Tensile mechanism of wear-resistant Cr/CrN/Cr/CrAlN multilayer film

In this work, we deposited the Cr/CrN/Cr/CrAlN multilayer films with various thickness on TC4 titanium alloy substrates by cathodic arc system. The effects of film thickness on microstructure, mechanical properties, tribological properties and tensile properties were mainly investigated. The results show that the thickness of the multilayer film is about 200 nm per cycle for 18, 36, 54 and 72 cycles, and that the number of large particles on the surface increases from 8% to about 13% with increasing film thickness. The residual stress also increased gradually from-1.633 +/- 0.082 GPa at 18 cycles to-3.851 +/- 0.169 GPa at 72 cycles. And the difference in hardness was not significant, but the best bonding and crack extension resistance was achieved at 54 cycles. The wear resistance of the four groups of multilayer films was good, with a coefficient of friction of around 0.6. In addition, the tensile strength of the coated samples increased compared to the uncoated samples, with an in-crease of nearly 3% in the strength index, and the phenomenon of increasing and then decreasing with the number of film cycles, but with a decreasing trend in elongation after break. Based on this phenomenon, the fracture mechanism of the hard film affecting the titanium alloy substrate was analysed.

Automated summary

In this study, Cr/CrN/Cr/CrAlN multilayer films with various thickness were deposited on TC4 titanium alloy substrates using a cathodic arc system. The effects of film thickness on microstructure, mechanical properties, tribological properties, and tensile properties were investigated. The results showed that increasing film thickness led to an increase in the number of large particles on the surface and residual stress. The hardness difference was not significant, but the best bonding and crack extension resistance were achieved at 54 cycles. The multilayer films exhibited good wear resistance and increased tensile strength compared to uncoated samples.