equiaxed grains, the degree of anisotropy was reduced and the material became better for forming half-cells. 10 In a related study of a different batch from Tokyo-Denkai, the texture and microstructure differed from those shown here. The anisotropy was characterized carefully and a methodology to model its anisotropic yield surface was developed.…”

“…10 Microstructure and texture heterogeneity were measured using through-thickness orientation imaging microscopy (OIM) scans, obtained in a field-emission scanning-electron microscope (FE-SEM) (CAMSCAN 44FE) using a TSL system and software (TexSEM Laboratories, Draper Utah). The average grain size in the Wah-Chang sheet was 40 m; however, there was a region of larger grains having greater <001> || normal direction (ND) that would alter the local mechanical properties as a secondary microstructural component with a different texture (shown in red in Figure 2, left side; maps are from the ND perspective).This <001> component may account for the observed anisotropy of mechanical properties observed in the stress-strain curves in different directions with respect to the rolling direction, which is undesirable when forming precise shapes (e.g., at a stress of about 125 MPa in a biaxial stretch, the strains in different directions can vary by a factor of~2).…”

“…Prior recrystallization studies of rolled niobium sheet by Jiang et al [8][9][10] showed that recrystallization differed from interstitial-free (IF) steel. [17][18][19][20] Interstitial-free steel differs from niobium in having a complex phase transformation that also generates very fine carbides, but like pure niobium, it has a low interstitial content.…”

“…7 To put these newer ideas into context, some relationships between texture, microstructure, and properties of conventionally processed sheet niobium are first illustrated. [7][8][9][10][11][12][13][14][15] …”