多主元烧绿石重离子辐照效应与硬化机制研究

Study on Heavy Ion Irradiation Effects and Hardening Mechanisms in Multi-Principal Element Pyrochlores

摘要

高放废物（HLW）的安全处置是核能可持续发展的关键挑战之一，烧绿石陶瓷因优异化学稳定性被视为锕系核素理想固化基材。然而，传统烧绿石在强辐照场下易发生非晶化，导致结构失效。本研究设计制备四种多主元钛酸盐烧绿石（#1-#4），通过31 MeV Kr离子辐照实验，结合XRD、拉曼光谱及维氏硬度测试，系统研究相结构对辐照非晶化与硬度的影响机制。结果表明：单相烧绿石抗辐照稳定性更高，在注量1.36×10¹⁴ cm^-2下仍保留部分晶体衍射峰，双相材料则非晶化程度更严重且辐照硬化更显著。拉曼光谱表明，辐照加剧晶格畸变并诱导有序-无序转变（烧绿石相→萤石相）。本研究阐明相结构调控对抗辐照性能的关联机制，为抗辐照固化基材设计提供理论依据。

Abstract

The safe disposal of high-level radioactive waste (HLW) represents a critical challenge for the sustainable development of nuclear energy. Pyrochlore ceramics are regarded as an ideal matrix for immobilizing actinide nuclides due to their exceptional chemical stability. However, conventional pyrochlores are susceptible to amorphization under intense irradiation fields, leading to structural failure. This study designed and fabricated four types of multi-principal element titanate pyrochlores (#1-#4). Utilizing 31 MeV Kr ion irradiation experiments combined with XRD, Raman spectroscopy, and Vickers hardness testing, the influence mechanisms of phase structure on irradiation-induced amorphization and hardness were systematically investigated. The results demonstrate that single-phase pyrochlores exhibit superior irradiation resistance, retaining partial crystalline diffraction peaks up to a fluence of 1.36×10¹⁴ cm^-2. In contrast, dual-phase materials experienced more severe amorphization and more significant irradiation hardening. Raman spectra revealed that irradiation intensifies lattice distortion and induces an order-disorder transition (pyrochlore → fluorite). This research elucidates the correlation mechanism between phase structure regulation and irradiation resistance, providing a theoretical basis for designing irradiation-tolerant waste form matrices.

关键词

烧绿石陶瓷 / 重离子辐照 / 核废料固化 / 辐照硬化 / 高熵陶瓷

Key words

Pyrochlore / Heavy ion irradiation / Nuclear waste immobilization / Irradiation hardening / High-entropy ceramics

参考文献

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