Tensile and fatigue properties of potassium doped and rhenium containing tungsten rods for fusion reactor applications

In this study, large diameter pure tungsten (PW) and potassium doped W (KW) rods fabricated using a swaging process were investigated, in order to develop high performance plasma-facing materials (PFM) for fusion reactor applications. The KW rods show a finer grain size, a more compact [1 1 0] grain orientation, and a more uniform grain size distribution than that of the PW rods. Tensile tests of the KW rods along the axial direction indicated higher tensile strength at each test temperature than what is found in PW rods. On the other hand, both types of rod have nearly identical elongation values. Further comparison of the rods with rolled PW and KW plates indicate that the W rods show larger elongation and lower strength than what is observed in W plates. Meanwhile, the longer fatigue life was observed for the W rods, as predicted by Manson's universal slope method. In addition, a K-doped W rod with 3% rhenium (Re) (KW3Re) was investigated in this study, which featured improved recrystallization and grain growth behavior. Suppression of grain growth after recrystallization was observed in KW3Re rod. High performance PFMs based on these materials can be expected with careful consideration of the fabrication process and additional elements used in their creation.