Ta - 2.5 W Alloy In Cold Rolling Deformation And Annealing The Structure And Texture In The Process Of Evolution

The Ta-2.5W alloys were fabricated by powder metallurgy technology. Through cold rolling technology, we obtain different cold rolling reduction of Ta-2.5W alloy plates which were annealed at different temperature for1h. The structure and properties of these plates were investigated by the optical microscope (OM), X-ray diffraction (XRD), SEM, EBSD and TEM. The conclusions were obtained as follows:1. In order to obtain suitable microstructure for further cold-rolled, the proper technology of producing Ta-2.5W plates is90%cold-rolled reduction+annealing at1080℃for1h.2. As the cold-reduction increases, the deformation texture intensity of Ta-2.5W plates is improved gradually, the main texture components are a-fibre and y-fibre; Meanwhile, the density of dislocation of different orientation increases irrespectively, the sequence of the density of dislocation is{200}<{211}<{222}<{110}.3. The deformation structure and process in different orientation grains are quite different during the cold-rolled process. Usually, compared with y-fibre, the deformation structure in a-fibre is more homogenous, the typical deformation structure in{001}<110> is equiaxial cell structure, while a set of long straight GNBs are formed in y-fibre grains which can cause the anisotropic microstructure and property.4. The type of texture in Ta-2.5W plates does not change during the annealing process. When annealing under1080℃, the density of {001}<110> orientation increases and the intensity of γ-fibre decreases as the increase of temperature; When annealing at1080℃for1h, the intensity of a-fibre reaches a maximum value, while y-fibre reaches a minimum value. When annealing above1080℃, the intensity of a-fibre orientation decreases and the intensity of γ-fibre increases as the temperature increases, meanwhile, the intensity of{111}<112> orientation is higher than that of{111}<110>.5. When annealing temperature is lower than1080℃, the γ-fibre grains recrystallize faster than a-fibre, especially the grains with{001}<110> orientation, which are increased during this process.