Effect of Ultrasonic Peening Treatment on VHCF Behavior of Friction Stir Welded Joints in Aluminum Alloys

摘要

Studying the mechanical properties of aluminum alloy 6061 friction stir welded(FSW)joints after ultrasonic peening treatment(UPT)under very high cycle fatigue(VHCF)loading.The effect of joints ultrasonic peening treatment was explored.It can be seen from the results that the ultrasonic peening treatment can form a reinforced layer on the surface of joints,and the fatigue crack source is transferred from the surface of the specimen to the inside.However,the change of fatigue crack initiation site does not improve the fatigue strength of specimen through ultrasonic peening treatment.The fatigue strength of the aluminum alloy 6061 joint after ultrasonic peening treatment is even lower than as a received condition.The characteristics of fatigue crack initiation and the mechanism of surface strengthened layer on fatigue strength were analyzed and discussed.