Multifractal Analysis of Morphology of AlMg6 Alloy Fracture Surface under Consecutive Dynamic and Gigacycle Loading

The influence of consecutive dynamic and gigacycle fatigue loads on the lifetime of aluminum-magnesium alloy AlMg6 (5083) has been studied to analyze the fracture surface morphology (roughness scaling) and generalized fatigue crack kinetics, taking into account the correlated behavior of defects at the crack tip area (process zone). The samples were dynamically preloaded by a split-Hopkinson bar device. Fatigue tests of the preloaded samples were conducted on a Shimadzu USF-2000 ultrasonic fatigue testing machine. A New-View 5010 interferometer-profiler of high structural resolution (resolution of 0.1 nm) was used for quantitative fracture surface analysis. The analysis provided data for finding the correlation between mechanical properties and scale-invariant characteristics of damage-induced roughness formed under dynamic and gigacycle fatigue loads.