The energy of helium filled platelets and bubbles in molybdenum

Influence of dose rate on bubble formation by high energy He implantation in silicon

“…It has been found that under conditions of high internal pressure, a cluster of several bubbles has a lower total energy than one single large bubble. 27,28 This can be understood on the basis of elastic interactions between bubbles placed in a lattice, assuming that this is approximately the same in magnitude as for a void lattice. Thus, upon annealing platelets were first created and then transformed into planar clusters of bubbles.…”

Helium bubble formation in ultrafine and nanocrystalline tungsten under different extreme conditions

“…It has been reported that under high internal pressure, several small bubbles are a lower energy configuration than one single large bubble. 38 It might be expected that the grain boundaries, which are effective helium traps, 39 demonstrated how helium retention in the tungsten matrix decreases with increasing temperature. 19 If this process (helium migration to the surface) had a greater effect than the similarly-increased thermal vacancy production rate, then it will have lowered the number of bubble nucleation sites meaning a helium atom is more likely to escape to a surface or grain boundary before it is trapped in the matrix.…”

Dislocations induced by bubble formation in high energy He implantation in silicon

“…The determination of the cavity volume allows for the estimation of the pressure after the process, when bubbles have been relaxed. The He density in bubbles has been estimated by assuming that all the He is still in bubbles; that leads to 1.32ϫ10 23 He/cm 3 . The internal cavity pressure is then of 5 GPa using the MLB EOS of helium.…”

“…9 In fact, during annealing (Tу800°C), the platelets change into planar arrangements of spherical bubbles. Finnis et al 23,24 found that the spherical bubble is always the preferred configuration and that under conditions of high internal pressure, a cluster of several bubbles has a lower total energy than one single large bubble. This can be understood on the basis of the elastic interactions between bubbles placed on a lattice, if one assumes that this is approximately the same in magnitude as for a void lattice.…”