摘要
本工作利用腐蚀电化学计算腐蚀界面能,构建了锆合金腐蚀过程的相场模型.首先,利用所建立的模型模拟了Zr-2.5Sn合金均匀腐蚀过程,模拟结果显示该合金的腐蚀动力学曲线符合立方规律,与实验结果一致.分析发现,在氧化层生成的初期,氧化层生长速率很高,但是受温度的影响不明显;随着氧化层厚度的增长,温度对氧化层生长曲线的影响变大,温度越高腐蚀速率越快.多晶Zr-2.5Sn合金腐蚀行为的模拟结果表明,在锆合金基体晶界处由于具有更大的氧扩散速率,氧化速率加快,并在金属-氧化层界面朝向金属基体一侧形成了沿晶界的具有更高浓度的O^(2–)带,且对氧化腐蚀速率的影响主要表现在氧化初期,相场模拟获得的腐蚀动力学曲线与实验结果符合非常好.
Due to the small neutron absorption cross section and excellent thermal creep performance,zirconium alloy is one of the most important cladding materials for fuel rods in commercial fission reactors.However,quantitative analysis of the effects of temperature and grain boundaries on the corrosion microstructure evolution of zirconium alloys is still needed.The establishing of a phase field simulation for the corrosion process of polycrystalline zirconium alloy and the systematical investigating of the thermodynamic influence are both very important.In this study,the phase field model of the corrosion process in zirconium alloys is developed by combining corrosion electrochemistry through calculating the interfacial energy at the metal-oxide and oxide-fluid boundaries.Then the model is used to investigate the uniform corrosion behavior on the surface of Zr-2.5Sn alloy,which demonstrates that the corrosion kinetic curve follows a cubic rule.Subsequently,the influence of temperature on the corrosion thickening curve of zirconium alloy is examined,and good agreement between simulation and experimental results is achieved.It is observed that during early stage of oxide layer formation,there is a high growth rate with minimal temperature dependence;however,as the oxide layer thickness increases,temperature becomes a significant factor affecting its growth rate,with higher temperatures resulting in faster corrosion rates.Furthermore,the effect of polycrystalline zirconium alloy matrices on corrosion rate is investigated,revealing that the grain boundaries accelerate oxide layer thickening due to enhanced oxygen diffusion rates.At metal-oxide interface,O^(2–)bands are formed in areas with higher O^(2–)concentration along these grain boundaries towards the metal matrix,which mainly influences oxidationcorrosion rate during the initial oxidation stage.
作者
刘续希
高士森
喇永孝
玉栋梁
柳文波
Liu Xu-Xi;Gao Shi-Sen;La Yong-Xiao;Yu Dong-Liang;Liu Wen-Bo(Institute of Nuclear Science and Technology,Xi’an Jiaotong University,Xi’an 710049,China;Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第14期258-267,共10页
Acta Physica Sinica
基金
国家自然科学基金委员会-中国工程物理研究院联合基金(NSAF联合基金)(批准号:U2130105)
中国核工业集团有限公司领创科研项目资助的课题.
