Three-dimensional investigation of long-range internal stresses in a single crystal deforming by nonsymmetrical slip

Long-range internal stresses (LRIS) are investigated in a [112]-oriented tensile-copper single crystal. The three-dimensional investigation of asymmetric X-ray profiles, measured by a high resolution diffractometer and using all Bragg reflections, allows the determination of the full long-range strain tensor. The corresponding stress tensor, determined by the generalized Hooke’s law, reveals a complicated behavior inconsistent with a uniaxial stress state in the [112] direction. It reveals, instead, a principal stress axis in the [001] direction. This stress state is different from the applied stress state predicted by numerical simulations of the tensile test. The LRIS and applied stresses are both deviated from the initial tensile axis in two opposite directions. An interpretation of these results is proposed in this article, taking into account active slip mechanisms and the geometrical contrast of interface dislocations introduced in the composite model of Mughrabi.