Isotropic thermal conductivity in rolled large-sized W-Y2O3 bulk material prepared by powder metallurgy route and rolling deformation technology

Abstract

Tungsten (W) or W alloys are the main candidates for plasma-facing materials of future fusion reactors. Large-sized W-Y2O3 bulk material has been successfully produced in this study for future engineering applications. Wet chemical method and continuous hydrogen (H2) reduction were applied to achieve mass preparation of W-Y2O3 composite powder. The final bulk material was obtained using the H2 atmosphere sintering technique and rolling deformation process. Conventional X-ray diffraction patterns were used to characterize the different surfaces of the rolled specimen, which coincide with the results of electron backscatter diffraction detection, to evaluate the texture information. The 50% rolled W-Y2O3 bulk material have three types of textures, namely, θ-fiber, α-fiber, and γ-fiber. Notably, the thermal conductivity exhibits no obvious difference between sintered bulk at the original state and rolled bulk along various directions. After rolling deformation of the W-Y2O3 bulk material, the effect of the anisotropic microstructure on the thermal conductivity can be offset by the effect of the fiber geometric structure. For the body-centered cubic structure of W, the thermal conductivity versus the crystal orientation should be λ[100] >λ[110].