The Fatigue Performance and Fatigue Crack Propagation Behavior of 2E12 Al Alloy

The fatigue performance and fatigue crack growth rate in 2E12 alloy were studied under different stress radio.At the same time,TEM and SEM were applied to analyze the microstructures and fracture appearance.It is shown that the excellent fatigue damage tolerance would be exhibited in 2E12 alloy.On the condition of R=0.1,the fatigue limit is 172 MPa,and the value would be increased by 60% on the condition of R=0.5.These existing notches resulted in reduction of fatigue limit of this alloy.On the condition of R=0.1,ΔK=30 MPa·m1/2,the fatigue crack growth rate (da/dN) would be 2.7×10-3 mm/cycle,which is lower by 60% than that of 2024 alloy.The fracture appearance of 2E12 alloy consist of fatigue crack initiation zone,fatigue crack propagation zone and final fracture zone.The locations of initial fatigue cracks generally are on the surface stress concentrated or on the different defects in this alloy.