ELEVATED-TEMPERATURE IMPLANTATIONS OF AU INTO ZR

Polycrystalline Zr samples were implanted with 200 keV Au ions at several temperatures between 295 and 790 K to a dose of 5 x 10(15)/cm2. The implanted Au distributions were analyzed with RBS. A strong dependence of the Au distribution on implantation temperature was found for temperatures greater-than-or-equal-to 450 K, in good agreement with previous studies of interdiffusion and ion-beam mixing in Au/Zr multilayer specimens. For implantation temperatures between 500 and 600 K, a narrowing of the implanted distribution and an increase in the peak concentration were observed. At implantation temperatures greater-than-or-equal-to 650 K, a substantial fraction of the Au migrated toward the implanted surface. Systematic shifts of the peak in the implanted distribution were also found. The effects observed at the higher temperatures can be understood qualitatively in terms of radiation-induced segregation (RIS) and radiation-enhanced diffusion (RED) becoming dominant. The combined effects of sputtering, RIS, and RED substantially reduce the fraction of Au retained at elevated temperature.