The Ni9.3 W alloy with no ferromagnetism and high yield strength is one of the most promising textured substrate materials for coated conductors,but its low stacking fault energy makes it difficult to obtain a strong cube texture by traditional rolling methods and recrystallization anneals.This paper introduces four-time static recoveries during the rolling process.Rolled tapes with80 μm in thickness were obtained by applying various deformation sequences between static recoveries to study their effects on the cube texture formation in Ni9.3 W alloy substrates.The results show that rising gradient deformation sequence is an advantageous way to obtain a higher amount of cube texture,its content increases by 29.2%compared to that of traditional deformation sequence.The effect of the new recrystallization annealing process on the cube texture formation was analyzed.It is shown that the cube texture content increases with anneal temperature increasing in one-step anneal,but decreases again at higher anneal temperature.Two-step anneal could effectively improve the cube texture content,which could be further enhanced by extending holding time during the first-step anneal.However,too long holding time leads to the decrease in cube texture content.Finally,Ni9.3 W alloy substrates with a cube texture content of ～90.0 vol%(<15°) are obtained by optimized two-step anneal.
The cube texture evolution of Ni-5 at%W alloy deformed up to a very high strain was thoroughly investigated by X-ray diffraction(XRD) and electron back-scattered diffraction(EBSD) during the process of deformation,recrystallization and grain growth.A typical copper-type rolling texture,mainly consisting of components of S,copper and brass orientations,is obtained after heavy cold rolling.The fraction of rolling texture is slightly strengthened during recovery and then strongly reduced during recry stallization process.The cube texture is formed by consuming the rolling texture components during the discontinuous recry stallization process.The cube grains have a size advantage with respect to the non-cube grains.A strong cube-textured Ni5 W alloy substrate with cube texture area fraction of 98.2 %(<10°) is obtained after annealing at 1050℃ for 1 h.The full width half maximum(FWHM) values for the X-ray(111) φ-scan and the(002)ω-scan of this substrate are 5.84° and 4.76°,respectively.Furthermore,the area fraction of {001}(110) orientation of the epitaxially grown La_(2)Zr_(2)O_(7) buffer layer is 97.1 %(<10°),and the FWHM values of(111) φ-scan and(002)ω-scan are 5.22° and 5.00°,respectively.
Pan WangHui TianHong-Li SuoCheng RenYa-Ru LiangLin MaMin Liu
