Correlation Characteristics of the Deformation Relief of an Aluminum Alloy Under High-Cycle Fatigue

The mechanical properties, alloy microstructure, and fatigue resistance under cyclic loading of a 1.5 mm thick D16 sheet with a stress concentrator in the form of a central hole were investigated. In the process of fatigue damage accumulation in the area of the stress concentrator, changes in the microdeformation relief in the form of peaks and troughs were periodically recorded to quantitatively assess the parameters of the discrete deformation relief on the surface of specimens. To analyze mesostructural deformations, the surface relief of specimens was observed by illuminating their surface with a coherent irradiation source with a wavelength of 0.45 μm. Kinetic plots of the deformation parameters of the surface of specimens at the stages of high-cycle deformation were constructed, and the parameters of the deformation relief of the surface layer, which correlates with the scattered damage, were determined. Based on the measurements of the spatial parameters of local peaks and troughs of the deformed specimen surface, kinetic plots of fatigue localization were constructed. It is shown that these plots can be used to judge the residual life of a cyclically loaded material.