Fatigue Strength Prediction and Degradation Behavior Analysis of 6005A-T6 Aluminum Alloy Considering Fatigue Aging Effects

This study conducts an in-depth analysis of the mechanical property changes of 6005A-T6 aluminum alloy under different fatigue aging states (the process in which the material's performance gradually deteriorates over time under cyclic loading). First, the evolution of surface displacement fields was analyzed using digital image correlation combined with various levels of fatigue aging pretreatment. Through single-cycle tests and tensile tests, the displacement field responses of the material in different degradation states were examined, and changes in ultimate strength, yield strength, elongation, and section shrinkage were further analyzed. Based on the existing yield strength-tensile strength-fatigue strength (Y-T-F) model, an improved approach, the Y-T-F-II model, was proposed to account for fatigue aging effects and validated for fatigue strength prediction, achieving a maximum error of only 0.17%. The results showed that fatigue aging significantly affects the fatigue strength, ductility, and toughness of 6005A-T6 aluminum alloy, and the improved model provides more accurate fatigue strength predictions under various degradation states.