Low-magnetism or magnetism-free and high-strength Ni-W alloy composite base band and preparation method thereof

Abstract

The invention provides a low-magnetism or magnetism-free and high-strength Ni-W alloy composite base band and a preparation method thereof, belonging to the technical field of a high-temperature super-conductive coating conductor texture metal base band. According to the Ni-W alloy composite base band disclosed by the invention, a surface layer is a Ni-W alloy with high W content and the atom percentage content of the W is 7.5-9.3%; and a core layer is a nickel-tungsten alloy with the tungsten atom percentage content of 9.3-12%. The preparation method comprises the following steps of sequentially placing a high-W-content Ni-W alloy blank ingot (A) which is prepared by a smelting method and has the atom percentage content of the W of 7.5-9.3%, and Ni-W mixed powder (B) with the atom percentage content of the W of 9.3-12% into a mould according to the sequence of A-B-A; utilizing a discharge plasma sintering technology to sinter to obtain a composite blank ingot; then, carrying out hot rolling and carrying out cold rolling treatment on a hot rolling blank ingot; and then, crystallizing and annealing, carrying out cold rolling to obtain the composite base band, and re-crystallizing and annealing the base band under the protection of Ar / H2 mixed gas to obtain the Ni-W alloy composite base band. The composite base band has the advantages of high strength, low magnetism or no magnetism and strong cubic structure, and can further meet the requirement of further improving the performance of an YBCO (Yttrium Barium Copper Oxide) coating conductor.

Description

technical field [0001] The invention relates to a low or non-magnetic, high-strength Ni-W alloy composite substrate and a preparation method thereof, belonging to the technical field of high-temperature superconducting coating conductor textured metal substrates. Background technique [0002] With the improvement of the performance of high-temperature superconducting materials and the continuous progress of refrigeration technology, as well as its inherent superior physical properties, high-temperature superconducting technology will be increasingly applied to various fields of our lives, such as electricity, transportation, transportation, magnets technology, military, etc. In 1996, Amit Goyal et al. of Oak Ridge National Laboratory in the United States obtained a metal substrate with a sharp biaxial texture through a process of large-scale rolling of pure nickel and subsequent recrystallization annealing, and then layer by layer on the metal substrate. The epitaxial growt...

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Problems solved by technology

The preparation technology of the baseband is the key to the RABiTS technology. Pure nickel can easily form a strong cubic texture, but pure nickel is ferromagnetic, which will cause hysteresis loss in the application of alternating current, and the yield strength is also low, which cannot meet the high temperature requirements of YBCO. In the production and application of coated conductor strips, people later solved the above problems through the idea of ​​solute solid solution. NiW alloy base strip is the most widely studied alloy base strip. At present, the preparation of Ni-5at.%W (Ni5W) alloy base strip The process is very mature and has been commercially produced, but because its Curie temperature is 330K, it has ferromagnetism (under T=77K), and its yield strength is not very high, which can only meet some applications of high-temperature coated conductors. As the W atomic content increases, the yield strength of the alloy base strip increases, and the magnetic properties also decrease. When the W atomic percentage reaches 9.3%, the alloy base strip is non-magnetic at 77K, but when the W atomic percentage is greater than 5%, it passes It is difficult to obtain strong cubic texture by traditional large deformation cold rolling and recrystallization annealing

In order to prepare a high-strength, low / non-magnetic alloy substrate, Germany adopted the casing method in 2004 (see the document Trans. Indian Inst. Met. Vol.57, No. 6, December 2004, pp. 651-657), namely Ni -5%W is used as the sheathing material, and the high-strength, non-magnetic Ni-10%W rod is inserted into the sheathing material as the core material, and the composite ingot is obtained by hot rolling. It is easy to crack during the cold rolling process, the recrystallization process of the base strip is seriously affected by the properties of the inner and outer layer materials, and the processing technology is more complicated, and the length of the strip is also limited to a certain extent

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