New opportunities for quantitative tracking of polycrystal responses in three dimensions

An important advance in understanding the mechanics of solids over the last 50 years has been development of a suite of models that describe the performance of engineering materials while accounting for internal fluctuations and anisotropies (ex., anisotropic response of grains) over a hierarchy of length scales. Only limited engineering adoption of these tools has occurred, however, because of the lack of measured material responses at the length scales where the models are cast. Here, we demonstrate an integrated experimental capability utilizing high energy X-rays that provides an in situ, micrometer-scale probe for tracking evolving microstructure and intergranular stresses during quasi-static mechanical testing. We present first-of-a-kind results that show an unexpected evolution of the intergranular stresses in a titanium alloy undergoing creep deformation. We also discuss the expectation of new discoveries regarding the underlying mechanisms of strength and damage resistance afforded by this rapidly developing X-ray microscopy technique.