SPATIAL VARIATION IN VOID VOLUME DURING CHARGED-PARTICLE BOMBARDMENT - EFFECTS OF INJECTED INTERSTITIALS

Experimental observations of the void volume at several depths along the range of 4 MeV Ni ions in 316 stainless steel are reported. The specimens were first preconditioned by neutron irradiation at temperatures of 450 and 584°C to fluences of approximately 8 × 1026 n/m-2. The void volume after ion bombardment to 60 dpa at the peak damage depth is significantly lower at the peak damage depth than in the region between that and the free surface. The ratio of the step height to void volume at the depth of peak energy deposition between regions masked from and exposed to the beam is strongly dependent on bombardment temperature. The reduction of void volume near the peak damage depth is larger for the 584°C than for the 450°C neutron irradiated material. These observations are consistent with recent theoretical results which account for the injection of the bombarding ions as self-interstitials. © 1979.