Journal Article Gaussian process regression X-ray computed tomography additive manufacturing diffraction analysis elastic strains ferroelectrics fracture grain morphology granular materials heat-transfer and fluid-flow modeling high-energy X-rays in situ laser melting machine learning modeling nanodiffraction polycrystalline solids rotations slip system activity slip systems strain stress superalloys synchrotron X-ray diffraction temperature-distribution metrics thermomechanical stress thin films three-dimensional X-ray diffraction