A newly developed large-volume potassium-doped tungsten (W–K) plate with a thickness of 15 mm and a weight of 25 kg by powder metallurgy plus hot rolling was prepared to meet the requirements of the International Thermonuclear Experimental Reactor (ITER) in engineering application. In order to clarify the effect of K doping on the thermal shock performance of W–K alloy, transient thermal shock tests with a single-pulse duration of 1 ms for 100 shots at room temperature were performed. The absorbed power density is set to 0.33, 0.44, 0.55 and 0.66 GW m−2, respectively. Furthermore, the microstructure, Vickers micro-hardness before and after the transient thermal shock, thermal conductivity and relative density were also characterized. The results indicate that the cracking threshold of rolled W–K is 0.44–0.55 GW m−2, which possesses a better transient thermal shock resistance compared with the most of advanced W-based materials. This is mainly because K doping can significantly improve the high-temperature stability and mechanical properties of W material without reducing its thermal conductivity. In particular, K bubbles can also effectively inhibit the formation and propagation of cracks during thermal shock. Moreover, the cracking mechanism of rolled W–K alloy is also discussed in detail. This study is helpful for building a trusted ITER database on advanced W-based materials that provides useful references for the selection of future plasma-facing materials.
新开发的大尺寸钾掺杂钨（W-K）板材，厚度为25 mm，重量为25 kg，采用粉末冶金结合热轧工艺制备，以满足国际热核实验反应堆（ITER）工程应用的要求。为明确钾掺杂对W-K合金抗热冲击性能的影响，在室温下进行了单脉冲持续时间为1 ms、累计100次的热冲击实验，吸收功率密度分别设定为0.33、0.44、0.55和0.66 GW·m⁻²。此外，还表征了热冲击前后样品的微观组织、维氏显微硬度、热导率及相对密度。结果表明，轧制态W-K合金的裂纹萌生阈值为0.44–0.55 GW·m⁻²，相较于大多数先进钨基材料具有更优的抗热冲击性能。这主要归因于钾掺杂在不降低热导率的前提下显著提高了钨材料的高温稳定性和力学性能。特别是，钾泡能够有效抑制热冲击过程中裂纹的萌生与扩展。此外，本文还详细讨论了轧制态W-K合金的抗热冲击裂纹机制。该研究为建立面向未来等离子体 facing 材料的ITER数据库提供了重要参考，并为筛选下一代等离子体 facing 材料提供了理论依据。