摘要
SiC纤维增韧SiC基复合材料(SiCf/SiC)由于其优越的性能而成为新一代核能系统重要候选材料之一.材料中的缺陷会使材料的力学性能发生变化,本文运用分子动力学程序LAMMPS模拟计算了分别含有空位、微空洞和反位替代三种缺陷的3C-SiC结构体系沿[100]方向的拉伸变形过程,原子间相互作用采用Tersoff多体势描述.通过模拟得到不同缺陷体系的应力-应变曲线和拉伸过程中体系能量,通过分析应力-应变曲线,得到了不同缺陷体系的杨氏模量、断裂应变、拉伸强度随缺陷"浓度"的变化关系,最后分析了3C-SiC拉伸断裂机理.研究结果表明,空位和微空洞对杨氏模量、拉升强度的影响类似,都是随着缺陷"浓度"的增加而减小,反位替代缺陷使体系的杨氏模量随缺陷"浓度"的增加而增大.
Continuous silicon carbide fiber-reinforced SiCf/SiC composites have been considered to be used as structural materials in advanced nuclear reactors due to their excellent properties.The mechanical performances were changed by defects in material.In this study,molecular dynamics simulation has been used to study the mechanical behaviors of the 3C-SiC deformed along[100]-oriented tension using LAMMPS(Large-scale Atomic/Molecular Massively Parallel Simulator).The interaction between atoms were described by an optimized Tersoff many body potential.The total energy,Young’s modulus,tensile strength and elongation of perfect 3C-SiC are compared with single vacancies,small vacancy micro-voids and antisite in 3C-SiC.The stress-strain curves and total energy was obtained in simulation system with different defects.The change of tensile strength,young’s modulus and elongation was obtained with the concentration of defect according to the stress-strain curves.And the fracture mechanism of 3C-SiC was analyzed along[100]-oriented tension.The results show that Young’s modulus and tensile strength of vacancies and micro-voids demonstrate the similar effects;both of them decrease with the defects concentration,But Young’s modulus increase with the defects concentration in antisite system.
作者
马小强
徐喻琼
苏华山
杜晓超
袁显宝
周建军
MA Xiao-Qiang;XU Yu-Qiong;SU Hu-Shan;DU Xiao-Chao;YUAN Xian-Bao;ZHOU Jian-Jun(Hubei Key Laboratory of Hydroelectric Machinery Design and Mainteance,College of Mechanical and Power Engineering,China Three Gorges University,Yichang 443002,China)
出处
《原子与分子物理学报》
CAS
北大核心
2019年第4期688-695,共8页
Journal of Atomic and Molecular Physics
基金
三峡大学高层次人才启动基金
关键词
3C-SIC
分子动力学
单轴拉伸
力学性能
断裂机理
3C-SiC
Molecular dynamics
Uniaxial tension
Mechanical properties
Fracture mechanism
