NUCLEATION AND GROWTH OF AR BUBBLES ON CU GRAIN-BOUNDARIES

Bubble formation and growth on grain boundaries under Ar ion implantat ion were investigated using Cu bicrystals which have symmetric [0, 1, 1] tilt boundaries. Density and growth rate of bubbles increase with g rain boundary (GB) energy which is determined from the lenticular shap e of bubbles on the grain boundary. These results show that the fluenc e of Ar as solutes into GB increases with GB energy increase, because the solute is easy to precipitate on high energy GB. On the other hand point defect inflow to the GB does not depend on GB energy. The origi n of the difference of these phenomena between solutes and point defec ts is thought to be as follows: Solute atoms remain on the GB but poin t defects disappear when they are absorbed on the GB.