First-principles investigation of grain boundary morphology effects on helium solutions in tungsten

Helium solutions at eight symmetric tilt grain boundaries (GBs) in tungsten (W) have been investigated through first-principles calculations. The GBs are constructed by the coincidence site lattice (CSL) model and all interstitial sites at GBs are identified with convex deltahedra. For each GB, helium atom prefers to dissolve in interstitial sites with the lowest charge density. Interactions between the helium atom and the GBs atoms are rather...