The direct observation of point defects in irradiated or quenched metals by quantitative field ion microscopy7

Abstract. The progress made at Cornell University over the past few years in applying the field ion microscope (RM) technique to the study of point defects in irradiated or quenched metals is reviewed. The techniques involve essentially the atom by atom dissection of speci-mens by pulse field evaporation and the corresponding recording on film of the extensive number of RM images produced at each stage of the process. Methods have been developed which allow the recording and the analysis of as many as approximately 5 x lo5 frames of 35 mm cine film for a single investigation. The application of these techniques to the following problems were discussed: (i) the mobility of self interstitial atoms (SIA) in substage I, of irradiated tungsten and platinum, (ii) the geometric configuration of the SIA, (iii) the point defect structure of depleted zones in tungsten and (iv) the properties of monovacancies and divacancies in quenched platinum. 1