Quantification of local dislocation density using 3D synchrotron monochromatic X-ray microdiffraction

A novel approach evolved from the classical Wilkens' method has been developed to quantify the local dislocation density based on X-ray radial profiles obtained by 3D synchrotron monochromatic X-ray microdiffraction. A deformed Ni-based superalloy consisting of gamma matrix and gamma ' precipitates has been employed as model material. The quantitative results show that the local dislocation densities vary with the depths along the incident X-ray beam in both phases and are consistently higher in the gamma matrix than in the gamma ' precipitates. The results from X-ray microdiffraction are in general agreement with the transmission electron microscopic observations. IMPACT STATEMENT A new approach based on 3D synchrotron microdiffraction showing broad application potential in heterogeneous materials was developed and applied to quantify local dislocation densities in a fatigued two-phase Ni-based superalloy.

Automated summary

A novel approach based on the classical Wilkens' method has been developed to quantify the local dislocation density using X-ray radial profiles obtained by 3D synchrotron monochromatic X-ray microdiffraction. The results show that the local dislocation densities vary with depths along the incident X-ray beam in both phases, with consistently higher densities in the gamma matrix than in the gamma ' precipitates. The new method shows broad application potential in heterogeneous materials and was applied to quantify local dislocation densities in a fatigued two-phase Ni-based superalloy.