Atomic study on the deform mechanism of CuTa/Cu and CuTa/Ta nanolaminates

The purpose of this paper is clarifying the deform mechanism of CuTa/Cu and CuTa/Ta nanolaminates during nanoindentation test. Firstly, two kinds of amorphous and nanocrystalline interface model were built. Additionally, the Cu layer thickness in CuTa/Cu are λ between 3 Å and 12 Å. The Ta layer thickness in CuTa/Ta are μ between 3 Å and 12 Å. Secondly, nanoindentation test were introduced to get the elastic modulus and hardness of nanolaminates. As the results claimed that different deform mechanisms play the dominant role during the indentation load and unload. More exactly, when the Cu layer is less than 7 Å the Cu layer dominate the deform mechanism, the elastic modulus and harness increase with increasing Å. As Å increasing much more, the CuTa layer will dominate the deform mechanism. In the contrast, the elastic modulus and hardness will decrease with increasing Å. Similarly as CuTa/Cu model, CuTa/Ta model has an obviously change in the dominant role of deform mechanism. In the end, the influence of penetrate rate was discussed.