Microstructural study of hydrogen-implanted beryllium

Hot pressed beryllium (TGP-56) was implanted by 650 keV H+ ions to a dose o f 6.7 x 10(16) cm(-2) at a temperature below 50 degrees C. TEM examinations were performed both at as-irradiated specimens and after post-irradiation annealings at 400-600 degrees C for 15 min. After irradiation, a high densi ty of "black dot" defects with a size of about 5 nm is observed in the stra ggling zone, some of which are resolved as small dislocation loops. During post-irradiation annealing, growth of dislocation loops and oriented gas-fi lled bubbles are observed in the damaged zone. The bubbles are strongly elo ngated along the [0 0 0 1] direction, and their sidelong facts lie along {1 -1 0 0} planes. These facets have a regular "toothed" surface with "tooth" facets on {1-1 0 0} planes. The size of the "teeth" increases with annealin g temperature, as well as the total volume of bubbles, with their length gr owing faster than their width. (C) 1998 Elsevier Science B.V. All rights re served.