The inclusion and role of micro mechanical residual stress on deformation of stainless steel type 316L at grain level

Validating crystal plasticity models requires careful consideration of all aspects. The initial conditions are important when comparing a model and experiment, as the initial residual stresses within the material can be significant but are often overlooked due to experimental limitations. Therefore, their inclusion has the potential to improve model predictions. This work explores the efficacy of using type-III residual elastic stresses, measured using high resolution electron backscatter diffraction (HR-EBSD),as pre-test stress distributions in 316L stainless steel. Two methods of processing the stresses collected (direct and using a least squares solver) were used. A existing method was used to incorporate the experimental measurements as initial residual stresses; The model results were compared with each other, a model containing no residual stress and the experiment. The least squares method helped remove extreme stresses calculated by the cross-correlation method at points with high mean angular error. The modelled stress distributions from both the direct and least squares model did not fully match the experimentally observed stresses but similarities were seen within some grains.

After loading, little difference was seen between the models, with and without the inclusion of residual stress, implying a negligible effect on the deformation response of the material. However, the predicted stress distribution did not match with the experimentally measured stress distribution after deformation, suggesting further physical effects must be accounted for in crystal plasticity models.