摘要
氢化物是锆合金包壳管在核电厂正常运行过程中与一回路冷却剂发生锆水反应而产生的常见缺陷。本文利用分子动力学方法,采用第三代电荷优化多体(Third-generation Charge-Optimized Many-Body,COMB3)势函数,构建含氢化物的锆基模型进行单轴拉伸模拟,探究了氢化物密度对锆力学性能的影响。研究结果表明:当氢化物密度在0~1078μg·g^(−1)时,随着氢化物密度的增加,屈服强度、应变和杨氏模量降低。在弹性阶段,氢化物密度的增加使应力集中区域增大,有利于位错形核;在塑性变形阶段,随着氢化物密度的增大,初始位错更倾向于在氢化物周围扩展。当氢化物密度在1078~2311μg·g^(−1)时,随氢化物密度的增加,屈服强度、应变和杨氏模量升高,这是由于当氢化物密度较高时产生了大量位错并造成位错塞积。
[Background]Hydride is a common defect caused by the reaction of zirconium water with primary coolant in the normal operation of zirconium alloy clad tubes in nuclear power plants.[Purpose]This study aims to study the effect of hydride on mechanical properties of zirconium alloy.[Methods]In this study,molecular dynamics method and third-generation charge-optimized many-body(COMB3)potential function were used.Firstly,the molecular dynamics software large-scale atomic/molecular massively parallel simulator(LAMMPS)was used to construct zirconium base models containing different hydrides.Relaxation was performed at 300 K for 50 ps.Then uniaxial stretching was performed at a strain rate of 1010 s−1 in the direction[0001]for 30 ps,which was 30%strain.[Results]The results show that the yield strength,strain and Young's modulus of the alloy decrease with the increase of hydride density in the range of 0~1078μg·g^(−1).When the hydride density is between 1078μg·g^(−1)and 2311μg·g^(−1),the yield strength,strain and Young's modulus increase with the increase of hydride density.When the hydride density is 1078μg·g^(−1),the yield stress of the model drops to the lowest value of 7.69 GPa,which is 42.22%lower than that of the pure Zr model.The yield strain decreases to the lowest value 0.0895,which is 39.34%lower than that of the pure Zr model.Young's modulus drops to the lowest value of 112.18 GPa,which is 8.94%lower than that of the pure Zr model.[Conclusions]When the hydride density is in the range of 0~1078μg·g^(−1),in the elastic stage,the increase of hydride density increases the stress concentration area,which is conducive to dislocation nucleation.In the plastic deformation stage,with the increase of hydride density,the initial dislocation is more inclined to expand around the hydride.When the hydride density is in the range of 1078μg·g^(−1)to 2311μg·g^(−1),a large number of dislocations are generated due to the high hydride density,resulting in dislocation plugging.
作者
刘潇雅
马雁
张智鑫
LIU Xiaoya;MA Yan;ZHANG Zhixin(College of Nuclear Science and Engineering,North China Electric Power University,Beijing 102206,China)
出处
《核技术》
北大核心
2025年第5期213-219,共7页
Nuclear Techniques
基金
国家自然科学基金(No.12275083)资助。
关键词
锆合金
氢化物
单轴拉伸
力学性能
分子动力学
Zirconium alloy
Hydride
Uniaxial tensile
Mechanical property
Molecular dynamics
