A molecular dynamics simulation of energetics and diffusion of point defects in a Au–Ag alloy

  • Ru-song LiEmail author
  • Fei Li
  • Du-qiang Xin
  • Ji-jun Luo
  • Saifei Chen
  • Yu Zhang


For revealing an aging mechanism for self-irradiation in a Pu–Ga alloy, we carried out a molecular dynamics (MD) simulation on a substitutional material, i.e., Au–Ag alloy. In this work, we estimate physical and microscopic properties of the Au–Ag alloy containing various point defects using a MD method, in particular, formation energy for point defects, migration energy for point defects diffusion into interstitial sites, and diffusion coefficient for the Au–Ag alloy containing point defects, such as vacancy, He atom and He-vacancy (He-V) cluster. The results indicate that volumetric heat capacity and linear expansion coefficient would decrease due to the various point defects, and He atom has the most remarkable influence on the physical properties of the Au–Ag alloy for point defects considered in this work. The formation energy of Au and Ag self-interstitial atom indicates that Octa1 is the most stable site, and structural stability of octahedral (Octa) interstitial sites for the He atom obeys \(\hbox {Octa1}> \hbox {Octa2}> \hbox {Octa4} > \hbox {Octa3}\). For the \(\hbox {He}_{n}\hbox {V}_{m}\) cluster, the formation energy of the defect structure is most stable at \(n = m\). The diffusion coefficient of the He-V cluster is relatively smaller, showing that vacancy defects would further decrease atomic diffusion. An influence of various point defects on the diffusion velocity in the Au–Ag alloy obeys the He-V \(\hbox {cluster}> \hbox {He}> \hbox {vacancy}> \hbox {Ag} > \hbox {Au}\).


Radiation damage point defects formation energy migration energy molecular dynamics 



This work is supported by the National Science Foundation of China under contract nos. 51401237, 11474358 and 51271198; the Scientific Research Program Funded by Shaanxi Provincial Education Department (program no. 18JK1207); and the Defence Technology Foundation of China under contract no. 2301003.


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Copyright information

© Indian Academy of Sciences 2019

Authors and Affiliations

  1. 1.Xijing UniversityXi’anPeople’s Republic of China

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