Abstract
Variation of the image position of the loop dislocation with the change in diffraction condition indicates that the dislocation loops formed in aluminum by electron irradiation in a high voltage electron microscope at room temperature or above may be identified to be of interstitial type. This result is confirmed by comparison of the weak and strong contrast from the stacking fault of irradiation induced loops with that of quench induced vacancy type dislocation loops. Quench induced vacancy type dislocation loops shrink and disappear by electron irradiation, and their absorption of interstitial atoms suppresses the formation of irradiation induced interstitial type loops. The upper limit of temperature for loop formation depends on irradiation intensity, and is about 160°C for 2×1019 electrons/cm2·sec at 1000 kV. Enhanced formation of interstitial loops is observed on both intrinsic and extrinsic stacking faults which suggests the existence of attractive interaction between the fault and interstitial atoms.
