Fabrication and Characterization of W-Re-Os Alloys for Studying Transmutation Effects of W in Fusion Reactors

Abstract

Tungsten (W) is a candidate material for plasma-facing components in fusion reactors. Large amounts of solid transmuted elements of W such as Re and Os will be produced under fusion neutron irradiation. In order to investigate the effects of transmutation products, a series of W-Re-Os alloys were fabricated by an arc melting method. The nominal compositions of these samples were selected based on theoretical predictions of changes in chemical composition for the transmutation of W to Re and Os. Significant hardening, an increase in electrical resistivity and changes in the lattice constant were observed as a function of the Re and Os content. Microstructural observations revealed the existence of the σ phase precipitate, which did not significantly affect physical properties and hardness compared with solid solution effect. The main objectives of this work were to demonstrate the processes of material fabrication and to study unirradiated material properties.