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Abstract Tungsten-potassium-titanium (W-K-Ti) alloys were fabricated by spark-plasma-sintering (SPS) and traditional rotary swaging (RS) techniques. Doping conditions and sintering methods were compared on the relative density, microstructure, hardness, recrystallization temperature, and the thermal shock resistance properties. Transient heat loads under 0.37 GW m−2 were applied on the W-K-Ti samples at room temperature for different cycles and pulsed durations. It was found that moderate Ti-doping (0.05 and 0.075 wt%) in W-K alloys can enhance the thermal shock resistance. Low-cycle thermal fatigue test suggested better thermal shock resistance in SPS-sintered W-K-Ti alloy (SPS-W-K-Ti) using TiH 2 dopant. The main reason was that the decomposition of TiH 2 significantly reduced the oxygen content of the ingots, which improved the ductility and thermal shock resistance of tungsten alloys. Further fracture analyses indicated that Ti-doping through TiH 2 formed intra- and inter- Ti-rich voids in TiH 2 -doped W-K alloy, while only intergranular Ti particles were found lying along grain boundaries in the Ti-doped one. The formation mechanism of the Ti-rich voids was investigated in detail. This work provides a potential route for obtaining plasma facing materials with high thermal shock resistance. Highlights • Novel W-K-Ti alloys were fabricated by spark-plasma-sintering and rotary swaging. • Positive effect was found by proper Ti doping for enhancing thermal shock resistance. • Novel phenomenon of TiH 2 doping was observed, resulting in better heat resistance. • The different properties of W-K alloys are due to the respective forms of Ti dopant. • The formation mechanism of Ti aggregation is presented for the first time. [ABSTRACT FROM AUTHOR]

W-K-TiC alloys with different titanium carbide concentration (0.05, 0.1, 0.25, 1) wt.% were fabricated through spark plasma sintering (SPS) method. Single shot thermal shock tests with a length of 5 ms and 100 shots thermal shock tests with a length of 1 ms were carried out. The microstructure and Vickers micro-hardness of each sample were investigated. It is revealed that the surface of the samples began to recrystallize after thermal shock tests, and the samples with 5 ms for single shot had more serious recrystallization than the samples with 1 ms for 100 shots because of its higher surface temperature after thermal shock tests. The samples were annealed at 1400 °C, 1600 °C, 1800 °C, respectively. It is shown that the addition of TiC particles could slow down recrystallization of W-K-TiC alloy, and its recrystallization temperature can reach to between 1400 °C and 1600 °C. [ABSTRACT FROM AUTHOR]

Novel tungsten-based W-K-Y alloys were sintered by spark plasma sintering (SPS) method using fine-grained yttrium doped tungsten-potassium (W-K) powder. The relative density, microstructure, hardness and the resistance to thermal shock damage of the sintered samples were characterized. With the enhanced Y doping, the grain size decreased and the hardness increased. Thermal shock test under 0.37 GW/m 2 heat load showed that low yttrium doping (0.05 wt%, 0.1 wt% and 0.5 wt%) in W-K-Y alloys can improve the resistance to thermal shock damage comparing with traditional commercial W-K, while high yttrium doping (1 wt%) easily leads to crack formation. This study will provide helpful information to optimize the preparation of tungsten-based plasma facing materials through composite tuning. [ABSTRACT FROM AUTHOR]

W K Mo Ti Y powder were mechanically alloyed (MA) and then consolidated through spark plasma sintering (SPS). Four different concentrations of molybdenum, i.e ., (0, 2, 5, 10) wt%, were applied to investigate the behavior of the alloys. The microstructure, Vickers micro-hardness and thermal shock behavior were analyzed. It is found that the molybdenum doping can mechanically alloy with tungsten and occupy tungsten lattice, which results in a correspondingly decrease of Vickers micro-hardness and thermal conductivity at the room temperature. Among the molybdenum doped samples, W K-2wt% Mo Ti Y alloy displays highly enhanced resistance against thermal shock. It is suggested that appropriate molybdenum doping in W K Mo Ti Y alloy is beneficial in consolidating and improving its thermal shock resistance. [ABSTRACT FROM AUTHOR]

Dense potassium-doped tungsten (W–K) ingots with homogeneously dispersed nanoscaled bubbles were fabricated by spark plasma sintering (SPS) using Al–K–Si (AKS) doped tungsten powder. Parameters such as sintering temperature, holding time and sintering pressure were considered to tune the grain size, density, microhardness, bubble formation and impurity contents. In addition, a two-step sintering scheme was designed to reduce Al/Si impurity contents and enhance the density. The sample prepared by the two-step sintering scheme displays both inter- and intra-granular nanocomposites, which is expected to have better creep resistance, high bending strength and fracture toughness. Potassium was detected inside the bubbles, determining the crucial role in the bubble formation process, and thus leading to compatible properties as plasma-facing material. [ABSTRACT FROM AUTHOR]