Papers by Author: Kazuyoshi Sekine

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Authors: Zheng Rong Zhang, Kazuyoshi Sekine
Abstract: In order to obtain a sharply cube textured silver sheet as the substrate for high temperature superconductor (HTS) film with high Jc (critical current density), warm rolling combined with two step annealing treatment has been performed to clarify the perspective of texture formation in pure silver. Two kinds of starting material, which are silver ingots of commercial purity obtained by casting in air and vacuum, were used to examine the effect of oxygen on texture development. The main feature of warm rolling texture obtained in this study was a strong Brass {011}<211> component with minor S {123}<412> component, and in some cases, cube {001}<100> component or Copper {112}<111> component appeared also depending on the warm rolling procedures. Upon crystallization, {001}<100>, {124}<4,12,7> and {13,6,15}<365> orientations were formed as the dominant components in silver sheets and the relative amount of their orientation components depended on the concrete annealing conditions applied and on the oxygen content. A very sharp single-crystal like cube texture has been successfully realized in the specimen, which was cast in vacuum, warm rolled by 95 percent and subsequently annealed as 1500C×10 min-5000C×30 min in nitrogen. Finally, we discussed the technological basis on sharp cube texture formation in f.c.c. pure metals with low stacking fault energy.
Authors: Zheng Rong Zhang, Kazuyoshi Sekine
Abstract: In order to demonstrate the effect of deformation temperature on texture formation in silver alloy sheet for superconducting types, the deformation and annealing textures of Ag-10 at% Pd alloy rolled at the temperatures from -1960C to 1600C and subsequently annealed were examined. A single Copper type texture with high intensity in ODFs has been realized in this study. Based on the experimental results, a metallurgical processing to get a sharp single orientation type texture in Ag-Pd alloy has been presented for manufacturing highly oriented superconducting substrate tapes.
Authors: Kazuyoshi Sekine, Zheng Rong Zhang
Abstract: Texture transition in silver introduced by the addition of 10 at% Pd alloying element was analyzed in this study. Experimental results show that the dependence of rolling texture on rolling reduction in thickness rather than on rolling temperature has been mostly detected, and the recrystallization texture transition process in pure silver is so strongly influenced by the addition of alloying element palladium that the final stable state of recrystallization texture has been changed from Brass {011}<211> orientation to Copper {112}<111> orientation. The single cube {001}<100> recrystallization texture in warm rolled silver, Brass {011}<211> recrystallization texture in room-temperature rolled silver, and Copper {112}<111> recrystallization texture in room-temperature rolled or warm rolled Ag-10 at% Pd alloy have been successfully developed for the fabrication of metallic substrates suitable for high-temperature superconducting tapes.
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