Molecular dynamics study of TiAlCN coatings: role of arc current and substrate temperature in hardness and surface morphology

Abstract In this study, a molecular dynamics (MD) simulation approach was employed to investigate the deposition process and properties of TiAlCN thin films fabricated via cathodic arc evaporation. The theoretical model was constructed based on many-body interaction potentials (MEAM, Tersoff, Vashishta) to accurately describe the atomic-scale interactions among Ti, Al, C, N, and Fe atoms. Simulations were conducted using the LAMMPS package, with deposition of Ti, Al, C, and N atoms onto an Fe (100) substrate under varying process conditions. The simulation parameters were designed to reflect typical experimental ranges: arc current intensities from 60 A to 100 A and substrate temperatures from 300 K to 673 K. The deposition model accounted for atomic flux, kinetic energies of incident species and substrate temperature. Key film properties: Hardness, surface roughness and friction coefficient were extracted from atomistic configurations using post processing tools (e.g., OVITO virtual nanoindentation). The results show that the simulated film achieves a maximum hardness of 32 GPa at an arc current of 80 A, with a corresponding minimum roughness of 3.80 Å and a friction coefficient of 0.25. Similarly, at a substrate temperature of 573 K, the model predicts 29.2 GPa hardness 3.74 Å roughness, and a friction coefficient as low as 0.24. These values are in strong agreement with experimentally reported data for TiAlCN coatings, validating the simulation approach. This work demonstrates that MD simulation can be used not only to replicate experimental trends but also to guide process optimization towards higher hardness and lower friction through control of deposition parameters. The modeling framework provides a reliable tool for predicting coating behavior and tailoring material properties for advanced surface engineering applications.