Molecular dynamics study on the origin of fuzz structure on tungsten surface

Abstract Molecular dynamics was used to investigate the migration of He–V cluster and the irradiation of He on W(110) surface. Our research shows that the He-V complex can still move in the microsecond scale and tend to migrate to the surface. The formation of tungsten surface fuzz comes from two synergistic factors. On the one hand, the self-interstitial dislocation loop produced during the growth of helium bubbles annihilate at the surface and form adsorbed atoms, which leads to the formation of protrusions on the surface and increases the surface area; On the other hand, the enlarged surface attracts helium bubble and accelerates the coalescence and rupture of helium bubbles near the surface, resulting in formation of holes on the surface, further roughening and enlarging the surface. With the increase of irradiation fluence, the height of protrusions continues to increase, eventually forming fuzz. This formation mechanism is considered reasonable due to it can explain many experimental phenomena.