Mechanical and tribological properties of a refractory high entropy HfMoNbTaTiVWZr thin film metallic glass implanted with nitrogen ions

This study examines nitrogen ion implantation's effects on the microstructure, mechanical behavior, and tribological performance of an octonary high-entropy thin film metallic glass HfMoNbTaTiVWZr. Ion implantation led to binary nitride formation, elemental redistribution, and surface modifications while maintaining significant degree of amorphization, what indicates local atomic rearrangement rather than crystallization. Structural and chemical analyses using TEM, XRD, and EDS mapping revealed phase stability changes and preferential segregation of heavy elements like hafnium and tantalum at high doses. Hardness enhancement was attributed to solid solution strengthening, fine nitride formation, increased lattice distortion, residual stress, and densification. At an optimal implantation dose (1e17 ions/cm 2 ), hardness increased to 20 GPa, reducing the coefficient of friction and improving wear resistance. A comparison with a magnetron-sputtered (HfMoNbTaTiVWZr)N thin film showed distinct hardness-depth profiles, confirming localized strengthening effects. These findings highlight nitrogen implantation as an effective surface engineering technique for optimizing material performance in demanding applications.