Molecular dynamics simulations, which were based upon an n-body potential, were used to investigate amorphization in Ni/Zr bi-layers and multi-layers during annealing at temperatures of 373 to 873K. Sandwich-models, which consisted of atomic planes with various orientations, and a bi-layer model with a pre-set disordered interfacial layer, were constructed in order to reveal the effect of interfacial texture upon amorphous layers. It was found that, when the multi-layers had semi-coherent interfaces in sandwich models which consisted of Ni close-packed planes parallel to the interfaces, amorphization was frustrated; even up to a temperature of 873K. This was because of large associated negative interfacial energies, which suppressed interdiffusion at the interfaces. In models which were constructed from non close-packed planes of Ni, the simulations showed that amorphization could take place at temperatures as low as 673K and was initiated by across-interface diffusion, diffusion-induced alloying and the subsequent growth of an interfacial amorphous layer. This eventually resulted in the formation of a uniform amorphous phase. The growth of the amorphous layer obeyed a t½-law, thus indicating that the solid-state amorphization was diffusion-limited. An asymmetrical behavior was observed, in that the growth rate towards Ni was greater than that towards Zr.

Influence of Interfacial Texture and Asymmetric Growth in Diffusion-Limited Amorphization in Ni-Zr Multi-Layers upon Medium-Temperature Annealing W.S.Lai, B.X.Liu: Physical Review B, 1998, 58[10], 6063-73