INFLUENCES OF DISPERSED LANTHANUM OXIDE ADDITIVE ON THE PROPERTIES OF TUNGSTEN-BASED PLASMA-FACING MATERIAL

摘要

To investigate the influences of dispersed lanthanum oxide (La_2O_3) additive on the properties of a tungsten (W)-based plasma-facing material, ultrafine-grained W-1% La_2O_3 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 micro-hardness, 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 La_2O_3 additive as second-phase particles being dispersed in W-based plasma-facing material degrades the material resistance ability under plasma heat loading.