Characterization of high energy Xe ion irradiation effects in single crystal molybdenum with depth-resolved synchrotron microbeam diffraction

• Microbeam X-ray diffraction experiments were conducted on fission fragment energy Xe ion irradiated single crystal Mo.
• Lattice strain measurements were obtained with a depth resolution of 0.7 μm.
• From the measurements, it is observed that lattice strain decreases with increasing irradiation damage.
• The evolution from individual dislocation loops to dislocations and then to a dislocation network is thought to lower the lattice strain.
• MD simulations were also performed to help interpret the lattice strain measurement results from the experiment.

Microbeam X-ray diffraction experiments were conducted at beam line 34-ID of the Advanced Photon Source (APS) on fission fragment energy Xe heavy ion irradiated single crystal Molybdenum (Mo). Lattice strain measurements were obtained with a depth resolution of 0.7 μm, which is critical in resolving the peculiar heterogeneity of irradiation damage associated with heavy ion irradiation. Q-space diffraction peak shift measurements were correlated with lattice strain induced by the ion irradiations. Transmission electron microscopy (TEM) characterizations were performed on the as-irradiated materials as well. Nanometer sized Xe bubble microstructures were observed via TEM. Molecular Dynamics (MD) simulations were performed to help interpret the lattice strain measurement results from the experiment. This study showed that the irradiation effects by fission fragment energy Xe ion irradiations can be collaboratively understood with the depth resolved X-ray diffraction and TEM measurements under the assistance of MD simulations.