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