Study on very-high-cycle fatigue property of 2A60 aluminum alloy

Abstract

Abstract During the rotation, aero-engine impeller blades are subjected to the alternating load of high frequency, low stress and small strain, so it is effortless for the impeller blades to enter the stage of very-high-cycle fatigue (VHCF). The research on the VHCF performance of 2A60 aluminum alloy is of great engineering significance to verify the reliability of the impeller in service. In this paper, the VHCF performance of 2A60 aluminum alloy is studied by fatigue life curve and fracture morphology. The results show that the fatigue properties of 2A60 aluminum alloy under different cooling conditions are different, and the VHCF properties under ethanol cooling conditions are better than those under water cooling conditions. However, under either water-cooled or ethanol-cooled conditions, the fatigue fracture mode of 2A60 aluminum alloy is single, showing a surface crack initiation mode, and the S-N curve shows a continuous downward trend without the intermediate platform. The VHCF crack originated from the stress concentration on the sample surface and the cleavage fracture occurred in the grains near the crack source in the early stage of crack initiation. The VHCF process of the sample is also the relaxation process of its residual stress.