Hard yet tough thermodynamics-driven nanostructured (AlCrNbSixTi)N multicomponent nitride hard coating

Breaking the hardness-toughness trade-off has always been a critical issue for hard protective coatings. Rational materials design, which simultaneously incorporate multiple strengthening and toughening me-chanisms, could provide pathways toward hard yet tough materials. In this study, (AlCrNbSixTi)N multicomponent nitride coatings with various Si content are fabricated via magnetron co-sputtering. Multi-dimensional strengthening and toughening mechanisms are found in thermodynamics-driven nanostructured (AlCrNbSixTi)N. Enhanced atomic packing, nanostructure forma-tion, and microstructural modification originate from spinodal decomposition contribute to multiple strengthening and toughening mechanisms after Si incorporation. From atomic-level packing, spinodal-decomposed nanostructure, to microstructure, the evolutions are quantitatively characterized and corre-lated to mechanical properties. With the addition of 4.4 at% of Si, maximum hardness of 27.2 GPa is achieved while maintains high fracture toughness of 3.66 +/- 0.37MPa m. On the other hand, the maximum fracture toughness is found for (AlCrNbSi7.6Ti)N and is attributed to the featureless microstructure, na-nostructure formation and non-complete amorphization. (c) 2023 Published by Elsevier B.V.

Automated summary

In this study, (AlCrNbSixTi)N multicomponent nitride coatings with various Si content were fabricated and it was found that multi-dimensional strengthening and toughening mechanisms were present. The addition of Si contributed to enhanced atomic packing, nanostructure formation, and microstructural modification, leading to multiple strengthening and toughening effects. The maximum hardness of 27.2 GPa and high fracture toughness of 3.66 +/- 0.37MPa m were achieved with the addition of 4.4 at% of Si. The (AlCrNbSi7.6Ti)N coating exhibited the highest fracture toughness due to featureless microstructure, nanostructure formation, and non-complete amorphization.