Structure and mechanical properties of multi-principal-element (AlCrNbSiTi)N hard coating

Multi-principal-element nitride (MPEN) has great potential in the application of cutting tool protective coatings . However, the investigation of the nanostructured MPEN coatings is still insufficient. In this paper, we study (AlCrNbSiTi)N MPEN coatings deposited at various bias voltages ranging from −50 to −200 V, using RF magnetron sputtering technique. The microstructure and mechanical performance e of the coatings are systematically investigated. The results show that the (AlCrNbSiTi)N coating forms an FCC crystal structure and exhibits columnar grains. In the elongated grain, there exists a nanocomposite structure with (AlCrNbTi)N nanograins surrounded with crystallized Si 3 N 4 interfaces. The mechanical performance and wear resistance of the coating is enhanced first and then degraded with the increasing bias voltage. The coating deposited at −150 V exhibits the highest hardness and elastic modulus of 39.8 and 436.7 GPa, respectively, and has the lowest wear rate of 6.7 × 10 −6 mm 3 ·N −1 ·m. These results show that the (AlCrNbSiTi)N coating is a competitive candidate for protective coating applications. • The (AlCrNbSiTi)N multi-principal element coating was deposited using RF sputtering. • The Si 3 N 4 is crystallized and growth coherently on the neighboring (AlCrNbTi)N grains. • The coating could achieve a high hardness of 39.8 GPa. • The coating exhibits a low wear rate of 6.7 × 10 −6 mm 3 N −1 m.