Influences of Dispersed Lanthanum Oxide Additive on the Properties of Tungsten-Based Plasma-Facing Material

To investigate the influences of dispersed lanthanum oxide (La₂O₃) additive on the properties of a tungsten (W)-based plasma-facing material, ultrafine-grained W-1% La₂O₃ composite has been successfully fabricated using the resistance sintering under ultrahigh pressure method, which can suppress W grain growth during sintering processes. Its relative density, Vickers microhardness, microstructure, and thermal conductivity have been analyzed and compared with those of pure W. Moreover, its behaviors under fusion-related conditions, i.e., edge plasma loading in the HT-7 tokamak and transient heat flux simulated by a high-intensity pulsed ion beam, have been evaluated. It is shown that without the fine-grain strengthening effect of dispersed particles, the La₂O₃ additive as second-phase particles being dispersed in W-based plasma-facing material degrades the material resistance ability under plasma heat loading.