摘要
微结构特征和结构演化机制是非晶态材料的研究重点,非晶合金的动力学行为可以揭示非晶合金的形成过程和结构演化机制.本文采用分子动力学模拟方法探讨了在Pd-Si非晶合金体系中,Pd原子的浓度对Si原子扩散的阻碍作用及其对体系对称性和有序度的影响.并对与原子扩散、体系的对称性及有序度有关的参数进行了分析,结果表明,增加Pd原子的浓度会导致Si原子的扩散受到更明显的阻碍,表现为Si原子的非高斯参数异常峰的峰值增大和位移的标准差减小.这一现象表明,增加Pd原子浓度会增强了Si原子的牢笼效应,限制Si原子的扩散.此外,Pd原子浓度的增加促进了Pd-Si非晶合金中不饱和键型向饱和键型的转变,且体系的构型熵降低,提高了Pd-Si非晶合金的局域对称性和有序度,使得Si原子处于封闭性更强、对称性更高、结构更加紧凑的团簇结构中,增强了其牢笼效应和局域对称性.本文探讨了Pd原子浓度对Si原子的扩散行为及局域环境的影响机制,为深入理解非晶合金的结构演化提供了新的视角.
In amorphous alloys,the atomic arrangement exhibits short-range order while lacking long-range order.Despite the lack of long-range order,the local atomic arrangements and interactions can still significantly affect the motion of atoms.The microstructural features and structural evolution mechanisms of amorphous materials are key areas of research,and the dynamics of amorphous alloys can provide insights into their formation process and structural evolution.The cage effect refers to the phenomenon where atoms are trapped by their surrounding atoms,making them difficult to migrate or diffuse freely.This leads to slower diffusion rates and higher viscosities in these materials.Atomic concentration is one of the crucial factors that influence the structures and properties of amorphous materials.Variation in concentration can significantly change the material’s structure.Adjusting the atomic concentration can lead to the difference in diffusion rate between elements in the amorphous alloys,resulting in heterogeneous distributions of elements in different regions,which in turn affects the deformation characteristics of amorphous materials.This study aims to investigate the effect of Pd atomic concentration on the diffusion hindrance of Si atoms,as well as its influence on the local symmetry and order of the system.To achieve this objective,molecular dynamics simulations are employed to explore the relaxation process of atoms in Pd-Si amorphous alloys at different Pd atomic concentrations,and parameters related to atomic diffusion,displacement distribution,system symmetry,and order are analyzed.The results show that increasing the concentration of Pd atoms leads to a more significant hindrance to the diffusion of Si atoms,manifested as an increase in the abnormal peak values of the non-Gaussian parameters and a decrease in the standard deviation of the displacement.This indicates that a higher Pd atom concentration enhances the cage effect of Si atoms,thus restricting their diffusion.Additionally,the increase in Pd c
作者
陈贝
王小云
刘涛
高明
文大东
邓永和
彭平
Chen Bei;Wang Xiao-Yun;Liu Tao;Gao Ming;Wen Da-Dong;Deng Yong-He;Peng Ping(School of Computational Science and Electronics,Hunan Institute of Engineering,Xiangtan 411104,China;School of Physics and Mechanical&Electrical Engineering,Jishou University,Jishou 416000,China;School of Materials Science and Engineering,Hunan University,Changsha 410082,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第24期210-217,共8页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51701071)
湖南省自然科学基金(批准号:2022JJ50115,2021JJ30179)
湖南省教育厅科学研究项目(批准号:22A0522)
湖南省研究生创新项目(批准号:CX20221118)资助的课题.
