Microstructure And Texture Of Niobium Plates/Foils Fabricated By Different Rolling Methods

Niobium is a high-melting metal, and widely used in modern industry as structural material and functional material, just like electronic industry, chemical industry, atomic energy industry, aerospace industry, thin film technology, superconducting technology and so on. Its performance is affected by microstructure and texture of the niobium plate and niobium foil. The microstructure and texture of pure niobium plates/foils which were rolled and vacuum annealing in different temperature were studied by orientation distribution function and microstructure analysis. The texture transformation of niobium plates/foils was analysed by recrystallization model proposed by D N Lee. The main results of the present work can be summarized as follows:(1) Rather strong{001}<110> texture can be developed by the cross-rolled, After the annealing, a stronger{111}<uvw> texture together with weaker{001}<100> texture is developed in the cross-rolled foils.A stronger{001}<100> texture is developed in the other methods except cross-rolled. The deformation textures{111}<110> can not be strengthened after being processed by the four different cold-rolled methods, While the textures{111}<110> can be strengthened by annealing. Higher annealing temperature can weaken the a-fiber to enhance the uniformity of the materials.(2) The recrystallization temperature of niobium plates/foils reduce gradually by the increase of the deformation.When the deformation is80%and850℃/1h annealing, the size of the grains was27μm. When the deformation is80%, the recrystallization temperature of niobium plates/foils is about750℃, after the1150℃/1h annealing, the size of the grains was9μm.(3) A model of the recrystallization texture in body centered cubic metals proposed by D N Lee was applied to explain the20°-<110> relationship from niobium deformation textures and recrystallization textures. (4) The niobium plate form the lamellar structure after the switch rolling, which is different from the fibrous structure.The switch rolling can reduce the deformation texture{001}<110> effectively, the texture uniformity of niobium plate is better than the other two rolling methods. The switch rolling and dragon rolling can develop the texture {001}<100}<100> and...