Research Progress on Preparation and Service Properties of Plasma-Facing Self-passivating Tungsten Alloys

Tungsten is considered as one of the most promising candidates for plasma-facing materials in future nuclear fusion devices due to its merits of high melting point, high thermal conductivity, low sputtering rate and low deuterium/tritium retention. However, tungsten has poor oxidation resistance. In the event of the loss-of-coolant accident accompanied by vacuum chamber rupture, tungsten rapidly oxidizes and sublimates, exposing the fusion device to the risk of radioactive material leakage. Solving the problem of high-temperature oxidation resistance from improving tungsten materials and enhancing surface protection is of great significance for fundamentally solving the safe operation of nuclear fusion devices. For this purpose, the concept of self-passivating tungsten alloys is proposed. The high-temperature oxidation characteristics and antioxidation strategies and mechanisms of tungsten are introduced. The preparation methods of self-passivating tungsten alloys are described. The anti-oxidation strategies of self-passivating tungsten alloys are analyzed from the aspects of composition and microstructure. The service properties such as mechanical, thermal and irradiation properties of self-passivating tungsten alloys are reviewed, and the future research directions are proposed.