• The AlCrSiN/AlCrN/CrN/Cr multilayer coating achieved a critical load of 87.8 N, indicating excellent adhesion.
• Silicon doping induced nanocrystallization and amorphization, increasing hardness to 26 GPa.
• A nanoscale Cr-rich (Cr,Al)2O3 layer formed at high temperatures, effectively inhibiting oxygen diffusion.
• AIMD simulations revealed that Cr atoms have higher oxygen-capture capability than Al, and Si atoms act as diffusion barriers, enhancing oxidation resistance.