中国物理B ›› 2019, Vol. 28 ›› Issue (8): 83401-083401.doi: 10.1088/1674-1056/28/8/083401

• ATOMIC AND MOLECULAR PHYSICS • 上一篇    下一篇

Energetics and diffusion of point defects in Au/Ag metals:A molecular dynamics study

Zhi-Yong Liu(刘志勇), Bin He(何彬), Xin Qu(瞿鑫), Li-Bo Niu(牛莉博), Ru-Song Li(李如松), Fei Wang(王飞)   

  1. Xi'an High Technology Institute, Xi'an 710025, China
  • 收稿日期:2019-03-08 修回日期:2019-05-10 出版日期:2019-08-05 发布日期:2019-08-05
  • 通讯作者: Ru-Song Li, Fei Wang E-mail:rusong231@126.com;wf285352065@sina.com
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51401237, 11474358, and 51271198), the Fund from Shaanxi Provincial Education Department, China (Grant No. 18JK1207), and the Defence Technology Foundation of China (Grant No. 2301003).

Energetics and diffusion of point defects in Au/Ag metals:A molecular dynamics study

Zhi-Yong Liu(刘志勇), Bin He(何彬), Xin Qu(瞿鑫), Li-Bo Niu(牛莉博), Ru-Song Li(李如松), Fei Wang(王飞)   

  1. Xi'an High Technology Institute, Xi'an 710025, China
  • Received:2019-03-08 Revised:2019-05-10 Online:2019-08-05 Published:2019-08-05
  • Contact: Ru-Song Li, Fei Wang E-mail:rusong231@126.com;wf285352065@sina.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51401237, 11474358, and 51271198), the Fund from Shaanxi Provincial Education Department, China (Grant No. 18JK1207), and the Defence Technology Foundation of China (Grant No. 2301003).

摘要: To reveal the potential aging mechanism for self-irradiation in Pu-Ga alloy, we choose Au-Ag alloy as its substitutional material in terms of its mass density and lattice structure. As a first step for understanding the microscopic behavior of point defects in Au-Ag alloy, we perform a molecular dynamics (MD) simulation on energetics and diffusion of point defects in Au and Ag metal. Our results indicate that the octahedral self-interstitial atom (SIA) is more stable than the tetrahedral SIA. The stability sequence of point defects for He atom in Au/Ag is:substitutional site > octahedral interstitial site > tetrahedral interstitial site. The He-V cluster (HenVm, V denotes vacancy) is the most stable at n=m. For the mono-vacancy diffusion, the MD calculation shows that the first nearest neighbour (1NN) site is the most favorable site on the basis of the nudged elastic band (NEB) calculation, which is in agreement with previous experimental data. There are two peaks for the second nearest neighbour (2NN) and the third nearest neighbour (3NN) diffusion curve in octahedral interstitial site for He atom, indicating that the 2NN and 3NN diffusion for octahedral SIA would undergo an intermediate defect structure similar to the 1NN site. The 3NN diffusion for the tetrahedral SIA and He atom would undergo an intermediate site in analogy to its initial structure. For diffusion of point defects, the vacancy, SIA, He atom and He-V cluster may have an analogous effect on the diffusion velocity in Ag.

关键词: interatomic potential, radiation damage, point defect, diffusion barrier

Abstract: To reveal the potential aging mechanism for self-irradiation in Pu-Ga alloy, we choose Au-Ag alloy as its substitutional material in terms of its mass density and lattice structure. As a first step for understanding the microscopic behavior of point defects in Au-Ag alloy, we perform a molecular dynamics (MD) simulation on energetics and diffusion of point defects in Au and Ag metal. Our results indicate that the octahedral self-interstitial atom (SIA) is more stable than the tetrahedral SIA. The stability sequence of point defects for He atom in Au/Ag is:substitutional site > octahedral interstitial site > tetrahedral interstitial site. The He-V cluster (HenVm, V denotes vacancy) is the most stable at n=m. For the mono-vacancy diffusion, the MD calculation shows that the first nearest neighbour (1NN) site is the most favorable site on the basis of the nudged elastic band (NEB) calculation, which is in agreement with previous experimental data. There are two peaks for the second nearest neighbour (2NN) and the third nearest neighbour (3NN) diffusion curve in octahedral interstitial site for He atom, indicating that the 2NN and 3NN diffusion for octahedral SIA would undergo an intermediate defect structure similar to the 1NN site. The 3NN diffusion for the tetrahedral SIA and He atom would undergo an intermediate site in analogy to its initial structure. For diffusion of point defects, the vacancy, SIA, He atom and He-V cluster may have an analogous effect on the diffusion velocity in Ag.

Key words: interatomic potential, radiation damage, point defect, diffusion barrier

中图分类号:  (Interatomic potentials and forces)

  • 34.20.Cf
61.80.-x (Physical radiation effects, radiation damage) 61.72.-y (Defects and impurities in crystals; microstructure) 36.40.Sx (Diffusion and dynamics of clusters)