Surface damages of ITER-like W/Cu monoblocks in the lower divertor of EAST

作者：Yang Wang, Dahuan Zhu, Chuanshi Feng, Zongxiao Guo, Pengfei Zi, Changjun Li, Chuannan Xuan, Chunyu He, Wenxue Fu, Binfu Gao, Baoguo Wang, Rui Ding, Junling Chen, the EAST Team · 发表于：Nuclear Fusion · 年份：2025 · DOI：10.1088/1741-4326/adf3c7 · 被引用次数：2 · 研究领域：Fusion materials and technologies、Nuclear Materials and Properties、Metallurgical Processes and Thermodynamics

Abstract In future ITER operations, it is crucial to maintain the performance of plasma-facing components, particularly in regions subject to high thermal loads. Studies on component damage in existing tokamaks provide important reference data for predicting potential damage in ITER and future fusion devices, ensuring the most effective response strategies during future operations. In 2021, ITER-like W/Cu monoblocks featuring a large chamfer (1.5 mm × 17 mm) were installed on the lower divertor target of EAST. The structural design of W/Cu monoblocks with inclination angles can reduce the probability of melting but may also induce other types of damage, similar to the fish-scale surface of the divertor in ITER (toroidal bevel with a depth of 0.5 mm). After three plasma campaigns, post-mortem analysis identified significant surface damages, including crust formation, increased surface roughness, macrocracks, and other types of damage. The spatial distribution of damage is strongly correlated with the heat flux distribution and the degree of misalignment. At the leading edge areas, macrocracks are caused by plastic strain under steady-state heat loads, while microcracks are brittle cracks mainly caused by transient heat loads. The net-like cracks displayed four distinct morphological characteristics, attributed to variations in heat load and incident angles. Abnormal grain growth was observed in the vicinity of the melted components, with grain sizes reaching an extraordinary 7...