Misfit dislocation networks in the γ¦γ′ phase interface of a Ni-based single-crystal superalloy:: Molecular dynamics simulations -: art. no. 014111

The structure of the gamma/gamma' phase interface in a Ni-based single-crystal superalloy is simulated by molecular dynamics (MD) using an embedded atom method potential. From the calculated results we find that three dislocation network patterns, namely square, rectangle, and equilateral triangle, appear on {100}, {110}, and {111} interphase interface, respectively. The dislocation networks consist of four edge dislocations (< 011 > {100}, < 110 > {110}, < 001 > {110}, and < 112 > {111}). The energy of the gamma/gamma(') phase interface for {100}, {110}, and {111} plane is 271 mJ/m(2), 240 mJ/m(2), and 32 mJ/m(2). The side length of network is 166.8 angstrom for the square, 166.8 angstrom and 235.8 angstrom for the rectangle and 166.8 angstrom for the equilateral triangle. The relationship between the size of network and mismatch is presented quantitatively. The calculated results can be supported by very recent experiments. Based on the MD simulation and the energy analysis we have revealed the basic characteristic of structure on gamma/gamma' phase interface. The related mechanism of the stability of the interphase interface is also discussed.