TEM INVESTIGATION OF THE MICROSTRUCTURAL EVOLUTION DURING MEV HELIUM IMPLANTATION IN COPPER

A report is presented on TEM investigations of the early stages of microstructural evolution during room temperature (T less than 100 degree C) He implantation in Cu. For c//H//e APP 1STH 0. 6 at% clustering of irradiation-induced Frenkel defects leads to the formation of dislocation loops and stacking fault tetrahedra. For 0. 6 APP 1STH c//H//e APP 1STH 3 at % the microstructure is dominated by a high density of small cavities resulting from the precipitation of the implanted helium. Of particular importance is the observation that two types of vacancy clusters, stacking fault tetrahedra and He-containing cavities coexist in this concentration range.