Strain-induced folding on [1(1)over-bar(1)over-bar]-copper single crystals under uniaxial compression

Using uniaxial compression we studied the mechanical instability by folded structure formation on initially smooth and plain faces of copper single crystals with deformation axis orientation along [1 (1) over bar(1) over bar]. These folded structures can be found within several zones on the crystal's faces after compression test. We classified the folds based upon their scale, localization, state of the interfold boundaries, presence and amount of the slip bands in the folds. Subsurface crystalline lattice reorientation by deformation banding has been found to be the reason for folded structures generation. We suggest that folds generated on the [1 (1) over bar(1) over bar]-single crystals under compression are the inherent surface relief components which denote the deformation processes occurring both in the subsurface and in the bulk of the sample. In view of that, they can be used for analyzing the deformation under compression along with other surface structural components. The main specificity behind the folded structure generation mechanism which differs them from other orientations is slipping by parallel octahedral planes in some specific local areas. (C) 2016 Elsevier B.V. All rights reserved.