Gold slows down the growth of helium bubble in iron
  We predict by first-principles calculations that Au have strong affinity to He in bcc Fe. The Au-Au bonding in the segregated Au layer at the He bubble surface is stronger than Fe-Fe and Au-Fe interactions; therefore this layer becomes an effective barrier to further He and slows down the bubble growth. 
W. Hao and W. T. Geng
cond-mat.mtrl-sci