Fatigue properties of notched aluminum specimens after hard rolling

Research results of the application of hard-rolling treatment to aluminum surface modification are presented. The main objective of the research presented here was to study the change in fatigue properties, particularly fatigue crack behavior of notched aluminum specimens after hard rolling. The results indicated an obvious improvement in fatigue properties of the aluminum specimens after hard rolling, but the extent of enhancement of fatigue strength was nearly the same or even decreased slightly with the increase of the hard-rolling value. Fatigue crack initiation and propagation behavior displayed different characteristics for specimens with different hard-rolling values. The microstructural change and the appearance of compressive residual stress at the notch were employed to explain the effect of hard rolling on the fatigue properties of aluminum. In addition, a saturation condition was observed in the compressive residual stress introduced by hard rolling. This phenomenon was explained in terms of the intrinsic properties of the material studied in this work.