HIGH RESOLUTION ELECTRON MICROSCOPY OF RADIATION DEFECTS IN ORDERED ALLOYS INDUCED BY 1 Mev ELECTRONS.

Radiation defects induced by 1 Mev electrons in Zr//3Al, Au//3Cd and Au//3Mn have been investigated. For the Ll//2 type intermetallic compound Zr//3Al, the changes in contrast of superstructure images with electron irradiation suggest that replacement disordering occurs in atom rows parallel to the incident beam. Neither dislocation loops nor voids were observed in specimens damaged to 0. 5 dpa. In Au-Cd alloys, dislocation loops smaller than one nm in radius are identified at electron irradiation at 2 multiplied by 10**2**2 cm** minus **2. In Au-Mn alloys, dislocation loops are formed with preferential displacement of Mn atoms. The image contrast of irradiated Zr//3Al is discussed in comparison with images computated by the multislice method.