Abstract
The evolution of dislocation structures during cyclic plastic loadings is investigated. The loading paths of cyclic plastic loadings conducted in this study are tension-compression, torsion, cruciform, and circular loading under constant strain amplitudes. The dislocation structures of the specimens after the cyclic loadings are observed by Transmission Electron Microscope (TEM). The meso-structures, the dislocation structures of five neighbourhood grains, are also observed to verify the inhomogeneity of deformation of polycrystalline metals. Finally the relationships between cyclic plastic loadings and the evolution of dislocation structures are discussed.