Molecular dynamics simulation of nanoindentation of nanocrystalline Al/Ni multilayers

• Published in: Computational materials science 2016-02, Vol.112, p.175-184
• Main Authors: Chamani, M., Farrahi, G.H., Movahhedy, M.R.
• Format: Article
• Language: English
• Subjects: Aluminum; Computer simulation; Dislocation; Grain boundary; Grain size; Grains; Hardness; Molecular dynamics; Multilayers; Nanocrystalline multilayers; Nanocrystals; Nanoindentation; Nickel
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2015.10.022

[Display omitted] •Study of MD simulation of columnar and non columnar nanocrystalline Al substrate.•Concurrent study of grain size and layer number in nanocrystalline Al/Ni multilayer.•Thickness of grain boundaries has great influence on the hardness of NC structure.•Hardness is not necessarily related to grain morphology.•Layer thickness has more influence on hardness of NC Al/Ni rather than grain size. Molecular dynamics simulations are employed to investigate material properties of nanocrystalline aluminum and nanocrystalline Al/Ni multilayers at low temperature. For this purpose, both single crystal and nanocrystalline multilayers with different grain sizes and grain morphology are used as the substrate. The results of the simulations show that hardness and elastic modulus decrease with refinement of grain size in nanocrystalline aluminum and refinement of grain size and layer thickness in nanocrystalline Al/Ni multilayers, regardless of grain morphology. Furthermore, the angle between two adjacent grains, which is directly connected to the grain boundary thickness, has a great influence on the hardness and elastic modulus in nanocrystalline single layer and multilayers. It is shown that for grain size between 4.5 and 9.5nm and layer thickness less than 8nm, hardness of nanocrystalline Al/Ni multilayer is more affected by the layer thickness rather than the grain size.