摘要
采用扫描电子显微镜(SEM)/原位拉伸试验研究了失水事故(LOCA)工况温度下的锆合金韧-脆转变行为,通过对材料的断裂形式、断口组织形貌进行分析可知:经650~1200℃高温水蒸气氧化后,塑韧性逐渐降低,1100℃氧化转折温度点之后,韧性下降明显,1200℃时完全脆性断裂;预氢化处理显著影响了高温氧化锆合金的韧-脆断裂机制,即使低于1200℃,包壳也发生严重的脆性失效断裂。研究认为,LOCA工况温度下化学元素分配导致生成的α-Zr'脆性网络与氢化物在锆合金的“剩余韧带”联通机制是锆包壳韧性降低的主要原因。本文为核电关键材料锆合金的国产化应用及核安全屏障设计提供了“从试验数据到失效机理”全链条支撑,对于完善和建立安全评价准则具有重要意义。
In this study,scanning electron microscopy(SEM)/in-situ tensile tests were utilized to investigate the ductile-brittle behavior of zirconium alloys under loss of coolant accident(LOCA)temperature conditions.Analysis of the fracture modes and fractography of the materials demonstrates the following:after high-temperature steam oxidation at 650~1200℃,the plasticity and toughness gradually degrade;above the oxidation transition temperature of 1100℃,the toughness decreases remarkably,with complete brittle fracture occurring at 1200℃.Prehydrogenation treatment exerts a significant influence on the ductile-brittle fracture mechanism of high-temperature oxidized zirconium alloys,causing severe brittle failure of the cladding even below 1200℃.It is proposed that the primary causes underlying the toughness degradation of zirconium cladding under LOCA temperatures are the formation of anα-Zr'brittle network induced by chemical element partitioning and the interconnection mechanism of hydrides within the"remaining ligaments"of the zirconium alloy.This work offers full-chain support spanning from test data to failure mechanisms for the domestic application of zirconium alloys(a critical nuclear power material)and the design of nuclear safety barriers,and holds considerable significance for refining and establishing safety evaluation criteria.
作者
赵琬倩
彭小明
杨忠波
杨育峰
高心蕊
唐彦
Zhao Wanqian;Peng Xiaoming;Yang Zhongbo;Yang Yufeng;Gao Xinrui;Tang Yan(State Key Laboratory of Advanced Nuclear Energy Technology,Nuclear Power Institute of China,Chengdu,610213,China)
出处
《核动力工程》
北大核心
2025年第S2期92-98,共7页
Nuclear Power Engineering
基金
中核集团耐事故燃料技术研发项目(Z1041)
中核集团稳定支持项目(YC2310)。
关键词
锆合金
包壳
失水事故(LOCA)
韧-脆转变行为
Zirconium alloy
Cladding
Loss of coolant accident(LOCA)
Ductile-brittle transition behavior
