Correlation between the microstructure, mechanical/thermal properties, and thermal shock resistance of K-doped tungsten alloys

The microstructure of the materials always has a great impact on their mechanical and thermal properties, and hence on the thermal shock resistance. It is, therefore, of great concern to investigate the correlation between the microstructure, mechanical/thermal properties, and thermal shock resistance of K-doped tungsten (W-K) alloys that have recently generated considerable research interest in nuclear fusion materials community. Thus, in this study, a series of highly dense K-doped tungsten alloys with close grain size values (within a narrow range around 3.5 mu m) but different K bubble characteristics, i.e., average bubble sizes (33.7 nm -> 82.1 nm), were fabricated through controlling the K content (46/82/108/122/144 ppm). The thermal conductivity decreased, and the fracture toughness increased, with the increased K content, while the W-K samples with K of 82 ppm presented the highest tensile strength and thermal shock resistance. The correlation between the microstructure, mechanical/thermal properties, and thermal shock resistance of K-doped tungsten alloys are then discussed. These investigations can help to design highly thermal shock resistant materials with high strength and toughness. (C) 2019 Elsevier B.V. All rights reserved.