The Effect Of Ag On The Texture Formation And Morphology Of Ni-7at.%W Alloy Substrate

The second generation of coated superconductors,represented by YBCO,have a wide range of applications in electromagnetic field due to their higher irreversible field and stronger current carrying ability.Ni-W alloy has obvious advantages in oxidation resistance and lattice matching with superconducting layer,and is one of the commonly used textured metal substrates for YBCO superconducting wire.In recent years,it has been found that Ag can control the grain morphology of Ni-W alloy substrates with low W content(<5at.%W),and the elongated grains can significantly improve the current transmission ability of superconducting materials.If Ag can achieve the same optimization effect in high W alloy substrates,it will help to further broaden the research direction of Ni-W substrates.Therefore,this paper has carried out the research on the influence of Ag on Ni-7at.%W substrate.Based on the RABiTS route,the effect of Ag on the texture and grain morphology of the substrate was discussed,and the experimental results were further optimized through the discussion of the rolling intermediate recovery annealing process.The innovative research results are as follows:It is found that Ag can reduce the content of s-orientation in Ni-7at.%W,and then affect the formation of recrystallized cube texture in substrate.The deformation factor R of cold-rolled substrate can be increased from 0.72 to 1.05 and the content of copper texture can be increased by introducing the intermediate recovery annealing of 550? for 2 hours when the rolling deformation is 95%.The orientation of cube increases by 65%,which is beneficial to the nucleation rate of recrystallized cube texture.Finally,after recrystallization annealing,the substrate of Ni-7at.%W-100ppmAg alloy with 97%cube texture content.The content of grain aspect ratio between 0.4-0.6 was 35%,and the content of small-size grain was more than 10%higher than that of Ni7W.Based on the research of substrates deformation,recovery and recrystallization structure,this paper analyzes the influence mechanism of Ag on Ni7W,and obtains the best amount of Ag,which is further extended to the optimization of substrate texture and morphology.The research results of Ni7W-Ag alloy from the experiment lay a theoretical foundation and experimental ideas for the preparation of high-performance coated conductors in the future.