Relationship between stress and dislocation structure of fatigued polycrystalline copper

The relationship between the saturated stress and the dislocation structures in fatigued polycrystalline copper is quantitatively evaluated from region A to region C. It is revealed that the saturated stress is linearly related to the inverse spacing between the dislocation walls. The value of the coefficient K in the meshlength theory is determined to be equal to 7.89 and is in agreement with the value of 8 obtained from theoretical considerations. In addition, the relationship between the saturated back stress and dislocation structures is established. The saturated back stress is found to be half of the stress to bow out the dislocation from the dipolar walls. Furthermore, the stress in the PSB structures is examined. It is found that the meshlength theory provides a good prediction of the stress in the PSBs formed at room temperature.