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Streszczenie:
Plasma nitriding is a promising method for enhancing the surface mechanical properties of compositionally complex alloys (CCAs), though the mechanisms governing phase evolution and property changes remain unclear. This study investigates the microstructural evolution and mechanical response of a Zr45Ti31.5Nb13.5Al10 alloy after plasma nitriding, combining experimental techniques with thermodynamic calculations. Mechanical properties were assessed via nanoindentation, including hardness, H/E, and H3/E2 ratios. Nitriding produces a chemically and structurally graded surface layer consisting of a near-surface FCC (B1-type) multicomponent nitride, a transition region with mixed FCC/HCP structure, and a BCC substrate. This gradient results from nitrogen diffusion and element-specific nitride formation, as confirmed by EBSD, TEM (SAED, EDS), and XRD analyses. Surface hardness increases more than fivefold, from ∼5 GPa to ∼28 GPa, due to a combination of nitride formation, solid-solution strengthening, and nanoscale microstructural refinement. The nitriding response is primarily controlled by strong nitride-forming elements (Zr, Ti, Nb), which facilitate uniform nitrogen incorporation and formation of a dense multicomponent nitride layer. Notably, aluminum is incorporated into the nitride lattice without forming a separate AlN phase. These results provide new insights into multicomponent nitride formation and highlight plasma nitriding as an effective strategy for tailoring surface properties of advanced CCAs.

Słowa kluczowe:
Compositionally complex alloys, Plasma nitriding, Multicomponent nitrides, Microstructure, Nanoindentation

Streszczenie:
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/cm2), 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

Słowa kluczowe:
High entropy film metallic glasses, Ion implantation, Microstructure, Indentation, Surface characteristics