Theoretical derivation and MD simulation of size dependent mechanical properties of grains and grain boundaries in nanocrys-talline nickel Bi-crystal
This paper studied the Σ5 grain boundaries of FCC pure nickel and derived the size-dependent analytical formulas of the equivalent mechanical properties of grains and grain boundaries in the anisotropic bi-crystal model based on the interface eigenstress model and nonlinear elastic constitutive model.Molecular dynamics simulations were performed to validate the theoretical analytical formulas and determine the material parameters of the grain boundary.These analytical formulas can accurately predict pure nickel(Σ5 grain boundary)with different sizes and thicknesses.The results show that the grain boundary has a lower biaxial modulus than the grain,resulting in an increase in the apparent biaxial modulus of the bi-crystal with model thickness.The theoretical model can accurately describe the relaxation process caused by the eigenstress of the grain boundary in the bi-crystal model and the size-dependent behavior of the equivalent mechanical properties.The theoretical model can be directly applied to other nanocrystalline bi-crystal systems.
NETL
NSTL
万方数据
