Development of tungsten as plasma-facing materials by doping tantalum carbide nanoparticles

Tungsten and its alloys are primary plasma-facing materials in fusion reactors. In this study, pure W and WfraC alloys and their powders were developed via a powder metallurgical method and a novel wet chemical process, respectively. W alloys with 1,2, and 4 wt.% TaC were sintered via spark plasma sintering at 1800 degrees C for 1 min. The sintered samples were characterized using field-emission scanning electron and transmission electron microscopes. TaC particles were found in grain boundaries, which could be crack sources. TaC particles were also found in grain interiors, which changed the crack propagation path, thereby improving material toughness. The microhardness and thermal conductivity of the pure and doped W materials were investigated. The particle microhardnesss increased with the increase in TaC content. The W-1 wt.% TaC alloy exhibited the highest thermal conductivity (up to 183.8 W/mK). (C) 2014 Elsevier B.V. All rights reserved.