Density functional theory calculations in conjunction with the climbing images nudged elastic band method are conducted to study the diffusion phenomena of the Ni-based single crystal superalloys.We focus our attentio...Density functional theory calculations in conjunction with the climbing images nudged elastic band method are conducted to study the diffusion phenomena of the Ni-based single crystal superalloys.We focus our attention on the diffusion processes of the Ni and Al atoms in the γ and γ ' phases along the direction perpendicular to the interface.The diffusion mechanisms and the expressions of the diffusion coefficients are presented.The vacancy formation energies,the migration energies,and the activation energies for the diffusing Ni and Al atoms are estimated,and these quantities display the expected and clear transition zones in the vicinity of the interface of about 3–7(002) layers.The local density-of-states profiles of atoms in each(002) layer in the γ and γ ' phases and the partial density-of-states curves of Re and some of its nearest-neighbor atoms are also presented to explore the electronic effect of the diffusion behavior.展开更多
The effect of H impurity on the misfit dislocation in Ni-based single-crystal superalloy is investigated using the molecular dynamic simulation.It includes the site preferences of H impurity in single crystals Ni and ...The effect of H impurity on the misfit dislocation in Ni-based single-crystal superalloy is investigated using the molecular dynamic simulation.It includes the site preferences of H impurity in single crystals Ni and Ni 3 Al,the interaction between H impurity and the misfit dislocation and the effect of H impurity on the moving misfit dislocation.The calculated energies and simulation results show that the misfit dislocation attracts H impurity which is located at the γ/γˊinterface and Ni_3 Al and H impurity on the glide plane can obstruct the glide of misfit dislocation,which is beneficial to improving the mechanical properties of Ni based superalloys.展开更多
基金Project supported by National Basic Research Program of China(Grant No.2011CB606402)the National Natural Science Foundation of China(Grant No.51071091)
文摘Density functional theory calculations in conjunction with the climbing images nudged elastic band method are conducted to study the diffusion phenomena of the Ni-based single crystal superalloys.We focus our attention on the diffusion processes of the Ni and Al atoms in the γ and γ ' phases along the direction perpendicular to the interface.The diffusion mechanisms and the expressions of the diffusion coefficients are presented.The vacancy formation energies,the migration energies,and the activation energies for the diffusing Ni and Al atoms are estimated,and these quantities display the expected and clear transition zones in the vicinity of the interface of about 3–7(002) layers.The local density-of-states profiles of atoms in each(002) layer in the γ and γ ' phases and the partial density-of-states curves of Re and some of its nearest-neighbor atoms are also presented to explore the electronic effect of the diffusion behavior.
基金supported by the National Basic Research Program of China (Grant No.2011CB606402)the National Natural Science Foundation of China (Grant No.51071091)
文摘The effect of H impurity on the misfit dislocation in Ni-based single-crystal superalloy is investigated using the molecular dynamic simulation.It includes the site preferences of H impurity in single crystals Ni and Ni 3 Al,the interaction between H impurity and the misfit dislocation and the effect of H impurity on the moving misfit dislocation.The calculated energies and simulation results show that the misfit dislocation attracts H impurity which is located at the γ/γˊinterface and Ni_3 Al and H impurity on the glide plane can obstruct the glide of misfit dislocation,which is beneficial to improving the mechanical properties of Ni based superalloys.
