氦氢的协同作用对V-4Cr-4Ti 低温辐照脆性的影响

Vanadium-based alloys have been developed for possible use in the structures of fusion reactors because of their potential for low activation and their attractive high-temperature properties. However, helium and hydrogen, which are produced by nuclear transmutation reaction in fusion reactor make vanadium-based alloys suffer from severe irradiation damage following the degradation of properties. Helium may promote the additional radiation hardening and embrittlement at relatively low temperature which causes the loss of uniform elongation.The effect of hydrogen on the irradiation damage of structural materials have been concerned in recent years,while the helium–hydrogen synergistic effects on irradiation damage need to be investigated. In this research, He and He/H ions would be used to irradiate V-4Cr-4Ti,then high resolution transmission electron microscopy(HVEM) and nanoindentation would be applied to study irradiation embrittlement at low temperature, and explore the recovery method for irradiation hardening and embrittlement. The practical study includes:1) effect of He on irradiation embrittlement of V-4Cr-4Ti at lower temperature; 2) effects of He-H synergy on irradiation embrittlement of V-4Cr-4Ti at lower temperature; 3)the post-irradiation annealing effect on irradiated V-4Cr-4Ti at lower temperature, to investigate the recovery method for irradiation hardening and embrittlement. This study will provide further insight into effects of He-H synergy on irradiation damage in vanadium-based alloy,and explore further advanced materials for improved performance for longer term fusion reactor systems.

作为核聚变堆候选结构材料，钒合金具有低活化性和优异的高温性能。但聚变堆中核嬗变反应产生大量的氦（He）、氢（H），使钒合金遭受严重的辐照损伤，进而导致力学性能恶化。低温下氦可能促进了额外的辐照硬化和脆化，使钒合金的均匀延伸率降低。同时，H与He在辐照中的潜在的协同效应尚不明确。本课题组采用氦离子及氦氢离子双束辐照V-4Cr-4Ti，随后用高分辨透射电子显微镜和纳米压痕法研究了合金的低温辐照脆性，并尝试提出辐照硬化和脆化的低温自恢复方法。具体内容包括：1）氦离子辐照对V-4Cr-4Ti的低温辐照脆性的影响；2）氦氢的协同辐照对V-4Cr-4Ti的低温辐照脆性的影响；3）针对1）2）辐照后的样品进行低温退火，研究辐照硬化和脆化的自恢复方法。本研究将进一步揭示氦氢对钒合金的辐照损伤的影响，以探索更先进的高性能的长期用于核聚变反应堆的结构材料。