Effect of contact pressure on torsional fretting fatigue damage evolution of a 7075 aluminum alloy. (September 2019) - Peng, Jinfang
Abstract: Contact pressure is a crucial factor which can affect fretting fatigue (FF) life significantly. In this research, the influence of contact pressure on torsional fretting fatigue (TFF) damage of a 7075 aluminum alloy is investigated. According to the experiment results, below 72.5 N⋅m torque as the contact pressure increases, the TFF life decreases firstly and then it reaches to the lowest point at 300 N, while afterward the TFF life increases. The P - N curve shows a C shape. The damage analysis results show that with increasing the contact pressure, the damage becomes severer. The oxidative products are mainly Al2 O3 and Al(OH)3, and the loading side is found to be more oxidized than the center position and fixed side. Highlights: The P - N curves show a C shape. The ratio Q/P is inversely correlated with the contact pressure. The degree of oxidation increases with the contact pressure, and the main oxidative products are Al2 O3 and Al(OH)3 . There are three stages of the crack propagation, and the crack directions are around 30°, 60° and 45° to the contact surface.