High-Resolution Digital Image Correlation study of the strain localization during loading of a shot-peened RR1000 nickel-based superalloy

Abstract The improved crack nucleation resistance of shot-peened materials has been usually studied from the point of view of the residual stresses. However, experimental limitations have made difficult to quantify strain localization during further deformation. In this study, we have used high-resolution digital image correlation (HRDIC) and electron backscatter diffraction (EBSD) in a large area covering shot-peened material and bulk to study quantitatively the strain distribution at the submicron scale. We found that, at the earlier deformation steps (e 2.5%), the strain distributions become similar along the material simultaneously to the residual stresses relaxation. A further analysis of the HRDIC maps allowed for the first time to quantify strain heterogeneity. This study reveals the importance of the local stress state and the strain history on the strain localization during loading of peened materials.