关键词: 铜单晶, 共轭双滑移, 循环形变, 位错结构, SEM-ECC技术, 晶体取向

Abstract: The dislocation structures in cyclically saturated copper single crystals oriented towards [2¯23] and [1¯12] conjugate double slip were observed and analyzed using electron-channelling contrast technique in scanning electron microscopy (SEM-ECC). It was found that the persistent slip bands (PSBs) might exhibit different dislocation features depending upon crystallographic orientation, such as ladder structures in the [1¯12] crystal and irregular or partially regular cell structures aligned along the primary slip plane in the [2¯23] crystal. Moreover, the dislocation microstructures in deformation bands (DBs) formed in the [2¯23] crystal were observed comprising irregular dislocation walls and cells. For the crystals located on the [001]-[1¯11] side of the standard stereographic triangle, the dislocation structures change regularly with the variation in crystallographic orientation. When the orientation varies from the [1¯12] orientation to [1¯11] or [001], the dislocation structures would evolve from PSB ladders as cells or labyrinths.