Fatigue properties improvement of high-strength aluminum alloy by using a ZrCu-based metallic glass thin film coating

• Metallic glass thin film (MGTF) coatings sputtered on high-strength aluminum alloy.
• The 45-time enhancement of fatigue life of MGTF-coated samples at 250 MPa was studied.
• MGTF-coated samples present 67% higher fatigue limit than the bare one

For further enhancing the fatigue properties of high-strength aluminum alloy, the coating, which was combined with a layer of 200 nm ZrCu-based metallic glass thin film (MGTF) coupled with 50 nm titanium thin film buffer layer, was applied to coat on the surface of 7075-T6 aluminum alloy by the DC sputtering method. The results show that the fatigue limit could be significantly improved from 150 MPa for the uncoated sample to 250 MPa (66.7% increase) for the samples coated with ZrCu-based MGTF. In parallel, the fatigue life of 7075-T6 aluminum alloy with ZrCu-based MGTF could be drastically improved 45 times at a stress level of 250 MPa than the bare one. The outstanding mechanical properties of ZrCu-based MGTF, such as high strength and good adhesion between the film and the substrate, are the key factors to enhance the fatigue resistance of the coated aluminum alloy.