Electrochemical Microalloying of Tungsten for Plasma Facing Component Applications

Tungsten and its alloys are candidates for plasma-facing-component heat sinks and armor used in fusion energy systems, due to their low sputtering rate, high melting point, high thermal conductivity, high strength at elevated temperatures, and low tritium inventory. However, tungsten¿s inherent low ductility makes it difficult to fabricate plasma facing components and limits its use as a structural material. Although advanced electrochemical forming techniques have been shown to enable the fabrication of complex tungsten components, such as helium cooled tungsten heat sinks, improvements in tungsten¿s fracture toughness and ductile-to-brittle transition temperature still are needed. Recent studies have shown that micro-alloying additions can improve the ductility of refractory metals. Based on these results, this project will determine the influence of electrolysis parameters and microalloying on structure, mechanical properties, and ductile-to-brittle transition temperature of electroformed tungsten. Commercial Applications and other Benefits as described by the awardee: Beyond fusion applications, electrochemical microalloyed tungsten should find use in non-eroding nozzles in rocket engines, crucibles for crystal growth, heat pipes, welding electrodes, x-ray targets, warhead penetrators, radiation/temperature shielding applications, and other high temperature furnace components. Electrochemical microalloyed tungsten would be much less expensive than current techniques in which tungsten is alloyed with rhenium, which costs ~$9,000/kg and is available largely from foreign sources.