Assessing the interfacial strength of an amorphous–crystalline interface

In this study, an amorphous-ZrCu/crystalline-Zr nanolaminate (500 nm each layer) was initially synthesised using sputter deposition and then fabricated into micropillar samples using focused ion beam machining with the amorphous–crystalline (a–c) interfaces inclined 45° to the pillar axis. These pillars were subsequently tested in compression in order to study the response of a–c interfaces to the applied shear stress, and further compared with the one that tested with their a–c interfaces normal to the compressive direction. By combining the stress–strain behavior and electron microscopic observations of fracture mode, we were able to estimate the a–c interfacial strength. It was strong (∼1.3 GPa), it could effectively transfer the load and it was capable of accommodating large shear strain, but it was not strong enough to suppress the interfacial sliding. Molecular statics simulations were also carried out to reveal the elastic–plastic behavior and, in particular, the deformation mode of the pillars. The computed results were in excellent agreement with the experimental observations.

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