Simulation of Helium Behaviour in Titanium Crystals Using Molecular Dynamics

The behaviour of helium in Ti crystals at 300K has been investigated by means of the molecular dynamics. The study is focused on the influences of He--Ti interaction on the aggregation of helium atoms in the substrate. When a Born--Mayer potential is used to describe the He--Ti interaction, the He atoms are unable to cluster with each other due to the weak bridge barrier that cannot trap the helium atoms, Whereas using a He--Ti potential that is constructed by fitting the ab initio pairwise He--Ti potential, the clustering of He atoms can be observed. The results indicate that suitable He--Ti potential plays an important role in the formation of He clusters in metals. Moreover, it is noted that the shape of the formed He cluster is irregular, and the produced defect prefers to congregating on one side of the He cluster rather than spreading symmetrically around it.