Investigation of high-cycle fatigue and fatigue crack propagation characteristic in 5083-O aluminum alloy

The objective of the present study is to investigate the high-cycle fatigue (HCF) and fatigue crack propagation (FCP) characteristic in relation to the microstructure in the 5083-O aluminum alloy. The FICF strengths of the 5083-O Al alloy in parallel to rolling direction (PD) and vertical to rolling direction (VD) specimens are 164 MPa and 165 MPa, respectively, However, the FCP resistance of the specimens reveals evident anisotropy. The FCP resistance of the PD specimen is less than that of the VD specimen, which is predominantly caused by the main crack expanding along the chain-shaped coarse inclusions in PD specimen. These chain-shaped coarse inclusions, particularly, Fe/Mn containing particles with secondary microcracks, might accelerate FCP rate and decrease FCP resistance.