Influence of a high-density pulsed electric current on the fatigue behaviour of prestrained aluminium alloys

•This study investigated the effects of high-density pulsed electric current (HDPEC) on fatigue behaviours of non-prestrained and prestrained aluminium alloys (A6061-T6).•Fatigue life of the specimen to which the HDPEC was applied increased significantly.•Decreased slip bands caused by the fatigue load leads to delay fatigue crack initiation.•Effect of local melting and thermal compressive stress, induced by Joule heating, caused a decrease in the FCG rates leading to delaying fatigue crack propagation. This study quantitatively analysed the effect of an electric current on improving the fatigue life of the aluminium alloy A6061-T6. The effect of a high-density pulsed electric current (HDPEC) was investigated for non-prestrained and prestrained aluminium alloys because they are frequently exposed to plastic deformation. The results showed that the HDPEC contributed to increasing the fatigue life of both materials with and without prestrain, and those without prestrain increased significantly with the HDPEC effect. Local melting sites were observed at the fatigue crack tip on the fracture surface of the non-prestrained and prestrained cases treated with HDPEC. Fatigue crack growth tests confirmed the improved fatigue life of the HDPEC effect. The results pave the way toward enhancing the resistance of fatigue crack growth in welded joints.