Effect of interface structure on dislocation glide behavior in nanolaminates

WR Jian and YQ Su and SZ Xu and WS Ji and IJ Beyerlein, JOURNAL OF MATERIALS RESEARCH, 36, 2802-2815 (2021).

DOI: 10.1557/s43578-021-00261-y

The ultra-high strength of nanolaminates arises from the effect of the fine layering on dislocation motion. Using atomistic simulations, we investigate the effect of the interface structure on the behavior of an edge dislocation driven to glide within a nanolayer of a nanolaminate. Three classes of interface structures are studied, including Cu/Nb or Cu/Cu incoherent interfaces and Nb/Nb coherent interface. Glide behavior is jerky when the interface is incoherent and composed of discrete misfit dislocation arrays. The resistance to glide is non-uniform among parallel glide planes, where planes with intersection lines coinciding with misfit dislocation lines experience greater resistances than those that do not. Interfaces containing misfit dislocations, which extend from the interface into a glide plane in the layer, severely obstruct glide, causing the dislocation to transfer to a parallel plane. Coherent interfaces, while posing the least resistance to initiate and promote smooth glide, lead to strain hardening. Graphic abstract

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