INERT-GAS BUBBLES

Nuclear reactions result in inert gas bubbles appearing in the microstructure of metals and alloys and this can have a profound influence on, for example, mechanical properties. For this reason, bubbles have been extensively studied within the nuclear industry and much progress has been made in understanding their behavior. However, significant advances have also been made within academia. It has been shown previously that Brownian motion of gas bubbles does indeed occur on annealing, leading to bubble coarsening. There have been examples where the pressure inside the bubbles has been so high that the atoms become so close together that the 'gas' takes on some of the properties of a solid. In such circumstances, the rate of migration of the bubbles is greatly diminished. The development of bubble growth mechanism maps is described.