X-ray Strain and Stress Tensor Tomography

The microscopic distribution of strain and stress plays a crucial role for the performance, safety, and lifetime of components in aeronautics, automotive and critical infrastructure [1]. While non-destructive methods for measuring the stress close to the surface have long been long established, only a limited number of approaches for depth-resolved measurements based on x-rays or neutrons are available [2]. These feature significant limitations, including long scan times, intricate experimental set-ups, limited spatial resolution or anisotropic gauge volumes with aspect ratios of 1:10 or worse. Here, we present a method that overcomes these limitations and obtains tomographic reconstructions of the full six-dimensional strain and stress tensor components. Using a simple and wide spread experimental set-up that combines x-ray powder diffraction with single axis tomography, we achieve non-destructive determination of depth-resolved strain and stress distributions with isotropic resolution. The presented method could be of interest for additive manufacturing of metals [3,4], battery research [5], in-situ metallurgy [6] and the experimental validation of finite element simulations [7].