Stable {110}⟨112⟩ textured Ag ribbons for biaxially-aligned YBa₂Cu₃O_7-δcoated tapes

Abstract

Texture development in pure Ag was investigated in order to obtain {110}⟨uvw⟩ textured Ag ribbons that can be used as a substrate for YBa2Cu3O7 superconducting coated tapes without any buffer layer. The starting material was 99.95% pure commercial Ag foils. A 20% deformation reduction was used at each step of the cold rolling process after which an optimal annealing was achieved at 800 °C for 4 h in a primary vacuum. This process leads to large-grain ribbons with the {110}⟨112⟩ orientation. A sharp and pure texture is obtained with a FWHM smaller than 6° in the three x-ray pole figures that were used to calculate the orientation distribution function. Crystallographic orientation maps achieved by electron back-scattering diffraction show a misorientation from the normal direction of less than 4°. A twinning mechanism is used to explain the formation of the {110}⟨112⟩ texture. The stability of the {110}⟨112⟩ texture is confirmed by further annealings up to 900 °C, a practical temperature for coated tapes preparation. Lengths up to 25 cm with a uniform {110}⟨112⟩ texture have been obtained.

Development of Sharp {011}⟨211⟩ Textured Silver Substrate for Superconducting Tapes

“…8. Compared to the result by Suo et al, 7) the Brass f011gh211i type recrystallization texture obtained by our improved metallurgical processing are much more simple. Only trace of f2; 2; 11gh1; 10; 2i orientation can be detected when the ODF and pole figures are plotted with lower contour levels.…”

“…13) It was suggested in the work of Suo et al that a first stage of fast temperature ramp up to 500 C would help the grain growth in f011gh211i orientation during the second stage of high temperature annealing. 7) Therefore, two-step annealing processes of 500 C-30 min + 850 C-300 min and 500 C-30 min + 850 C-480 min were initially employed on specimens rolled at room temperature and 150 C in this study. Figure 3 shows the ' 2 ¼ 0 and ' 2 ¼ 45 ODF sections and {111} pole figure of recrystallization texture after twostep annealing 500 C-30 min + 850 C-300 min in specimens cast in vacuum.…”

“…18,19) Suo et al have proposed an optimized method to get pure and stable f011gh211i textured silver ribbon with long length and the model on the formation of Brass f011gh211i texture in silver explained by twinning mechanism. 7) Following this, Doi et al reported their work on making Brass f011gh211i type textured silver tape. 13) In our work on warm rolling and subsequent annealing in silver, a very sharp Brass f011gh211i type texture with high intensity in ODF but with trace of other components was obtained.…”

“…After Hu's early study on the texture transition in pure silver, many recent research works have been concentrated mainly on achieving single orientation in the texture of silver substrate. [2][3][4][5][6][7][8][9][10] An advanced sharply cube-textured silver substrate was successfully obtained by simple warm rolling and subsequently annealing in our previous work.…”

Rolling and Recrystallization Textures of Ag-10 mol% Pd Alloy Substrate for Superconducting Tapes

“…[5][6][7][8][9][10][11][12][13] An advanced sharply cube-textured silver substrate was successfully obtained by simple warm rolling and subsequent annealing in our previous work. 14) All those endeavors have promoted the technological possibilities of silver substrate to be used in high-temperature superconductors.…”