RADIATION-DAMAGE OF ALPHA-AL2O3 IN THE HVEM .2. RADIATION-DAMAGE AT HIGH-TEMPERATURE AND HIGH-DOSE

Single-crystal α-Al2O3 has been irradiated with 1 MeV electrons in a high-voltage electron microscope at several fixed temperatures in the range 320-1070 K. The ensuing radiation damage features were monitored during the course of the irradiation using transmission electron microscopy and selected area diffraction measurements. At 770 K and below the nature of the observed damage could not be resolved. At 870 K and above island-like surface features rapidly formed followed by dislocations which grew to form a dense network. After high doses (>10 dpa) precipitates were observed. The associated diffraction patterns and their temperature dependence suggested that the precipitates were of aluminium metal. © 1979.