Study on Giga-Cycle Fatigue Properties and Non-Propagating Fatigue Crack for A5083P-O Aluminum Alloy

Abstract

In this study, Giga-cycle fatigue properties for A5083P-O aluminum alloy were investigated by ultrasonic fatigue testing at 20 kHz, rotating bending fatigue testing at 100 Hz and electromagnetic resonance type fatigue testing at 100 Hz. Not only the ultrasonic fatigue testing but also rotating bending fatigue testing were conducted up to 10¹⁰ cycles to validate the ultrasonic fatigue testing. The ultrasonic fatigue test results showed negligible difference from those of conventional fatigue testing results. In addition, the slope of S-N curve becomes smaller in 10⁸ ~ 10¹⁰ cycles and fatigue limit like behavior was discovered. Furthermore, successive surface observation discovered the phenomena that fatigue crack stopped propagating during 10⁹ cycles fatigue test. It is clarified that non-propagating microscopic fatigue crack develops fatigue limit of A5083P-O aluminum alloy.