Transmission Electron Microscopy Study of Cascade Collapse in Copper During in- Situ Ion- Irradiation at Elevated Temperatures

Abstract

The basic mechanisms driving the collapse of point defects produced in collision cascades are investigated by transmission electron microscope (TEM) characterization of defect microstructures produced in fcc-Cu irradiated with low-fluences of heavy (100 keV Kr) ions at elevated temperature (23–600°C). Areal defect yields are determined from direct TEM observation of the total defect production integrated over the duration of the in-situ ion-irradiation. They are unequivocally demonstrated to decrease with increasing lattice temperature. This decrease in defect yield indicates a proportional decrease in the probability of collapse of cascade regions into defects of size where visible contrast is produced in a TEM.