Strain-Hardening and Strain-Softening Phenomena Observed in Thin Nitride/Carbonitride Ceramic Coatings During the Nanoindentation Experiments
coatings 2025
Uldis Kanders, Kārlis Kanders, Ernests Jansons, Irīna Boiko, Artis Kromanis, Jānis Lungevičs, Armands Leitāns

This study investigates the nanomechanical and tribological behavior of multilayered nitride/carbonitride nanostructured superlattice type coatings (NTCs) composed of alternating TiAlSiNb-N and TiCr-CN sublayers, deposited via high-power ion-plasma magnetron sputtering (HiPIPMS) technique. Reinforced with refractory elements Cr and Nb, the NTC samples exhibit high nanohardness (39–59 GPa), low friction, and excellent wear resistance. A novel analytical approach was introduced to extract stress–strain field (SSF) gradients and divergences from nanoindentation data, revealing alternating strain-hardening and strain-softening cycles beneath the incrementally loaded indenter. The discovered oscillatory behavior, consistent across all samples under the investigation, suggests a general deformation mechanism in thin films under incremental loading. Fourier analysis of the SSF gradient oscillatory pattern revealed a variety of characteristic dominant wavelengths within the length-scale interval (0.84–8.10) nm, indicating multi-scale nanomechanical responses. Additionally, the NTC samples display an anisotropic coating morphology exhibited as unidirectional undulating surface roughness waves, potentially attributed to atomic shadowing, strain-induced instabilities, and limited adatom diffusion. These findings deepen our understanding of nanoscale deformation in advanced PVD coatings and underscore the utility of SSF analysis for probing thin-film mechanics.


Atslēgas vārdi
nitride/carbonitride multilayered coatings; nanoindentation; nanohardness; wear; friction coefficient; load-displacement loop; stress-strain field gradient and divergence; strain gradient plasticity
DOI
10.3390/coatings15060674
Hipersaite
https://www.mdpi.com/2079-6412/15/6/674

Kanders, U., Kanders, K., Jansons, E., Boiko, I., Kromanis, A., Lungevičs, J., Leitāns, A. Strain-Hardening and Strain-Softening Phenomena Observed in Thin Nitride/Carbonitride Ceramic Coatings During the Nanoindentation Experiments. coatings, 2025, Vol. 15, No. 674, 1.-18.lpp. Pieejams: doi:10.3390/coatings15060674

Publikācijas valoda
English (en)
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