Atomistic simulations of the characteristics of TiSiN nanocomposites of various compositions

We performed classical molecular dynamics simulations of thermodynamically preferred structures of Ti_(50-x)Si_xN₅₀ (x ≤ 0.3) nanocomposites of various compositions containing up to a quarter of million of atoms. We focus on the formation and growth of TiN nanocrystals, and investigate how the Si content affects their number, size distribution, Si content in them, and thickness of the amorphous phase between them. We observe 3 important cases, namely frequent formation of large crystals below 3% of Si, formation of fine nanocrystalline structures (with quantitatively correct experimental crystal size) around 7% of Si, and amorphization at and above 15% of Si. The results represent the first attempt to predict the structure of TiSiN or similar nanocomposite systems using classical molecular dynamics simulations, and they are compared with experimental measurements of material hardness and electrical resistivity.