Creep and dislocation structure in copper single crystals compressed in directions [010], [110] and [111]

The paper presents creep curves of copper single crystals of three crystallographic orientations, obtained at two applied stresses at each of the temperatures 773 and 873 K. The curves indicate a creep strength increasing in the sequence of the crystal loading axes [010], [110], and [111]. The effect of the crystal orientation can be correlated with the potential activity of slip systems estimated from the Schmid factors. The slip lines usually indicate an activity of less systems than the Schmid factor values suggest. Buckling of the specimens in compressive creep is connected with an inhomogeneity and asymmetry of slip. This is probably also a reason of the fact that the observed dislocation structures contain all types of dislocations including those which should not be active under the applied uniaxial load. (orig.)