Surface defects created by the forging process and their effects on the fatigue performance of a 6082 Al-alloy

Abstract

The increasing use of forged Al-alloy components in automotive vehicles has generated a large quantity of data which shows that a retained forged surface can have a significantly detrimental effect on fatigue performance. Extensive SEM studies of the fatigue crack initiation sites on four point bend S-N samples and the as-forged surface appearance of these and actual components have been undertaken. The results from these studies have shown common features across all the samples examined. These features, rather than the surface roughness, can be associated with multiple fatigue crack initiation sites and explain the observed reduction in fatigue properties.