| Summary: | Tungsten (W) fiber-reinforced tungsten (W<sub>f</sub>/W) composite with ultra-high strength and high-temperature resistance is considered an attractive candidate material for plasma-facing materials (PFM) in future fusion reactors. The main component of W<sub>f</sub>/W composite is tungsten wire, which is obtained through powder metallurgy and the drawing process. In this paper, high potassium (K)-doped tungsten wires with 98 ppm of K and 61 ppm of impurities are prepared using traditional and optimized processing technologies, respectively, and a comparative study with conventional K-doped tungsten wires with 83 ppm of K and 80 ppm of impurities is conducted. The high-temperature mechanical properties as well as the microstructure’s evolution of the prepared tungsten wires are investigated. The results show that the high-temperature performance of K-doped tungsten wires is improved by increasing the K content and by simultaneously reducing the impurities. By adopting small compression deformation and low-temperature processing technology, the high-temperature performance of high K-doped tungsten wires can be further improved. A microstructure analysis indicates that the excellent high-temperature performance is attributed to a combination of the small K bubble size, high K bubble number density, and long K bubble string, which are produced through optimization of the processing technology. A study on the processing technology and the performance of tungsten wires with a high K content and a high purity can provide important information regarding W<sub>f</sub>/W composites.
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