Self-irradiation induced lattice constant tuning in lithium tritide

Abstract

The X-ray diffraction spectra of long-time aged LiD/T were examined by a XRD. The lattice constant, grain size and strain were all estimated from the X-ray diffraction patterns. The interface effect on the self-irradiation swelling of lithium tritide was studied by theoretical simulation and experimental observation. The results show that the lattice constant, grain size and strain of LiD/T samples with different self-irradiation aging time fluctuate in different degrees. 3He atoms produced by tritium decay tend to diffuse to the grain boundaries. With the self-irradiation aging time increasing, interface proliferation appears in lithium tritide. In the same self-irradiation aging time, the cracks on the surface of the intact LiD/T sample are easy to widen, while the prefabricated cracks in the sample are not easy to widen. In addition, the accumulation of 3He in the crystal results in the lattice constant growing, and the migration to the grain boundary of 3He leads to the lattice constant contraction. Internal stress leads to grain fragmentation and grain refinement.