Thanks to their favorable strength-to-weight ratio, Aluminum-Zinc alloys are often used in high-performance industrial sectors. These alloys are characterized by poor erosion resistance, which could be increased by the deposition of thin films. For example, PVD (Physical Vapor Deposition) films can reduce wear and ensure appreciable performance in aggressive environments. This paper describes the effects of thin hard film deposition on the strength of AA7075 under cyclic loading. Uncoated samples and samples with a DLC (Diamond-Like Carbon) surface layer were tested with a rotating bending fatigue machine within the range of ${10}^5$–${10}^7$ cycles. Two regression models were tested to study the relationship between fatigue strength and number of cycles within the range considered. For the samples without the film, even a linear regression can be suitable. With regard to the fatigue strength of the samples with surface layer, a piecewise linear regression is suggested, although a high scatter of experimental data can be observed. Finite element (FE) modelling was used to calculate the stresses induced by bending moment. The bending stresses were added to the residual stresses induced by the film deposition. The maximum value was found beneath the sample surface. Therefore, crack nucleation is expected under the surface of samples with film. The fatigue cracks initiate at the surface in untreated samples.

由于铝锌合金具有良好的强度重量比，因此常用于高性能工业领域。这些合金的特点是耐蚀性差，可以通过沉积薄膜来提高耐蚀性。例如，PVD（物理气相沉积）膜可以减少磨损，并确保在侵蚀性环境中具有明显的性能。本文描述了循环载荷下硬质薄膜沉积对AA7075强度的影响。用旋转弯曲疲劳试验机对未涂覆的样品和具有DLC（金刚石样）表面层的样品进行测试，测试范围为${10}^5$–${10}^7$周期。测试了两个回归模型以研究疲劳强度与所考虑范围内的循环次数之间的关系。对于没有薄膜的样品，甚至线性回归也可能适用。关于具有表面层的样品的疲劳强度，建议进行分段线性回归，尽管可以观察到大量的实验数据。有限元（FE）建模用于计算弯矩引起的应力。弯曲应力被添加到由膜沉积引起的残余应力上。在样品表面下方发现最大值。因此，在带有薄膜的样品表面下预期会出现裂纹形核。在未处理的样品中，疲劳裂纹始于表面。