Mechanical performance and nanoindenting deformation of (AlCrTaTiZr)NCy multi-component coatings co-sputtered with bias

This work develops (AlCrTaTiZr)NC_y multi-component coatings by co-sputtering of AlCrTaTiZr alloy and graphite in an Ar/N₂ mixed atmosphere with the application of different substrate biases. All the (AlCrTaTiZr)NC_y coatings deposited in different conditions exhibited a simple face-centered cubic structure. As the applied substrate bias and graphite-target power increased, the (AlCrTaTiZr)NC_y coatings transformed from a large columnar structure with a 111] preferred orientation to a dense, ultrafine nanocomposite structure. With increasing substrate bias and graphite-target power, the hardness, H/E ratio and H³/E² ratio of the coatings increased from 20 to 35 GPa, from 0.07 to 0.12 and from 0.10 to 0.43 GPa, respectively, attributed to the densification of the coatings, the refinement of grains, the introduction of covalent-like carbide bonds, the formation of nanocomposite structure and the existence of large lattice distortions. Because of the severe distortions in the multi-component coatings caused by the addition of differently-sized atoms, the deformation mechanism was dominated by the activity of low-angle dislocations and/or stacking faults.