Tungsten (W) and beryllium (Be) have been chosen as plasma-facing materials for the ITER reactor and the main fuel component will be deuterium (D). Due to plasma–wall interactions, these materials will immediately mix via erosion, transport and re-deposition. We present the first atomistic study on the effect of D co-implanted with Be into W, by modelling D plus Be irradiation of W surfaces, at projectile energies and compositions relevant for the plasma–wall interactions. The D implantation and Be sticking yields increased with the Be fraction in the system, especially at the lowest energies, as a Be layer was deposited on the surface. Tungsten was sputtered by Be, although the yield was partially suppressed by the deposited Be–D layer, and the Be erosion was determined by the balance between the Be concentration at the surface and projectile energy. Molecules were also sputtered: a large fraction of the D is reflected as D2, and purely metallic molecules (Be2, BeW) as well as different Be–D compounds were sputtered. On the other hand, the D clustered when implanted in or beneath a pre-deposited Be–W layer.
Effect of rhenium on defects evolution behavior in tungsten under irradiation