Evolution Mechanism Of Recrystallization Microstructure And Texture Of Pure Copper Sheet Under A High Magnetic Field

In recent years, the strong magnetic field is more and more applied in metal heat treatment process, which is becoming a new research direction. The research work in this area can not only seek a new approach for the preparation of anisotropic metallic materials, but also provide a theoretical basis for the texture of the material designing and property controlling. At the same time, the research results can reveal the basic physical phenomena and rules obtained from preparation and service of materials under extreme conditions. In addition, it can also broaden and deepen the realization of the law of microstructure and texture formation and evolution in metal solid phase transformation and recrystallization process. Therefore, it is important to carry out the metal-solid phase transitions and recrystallization microstructure and texture research in strong magnetic field, which is of theoretical significance and potential practical value.In the present study, the pure copper sheet was selected as the guinea-pig. High magnetic field was applied during the different kinds of heat treatments. Macrostructures、 Microstructures and microhardness of the magnetically treated samples were examined by the conventional methods, and texture was investigated by XRD and EBSD analysis, respectively. Based on the experimental results and comparisons with the samples treated without magnetic field, the effects of magnetic field on microstructure and texture evolution were studied, and discusse the action of the grains orientation when playing the magnetic field along the samples’ rolling direction and transverse direction, respectively.Samples of the pure copper sheet were annealed at 240℃ holding for different time (10min,20min,30min,60min, and 120min) with and without a high magnetic field of 12T. During the magnetic field annealing, the magnetic field was applied along the samples’ rolling direction and transverse direction, respectively. The XRD results showed that the intensity value of the cube texture of samples with magnetic field is higher than without it. Compare with the samples without magnetic field, the XRD results showed that magnetic field annealing promoted the development of recrystallization. The EBSD results revealed, first, the Percentage of the small recrystallized grains with a high magnetic field is higher than the samples without it. It is attributied that magnetic field annealing has a tendency of promoting the recrystallization nucleation; Area percentage of recrystallized regions in samples annealed at 240℃ for different time with magnetic field is higher than without it; And when applying the high magnetic field, the strength of cube texture is higher than without it. With the rise of holding time, the grain size grew gradually, there are more and more annealing twins when applying magnetic field, which lead to the proportion of the∑3 twin crystal boundaries is higher than without it.Samples of the pure copper sheet were annealed at 240℃ holding for different time (10min,20min,30min,60min, and 120min) with and without a high magnetic field of 12T. During the magnetic field annealing, the magnetic field was applied along the samples’ transverse direction and transverse direction, respectively. The XRD results showed that the intensity value of the cube texture of samples with magnetic field is higher than without it. Compare with the samples without magnetic field, the XRD results showed that magnetic field annealing promoted the development of recrystallization. The EBSD results showed that the Percentage of the small recrystallized grains with a high magnetic field is higher than the samples without it. It is attributied that magnetic field annealing has a tendency of promoting the recrystallization nucleation; Area percentage of recrystallized regions in samples annealed at 240℃ for different time with magnetic field is higher than without it; And when applying the high magnetic field, the strength of cube texture is higher than without it. With the increase of holding time, Frequencies of CSL boundaries of recrystallized grains in annealed samples with and without magnetic field have a quiet difference, the frequencies with magnetic field is higher than without it, and the proportion of small angle boundaries decreases, the proportion of the E 3 twin crystal boundaries is increases, it results in the percentage of medium grains and large grains with high magnetic field is lower than without it.And when the magnetic field was applied along the samples’ rolling direction, cube teture、area percentage of recrystallized regions and the ∑ 3 twin crystal boundaries in samples were higher than the results of when the magnetic field was applied along the samples’ transverse direction accordingly. The result show that the recrystallization is promoted by the applied magnetic field, and the value is better when applying the high magnetic field along the samples’ rolling direction than it along the samples’ transverse direction.