Void Swelling in Molybdenum Alloys In Situ Observed by a High-Voltage Electron Microscope

As a simulation of neutron radiation damage, in situ observations were made by a 1250-kV high-voltage electron microscope (HVEM) with the specimens heated to 1350 K. The objective of this study is to clarify the elemental process of void swelling, the effect of preinjected helium, and the effect of rhenium addition on void swelling in molybdenum alloys. Dose dependence and temperature dependence of void swelling were analyzed by the linear after-incubation-swelling model. Helium preinjection made the in situ HVEM experiment more effective as a simulation experiment of fusion reactor and fast breeder reactors. Rhenium addition was very effective in suppressing void swelling in molybdenum alloys and in shifting slightly higher the peak swelling temperature.