Development of Tungsten Composites as Plasma-Facing Materials by Doping Rare-Earth Boride Particulate

Tungsten (W) and its alloys are considered to be the most promising plasma-facing materials (PFMs) in divertor components due to their high melting point, high strength at elevated temperatures, and high resistance to neutron damage. To overcome severe problems such as brittleness and severe plastic deformation, rare-earth borides that have a high melting point, hardness, neutron absorbability, and low electronic work function, volatility can be reinforced to W matrix. In this study, high purity and nanoscale 2 wt.% rare-earth boride (CeB₆, NdB₆, and ErB₄) powders were reinforced to pre-alloyed W1Ni that is milled for 6 h at 800 rpm. According to the X-ray diffraction (XRD) results, W peaks were obtained with a small amount of WC impurity. The average particle and crystallite size and lattice strain of composite powders were measured. The powders were consolidated with the pressureless sintering (1400 °C for 1 h). Three different phases were determined for the composites based on the scanning electron microscopy. While the Vickers microhardnesses of W1Ni-2CeB₆, NdB₆, and ErB₄ composites were measured as 6.79, 6.36, and 6.53 GPa, respectively, the wear volume losses were measured as 0.99, 1.68, and 3.17 × 10^–4 mm³, respectively. These results were supported by wear rates and wear friction coefficient. The PS’ed composites were exposed to He⁺ ions. The mechanical and irradiation behavior of tungsten was investigated with addition rare-earth borides into W matrix in this study.