Comparison of Single Crystalline and Polycrystalline Behavior under High Pressure Torsion
By using techniques of severe plastic deformation a metallic material can be subjected to an enormous strain that is not achievable by conventional methods of deformation. In this study nickel single crystals with different crystallographic orientation and nickel polycrystals were deformed by high pressure torsion. All nickel samples were processed up to the evolution of a saturation microstructure where no further hardening of the material can be observed. In this region all samples develop a similar microstructure and micro-texture. The differences in the fragmentation of the microstructure and the micro-texture development between the single crystals and the polycrystalline aggregate were examined using EBSD. A major difference between single crystals and polycrystals was not only the microstructure evolution at low equivalent strains, but also the development of a stable micro-texture, which is achieved earlier by the use of a polycrystalline aggregate.
P. B. Prangnell and P. S. Bate
M. Hafok and R. Pippan, "Comparison of Single Crystalline and Polycrystalline Behavior under High Pressure Torsion", Materials Science Forum, Vol. 550, pp. 277-282, 2007