TEM investigation of multidirectionally deformed copper

Polycrystalline samples of Cu 99.95% were deformed by equal channel angular (ECA) pressing by rotating the sample after each pass and by subsequent compression or combined compression torsion. The resulting microstructure was analysed by TEM methods. In case of pure ECA deformation the grain sizes remain unchanged with the number of passes; the misorientation of the grains increases and the distribution of grain sizes gets narrower. When applying additional deformations subsequent to ECA pressing both grain sizes and the number of adjacent grains with large misorientations increase. The changes in distribution of grain sizes depend on the mode of deformation following the ECA deformation.