Difficulty of dislocation-punching from densely distributed high pressure bubbles

The dislocation punching mechanism for assessing internal bubble pressure, due to Greenwood et al, is criticized. The formalism has been modified by adding lateral stress field due to bubble swelling and the thermodynamic osmotic pressure due to radiation induced vacancy supersaturation. This gives a necessary punching pressure of more than three times that of Greenwood's estimation during the implantation of aluminium by hydrogen ions. (author)