Effects of Helium on Void Swelling Behavior of Vanadium Alloys Using Dual Ion Beam Irradiation

Abstract

In previous experiments we utilized irradiation in FFTF/MOTA (Fast Flux Test Facility / Materials Open Test Assembly) to investigate the swelling behavior of vanadium alloys and have applied the boron-doping technique to study the effect of helium. In this study, dual ion beam irradiation experiments were carried out to distinguish the helium effect from the chemical effect of dopant boron on the swelling behavior of vanadium alloys containing undersized atoms such as iron that are known to eliminate the swelling resistance to void swelling of vanadium alloys. Displacement damage by nickel ions without simultaneous helium implantation makes nucleation of cavities occur near grain boundaries rather than in the matrix in V and V-5Fe. The simultaneous implantation of helium ions strongly assists nucleation of cavities in the matrix to form a uniform distribution of cavities in the matrix of both V and V-5Fe. Boron additions also affect the swelling behavior of these alloys.