Surface Relief and Dislocation Structure in Fatigued Copper Single Crystal

Abstract

Copper single crystals oriented for single slip were cyclically strained with constant plastic strain amplitude up to fracture. The surface relief and internal dislocation structure of the persistent slip macrobands were studied using direct observation in the scanning electron microscope, interferometry and transmission electron microscopy. The height of the protrusions was found to be approximately proportional to their width. Two types of the internal dislocation structure in the macroband, i.e. closely spaced ladder structure separated by thin sheets of the matrix and cell structure bounded by the ladder structure at the interface to the matrix were found. These findings were discussed using the recent model of surface relief evolution in cyclic straining.