聚变堆面向等离子体材料钨钾合金的辐照损伤及其机理研究

Plasma facing material (PFM) is one of the most crucial issues for fusion facilities, due to its severe working conditions under high flux H/He plasma, high thermal load and high-energy/high-fluence neutron irradiation. Tungsten-based materials have been regarded as the most promising candidates for such condition owing to its high melting point, outstanding thermal conductivity, good resistance to erosion and sputtering. However, tungsten itself as PFM is not perfect yet, because its embrittlement, recrystallization, or irradiation damage in the working condition will lead to its fracture and shorten its lifetime. Material doping provides a useful consideration to improve its service performance. Among these systems, potassium doped tungsten has been regarded as one of the most promising candidates. However, the irradiation effects of W-K alloy had rarely been investigated just using the commercial samples. In this proposal, irradiation effects of W-K alloy with meso-scale grain/nano potasium bubble microstructure will be studied using high flux proton, heavy ion and H-He plasma under fusion ractor conditions, and the effect of thermal shock to W-K, as well as the related mechanism will also be investigated. On this basis, the components and microstructure will optimaized to futher improve its torlerance from high-flux proton/ion/H-He plasma irradiation and thermal shock. The systematic investigation is very helpful to understand the irradiation effects of PFMs, and more importantly can provide experimental and theoretical information to design high-performance PFMs.

面向等离子体材料（PFMs）由于遭受着高温、高热负荷、强束流粒子与中子辐照等的综合作用，是聚变装置中最关键的问题之一。由于钨具有高熔点、低溅射产额、良好的热导率与高温强度等优点，目前被认为是PFMs的首选材料。但是，其热学、抗辐照、抗刻蚀性能还有待进一步改善。掺杂合金化是提高其服役性能的有效途经。为此，人们发展了众多的钨基PFMs体系，其中，W-K合金被认为是最具前景的PFMs候选材料之一。但是，目前国内外对W-K合金的辐照损伤研究还非常初步。因此，本课题将系统研究不同晶粒/钾泡尺度的W-K合金在模拟聚变堆环境下的强流质子/重离子/ H-He等离子体的辐照损伤行为，耐热冲击性能，以及其相应的机理等重要的科学问题，并在此基础上对其成分和微观结构进行优化以进一步提高材料在聚变堆中的服役性能。这不但能深化对PFMs辐照损伤机理的理解，而且可为设计、制备服役性能优良的PFMs提供实验和理论依据。

面向等离子体材料（PFMs）由于遭受着高温、高热负荷、强束流粒子与中子辐照等的综合作用，是聚变装置中最关键的问题之一。由于钨具有高熔点、低溅射产额、良好的热导率与高温强度等优点，目前被认为是PFMs 的首选材料。但是，其热学、抗辐照、抗刻蚀性能还有待进一步改善。掺杂合金化是提高其服役性能的有效途经。在众多的钨基PFMs 体系中，W-K 合金被认为是最具前景的PFMs 候选材料之一。但是，目前国内外对W-K 合金的辐照损伤研究还非常初步。本课题研究了不同晶粒/钾泡尺度的W-K 合金在模拟聚变堆环境下的强流质子/重离子/ H-He 等离子体的辐照损伤行为，耐热冲击性能，以及其相应的机理等重要的科学问题，并在此基础上对其成分和微观结构进行优化以进一步提高材料在聚变堆中的服役性能。研究结果表明，通过调节SPS烧结工艺，可制备出钾泡平均尺度~47nm的钨钾合金，其拉伸强度、断裂韧性同时增强，再结晶温度（RCT）可达1800℃，韧脆转变温度（DBTT）可降低至200℃，从而具备优异的抗热冲击性能。该合金同时具有比ITER级纯钨更优的抗等离子体辐照性能，D滞留与ITER级别纯钨相当。这不但能深化对PFMs 辐照损伤机理的理解，而且可为设计、制备服役性能优良的PFMs 提供实验和理论依据。