In operando 3D mapping of elastic deformation fields in crystalline solids

Revealing the distribution of elastic deformations in anisotropic solids is of crucial importance for evaluating the mechanical performance of complex materials. However, elastic deformation fields (EDFs) need to be investigated under applied loads and in 3D, so they are often limited to planar approaches or simplifying assumptions. Here, we introduce 3D-RISM, a method by which the 3D spatial distribution of EDFs can be mapped in operando and with submicron resolution in laser-translucent materials. Taking examples of geological and biological ceramics, we visualize the 3D distribution and stepwise development of anisotropic EDFs under Hertzian contacts. We leverage our method to showcase how the anisotropy of elastic behavior regulates the distribution of induced plasticity and the direction of microcracking in crystals. 3D-RISM offers a promising platform for real-time mapping of deformation tensors in complex materials and devices, opening new avenues for better understanding the behavior of materials with azimuthal anisotropy in Poisson's ratio.