Insight into the corrosion mechanism of pre-stressed 9Cr RAFM steel with long-term thermal aging exposed to oxygen saturated LBE at 550 ℃

IF 10.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Corrosion Science Pub Date : 2026-04-01 Epub Date: 2026-01-15 DOI:10.1016/j.corsci.2026.113619

Chao Hai , Tingjun Huang , Huaiyun Cui , Qunying Huang , Yutao Zhai

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Abstract

In fast neutron reactors, the degradation of microstructures and buildup of stress in structural materials significantly affect their performance and structural integrity under high temperatures and corrosive coolant environments. This study examines the microstructural evolution of 9Cr reduced activation ferritic-martensitic (RAFM) steel after thermal aging at 550℃ for 2000 h, and its subsequent influence on oxidation corrosion under stress in an oxygen-saturated lead-bismuth eutectic (LBE) environment. The resulting oxide layer was found to comprise Fe₃O₄, Fe-Cr spinel and an inner oxidation zone (IOZ). During the thermal aging, coarsening of M₂₃C₆ carbides reduced the passivation capability of the steel and accelerated the initial stage of LBE corrosion. Moreover, those coarsened M₂₃C₆ precipitates preferentially oxidized to form oxides Cr₂O₃, which increased the thickness of IOZ layer. The stress was observed to markedly enhance the corrosion rate, an effect that was further amplified by long-term thermal aging. The underlying mechanisms were discussed with the framework of the available space model.

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550℃饱和氧LBE下长期热时效的预应力9Cr RAFM钢腐蚀机理研究

在快中子反应堆中，在高温和腐蚀性冷却剂环境下，结构材料中微结构的退化和应力的积累会严重影响其性能和结构的完整性。本文研究了9Cr还原活化铁素体-马氏体（RAFM）钢在550℃2000 h热时效后的显微组织演变，以及随后在氧饱和铅铋共晶（LBE）环境下应力氧化腐蚀的影响。氧化层由Fe3O4、Fe-Cr尖晶石和内氧化区组成。在热时效过程中，M23C6碳化物的粗化降低了钢的钝化能力，加速了LBE腐蚀的初始阶段。粗化的M23C6析出物优先氧化形成Cr2O3氧化物，增加了IOZ层的厚度。观察到应力显著提高了腐蚀速率，长期热老化进一步放大了这一效应。在可用空间模型的框架下，讨论了其基本机制。

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来源期刊

Corrosion Science 工程技术-材料科学：综合

CiteScore

13.60

自引率

18.10%

发文量

763

审稿时长

46 days

期刊介绍： Corrosion occurrence and its practical control encompass a vast array of scientific knowledge. Corrosion Science endeavors to serve as the conduit for the exchange of ideas, developments, and research across all facets of this field, encompassing both metallic and non-metallic corrosion. The scope of this international journal is broad and inclusive. Published papers span from highly theoretical inquiries to essentially practical applications, covering diverse areas such as high-temperature oxidation, passivity, anodic oxidation, biochemical corrosion, stress corrosion cracking, and corrosion control mechanisms and methodologies. This journal publishes original papers and critical reviews across the spectrum of pure and applied corrosion, material degradation, and surface science and engineering. It serves as a crucial link connecting metallurgists, materials scientists, and researchers investigating corrosion and degradation phenomena. Join us in advancing knowledge and understanding in the vital field of corrosion science.