Interface reconstruction and dislocation networks for a metal/alumina interface: an atomistic approach

Abstract

Misfit dislocation is an important component of the semi-coherent interface. Usually, it forms a dislocation network as the strain concentration area on an interface and makes the other part coherent. This is the regular case, but there are also some exceptions. In this work, we show that the Ni/(Al2O3)Al interface has a reconstruction at the first monolayer of the metal side, which works as a transition layer between Ni and Al2O3 lattices. Under these conditions, the misfit dislocation cannot be confirmed by drawing a Burgers circuit because the interface is incoherent. However, due to the lattice misfit, there are areas of strain concentration and areas without strain distributed on the interface plane. So, for describing this strain distribution, we again use the concept of a dislocation network but redefine it as the separate line between these two parts. As a result, we find that the dislocation network appears when the metal part is thicker than 12.4 Å, and it shrinks as the metal film grows, resulting in an ultimate structure with a mesh size of 28.1 Å.

Reconstruction of 2D Al3Ti on TiB2in an aluminium melt

“…Both Ag/Ru and Ni/Al 2 O 3 display a triangular pattern for their interface reconstruction, similar to our results. This type of interface reconstruction is also termed a dislocation network [1,34,35]. It differs from the regular misfit dislocation since the dislocation network cannot be analysed by drawing a Burgers circuit.…”

Nanostructure, Plastic Deformation, and Influence of Strain Rate Concerning Ni/Al2O3 Interface System Using a Molecular Dynamic Study (LAMMPS)

“…Considering the lattice misfit between Ni and Al 2 O 3 (9.3%), the ratio of Ni unit cells to Al 2 O 3 unit cells in the misfit plane was set to 11:10. According to the different atomic structures of the terminating Ni layers observed in experiment [ 26 ] and atomistic simulation [ 11 , 25 ], two interface models with misfit planes located at the first monolayer and second monolayer of metal side were established. For convenience, we refer to the first interface structure as Type I and the second interface structure as Type II in the following text.…”

“…The Al-O interactions in the Al 2 O 3 were omitted by fixing the Al 2 O 3 atoms in their crystal positions before interface relaxation. This is the primary approximation of the Ni/Al 2 O 3 interface system but is sometimes reasonable for atomistic simulation studies on metal/ceramic interfaces [ 25 , 26 , 30 , 36 ]. First, Ni/Al 2 O 3 interfaces are relatively brittle, and the plasticity accompanying interface cracking is due to generation and movement of dislocations within the metal [ 12 ].…”

“…Due to lattice mismatch, relative orientation, and a wide variety of defects that can form at the interface, the Ni/Al 2 O 3 interface at equilibrium develops unique structural characteristics. Atomistic simulations showed the Ni/Al 2 O 3 interface is reconstructed at the terminating Ni layer, and the misfit dislocation is placed in the energy-preferred second monolayer of the metal side by a (n + 1 n + 1:n n) mismatch plane [ 25 ]. However, experimental observation by aberration-corrected transmission electron microscopy revealed the solid Ni/Al 2 O 3 interfaces at equilibrium develop delocalized coherency in the terminating Ni layer where the misfit dislocation is introduced [ 26 ].…”

“…Based on ab initio adhesive energies, Long and Chen derived a series of Rahman–Stillinger–Lemberg potentials without any prerequisite of the function forms. These potentials have proven to be successful in investigating the interface structures and adhesive properties of Ni/Al 2 O 3 interface [ 25 , 26 ] and metal/MgO interfaces [ 32 , 33 ].…”