中国物理B ›› 2024, Vol. 33 ›› Issue (7): 76201-076201.doi: 10.1088/1674-1056/ad3b83

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Influence of temperature, stress, and grain size on behavior of nano-polycrystalline niobium

Yu-Ping Yan(晏玉平), Liu-Ting Zhang(张柳亭), Li-Pan Zhang(张丽攀)†, Gang Lu(芦刚), and Zhi-Xin Tu(涂志新)   

  1. School of Acronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China
  • 收稿日期:2024-01-12 修回日期:2024-03-30 接受日期:2024-04-07 出版日期:2024-06-18 发布日期:2024-06-20
  • 通讯作者: Li-Pan Zhang E-mail:yypgoodluck87@163.com
  • 基金资助:
    Project supported by the Doctoral Scientific Research Starting Foundation of Nanchang HangKong University, China (Grant No. EA201903209).

Influence of temperature, stress, and grain size on behavior of nano-polycrystalline niobium

Yu-Ping Yan(晏玉平), Liu-Ting Zhang(张柳亭), Li-Pan Zhang(张丽攀)†, Gang Lu(芦刚), and Zhi-Xin Tu(涂志新)   

  1. School of Acronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China
  • Received:2024-01-12 Revised:2024-03-30 Accepted:2024-04-07 Online:2024-06-18 Published:2024-06-20
  • Contact: Li-Pan Zhang E-mail:yypgoodluck87@163.com
  • Supported by:
    Project supported by the Doctoral Scientific Research Starting Foundation of Nanchang HangKong University, China (Grant No. EA201903209).

摘要: Atomic simulations are executed to investigate the creep responses of nano-polycrystalline (NC) niobium established by using the Voronoi algorithm. The effects of varying temperature, applied stress, and grain size (GS) on creep properties and mechanisms are investigated. Notably, the occurrence of tertiary creep is exclusively observed under conditions where the applied stress exceeds 4.5 GPa and the temperature is higher than 1100 K. This phenomenon can be attributed to the significant acceleration of grain boundary and lattice diffusion, driven by the elevated temperature and stress levels. It is found that the strain rate increases with both temperature and stress increasing. However, an interesting trend is observed in which the strain rate decreases as the grain size increases. The stress and temperature are crucial parameters governing the creep behavior. As these factors intensify, the creep mechanism undergoes a sequential transformation: initially from lattice diffusion under low stress and temperature conditions to a mixed mode combining grain boundaries (GBs) and lattice diffusion at moderate stress and mid temperature levels, and ultimately leading to the failure of power-law controlled creep behavior, inclusive of grain boundary recrystallization under high stress and temperature conditions. This comprehensive analysis provides in more detail an understanding of the intricate creep behavior of nano-polycrystalline niobium and its dependence on various physical parameters.

关键词: creep behavior, molecular dynamics simulation, activation energy, stress exponent, nano-polycrystalline niobium

Abstract: Atomic simulations are executed to investigate the creep responses of nano-polycrystalline (NC) niobium established by using the Voronoi algorithm. The effects of varying temperature, applied stress, and grain size (GS) on creep properties and mechanisms are investigated. Notably, the occurrence of tertiary creep is exclusively observed under conditions where the applied stress exceeds 4.5 GPa and the temperature is higher than 1100 K. This phenomenon can be attributed to the significant acceleration of grain boundary and lattice diffusion, driven by the elevated temperature and stress levels. It is found that the strain rate increases with both temperature and stress increasing. However, an interesting trend is observed in which the strain rate decreases as the grain size increases. The stress and temperature are crucial parameters governing the creep behavior. As these factors intensify, the creep mechanism undergoes a sequential transformation: initially from lattice diffusion under low stress and temperature conditions to a mixed mode combining grain boundaries (GBs) and lattice diffusion at moderate stress and mid temperature levels, and ultimately leading to the failure of power-law controlled creep behavior, inclusive of grain boundary recrystallization under high stress and temperature conditions. This comprehensive analysis provides in more detail an understanding of the intricate creep behavior of nano-polycrystalline niobium and its dependence on various physical parameters.

Key words: creep behavior, molecular dynamics simulation, activation energy, stress exponent, nano-polycrystalline niobium

中图分类号:  (Creep)

  • 62.20.Hg
87.15.ap (Molecular dynamics simulation) 61.82.Rx (Nanocrystalline materials)