An Ni-AI-Co system embedded-atom-method potential is constructed for the γ（Ni）/γ＇（Ni3A1） superalloy based on experiments and first-principles calculations. The stacking fault energies （SFEs） of the Ni（Co, A1...An Ni-AI-Co system embedded-atom-method potential is constructed for the γ（Ni）/γ＇（Ni3A1） superalloy based on experiments and first-principles calculations. The stacking fault energies （SFEs） of the Ni（Co, A1） random solid solutions are calculated as a function of the concentrations of Co and A1. The calculated SFEs decrease with increasing concentrations of Co and A1, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence on the SFEs of the random solid solutions. The cross-slip processes of a screw dislocation in homogenous Ni（Co） solid solutions are simulated using the present potential and the nudged elastic band method. The cross-slip activation energies increase with increasing Co concentration, which implies that the creep resistance of γ（Ni） may be improved by the addition of Co.展开更多
We study the interaction potential of two nonidentical ground-state atoms coupled to a scalar field in a vacuum by separately calculating the contributions of vacuum fluctuations and those of the radiation reaction of...We study the interaction potential of two nonidentical ground-state atoms coupled to a scalar field in a vacuum by separately calculating the contributions of vacuum fluctuations and those of the radiation reaction of the atoms.Both cases of atoms in a free space and in parallel or vertical alignment to a reflecting boundary are considered.For the former case,we find that the leading-order interaction potential in the regionλA?L?λB exhibits the same separationdependence as that in the region L?λA?λB,where L,λA andλB are respectively the interatomic separation and the transition wavelengths of two atoms withλA?λB.For the latter case,we find that boundary-induced modifications are very remarkable when L?z,with z characterizing the separation between the two-atom system and the boundary.Particularly,when L further satisfies L?λA and L?λB,the interaction potential in the parallel-and the verticalalignment cases respectively scales as z4L-7 and z2L-5,the L-dependence of which is one order higher than those of two atoms in regions where L?z and meanwhile L?λA or/and L?λB.Our results suggest that retardation for the interaction potential of two nonidentical atoms with remarkably distinctive transition frequencies happens only when the interatomic separation is much greater than the transition wavelengths of both atoms.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2011CB606402)the National Natural Science Foundation of China(Grant No.51071091)
文摘An Ni-AI-Co system embedded-atom-method potential is constructed for the γ（Ni）/γ＇（Ni3A1） superalloy based on experiments and first-principles calculations. The stacking fault energies （SFEs） of the Ni（Co, A1） random solid solutions are calculated as a function of the concentrations of Co and A1. The calculated SFEs decrease with increasing concentrations of Co and A1, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence on the SFEs of the random solid solutions. The cross-slip processes of a screw dislocation in homogenous Ni（Co） solid solutions are simulated using the present potential and the nudged elastic band method. The cross-slip activation energies increase with increasing Co concentration, which implies that the creep resistance of γ（Ni） may be improved by the addition of Co.
基金supported in part by the NSFC under Grant Nos.11690034,12075084,11875172,12047551 and 12105061the KC Wong Magna Fund in Ningbo University。
文摘We study the interaction potential of two nonidentical ground-state atoms coupled to a scalar field in a vacuum by separately calculating the contributions of vacuum fluctuations and those of the radiation reaction of the atoms.Both cases of atoms in a free space and in parallel or vertical alignment to a reflecting boundary are considered.For the former case,we find that the leading-order interaction potential in the regionλA?L?λB exhibits the same separationdependence as that in the region L?λA?λB,where L,λA andλB are respectively the interatomic separation and the transition wavelengths of two atoms withλA?λB.For the latter case,we find that boundary-induced modifications are very remarkable when L?z,with z characterizing the separation between the two-atom system and the boundary.Particularly,when L further satisfies L?λA and L?λB,the interaction potential in the parallel-and the verticalalignment cases respectively scales as z4L-7 and z2L-5,the L-dependence of which is one order higher than those of two atoms in regions where L?z and meanwhile L?λA or/and L?λB.Our results suggest that retardation for the interaction potential of two nonidentical atoms with remarkably distinctive transition frequencies happens only when the interatomic separation is much greater than the transition wavelengths of both atoms.
