摘要
基于离散位错理论,建立了裂纹尖端渗入氢原子影响下的裂纹与位错相互作用模型,并在此模型的基础上考虑了氢原子对位错穿晶、晶界裂纹萌生以及主裂纹产生的影响.通过计算,分析了不同裂纹尖端渗氢浓度与范围对裂纹前方位错分布产生的影响,给出了晶界裂纹萌生与裂纹尖端氢原子的关系,分析了主裂纹前方无位错区内切应力受裂纹尖端渗氢的影响.
To investigate how hydrogen atoms affect the fracture of metallic materials at the micro-scopic level,this paper develops a model of crack-dislocation interaction incorporating hydrogen infiltration at the crack tip across multiple grains,based on discrete dislocation theory.The model examines how hy-drogen alters dislocation distribution on slip planes within grains,affects dislocation penetration through grain boundaries,and initiates wedge cracks at these boundaries.It applies to both body-centered cubic(BCC)and face-centered cubic(FCC)crystals.Through calculations,theimpact of varying hydrogen concentrations and infiltration ranges at the crack tip on dislocation distribution in front of the crack is analyzed.Results show that hydrogen at the crack tip promotes dislocation emission,increases the driving force for dislocation movement on slip planes,and facilitates dislocation penetration through grain boundaries.The relationship between wedge crack initiation at grain boundaries and hydrogen presence at the crack tip is explored.It is found that at large grain boundary angles,an increase in the hydrogen concentration and infiltration range at the crack tip makes it easier for wedge cracks to initiate at grain boundaries.Additionally,the model assesses how hydrogen infiltration at the crack tip influences shear stress in the dislocation-free zone in front of the main crack.It reveals that increased hydrogen concentration and in-filtration range at the crack tip enlarge the dislocation-free zone in front of the crack,reducing the shielding effect of dislocations and facilitating crack propagation.This model effectively demonstratesthe influence of hydrogen atoms at crack tips on dislocations in crystals,providing a foundation for studying metal fracture in hydrogen environments.
作者
生月
李明
党键
李衍杰
Yue Sheng;Ming Li;Jian Dang;Yanjie Li(CRRC Qingdao Sifang Co.,Ltd.,Qingdao,266109;China Railway Jinan Group Co.,Ltd.,Jinan,250031)
出处
《固体力学学报》
北大核心
2025年第3期423-436,共14页
Chinese Journal of Solid Mechanics
关键词
裂纹
离散位错
氢环境
滑移面
晶界
crack
discrete dislocation
hydrogen environment
slip plane
grain boundary
